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Bouaka Tsakeng CU, Melachio Tanekou TT, Ngambia Freitas FS, Tirados I, Tsagmo Ngoune JM, Bigoga JD, Njiokou F, Wondji CS. Patterns of microbiome composition in tsetse fly Glossina palpalis palpalis during vector control using Tiny Targets in Campo, South Cameroon. Microbiol Spectr 2024; 12:e0093524. [PMID: 39297636 PMCID: PMC11540164 DOI: 10.1128/spectrum.00935-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 08/22/2024] [Indexed: 11/08/2024] Open
Abstract
Novel vector control tools against African trypanosomiases require a deep understanding of the factors driving tsetse vector fitness or population resilience in their ecosystems. Following evidence of microbiota-mediated host fitness or traits shaping, including insecticide resistance in arthropod populations, we undertook a comparative study of the microbiota in wild-caught tsetse flies during vector control with deltamethrin-impregnated traps called Tiny Targets. The bacterial microbiome composition of tsetse flies collected before and after 6, 12, and 18 months of vector control were characterized using high-throughput sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene and compared. Overall, 48 bacterial genera and five phyla were identified. The primary symbiont Wigglesworthia dominated almost all the samples with an overall relative abundance of 71.76%. A significant increase was observed in microbiome diversities over the vector control with new taxa identified. Interestingly, few genera, like Curvibacter for instance, displayed a regularly increasing abundance, from 0.57% to 0.65%, 4.73%, and 8.57% after 6, 12, and 18 months of tsetse control, respectively. This study provided preliminary for further investigation into the role and mechanism of action of microbiota in tsetse fly fitness under selective pressure like insecticides.IMPORTANCEThe interest in vector control in the fight against African trypanosomiases has been reinforced in recent years, with the development of small insecticide-impregnated screens, known as "Tiny Targets". As some tsetse biotopes are difficult to access for their installation, other tools are under consideration that involve using bacteria harbored by the tsetse vector to block the development of trypanosomes or impair the tsetse's fitness in its natural environment. Several bacterial symbionts were previously described as important for tsetse fly development, and some like Burkholderia and Citrobacter also found in tsetse flies were found associated with insecticide tolerance in other arthropods. In this research, we found the bacterial genera, Curvibacter and Acinetobacter, increased in abundance in tsetse flies during vector control. These bacteria deserve further attention to determine if they can interfere with insecticides used to control tsetse fly populations.
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Affiliation(s)
- Calmes Ursain Bouaka Tsakeng
- Centre for Research in
Infectious Diseases (CRID),
Yaoundé, Cameroon
- Department of
Biochemistry, Faculty of Science, University of Yaoundé
I, Yaoundé,
Cameroon
| | - Tito Tresor Melachio Tanekou
- Centre for Research in
Infectious Diseases (CRID),
Yaoundé, Cameroon
- Department of
Microbiology and Parasitology, Faculty of Science, University of
Bamenda, Bamenda,
Cameroon
| | | | - Inaki Tirados
- Department of Vector
Biology, Liverpool School of Tropical Medicine (LSTM), Pembroke
Place, Liverpool,
United Kingdom
| | - Jean Marc Tsagmo Ngoune
- Department of
Parasites and Insect Vectors, Trypanosome Transmission Group,
Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur,
Université Paris Cité,
Paris, France
| | - Jude Daiga Bigoga
- Department of
Biochemistry, Faculty of Science, University of Yaoundé
I, Yaoundé,
Cameroon
| | - Flobert Njiokou
- Department of Animal
Biology and Physiology, Faculty of Science, University of Yaoundé
I, Yaoundé,
Cameroon
| | - Charles Sinclair Wondji
- Centre for Research in
Infectious Diseases (CRID),
Yaoundé, Cameroon
- Department of Vector
Biology, Liverpool School of Tropical Medicine (LSTM), Pembroke
Place, Liverpool,
United Kingdom
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2
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Crump RE, Aliee M, Sutherland SA, Huang CI, Crowley EH, Spencer SEF, Keeling MJ, Shampa C, Mwamba Miaka E, Rock KS. Modelling timelines to elimination of sleeping sickness in the Democratic Republic of Congo, accounting for possible cryptic human and animal transmission. Parasit Vectors 2024; 17:332. [PMID: 39123265 PMCID: PMC11313002 DOI: 10.1186/s13071-024-06404-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 07/13/2024] [Indexed: 08/12/2024] Open
Abstract
BACKGROUND Sleeping sickness (gambiense human African trypanosomiasis, gHAT) is a vector-borne disease targeted for global elimination of transmission (EoT) by 2030. There are, however, unknowns that have the potential to hinder the achievement and measurement of this goal. These include asymptomatic gHAT infections (inclusive of the potential to self-cure or harbour skin-only infections) and whether gHAT infection in animals can contribute to the transmission cycle in humans. METHODS Using modelling, we explore how cryptic (undetected) transmission impacts the monitoring of progress towards and the achievement of the EoT goal. We have developed gHAT models that include either asymptomatic or animal transmission, and compare these to a baseline gHAT model without either of these transmission routes, to explore the potential role of cryptic infections on the EoT goal. Each model was independently calibrated to five different health zones in the Democratic Republic of the Congo (DRC) using available historical human case data for 2000-2020 (obtained from the World Health Organization's HAT Atlas). We applied a novel Bayesian sequential updating approach for the asymptomatic model to enable us to combine statistical information about this type of transmission from each health zone. RESULTS Our results suggest that, when matched to past case data, we estimated similar numbers of new human infections between model variants, although human infections were slightly higher in the models with cryptic infections. We simulated the continuation of screen-confirm-and-treat interventions, and found that forward projections from the animal and asymptomatic transmission models produced lower probabilities of EoT than the baseline model; however, cryptic infections did not prevent EoT from being achieved eventually under this approach. CONCLUSIONS This study is the first to simulate an (as-yet-to-be available) screen-and-treat strategy and found that removing a parasitological confirmation step was predicted to have a more noticeable benefit to transmission reduction under the asymptomatic model compared with the others. Our simulations suggest vector control could greatly impact all transmission routes in all models, although this resource-intensive intervention should be carefully prioritised.
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Affiliation(s)
- Ronald E Crump
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Maryam Aliee
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Samuel A Sutherland
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Ching-I Huang
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Emily H Crowley
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Simon E F Spencer
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Department of Statistics, University of Warwick, Academic Loop Road, Coventry, UK
| | - Matt J Keeling
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Chansy Shampa
- Programme National de Lutte Contre la Trypanosomiase Humaine Africaine (PNLTHA)-DRC, Kinshasa, Democratic Republic of Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte Contre la Trypanosomiase Humaine Africaine (PNLTHA)-DRC, Kinshasa, Democratic Republic of Congo
| | - Kat S Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK.
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK.
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3
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Tsague KJA, Bakwo Fils EM, Atagana JP, Mbeng DW, Palm L, Tchuinkam T, Schaer J. Molecular detection of trypanosomes of the Trypanosoma livingstonei species group in diverse bat species in Central Cameroon. Parasitol Res 2024; 123:280. [PMID: 39037445 PMCID: PMC11263222 DOI: 10.1007/s00436-024-08303-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 07/12/2024] [Indexed: 07/23/2024]
Abstract
Bats are hosts for diverse Trypanosoma species, including trypanosomes of the Trypanosoma cruzi clade. This clade is believed to have originated in Africa and diversified in many lineages worldwide. In several geographical areas, including Cameroon, no data about trypanosomes of bats has been collected yet. In this study, we investigated the diversity and phylogenetic relationships of trypanosomes of different bat species in the central region of Cameroon. Trypanosome infections were detected in six bat species of four bat families, namely Hipposideridae, Pteropodidae, Rhinolophidae, and Vespertilionidae, with an overall prevalence of 29% and the highest infection rate in hipposiderid bat species. All trypanosomes were identified as belonging to the Trypanosoma livingstonei species group with one clade that might represent an additional subspecies of T. livingstonei. Understanding the prevalence, distribution, and host range of parasites of this group contributes to our overall knowledge of the diversity and host specificity of trypanosome species that phylogenetically group at the base of the T. cruzi clade.
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Affiliation(s)
- K J A Tsague
- Laboratory of Biological Sciences, Faculty of Sciences of University of Maroua, Maroua, Cameroon
- Vector Borne Diseases Laboratory of the Research Unit for Biology and Applied Ecology (VBID-RUBAE), University of Dschang, Dschang, Cameroon
| | - E M Bakwo Fils
- Department of Environmental Sciences, Higher Institute of Agriculture, Forestry, Water and Environment (HIAFWE), University of Ebolowa, Ebolowa, Cameroon
| | - J P Atagana
- Department of Biological Science, Faculty of Science, University of Ngaoundere, Ngaoundere, Cameroon
| | - D W Mbeng
- Laboratory of Biological Sciences, Faculty of Sciences of University of Maroua, Maroua, Cameroon
| | - L Palm
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - T Tchuinkam
- Vector Borne Diseases Laboratory of the Research Unit for Biology and Applied Ecology (VBID-RUBAE), University of Dschang, Dschang, Cameroon.
| | - J Schaer
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany.
- Department of Biology, Muni University, Arua, Uganda.
- Museum Für Naturkunde, Leibniz-Institute for Evolution and Biodiversity Science, Berlin, Germany.
- Department of Biological Sciences, Macquarie University, Sydney, Australia.
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4
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Crilly NP, Zita MD, Beaver AK, Sysa-Shah P, Bhalodia A, Gabrielson K, Adamo L, Mugnier MR. A murine model of Trypanosoma brucei-induced myocarditis and cardiac dysfunction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.05.560950. [PMID: 37873308 PMCID: PMC10592974 DOI: 10.1101/2023.10.05.560950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Trypanosoma brucei is a protozoan parasite that causes human and animal African trypanosomiases (HAT and AAT). Cardiac symptoms are commonly reported in HAT patients, and intracardiac parasites with accompanying myocarditis have been observed in both natural hosts and animal models of T. brucei infection. Despite the importance of T. brucei as a cause of cardiac dysfunction and the dramatic socioeconomic impact of African trypanosomiases in sub-Saharan Africa, there are currently no reproducible murine models of T. brucei-associated cardiomyopathy. We present the first clinically relevant, reproducible murine model of cardiac dysfunction in chronic T. brucei infection. Similar to humans, mice showed histological evidence of myocarditis and elevation of serum NT-proBNP with electrocardiographic abnormalities. Serum NT-proBNP levels were elevated prior to the development of severe ventricular dysfunction. On flow cytometry, myocarditis was associated with an increase of most myocardial immune cell populations, including multiple T cell and macrophage subsets, corroborating the notion that T. brucei-associated cardiac damage is an immune-mediated event. This novel mouse model represents a powerful and practical tool to investigate the pathogenesis of T. brucei-mediated heart damage and supports the development of therapeutic options for T. brucei-associated cardiac disease.
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Affiliation(s)
- Nathan P. Crilly
- Department of Molecular and Comparative Pathobiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Marcelle Dina Zita
- Division of Cardiology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alexander K. Beaver
- Department of Molecular and Comparative Pathobiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Polina Sysa-Shah
- Department of Molecular and Comparative Pathobiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Molecular Imaging Service Center and Cancer Functional Imaging Core, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Aashik Bhalodia
- Division of Cardiology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Kathy Gabrielson
- Department of Molecular and Comparative Pathobiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Luigi Adamo
- Division of Cardiology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Monica R. Mugnier
- Department of Molecular and Comparative Pathobiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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5
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Feudjio Soffack S, Melachio Tanekou TT, Farikou O, Kame Ngasse GI, Tchami Mbagnia MC, Wondji M, Wondji CS, Abd-Alla AMM, Geiger A, Simo G, Njiokou F. The internal transcribed spacer 1 sequence polymorphism brings updates to tsetse species distribution in the northern Cameroon: Importance in planning efficient vector control. MEDICAL AND VETERINARY ENTOMOLOGY 2024; 38:216-226. [PMID: 38563591 DOI: 10.1111/mve.12717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 02/02/2024] [Indexed: 04/04/2024]
Abstract
Vector control remains one of the best strategies to prevent the transmission of trypanosome infections in humans and livestock and, thus, a good way to achieve the elimination of human African trypanosomiasis and animal African trypanosomiasis. A key prerequisite for the success of any vector control strategy is the accurate identification and correct mapping of tsetse species. In this work, we updated the tsetse fly species identification and distribution in many geographical areas in Cameroon. Tsetse flies were captured from six localities in Cameroon, and their species were morphologically identified. Thereafter, DNA was extracted from legs of each tsetse fly and the length polymorphism of internal transcribed spacer-1 (ITS1) region of each fly was investigated using PCR. ITS1 DNA fragments of each tsetse species were sequenced. The sequences obtained were analysed and compared to those available in GenBank. This enabled to confirm/infirm results of the morphologic identification and then, to establish the phylogenetic relationships between tsetse species. Morphologic features allowed to clearly distinguish all the tsetse species captured in the South Region of Cameroon, that is, Glossina palpalis palpalis, G. pallicera, G. caliginea and G. nigrofusca. In the northern area, G. morsitans submorsitans could also be distinguished from G. palpalis palpalis, G. tachinoides and G. fuscipes, but these three later could not be distinguished with routine morphological characters. The ITS1 length polymorphism was high among most of the studied species and allowed to identify the following similar species with a single PCR, that is, G. palpalis palpalis with 241 or 242 bp and G. tachinoides with 221 or 222 bp, G. fuscipes with 236 or 237 bp. We also updated the old distribution of tsetse species in the areas assessed, highlighting the presence of G. palpalis palpalis instead of G. fuscipes in Mbakaou, or in sympatry with G. morsitans submorsitans in Dodeo (northern Cameroon). This study confirms the presence of G. palpalis palpalis in the Adamawa Region of Cameroon. It highlights the limits of using morphological criteria to differentiate some tsetse species. Molecular tools based on the polymorphism of ITS1 of tsetse flies can differentiate tsetse species through a simple PCR before downstream analyses or vector control planning.
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Affiliation(s)
- Steve Feudjio Soffack
- Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Tito Tresor Melachio Tanekou
- Department of Microbiology and Parasitology, Faculty of Science, University of Bamenda, Bamenda, Cameroon
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Oumarou Farikou
- Faculty of Health Science, University of Bamenda, Bamenda, Cameroon
| | | | | | - Murielle Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Charles S Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Adly M M Abd-Alla
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Anne Geiger
- UMR177, Institut de Recherche pour le Développement (IRD)-CIRAD, Montpellier, France
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Flobert Njiokou
- Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
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Tsagmo JM, Njiokou F, Dziedziech A, Rofidal V, Hem S, Geiger A. Protein abundance in the midgut of wild tsetse flies (Glossina palpalis palpalis) naturally infected by Trypanosoma congolense s.l. MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:723-736. [PMID: 37357577 DOI: 10.1111/mve.12676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Tsetse flies (Glossina spp.) are major vectors of African trypanosomes, causing either Human or Animal African Trypanosomiasis (HAT or AAT). Several approaches have been developed to control the disease, among which is the anti-vector Sterile Insect Technique. Another approach to anti-vector strategies could consist of controlling the fly's vector competence through hitherto unidentified regulatory factors (genes, proteins, biological pathways, etc.). The present work aims to evaluate the protein abundance in the midgut of wild tsetse flies (Glossina palpalis palpalis) naturally infected by Trypanosoma congolense s.l. Infected and non-infected flies were sampled in two HAT/AAT foci in Southern Cameroon. After dissection, the proteomes from the guts of parasite-infected flies were compared to that of uninfected flies to identify quantitative and/or qualitative changes associated with infection. Among the proteins with increased abundance were fructose-1,6-biphosphatase, membrane trafficking proteins, death proteins (or apoptosis proteins) and SERPINs (inhibitor of serine proteases, enzymes considered as trypanosome virulence factors) that displayed the highest increased abundance. The present study, together with previous proteomic and transcriptomic studies on the secretome of trypanosomes from tsetse fly gut extracts, provides data to be explored in further investigations on, for example, mammal host immunisation or on fly vector competence modification via para-transgenic approaches.
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Affiliation(s)
- Jean Marc Tsagmo
- INTERTRYP, Institut de Recherche pour le Développement, University of Montpellier, Montpellier, France
- Faculty of Science, University of Yaoundé I, Yaounde, Cameroon
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors and INSERM U1201, Institut Pasteur, Paris, France
| | - Flobert Njiokou
- Faculty of Science, University of Yaoundé I, Yaounde, Cameroon
| | - Alexis Dziedziech
- Biology of Host-Parasite Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Valerie Rofidal
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Sonia Hem
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Anne Geiger
- INTERTRYP, Institut de Recherche pour le Développement, University of Montpellier, Montpellier, France
- Faculty of Science, University of Yaoundé I, Yaounde, Cameroon
- Center for Research on Filariasis and Other Tropical Diseases (CRFilMT), Yaounde, Cameroon
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7
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Melachio Tanekou TT, Bouaka Tsakeng CU, Tirados I, Acho A, Bigoga J, Wondji CS, Njiokou F. Impact of a small-scale tsetse fly control operation with deltamethrin impregnated "Tiny Targets" on tsetse density and trypanosomes' circulation in the Campo sleeping sickness focus of South Cameroon. PLoS Negl Trop Dis 2023; 17:e0011802. [PMID: 38011275 PMCID: PMC10732512 DOI: 10.1371/journal.pntd.0011802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 12/07/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND Significant progress has been made towards African sleeping sickness elimination in the last decade. Indeed, the World Health Organization (WHO) global goal of eliminating the chronic form of the disease as a public health problem was achieved in 2020 (i.e., < 2,000 new cases per year). Vector control has played an important role in achieving this goal. In this study, we evaluated the impact of the insecticide impregnated Tiny Targets on tsetse fly densities and their infection rates with Trypanosoma spp in the Campo sleeping sickness focus of South Cameroon. METHODS The study site was divided into two areas: (i) the south-west experimental area, which included vector control, and (ii) the eastern part as the non-intervention area. After compiling the baseline entomological data (tsetse densities and trypanosome infection rates), around 2000 Tiny Targets were deployed in the South-West area and replaced every six months for two years. Post-intervention surveys were conducted every six months to determine tsetse densities and levels of trypanosome infections with PCR-based methods. RESULTS Following the intervention, tsetse mean catches decreased by 61% after six months, and up to 73% after twelve months (pre-intervention: 2.48 flies/trap/day, 95%CI [1.92-3.14]; 12-months post-intervention: 0.66 tsetse/trap/day, 95%CI [0.42-0.94]). This decrease was not sustained after 18 months, and the mean catch doubled compared to that after 12 months. After 24 months, the mean catches still increased by 17% (18 months: 1.45 tsetse/trap/day, 95%CI [1.07-1.90] and 24 months: 1.71 tsetse/trap/day, 95%CI [1.27-2.24]). In the non-intervention area, a variation in tsetse catches was observed during the two years, with a general increase from 2.43 [0.73-5.77] to 3.64 [1.47-7.70] tsetse/trap/day. In addition, trypanosome infection rates dropped by 75% in both areas (P-value < 0.001) from 21.20% to 5.06% and from 13.14% to 3.45% in intervention and control areas respectively. CONCLUSION Tiny targets have proven useful in reducing tsetse population densities and trypanosome infection rates, providing evidence for the integration of this tool in current strategies towards trypanosomiasis elimination in Campo. The non-sustained decrease of tsetse densities after one year may indicate reinvasions from neighbouring breeding sites or that the intervention area was not large enough. Our results show the need to scale up by accessing difficult breeding sites and extend the tiny targets to the whole transborder focus.
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Affiliation(s)
- Tito Tresor Melachio Tanekou
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Microbiology and Parasitology, Faculty of Science, University of Bamenda, Bamenda, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Calmes Ursain Bouaka Tsakeng
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Inaki Tirados
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Alphonse Acho
- Programme National de Lutte contre la Trypanosomose Humaine Africaine (PNLTHA), Ministère de la Santé Publique, Cameroon
| | - Jude Bigoga
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
- Laboratory for Vector Biology and Control, National Reference Unit for Vector Control, The Biotechnology Centre, Nkolbisson, Yaoundé, Cameroon
| | - Charles Sinclair Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Flobert Njiokou
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
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8
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Magang EMK, Kamga RMN, Telleria J, Tichit M, Crouzols A, Kaboré J, Hardy D, Bouaka CUT, Jamonneau V, Rotureau B, Kuete V, Bart JM, Simo G. Prevalence of blood and skin trypanosomes in domestic and wild fauna from two sleeping sickness foci in Southern Cameroon. PLoS Negl Trop Dis 2023; 17:e0011528. [PMID: 37498955 PMCID: PMC10411957 DOI: 10.1371/journal.pntd.0011528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 08/08/2023] [Accepted: 07/12/2023] [Indexed: 07/29/2023] Open
Abstract
Although studies on African Trypanosomiases revealed a variety of trypanosome species in the blood of various animal taxa, animal reservoirs of Trypanosoma brucei gambiense and anatomical niches such as skin have been overlooked in most epidemiological settings. This study aims to update epidemiological data on trypanosome infections in animals from human African trypanosomiasis (HAT) foci of Cameroon. Blood and skin snips were collected from 291 domestic and wild animals. DNA was extracted from blood and skin snips and molecular approaches were used to identify different trypanosomes species. Immunohistochemical analyses were used to confirm trypanosome infections in skin snips. PCR revealed 137 animals (47.1%) with at least one trypanosome species in the blood and/or in the skin. Of these 137 animals, 90 (65.7%) and 32 (23.4%) had trypanosome infections respectively in the blood and skin. Fifteen (10.9%) animals had trypanosome infections in both blood and skin snip. Animals from the Campo HAT focus (55.0%) were significantly (X2 = 17.6; P< 0.0001) more infected than those (29.7%) from Bipindi. Trypanosomes of the subgenus Trypanozoon were present in 27.8% of animals while T. vivax, T. congolense forest type and savannah type were detected in 16.5%, 10.3% and 1.4% of animals respectively. Trypanosoma b. gambiense infections were detected in the blood of 7.6% (22/291) of animals. No T. b. gambiense infection was detected in skin. This study highlights the presence of several trypanosome species in the blood and skin of various wild and domestic animals. Skin appeared as an anatomical reservoir for trypanosomes in animals. Despite methodological limitations, pigs, sheep, goats and wild animals were confirmed as potential reservoirs of T. b. gambiense. These animal reservoirs must be considered for the designing of control strategies that will lead to sustainable elimination of HAT.
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Affiliation(s)
- Eugenie Melaine Kemta Magang
- Molecular Parasitology & Entomology Sub-unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
- Univ. Montpellier, CIRAD, IRD, Intertryp, Montpellier, France
| | - Rolin Mitterran Ndefo Kamga
- Molecular Parasitology & Entomology Sub-unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Jenny Telleria
- Univ. Montpellier, CIRAD, IRD, Intertryp, Montpellier, France
| | - Magali Tichit
- Histopathology Platform, Institut Pasteur, Paris, France
| | - Aline Crouzols
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur Paris, Université Paris Cité, Paris, France
| | - Jacques Kaboré
- Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Unité de recherche sur les maladies à vecteurs et biodiversité, Bobo-Dioulasso, Burkina Faso
| | - David Hardy
- Histopathology Platform, Institut Pasteur, Paris, France
| | | | - Vincent Jamonneau
- Univ. Montpellier, CIRAD, IRD, Intertryp, Montpellier, France
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur Paris, Université Paris Cité, Paris, France
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
| | - Victor Kuete
- Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | | | - Gustave Simo
- Molecular Parasitology & Entomology Sub-unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
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9
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Mewamba EM, Magang EMK, Tiofack AAZ, Woguia GF, Bouaka CUT, Kamga RMN, Farikou O, Fogue PS, Tume C, Ravel S, Simo G. Trypanosome infections in animals from tsetse infected areas of Cameroon and their sensitivity and resistance molecular profiles for diminazene aceturate and isometamidium chloride. Vet Parasitol Reg Stud Reports 2023; 41:100868. [PMID: 37208078 DOI: 10.1016/j.vprsr.2023.100868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 03/28/2023] [Accepted: 04/03/2023] [Indexed: 05/21/2023]
Abstract
Monitoring and assessment of control strategies for African trypanosomoses' elimination require not only updating data on trypanosome infections, but also to have an overview on the molecular profiles of trypanocides resistance in different epidemiological settings. This study was designed to determine, in animals from six tsetse-infested areas of Cameroon, the prevalence of trypanosome infections as well as the diminazene aceturate (DA) and isometamidium chloride (ISM) sensitivity/resistance molecular profiles of these trypanosomes. From 2016 to 2019, blood was collected in pigs, dogs, sheep, goats and cattle from six tsetse infested areas of Cameroon. DNA was extracted from blood and trypanosome species were identified by PCR. The sensitivity/resistance molecular profiles of trypanosomes to DA and ISM were investigated using PCR-RFLP. From 1343 blood samples collected, Trypanosoma vivax, Trypanosoma congolense forest and savannah, Trypanosoma theileri and trypanosomes of the sub-genus Trypanozoon were identified. The overall prevalence of trypanosome infections was 18.7%. These prevalence vary between trypanosome species, animal taxa, within and between sampling sites. Trypanosoma theileri was the predominant species with an infection rate of 12.1%. Trypanosomes showing resistant molecular profiles for ISM and DA were identified in animals from Tibati (2.7% for ISM and 65.6% for DA) and Kontcha (0.3% for ISM and 6.2% for DA). No trypanosome carrying resistant molecular profile for any of the two trypanocides was detected in animals from Fontem, Campo, Bipindi and Touboro. Mixed molecular profiles of sensitive/resistant trypanosomes were detected in animals from Tibati and Kontcha. Results of this study highlighted the presence of various trypanosome species as well as parasites carrying sensitive/resistant molecular profiles for DA and ISM in animals of tsetse infested areas of Cameroon. They indicate that the control strategies must be adapted according to epidemiological settings. The diversity of trypanosomes indicates that AAT remains a serious threat for animal breeding and animal health in these tsetse infested areas.
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Affiliation(s)
- Estelle Mezajou Mewamba
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Eugenie Melaine Kemta Magang
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Arnol Auvaker Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Gilles-Fils Woguia
- Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | - Calmes Ursain Tsakeng Bouaka
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon; Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon
| | - Rolin Mitterran Ndeffo Kamga
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Oumarou Farikou
- Special Mission for Eradication of Tsetse flies, Regional tsetse Division of Adamawa, MINEPIA, Ngaoundere, Cameroon; Department of Biological Sciences, Faculty of Science, University of Bamenda, Bamenda, Cameroon
| | - Pythagore Sobgwi Fogue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Christopher Tume
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon; Department of Biochemistry, Faculty of Science, University of Bamenda, Bamenda, Cameroon
| | - Sophie Ravel
- IRD INTERTRYP, CIRAD, University of Montpellier, Montpellier, France
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
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Wong ML, Zulzahrin Z, Vythilingam I, Lau YL, Sam IC, Fong MY, Lee WC. Perspectives of vector management in the control and elimination of vector-borne zoonoses. Front Microbiol 2023; 14:1135977. [PMID: 37025644 PMCID: PMC10070879 DOI: 10.3389/fmicb.2023.1135977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 02/28/2023] [Indexed: 04/08/2023] Open
Abstract
The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004.
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Affiliation(s)
- Meng Li Wong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Zulhisham Zulzahrin
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - I-Ching Sam
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Medical Microbiology, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
| | - Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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Trypanosome Infections and Anemia in Cattle Returning from Transhumance in Tsetse-Infested Areas of Cameroon. Microorganisms 2023; 11:microorganisms11030712. [PMID: 36985285 PMCID: PMC10058033 DOI: 10.3390/microorganisms11030712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/12/2023] Open
Abstract
The objective of this work was to assess the anemic status and the use of an immunological test and PCR-based methods to determine the infection rates of trypanosomes species. Transhumance aims to provide cattle with greener pastures and greater water resources than in the Djerem region during the dry season. Two criteria were used to assess the health status of the animals, the prevalence of trypanosomiasis and the level of anemia. In addition, we have evaluated the effectiveness, in trypanosomiasis detection, of the Very Diag Kit (CEVA Santé animale), a Rapid diagnosis test (RDT) based on immunological identification of T. congolense s.l. and T. vivax, responsible for AAT. Four trypanosome species (Trypanosoma congolense savannah type (Tcs), T. congolense forest type (Tcf), T. brucei s.l. (Tbr) and T. vivax (Tvx)) were identified in cattle sampled in four villages. The overall infection rate determined by PCR (68.6%) was much higher than those generally reported in cattle from the Adamawa region (35 to 50%). Infections (including mixed infections) by Tc s.l. (Tcs + Tcf) were predominant (45.7%). The infection rates were also determined using the Very Diag Kit allowing us to identify Tc s.l. and Tvx in the field in less than 20 min. This method provided, for the global infection, a higher rate (76.5%) than that determined by PCR (68.6%), although it is supposed to be less sensitive than PCR. Tc s.l. infection rate (37.8%) was similar to that (38.8%) determined by PCR (Tcs + Tcf single infections). In contrast, the prevalence of Tvx single infections measured by RDT (18%) was nearly two-fold higher than that (9.4%) measured by PCR. Thus, further comparative analyses seem to be needed in order to more accurately assess the sensitivity and specificity of the Very Diag test under our conditions of use on blood samples. The mean PCVs in trypanosome-infected as well as in uninfected cattle were below 25%, the threshold below which an animal is considered anemic. Our study shows that cattle return from transhumance in poor health. It raises questions about its real benefit, especially since the herds are themselves likely to become vectors of trypanosomiasis and possibly of other diseases. At least, effective measures have to be undertaken to treat all cattle coming back from transhumance.
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12
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Vourchakbé J, Tiofack AAZ, Kante ST, Barka PA, Simo G. Prevalence of pathogenic trypanosome species in naturally infected cattle of three sleeping sickness foci of the south of Chad. PLoS One 2022; 17:e0279730. [PMID: 36584086 PMCID: PMC9803169 DOI: 10.1371/journal.pone.0279730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 12/14/2022] [Indexed: 12/31/2022] Open
Abstract
Although a diversity of trypanosome species have been detected in various animal taxa from human African trypanosomosis (HAT) foci, cattle trypanosomosis has not been addressed in HAT foci of west and central African countries including Chad. This study aimed to determine the prevalence of pathogenic trypanosome species in cattle from three HAT foci of the south of Chad. Blood samples were collected from 1466 randomly selected cattle from HAT foci of Mandoul, Maro, and Moïssala in the south of Chad. For each animal, the sex, age and body condition were recorded. Rapid diagnostic test (RDT) was used to search Trypanosoma brucei gambiense antibodies while the capillary tube centrifugation (CTC) test and PCR-based methods enabled to detect and identify trypanosome species. From the 1466 cattle, 45 (3.1%) were positive to RDT. The prevalence of trypanosome infections revealed by CTC and PCR-based method were respectively 2.7% and 11.1%. Trypanosomes of the subgenus Trypanozoon were dominant (6.5%) followed by T. congolense savannah (2.9%), T. congolense forest (2.5%) and T. vivax (0.8%). No animal was found with DNA of human infective trypanosome (T. b. gambiense). The overall prevalence of trypanosome infections was significantly higher in animal from the Maro HAT focus (13.8%) than those from Mandoul (11.1%) and Moïssala HAT foci (8.0%). This prevalence was also significantly higher in animal having poor body condition (77.5%) than those with medium (11.2%) and good (0.5%) body condition. The overall prevalence of single and mixed infections were respectively 9.4% and 1.6%. This study revealed natural infections of several pathogenic trypanosome species in cattle from different HAT foci of Chad. It showed similar transmission patterns of these trypanosome species and highlighted the need of developing control strategies for animal African trypanosomosis (AAT) with the overarching goal of improving animal health and the economy of smallholder farmers.
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Affiliation(s)
- Joël Vourchakbé
- Department of Biological Science, Faculty of Science and Technology, University of Doba, Doba, Chad
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Arnol Auvaker Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Sartrien Tagueu Kante
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Padja Abdoul Barka
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
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Melachio Tanekou TT, Bouaka Tsakeng CU, Tirados I, Torr SJ, Njiokou F, Acho A, Wondji CS. Environmental mutations in the Campo focus challenge elimination of sleeping sickness transmission in Cameroon. MEDICAL AND VETERINARY ENTOMOLOGY 2022; 36:260-268. [PMID: 35593526 PMCID: PMC10138755 DOI: 10.1111/mve.12579] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/03/2022] [Indexed: 05/13/2023]
Abstract
Sleeping sickness is still prevalent in Campo, southern Cameroon, despite the efforts of World Health Organization and the National Control Programme in screening and treating cases. Reducing disease incidence still further may need the control of tsetse vectors. We update entomological and parasitological parameters necessary to guide tsetse control in Campo. Tsetse flies were trapped, their apparent densities were evaluated as the number of flies captured per trap per day and mapped using GIS tools. Polymerase chain reaction based methods were used to identify their trypanosome infection rates. Glossina palpalis palpalis was the dominant vector species representing 93.42% and 92.85% of flies captured respectively during the heavy and light dry seasons. This species presented high densities, that is, 3.87, 95% CI [3.84-3.91], and 2.51, 95% CI [2.49-2.53] flies/trap/day in the two seasons. Moreover, 16.79% (of 1054) and 20.23% (of 1132 flies) were found infected with at least 1 trypanosome species for the 2 seasons respectively, Trypanosoma congolense being the most prevalent species, and Trypanosoma. brucei gambiense identified in 4 samples. Tsetse flies are abundant in Campo and present high trypanosome infection rates. The detection of tsetse infected with human trypanosomes near the newly created palm grove show workers' exposition. Tsetse densities maps built will guide vector control with 'Tiny Targets'.
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Affiliation(s)
- Tito Tresor Melachio Tanekou
- Centre for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Biological Sciences, Faculty of ScienceUniversity of BamendaBamendaCameroon
| | - Calmes Ursain Bouaka Tsakeng
- Centre for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Biochemistry, Faculty of ScienceUniversity of Yaoundé IYaoundéCameroon
| | - Inaki Tirados
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Steve J. Torr
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Flobert Njiokou
- Department of Animal Biology and Physiology, Faculty of ScienceUniversity of Yaoundé IYaoundéCameroon
| | - Alphonse Acho
- Programme National de Lutte contre la Trypanosomose Humaine Africaine (PNLTHA)Ministry of Public HealthYaoundéCameroon
| | - Charles Sinclair Wondji
- Centre for Research in Infectious Diseases (CRID)YaoundéCameroon
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
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14
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Tsakeng CUB, Tanekou TTM, Soffack SF, Tirados I, Noutchih C, Njiokou F, Bigoga JD, Wondji CS. Assessing the Tsetse Fly Microbiome Composition and the Potential Association of Some Bacteria Taxa with Trypanosome Establishment. Microorganisms 2022; 10:1141. [PMID: 35744659 PMCID: PMC9229743 DOI: 10.3390/microorganisms10061141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 05/30/2022] [Indexed: 02/01/2023] Open
Abstract
The tsetse flies, biological vectors of African trypanosomes, harbour a variety of bacteria involved in their vector competence that may help in developing novel vector control tools. This study provides an inventory of tsetse bacterial communities in Cameroon and explores their possible associations with trypanosome establishment in Glossina palpalis palpalis. High throughput sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene, with subsequent metagenomic, multivariate, and association analyses, were used to investigate the levels and patterns of microbial diversity in four tsetse species. Overall, 31 bacterial genera and four phyla were identified. The primary symbiont Wigglesworthia dominated almost all the samples, with an overall relative abundance of 47.29%, and seemed to be replaced by Serratia or Burkholderia in some G. tachinoides flies. Globally, significant differences were observed in the microbiome diversity and composition among tsetse species and between teneral and non-teneral flies, or between flies displaying or not displaying mature trypanosome infections. In addition, differential abundance testing showed some OTUs, or some bacteria taxa, associated with trypanosome maturation in tsetse flies. These bacteria could be further investigated for an understanding of their mechanism of action and alternatively, transformed and used to block trypanosome development in tsetse flies.
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Affiliation(s)
- Calmes Ursain Bouaka Tsakeng
- Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (C.U.B.T.); (C.N.); (F.N.); (C.S.W.)
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Tito Tresor Melachio Tanekou
- Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (C.U.B.T.); (C.N.); (F.N.); (C.S.W.)
- Department of Biological Sciences, Faculty of Science, University of Bamenda, Bamenda P.O. Box 39, Cameroon
| | - Steve Feudjio Soffack
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Inaki Tirados
- Department of Vector Biology, Liverpool School of Tropical Medicine Pembroke Place, Liverpool L3 5QA, UK;
| | - Cedrique Noutchih
- Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (C.U.B.T.); (C.N.); (F.N.); (C.S.W.)
| | - Flobert Njiokou
- Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (C.U.B.T.); (C.N.); (F.N.); (C.S.W.)
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Jude Daiga Bigoga
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé P.O. Box 812, Cameroon;
| | - Charles Sinclair Wondji
- Centre for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (C.U.B.T.); (C.N.); (F.N.); (C.S.W.)
- Department of Vector Biology, Liverpool School of Tropical Medicine Pembroke Place, Liverpool L3 5QA, UK;
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Free-ranging pigs identified as a multi-reservoir of Trypanosoma brucei and Trypanosoma congolense in the Vavoua area, a historical sleeping sickness focus of Côte d'Ivoire. PLoS Negl Trop Dis 2021; 15:e0010036. [PMID: 34937054 PMCID: PMC8735613 DOI: 10.1371/journal.pntd.0010036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 01/06/2022] [Accepted: 11/28/2021] [Indexed: 12/03/2022] Open
Abstract
Background The existence of an animal reservoir of Trypanosoma brucei gambiense (T. b. gambiense), the agent of human African trypanosomiasis (HAT), may compromise the interruption of transmission targeted by World Health Organization. The aim of this study was to investigate the presence of trypanosomes in pigs and people in the Vavoua HAT historical focus where cases were still diagnosed in the early 2010’s. Methods For the human survey, we used the CATT, mini-anion exchange centrifugation technique and immune trypanolysis tests. For the animal survey, the buffy coat technique was also used as well as the PCR using Trypanosoma species specific, including the T. b. gambiense TgsGP detection using single round and nested PCRs, performed from animal blood samples and from strains isolated from subjects positive for parasitological investigations. Results No HAT cases were detected among 345 people tested. A total of 167 pigs were investigated. Free-ranging pigs appeared significantly more infected than pigs in pen. Over 70% of free-ranging pigs were positive for CATT and parasitological investigations and 27–43% were positive to trypanolysis depending on the antigen used. T. brucei was the most prevalent species (57%) followed by T. congolense (24%). Blood sample extracted DNA of T. brucei positive subjects were negative to single round TgsGP PCR. However, 1/22 and 6/22 isolated strains were positive with single round and nested TgsGP PCRs, respectively. Discussion Free-ranging pigs were identified as a multi-reservoir of T. brucei and/or T. congolense with mixed infections of different strains. This trypanosome diversity hinders the easy and direct detection of T. b. gambiense. We highlight the lack of tools to prove or exclude with certainty the presence of T. b. gambiense. This study once more highlights the need of technical improvements to explore the role of animals in the epidemiology of HAT. Significant efforts to control human African trypanosomiasis (HAT) since the 1990’s have drastically reduced the prevalence of the disease. Its elimination as a public health problem is being achieved. World Health Organization now targets the interruption of transmission for 2030. However, potential animal reservoirs of Trypanosoma brucei gambiense (T. b. gambiense), the main agent of HAT, may compromise this ambitious objective. It is the case in the Vavoua historical focus in Côte d’Ivoire where HAT cases were still diagnosed in the early 2010’s. During a study conducted in this area, we scrutinized the trypanosomes circulating in pigs and people sharing the same environment using serological, immunological, parasitological and molecular tools. No HAT cases were detected. We showed that T. brucei s.l. and T. congolense actively circulated in free-ranging pigs. Even if no tools were sensitive and specific enough to unambiguously identify T. b. gambiense directly from biological samples, six isolated strains from pigs positive for trypanosomes were amplified for TgsGP, the only currently accepted T. b. gambiense specific molecular marker. The apparent discrepancies between the presence of T. b. gambiense in pigs despite the absence of human cases is discussed. These results stress the need for an efficient “molecular toolbox” to easily detect and identify T. b. gambiense in any animal it may infect.
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Zhai J, Wu Y, Chen J, Zou J, Shan F, Li W, Chen W, Zhou N. Identification of Amblyomma javanense and detection of tick-borne Ehrlichia spp. in confiscated Malayan Pangolins. Int J Parasitol Parasites Wildl 2021; 14:107-116. [PMID: 33598400 PMCID: PMC7868807 DOI: 10.1016/j.ijppaw.2021.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/12/2021] [Accepted: 01/21/2021] [Indexed: 11/29/2022]
Abstract
Due to habitat destruction and illegal hunting and trade, the number of pangolins has been sharply reduced. To protect pangolins from extinction, relevant departments are combined and active action have been taken. A total of 21 confiscated Malayan pangolins were rescued in 2019, but died continuously for unknown reasons. This study aimed to investigate the reasons for the death of these pangolin and rescue them. 19 of the 21 confiscated pangolins had ticks on their body integument. A total of 303 ticks were collected and identified as Amblyomma javanense (A. javanense) according to their morphology and the sequences of 16S rRNA and internal transcribed spacer 2 (ITS2). There were multi-organ damages in the dead pangolins, especially congestion and hemorrhage in lung, heart and kidney and inflammation of which were observed using HE staining. Pathogens' nucleic acid detection showed ticks were only positive for Ehrlichia spp, with 56.7% positive rate of collected ticks (127/224), which was further confirmed in tissues from dead pangolins. Our findings confirm that ehrlichiosis caused by Ehrlichia spp. from A. javanense might accelerate the confiscated pangolin's death. More attention should be payed to tick-elimination work and the diagnoses and treatment of tick-borne diseases in the follow-up rescue operation.
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Affiliation(s)
- Junqiong Zhai
- Guangzhou Zoo, Guangzhou, 510070, China
- Wildlife Microbiology Laboratory, Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Yajiang Wu
- Guangzhou Zoo, Guangzhou, 510070, China
- Wildlife Microbiology Laboratory, Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Jinping Chen
- Guangdong Institute of Applied Biological Resources, Guangzhou, 510260, China
| | - Jiejian Zou
- Guangdong Provincial Wildlife Rescue Center, Guangzhou, 510520, China
| | - Fen Shan
- Guangzhou Zoo, Guangzhou, 510070, China
- Wildlife Microbiology Laboratory, Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Wanping Li
- Guangzhou Zoo, Guangzhou, 510070, China
- Wildlife Microbiology Laboratory, Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Wu Chen
- Guangzhou Zoo, Guangzhou, 510070, China
- Wildlife Microbiology Laboratory, Guangzhou Wildlife Research Center, Guangzhou, 510070, China
| | - Niu Zhou
- Guangzhou Zoo, Guangzhou, 510070, China
- Wildlife Microbiology Laboratory, Guangzhou Wildlife Research Center, Guangzhou, 510070, China
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Vourchakbé J, Tiofack ZAA, Kante TS, Mpoame M, Simo G. Molecular identification of Trypanosoma brucei gambiense in naturally infected pigs, dogs and small ruminants confirms domestic animals as potential reservoirs for sleeping sickness in Chad. ACTA ACUST UNITED AC 2020; 27:63. [PMID: 33206595 PMCID: PMC7673351 DOI: 10.1051/parasite/2020061] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 11/02/2020] [Indexed: 12/03/2022]
Abstract
Human African trypanosomiasis (HAT) has been targeted for zero transmission to humans by 2030. Animal reservoirs of gambiense-HAT could jeopardize these elimination goals. This study was undertaken to identify potential host reservoirs for Trypanosoma brucei gambiense by detecting its natural infections in domestic animals of Chadian HAT foci. Blood samples were collected from 267 goats, 181 sheep, 154 dogs, and 67 pigs. Rapid diagnostic test (RDT) and capillary tube centrifugation (CTC) were performed to search for trypanosomes. DNA was extracted from the buffy coat, and trypanosomes of the subgenus Trypanozoon as well as T. b. gambiense were identified by PCR. Of 669 blood samples, 19.4% were positive by RDT and 9.0% by CTC. PCR revealed 150 animals (22.4%) with trypanosomes belonging to Trypanozoon, including 18 (12%) T. b. gambiense. This trypanosome was found in all investigated animal species and all HAT foci. Between animal species or villages, no significant differences were observed in the number of animals harboring T. b. gambiense DNA. Pigs, dogs, sheep and goats appeared to be potential reservoir hosts for T. b. gambiense in Chad. The identification of T. b. gambiense in all animal species of all HAT foci suggests that these animals should be considered when designing new control strategies for sustainable elimination of HAT. Investigations aiming to decrypt their specific role in each epidemiological setting are important to achieve zero transmission of HAT.
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Affiliation(s)
| | - Zebaze Arnol Auvaker Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon
| | - Tagueu Sartrien Kante
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon
| | - Mbida Mpoame
- Laboratory of Applied Biology and Ecology (LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, PO Box 067 Dschang, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon
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Blood of African Hedgehog Atelerix albiventris Contains 115-kDa Trypanolytic Protein that Kills Trypanosoma congolense. Acta Parasitol 2020; 65:733-742. [PMID: 32385812 DOI: 10.2478/s11686-020-00211-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/01/2020] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Protozoan parasites of the Order Trypanosomatida infect a wide range of multicellular plants and animals, causing devastating and potentially fatal diseases. Trypanosomes are the most relevant members of the order in sub-Saharan Africa because of mortalities and morbidities caused to humans and livestock. PURPOSE There are growing concerns that trypanosomes are expanding their reservoirs among wild animals, which habours the parasites, withstand the infection, and from which tsetse flies transmit the parasites back to humans and livestock. This study was designed to investigate the potentials of the African hedgehog serving as reservoir for African animal trypanosomes. METHODS Five adult hedgehogs alongside five laboratory mice were intraperitoneally inoculated with 106 and 104 of Trypanosoma congolense cells, respectively, and monitored for parasitemia and survival. Serum from twenty hedgehogs was subjected to trypanocidal activity-guided fractionation by successive ion-exchange and gel-filtration chromatographies, followed by characterization with Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE). RESULTS Hedgehogs were resistant to the infection as no parasite was detected and none died even after 60 days, while all the mice died within 12 days. Both the serum and plasma prepared from hedgehogs demonstrated trypanocidal activity- rapidly killed trypanosomes even when diluted 1000 times. The trypanolytic factor was identified to be proteinaceous with an estimated molecular weight of 115-kDa. CONCLUSION For the first time, it is here demonstrated that hedgehog blood has significant trypanolytic activity against T. congolense. The potential application of the hedgehog protein for the breeding of trypanosomosis-resistant livestock in tsetse fly belt is discussed.
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Vourchakbé J, Tiofack AAZ, Mbida M, Simo G. Trypanosome infections in naturally infected horses and donkeys of three active sleeping sickness foci in the south of Chad. Parasit Vectors 2020; 13:323. [PMID: 32576240 PMCID: PMC7310289 DOI: 10.1186/s13071-020-04192-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/17/2020] [Indexed: 02/02/2023] Open
Abstract
Background Equine trypanosomiases are complex infectious diseases with overlapping clinical signs defined by their mode of transmission. Despite their economic impacts, these diseases have been neglected by the scientific community, the veterinary authorities and regulatory organizations. To fill the observed knowledge gap, we undertook the identification of different trypanosome species and subspecies naturally infecting horses and donkeys within the Chadian sleeping sickness focus. The objective of the study was to investigate the potential role of these domestic animals as reservoirs of the human-infective Trypanosoma brucei gambiense. Method Blood samples were collected from 155 donkeys and 131 horses in three human African trypanosomiasis (HAT) foci in Chad. Rapid diagnostic test (RDT) and capillary tube centrifugation (CTC) test were used to search for trypanosome infections. DNA was extracted from each blood sample and different trypanosome species and subspecies were identified with molecular tools. Results From 286 blood samples collected, 54 (18.9%) and 36 (12.6%) were positive for RDT and CTC, respectively. PCR revealed 101 (35.3%) animals with trypanosome infections. The Cohen’s kappa coefficient used to evaluate the concordance between the diagnostic methods were low; ranging from 0.09 ± 0.05 to 0.48 ± 0.07. Trypanosomes of the subgenus Trypanozoon were the most prevalent (29.4%), followed by T. congolense forest (11.5%), Trypanosoma congolense savannah (4.9%) and Trypanosoma vivax (4.5%). Two donkeys and one horse from the Maro HAT focus were found with T. b. gambiense infections. No significant differences were observed in the infection rates of different trypanosomes between animal species and HAT foci. Conclusions This study revealed several trypanosome species and subspecies in donkeys and horses, highlighting the existence of AAT in HAT foci in Chad. The identification of T. b. gambiense in donkeys and horses suggests considering these animals as potential reservoir for HAT in Chad. The presence of both human-infective and human non-infective trypanosomes species highlights the need for developing joint control strategies for HAT and AAT.![]()
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Affiliation(s)
- Joël Vourchakbé
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon.,Department of Chemistry-Biology-Geology, Faculty of Science and Technology, University of Doba, PO Box 03, Doba, Chad
| | - Arnol Auvaker Z Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Mpoame Mbida
- Laboratory of Applied Biology and Ecology (LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, PO Box 067, Dschang, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon.
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Mulandane FC, Snyman LP, Brito DRA, Bouyer J, Fafetine J, Van Den Abbeele J, Oosthuizen M, Delespaux V, Neves L. Evaluation of the relative roles of the Tabanidae and Glossinidae in the transmission of trypanosomosis in drug resistance hotspots in Mozambique. Parasit Vectors 2020; 13:219. [PMID: 32349788 PMCID: PMC7189697 DOI: 10.1186/s13071-020-04087-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/15/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Tsetse flies (Diptera: Glossinidae) and tabanids (Diptera: Tabanidae) are haematophagous insects of medical and veterinary importance due to their respective role in the biological and mechanical transmission of trypanosomes. Few studies on the distribution and relative abundance of both families have been conducted in Mozambique since the country's independence. Despite Nicoadala, Mozambique, being a multiple trypanocidal drug resistance hotspot no information regarding the distribution, seasonality or infection rates of fly-vectors are available. This is, however, crucial to understanding the epidemiology of trypanosomosis and to refine vector management. METHODS For 365 days, 55 traps (20 NGU traps, 20 horizontal traps and 15 Epsilon traps) were deployed in three grazing areas of Nicoadala District: Namitangurine (25 traps); Zalala (15 traps); and Botao (15 traps). Flies were collected weekly and preserved in 70% ethanol. Identification using morphological keys was followed by molecular confirmation using cytochrome c oxidase subunit 1 gene. Trap efficiency, species distribution and seasonal abundance were also assessed. To determine trypanosome infection rates, DNA was extracted from the captured flies, and submitted to 18S PCR-RFLP screening for the detection of Trypanosoma. RESULTS In total, 4379 tabanids (of 10 species) and 24 tsetse flies (of 3 species), were caught. NGU traps were more effective in capturing both the Tabanidae and Glossinidae. Higher abundance and species diversity were observed in Namitangurine followed by Zalala and Botao. Tabanid abundance was approximately double during the rainy season compared to the dry season. Trypanosoma congolense and T. theileri were detected in the flies with overall infection rates of 75% for tsetse flies and 13% for tabanids. Atylotus agrestis had the highest infection rate of the tabanid species. The only pathogenic trypanosome detected was T. congolense. CONCLUSIONS Despite the low numbers of tsetse flies captured, it can be assumed that they are still the cyclical vectors of trypanosomosis in the area. However, the high numbers of tabanids captured, associated to their demonstrated capacity of transmitting trypanosomes mechanically, suggest an important role in the epidemiology of trypanosomosis in the Nicoadala district. These results on the composition of tsetse and tabanid populations as well as the observed infection rates, should be considered when defining strategies to control the disease.
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Affiliation(s)
| | - Louwtjie P. Snyman
- Vectors and Vector Borne Diseases Research Program, Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
- Durban Museum of Natural History, Durban, South Africa
| | - Denise R. A. Brito
- Eduardo Mondlane University, Biotechnology Center (CB-EMU), Maputo, Mozambique
| | - Jeremy Bouyer
- CIRAD, UMR ASTRE CIRAD-INRA (Animal, Health, Territories, Risks and Ecosystems), Campus International de Baillarguet, 34398 Montpellier Cedex 05, France
- Insect Pest Control Laboratory, Joint Food and Agriculture Organization of the United Nations/International Atomic Energy Agency Programme of Nuclear Techniques in Food and Agriculture, 1400 Vienna, Austria
| | - José Fafetine
- Eduardo Mondlane University, Biotechnology Center (CB-EMU), Maputo, Mozambique
| | - Jan Van Den Abbeele
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
| | - Marinda Oosthuizen
- Vectors and Vector Borne Diseases Research Program, Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Vincent Delespaux
- Bio-engineering Sciences, Vrije Universiteit Brussel, Brussel, Belgium
| | - Luis Neves
- Eduardo Mondlane University, Biotechnology Center (CB-EMU), Maputo, Mozambique
- Vectors and Vector Borne Diseases Research Program, Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
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Human African trypanosomiasis: the current situation in endemic regions and the risks for non-endemic regions from imported cases. Parasitology 2020; 147:922-931. [PMID: 32338232 PMCID: PMC7391876 DOI: 10.1017/s0031182020000645] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Human African trypanosomiasis (HAT) is caused by Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense and caused devastating epidemics during the 20th century. Due to effective control programs implemented in the last two decades, the number of reported cases has fallen to a historically low level. Although fewer than 977 cases were reported in 2018 in endemic countries, HAT is still a public health problem in endemic regions until it is completely eliminated. In addition, almost 150 confirmed HAT cases were reported in non-endemic countries in the last three decades. The majority of non-endemic HAT cases were reported in Europe, USA and South Africa, due to historical alliances, economic links or geographic proximity to disease-endemic countries. Furthermore, with the implementation of the ‘Belt and Road’ project, sporadic imported HAT cases have been reported in China as a warning sign of tropical diseases prevention. In this paper, we explore and interpret the data on HAT incidence and find no positive correlation between the number of HAT cases from endemic and non-endemic countries. This data will provide useful information for better understanding the imported cases of HAT globally in the post-elimination phase.
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Nkieri M, Mbo F, Kavunga P, Nganzobo P, Mafolo T, Selego C, Mwamba Miaka E. An Active Follow-up Strategy for Serological Suspects of Human African Trypanosomiasis with Negative Parasitology Set up by a Health Zone Team in the Democratic Republic of Congo. Trop Med Infect Dis 2020; 5:tropicalmed5020053. [PMID: 32260405 PMCID: PMC7345707 DOI: 10.3390/tropicalmed5020053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 11/16/2022] Open
Abstract
Background: The World Health Organization aims for the elimination of Human African Trypanosomiasis (HAT) as a public health problem by 2020 and for full elimination (absence of new cases) by 2030. One of strategies to achieve this is the active follow-up of all HAT serological suspects found during passive screening who have never been re-tested for parasitology. This is important because these cases can maintain HAT transmission and may be responsible for reemergence of the disease. Methods: In order to improve case finding at low cost in the targeted population, a general recall was transmitted to aparasitemic serological suspects about the availability of confirmation services at the general referral hospital. Transport was facilitated for re-testing. The initial examinations were carried out in Health Centers from Bagata Health Zone (HZ) in the Democratic Republic of the Congo between January 2017 and April 2019. This strategy of using a HZ team has not been previously documented. Results: From a total sample of 74 serological suspects listed by the health centers, 36 cases were re-examined at the general reference hospital; 19% (7/36) self-presented and 81% (29/36) were actively followed up by HZ personnel. Of those re-examined at the general reference hospital, 39% (14/36) resulted in a parasitologically confirmed case. Of the 14 people diagnosed with HAT, 14% (2/14) self-presented and the remaining 86% (12/14) were diagnosed in suspects who were actively followed up. This new strategy of facilitating transport from the villages added value by contributing to the detection of 12 HAT cases, compared to the passive approach, waiting for self-reference, which resulted in the detection of 2 new HAT cases. The cost per detected patient was 70 USD from the group of 7 suspects who self-presented for testing at the hospital and 346 USD per detected case for the group of 29 patients who were actively followed up by health zone staff. Conclusion: Targeted active follow-up of aparasitemic serological suspects by HZ teams is a cost-effective and promising approach to identifying additional cases of HAT in areas of very low prevalence, which would contribute to the HAT elimination goal set by the World Health Organization.
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Affiliation(s)
- Matthieu Nkieri
- Bagata Health Zone, Avenue Kalanganda N 10, Mwendo Bagata,32 Kwilu Province, Democratic Republic of the Congo; (M.N.); (P.K.)
| | - Florent Mbo
- National Sleeping Sickness Control Program (PNLTHA) (PNMLS building), Boulevard Triomphale Crossing Av. 24 November, 10 Kinshasa, Democratic Republic of the Congo; (P.N.); (E.M.M.)
- HAT Platform, Avenue Milambo N 4 Quartier Socimat, Gombe, 10 Kinshasa, Democratic Republic of the Congo
- Correspondence: or ; Tel.: +243-814313838
| | - Papy Kavunga
- Bagata Health Zone, Avenue Kalanganda N 10, Mwendo Bagata,32 Kwilu Province, Democratic Republic of the Congo; (M.N.); (P.K.)
| | - Pathou Nganzobo
- National Sleeping Sickness Control Program (PNLTHA) (PNMLS building), Boulevard Triomphale Crossing Av. 24 November, 10 Kinshasa, Democratic Republic of the Congo; (P.N.); (E.M.M.)
| | - Titus Mafolo
- Provincial Health Ministry of Kwilu, Aviation/Ifuri/Bandundu town, Bandundu, Democratic Republic of the Congo; (T.M.); (C.S.)
| | - Chalet Selego
- Provincial Health Ministry of Kwilu, Aviation/Ifuri/Bandundu town, Bandundu, Democratic Republic of the Congo; (T.M.); (C.S.)
| | - Eric Mwamba Miaka
- National Sleeping Sickness Control Program (PNLTHA) (PNMLS building), Boulevard Triomphale Crossing Av. 24 November, 10 Kinshasa, Democratic Republic of the Congo; (P.N.); (E.M.M.)
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Cunningham LJ, Lingley JK, Tirados I, Esterhuizen J, Opiyo M, Mangwiro CTN, Lehane MJ, Torr SJ. Evidence of the absence of human African trypanosomiasis in two northern districts of Uganda: Analyses of cattle, pigs and tsetse flies for the presence of Trypanosoma brucei gambiense. PLoS Negl Trop Dis 2020; 14:e0007737. [PMID: 32255793 PMCID: PMC7164673 DOI: 10.1371/journal.pntd.0007737] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 04/17/2020] [Accepted: 02/20/2020] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Large-scale control of sleeping sickness has led to a decline in the number of cases of Gambian human African trypanosomiasis (g-HAT) to <2000/year. However, achieving complete and lasting interruption of transmission may be difficult because animals may act as reservoir hosts for T. b. gambiense. Our study aims to update our understanding of T. b. gambiense in local vectors and domestic animals of N.W. Uganda. METHODS We collected blood from 2896 cattle and 400 pigs and In addition, 6664 tsetse underwent microscopical examination for the presence of trypanosomes. Trypanosoma species were identified in tsetse from a subsample of 2184 using PCR. Primers specific for T. brucei s.l. and for T. brucei sub-species were used to screen cattle, pig and tsetse samples. RESULTS In total, 39/2,088 (1.9%; 95% CI = 1.9-2.5) cattle, 25/400 (6.3%; 95% CI = 4.1-9.1) pigs and 40/2,184 (1.8%; 95% CI = 1.3-2.5) tsetse, were positive for T. brucei s.l.. Of these samples 24 cattle (61.5%), 15 pig (60%) and 25 tsetse (62.5%) samples had sufficient DNA to be screened using the T. brucei sub-species PCR. Further analysis found no cattle or pigs positive for T. b. gambiense, however, 17/40 of the tsetse samples produced a band suggestive of T. b. gambiense. When three of these 17 PCR products were sequenced the sequences were markedly different to T. b. gambiense, indicating that these flies were not infected with T. b. gambiense. CONCLUSION The lack of T. b. gambiense positives in cattle, pigs and tsetse accords with the low prevalence of g-HAT in the human population. We found no evidence that livestock are acting as reservoir hosts. However, this study highlights the limitations of current methods of detecting and identifying T. b. gambiense which relies on a single copy-gene to discriminate between the different sub-species of T. brucei s.l.
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Affiliation(s)
- Lucas J. Cunningham
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jessica K. Lingley
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Iñaki Tirados
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Johan Esterhuizen
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mercy Opiyo
- Institute for Global Health, University of Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Clement T. N. Mangwiro
- Department of Animal Science, Bindura University of Science Education, Bindura, Zimbabwe
| | - Mike J. Lehane
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Stephen J. Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Grébaut P, Andjingbopou Y, Mansinsa DP, Manzambi EZ, Mpembelé F, Lejon V, Geiger A. Monitoring the presence of trypanosomes' DNA - Including Trypanosoma brucei gambiense DNA - From the midguts of riverine Glossina trapped in the south east outskirts of Kinshasa City (Democratic Republic of Congo). INFECTION GENETICS AND EVOLUTION 2019; 77:104095. [PMID: 31689541 DOI: 10.1016/j.meegid.2019.104095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/22/2019] [Accepted: 10/25/2019] [Indexed: 11/17/2022]
Abstract
Even if the number of Human African Trypanosomiasis (HAT) cases from Kinshasa province in DRC is going towards elimination for the last decade, cases still occur in the periphery of the city. The diagnosis of 21 cases in the south periphery of Kinshasa, between 2015 and 2017 gives evidence of the existence of an active focus in this area. Here, we present the results of a punctual entomological survey that was realized in july 2014 in the outskirts of the southeast of Kinshasa. Using pyramidal traps, we caught tsetse flies during 2 days, dissecting the fresh ones for further molecular analysis. The average Apparent Density of flies per Trap and per Day was three with a maximum of 5.6 flies in Nganda PIO. Polymerase chain reaction analysis of the midguts provided evidence of a high prevalence (57.2%) of infected flies. Ninety three percent of the trypanosomes that were identified belonged to the Nanomonas species, but Trypanozoon trypanosomes were also present in 24% of the infected flies, including mixed infections with Nanomonas, including 3 flies carrying Trypanosoma brucei gambiense, the human pathogen of trypanosomiasis. These results show that at the time of the field's study there was an active reservoir of trypanosomes, closed to pigsties, knowing that pig is a potential animal reservoir. It also demonstrates that xenomonitoring using the entomological approach can be an efficient tool for monitoring sleeping sickness. Finally, results are discussed in the frame of WHO's HAT elimination project. Regarding Kinshasa, it points out the need of regular epidemiologic surveys.
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Affiliation(s)
- Pascal Grébaut
- UMR INTERTRYP IRD/CIRAD TA A17 G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
| | - Yvon Andjingbopou
- Université Marien Ngouabi, Faculté des Sciences de la Santé, B.P. 69, Brazzaville, Congo
| | | | - Emile Zola Manzambi
- Institut National de Recherche Biomédicale, 5345 Avenue De la Démocratie, Kinshasa, Gombe, Congo
| | - Fabrice Mpembelé
- Programme National de Lutte contre la THA, 36 Avenue de la justice, BP 3040 KIN1, Kinshasa, Congo
| | - Veerle Lejon
- UMR INTERTRYP IRD/CIRAD TA A17 G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
| | - Anne Geiger
- UMR INTERTRYP IRD/CIRAD TA A17 G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France; Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
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Akazue PI, Ebiloma GU, Ajibola O, Isaac C, Onyekwelu K, Ezeh CO, Eze AA. Sustainable Elimination (Zero Cases) of Sleeping Sickness: How Far Are We from Achieving This Goal? Pathogens 2019; 8:E135. [PMID: 31470522 PMCID: PMC6789789 DOI: 10.3390/pathogens8030135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 01/02/2023] Open
Abstract
The recent massive reduction in the numbers of fresh Human African Trypanosomiasis (HAT) infection has presented an opportunity for the global elimination of this disease. To prevent a possible resurgence, as was the case after the reduced transmission of the 1960s, surveillance needs to be sustained and the necessary tools for detection and treatment of cases need to be made available at the points of care. In this review, we examine the available resources and make recommendations for improvement to ensure the sustenance of the already achieved gains to keep the trend moving towards elimination.
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Affiliation(s)
- Pearl Ihuoma Akazue
- Department of Biochemistry, Faculty of Life Sciences, University of Benin, Benin City 300283, Nigeria
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Olumide Ajibola
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul PO Box 273, The Gambia
| | - Clement Isaac
- Department of Zoology, Faculty of Life Sciences, Ambrose Alli University, Ekpoma 310101, Nigeria
| | - Kenechukwu Onyekwelu
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria
| | - Charles O Ezeh
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria
| | - Anthonius Anayochukwu Eze
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria.
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Mehlitz D, Molyneux D. The elimination of Trypanosoma brucei gambiense? Challenges of reservoir hosts and transmission cycles: Expect the unexpected. Parasite Epidemiol Control 2019; 6:e00113. [PMID: 31528738 PMCID: PMC6742776 DOI: 10.1016/j.parepi.2019.e00113] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/03/2019] [Accepted: 07/11/2019] [Indexed: 11/24/2022] Open
Abstract
The World Health Organisation has set the goal for elimination of Human African Trypanosomiasis (HAT), caused by Trypanosoma brucei gambiense (gHAT), as a public health problem for 2020 and for the total interruption of transmission to humans for 2030. Targeting human carriers and potential animal reservoir infections will be critical to achieving this ambitious goal. However, there is continuing debate regarding the significance of reservoir host animals, wild and domestic, in different epidemiological contexts, whilst the extent and duration of the asymptomatic human carrier state is similarly undefined. This paper reviews the status of the knowledge of latent infections in wild and domestic animal reservoir hosts towards the goal of better understanding their role in the transmission dynamic of the disease. Focus areas include the transmission cycles in non-human hosts, the infectivity of animal reservoirs to Glossina palpalis s.l., the longevity of infection and the stability of T. b. gambiense biological characteristics in antelopes and domestic animals. There is compelling evidence that T. b. gambiense can establish and persist in experimentally infected antelopes, pigs and dogs for a period of at least two years. In particular, metacyclic transmission of T. b. gambiense has been reported in antelope-G.p.palpalis-antelope and pig-G.p.gambiensis-pig cycles. Experimental studies demonstrate that the infectiveness of latent animal reservoir infections with T. b. gambiense is retained in animal-Glossina-animal cycles (antelopes and pigs) for periods of three years and human infectivity markers (human serum resistance, zymodeme, DNA) are stable in non-human hosts for the same period. These observations shed light on the epidemiological significance of animal reservoir hosts in specific ecosystems characterized by presently active, as well as known "old" HAT foci whilst challenging the concept of total elimination of all transmission by 2030. This target is also compromised by the existence of human asymptomatic carriers of T. b. gambiense often detected outside Africa after having lived outside tsetse infested areas for many years - sometimes decades. Non-tsetse modes of transmission may also play a significant but underestimated role in the maintenance of foci and also preclude the total elimination of transmission - these include mother to child transmission and sexual transmission. Both these modes of transmission have been the subject of case reports yet their frequency in African settings remains to be ascertained when the context of residual foci are discussed yet both challenge the concept of the possibility of the total elimination of transmission.
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Affiliation(s)
- D. Mehlitz
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Germany
| | - D.H. Molyneux
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Fermino BR, Paiva F, Viola LB, Rodrigues CMF, Garcia HA, Campaner M, Takata CSA, Sheferaw D, Kisakye JJ, Kato A, Jared CAGS, Teixeira MMG, Camargo EP. Shared species of crocodilian trypanosomes carried by tabanid flies in Africa and South America, including the description of a new species from caimans, Trypanosoma kaiowa n. sp. Parasit Vectors 2019; 12:225. [PMID: 31088523 PMCID: PMC6515670 DOI: 10.1186/s13071-019-3463-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 04/29/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The genus Trypanosoma Gruby, 1843 is constituted by terrestrial and aquatic phylogenetic lineages both harboring understudied trypanosomes from reptiles including an increasing diversity of crocodilian trypanosomes. Trypanosoma clandestinus Teixeira & Camargo, 2016 of the aquatic lineage is transmitted by leeches to caimans. Trypanosoma grayi Novy, 1906 of the terrestrial lineage is transmitted by tsetse flies to crocodiles in Africa, but the vectors of Neotropical caiman trypanosomes nested in this lineage remain unknown. RESULTS Our phylogenetic analyses uncovered crocodilian trypanosomes in tabanids from South America and Africa, and trypanosomes other than T. grayi in tsetse flies. All trypanosomes found in tabanids clustered in the crocodilian clade (terrestrial lineage) forming six clades: Grayi (African trypanosomes from crocodiles and tsetse flies); Ralphi (trypanosomes from caimans, African and Brazilian tabanids and tsetse flies); Terena (caimans); Cay03 (caimans and Brazilian tabanids); and two new clades, Tab01 (Brazilian tabanid and tsetse flies) and Kaiowa. The clade Kaiowa comprises Trypanosoma kaiowa n. sp. and trypanosomes from African and Brazilian tabanids, caimans, tsetse flies and the African dwarf crocodile. Trypanosoma kaiowa n. sp. heavily colonises tabanid guts and differs remarkably in morphology from other caiman trypanosomes. This species multiplied predominantly as promastigotes on log-phase cultures showing scarce epimastigotes and exhibited very long flagellates in old cultures. Analyses of growth behavior revealed that insect cells allow the intracellular development of Trypanosoma kaiowa n. sp. CONCLUSIONS Prior to this description of Trypanosoma kaiowa n. sp., no crocodilian trypanosome parasitic in tabanid flies had been cultured, morphologically examined by light, scanning and transmission microscopy, and phylogenetically compared with other crocodilian trypanosomes. Additionally, trypanosomes thought to be restricted to caimans were identified in Brazilian and African tabanids, tsetse flies and the dwarf crocodile. Similar repertoires of trypanosomes found in South American caimans, African crocodiles and tabanids from both continents support the recent diversification of these transcontinental trypanosomes. Our findings are consistent with trypanosome host-switching likely mediated by tabanid flies between caimans and transoceanic migrant crocodiles co-inhabiting South American wetlands at the Miocene.
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Affiliation(s)
- Bruno R. Fermino
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
| | - Fernando Paiva
- Biological Institute, Federal University of Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul Brazil
| | | | - Carla M. F. Rodrigues
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
- Instituto Nacional de Ciência e Tecnologia, EpiAmo, Porto Velho, Rondônia Brazil
| | - Herakles A. Garcia
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
| | - Marta Campaner
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
| | - Carmen S. A. Takata
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
| | - Desie Sheferaw
- Department of Veterinary Medicine, Hawassa University, Hawassa, Ethiopia
| | - John J. Kisakye
- Department of Zoology, Entomology and Fisheries Sciences, Makerere University, Kampala, Uganda
| | - Agapitus Kato
- Department of Zoology, Entomology and Fisheries Sciences, Makerere University, Kampala, Uganda
- Uganda Virus Research Institute, Entebbe, Uganda
| | | | - Marta M. G. Teixeira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
- Instituto Nacional de Ciência e Tecnologia, EpiAmo, Porto Velho, Rondônia Brazil
| | - Erney P. Camargo
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP Brazil
- Instituto Nacional de Ciência e Tecnologia, EpiAmo, Porto Velho, Rondônia Brazil
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Tsagmo Ngoune JM, Reveillaud J, Sempere G, Njiokou F, Melachio TT, Abate L, Tchioffo MT, Geiger A. The composition and abundance of bacterial communities residing in the gut of Glossina palpalis palpalis captured in two sites of southern Cameroon. Parasit Vectors 2019; 12:151. [PMID: 30940213 PMCID: PMC6444424 DOI: 10.1186/s13071-019-3402-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/20/2019] [Indexed: 01/10/2023] Open
Abstract
Background A number of reports have demonstrated the role of insect bacterial flora on their host’s physiology and metabolism. The tsetse host and vector of trypanosomes responsible for human sleeping sickness (human African trypanosomiasis, HAT) and nagana in animals (African animal trypanosomiasis, AAT) carry bacteria that influence its diet and immune processes. However, the mechanisms involved in these processes remain poorly documented. This underscores the need for increased research into the bacterial flora composition and structure of tsetse flies. The aim of this study was to identify the diversity and relative abundance of bacterial genera in Glossina palpalis palpalis flies collected in two trypanosomiasis foci in Cameroon. Methods Samples of G. p. palpalis which were either negative or naturally trypanosome-positive were collected in two foci located in southern Cameroon (Campo and Bipindi). Using the V3V4 and V4 variable regions of the small subunit of the 16S ribosomal RNA gene, we analyzed the respective bacteriome of the flies’ midguts. Results We identified ten bacterial genera. In addition, we observed that the relative abundance of the obligate endosymbiont Wigglesworthia was highly prominent (around 99%), regardless of the analyzed region. The remaining genera represented approximately 1% of the bacterial flora, and were composed of Salmonella, Spiroplasma, Sphingomonas, Methylobacterium, Acidibacter, Tsukamurella, Serratia, Kluyvera and an unidentified bacterium. The genus Sodalis was present but with a very low abundance. Globally, no statistically significant difference was found between the bacterial compositions of flies from the two foci, and between positive and trypanosome-negative flies. However, Salmonella and Serratia were only described in trypanosome-negative flies, suggesting a potential role for these two bacteria in fly refractoriness to trypanosome infection. In addition, our study showed the V4 region of the small subunit of the 16S ribosomal RNA gene was more efficient than the V3V4 region at describing the totality of the bacterial diversity. Conclusions A very large diversity of bacteria was identified with the discovering of species reported to secrete anti-parasitic compounds or to modulate vector competence in other insects. For future studies, the analyses should be enlarged with larger sampling including foci from several countries. Electronic supplementary material The online version of this article (10.1186/s13071-019-3402-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean Marc Tsagmo Ngoune
- INTERTRYP, Institut de Recherche pour le Développement, University of Montpellier, Montpellier, France.,Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Julie Reveillaud
- ASTRE, INRA, CIRAD, University of Montpellier, Montpellier, France
| | - Guilhem Sempere
- INTERTRYP, Institut de Recherche pour le Développement, University of Montpellier, Montpellier, France
| | - Flobert Njiokou
- Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Trésor T Melachio
- Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Luc Abate
- UMR Maladies Infectieuses Et Vecteurs Écologie, Génétique, Évolution Et Contrôle, IRD 224-Centre National de la Recherche Scientifique, 5290-UM1-UM2, Montpellier, France
| | - Majoline T Tchioffo
- UMR Maladies Infectieuses Et Vecteurs Écologie, Génétique, Évolution Et Contrôle, IRD 224-Centre National de la Recherche Scientifique, 5290-UM1-UM2, Montpellier, France
| | - Anne Geiger
- INTERTRYP, Institut de Recherche pour le Développement, University of Montpellier, Montpellier, France. .,Center for Research on Filariasis and other Tropical Diseases (CRFilMT), P.O. Box 5797, Yaoundé, Cameroon. .,Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
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Ofon E, Noyes H, Ebo’o Eyanga V, Njiokou F, Koffi M, Fogue P, Hertz-Fowler C, MacLeod A, Matovu E, Simo G. Association between IL1 gene polymorphism and human African trypanosomiasis in populations of sleeping sickness foci of southern Cameroon. PLoS Negl Trop Dis 2019; 13:e0007283. [PMID: 30908482 PMCID: PMC6448947 DOI: 10.1371/journal.pntd.0007283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/04/2019] [Accepted: 03/07/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Human African Trypanosomiasis (HAT) is a neglected tropical disease caused by infections due to Trypanosoma brucei subspecies. In addition to the well-established environmental and behavioural risks of becoming infected, there is evidence for a genetic component to the response to trypanosome infection. We undertook a candidate gene case-control study to investigate genetic associations further. METHODOLOGY We genotyped one polymorphism in each of seven genes (IL1A, IL1RN, IL4RN, IL6, HP, HPR, and HLA-G) in 73 cases and 250 controls collected from 19 ethno-linguistic subgroups stratified into three major ethno-linguistic groups, 2 pooled ethno-linguistic groups and 11 ethno-linguistic subgroups from three Cameroonian HAT foci. The seven polymorphic loci tested consisted of three SNPs, three variable numbers of tandem repeat (VNTR) and one INDEL. RESULTS We found that the genotype (TT) and minor allele (T) of IL1A gene as well as the genotype 1A3A of IL1RN were associated with an increased risk of getting Trypanosoma brucei gambiense and develop HAT when all data were analysed together and also when stratified by the three major ethno-linguistic groups, 2 pooled ethno-linguistic subgroups and 11 ethno-linguistic subgroups. CONCLUSION This study revealed that one SNP rs1800794 of IL1A and one VNTR rs2234663 of IL1RN were associated with the increased risk to be infected by Trypanosoma brucei gambiense and develop sleeping sickness in southern Cameroon. The minor allele T and the genotype TT of SNP rs1800794 in IL1A as well as the genotype 1A3A of IL1RN rs2234663 VNTR seem to increase the risk of getting Trypanosoma brucei gambiense infections and develop sleeping sickness in southern Cameroon.
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Affiliation(s)
- Elvis Ofon
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Harry Noyes
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Vincent Ebo’o Eyanga
- MINSANTE, Divisional Centre for Diseases, PNLTHA, Ministry of Public Health, Yaoundé, Cameroon
| | - Flobert Njiokou
- Laboratory of Molecular Biology, Department of Animal Biology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Mathurin Koffi
- Université Jean Lorougnon Guédé (UJLoG), UFR Environnement-Santé, Laboratoire des Interactions Hôte- Microorganismes-Environnement et Evolution (LIHME) Daloa, Côte d’Ivoire
| | - Pythagore Fogue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | | | - Annette MacLeod
- Wellcome Centre for Molecular Parasitology, University Place, Glasgow, United Kingdom
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, Kampala, Uganda
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
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Kanté ST, Melachio T, Ofon E, Njiokou F, Simo G. Detection of Wolbachia and different trypanosome species in Glossina palpalis palpalis populations from three sleeping sickness foci of southern Cameroon. Parasit Vectors 2018; 11:630. [PMID: 30541614 PMCID: PMC6292098 DOI: 10.1186/s13071-018-3229-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/23/2018] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND African trypanosomiases are caused by trypanosomes that are cyclically transmitted by tsetse. Investigations aiming to generate knowledge on the bacterial fauna of tsetse have revealed distinct symbiotic microorganisms. Furthermore, studies addressing the tripartite association between trypanosomes-tsetse-symbionts relationship have so far been contradictory. Most studies included Sodalis glossinudius and, consequently, the association involving Wolbachia is poorly understood. Understanding the vectorial competence of tsetse requires decrypting these tripartite associations. In this study, we identified Wolbachia and trypanosomes in Glossina palpalis palpalis from three human African trypanosomiasis (HAT) foci in southern Cameroon. METHODS Tsetse flies were captured with pyramidal traps in the Bipindi, Campo and Fontem HAT foci. After morphological identification, DNA was extracted from whole tsetse flies and Wolbachia and trypanosomes were identified by PCR using different trypanosome-specific primers and two Wolbachia-specific primers (Wolbachia surface protein and 16S rRNA genes). Statistical analyses were performed to compare the trypanosome and Wolbachia infection rates between villages and different foci and to look for an association between these microorganisms. RESULTS From a total of 2122 tsetse flies, 790 G. p. palpalis were analyzed. About 25.32% of flies hosted Wolbachia and 31.84% of non-teneral flies were infected by at least one trypanosome species. There was no significant difference between the global Wolbachia prevalence revealed by the two markers while some differences were observed between HAT foci. From 248 G. p. palpalis with trypanosome infections, 62.90% were with T. vivax, 34.68% with T. congolense forest, 16.13% with T. brucei (s.l.) and 2.42% with T. congolense savannah. Of all trypanosome-infected flies, 29.84% hosted Wolbachia and no association was observed between Wolbachia and trypanosome co-infections. CONCLUSIONS This study revealed differences in the prevalence of Wolbachia and trypanosomes in G. p. palpalis according to HAT foci. The use of only one marker has underestimated the prevalence of Wolbachia, thus more markers in subsequent studies may improve its detection. The presence of Wolbachia seems to have no impact on the establishment of trypanosomes in G. p. palpalis. The tripartite association between tsetse, Wolbachia and trypanosomes varies according to studied areas. Studies aiming to evaluate the genetic polymorphism of Wolbachia and its density in tsetse flies could help to better understand this association.
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Affiliation(s)
- Sartrien Tagueu Kanté
- Molecular Parasitology and Entomology Unit (MPEU), Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Trésor Melachio
- Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Elvis Ofon
- Molecular Parasitology and Entomology Unit (MPEU), Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Flobert Njiokou
- Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit (MPEU), Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
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Trypanosoma rangeli is phylogenetically closer to Old World trypanosomes than to Trypanosoma cruzi. Int J Parasitol 2018; 48:569-584. [PMID: 29544703 DOI: 10.1016/j.ijpara.2017.12.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/20/2017] [Accepted: 12/22/2017] [Indexed: 12/15/2022]
Abstract
Trypanosoma rangeli and Trypanosoma cruzi are generalist trypanosomes sharing a wide range of mammalian hosts; they are transmitted by triatomine bugs, and are the only trypanosomes infecting humans in the Neotropics. Their origins, phylogenetic relationships, and emergence as human parasites have long been subjects of interest. In the present study, taxon-rich analyses (20 trypanosome species from bats and terrestrial mammals) using ssrRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH), heat shock protein-70 (HSP70) and Spliced Leader RNA sequences, and multilocus phylogenetic analyses using 11 single copy genes from 15 selected trypanosomes, provide increased resolution of relationships between species and clades, strongly supporting two main sister lineages: lineage Schizotrypanum, comprising T. cruzi and bat-restricted trypanosomes, and Tra[Tve-Tco] formed by T. rangeli, Trypanosoma vespertilionis and Trypanosoma conorhini clades. Tve comprises European T. vespertilionis and African T. vespertilionis-like of bats and bat cimicids characterised in the present study and Trypanosoma sp. Hoch reported in monkeys and herein detected in bats. Tco included the triatomine-transmitted tropicopolitan T. conorhini from rats and the African NanDoum1 trypanosome of civet (carnivore). Consistent with their very close relationships, Tra[Tve-Tco] species shared highly similar Spliced Leader RNA structures that were highly divergent from those of Schizotrypanum. In a plausible evolutionary scenario, a bat trypanosome transmitted by cimicids gave origin to the deeply rooted Tra[Tve-Tco] and Schizotrypanum lineages, and bat trypanosomes of diverse genetic backgrounds jumped to new hosts. A long and independent evolutionary history of T. rangeli more related to Old World trypanosomes from bats, rats, monkeys and civets than to Schizotrypanum spp., and the adaptation of these distantly related trypanosomes to different niches of shared mammals and vectors, is consistent with the marked differences in transmission routes, life-cycles and host-parasite interactions, resulting in T. cruzi (but not T. rangeli) being pathogenic to humans.
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Büscher P, Bart JM, Boelaert M, Bucheton B, Cecchi G, Chitnis N, Courtin D, Figueiredo LM, Franco JR, Grébaut P, Hasker E, Ilboudo H, Jamonneau V, Koffi M, Lejon V, MacLeod A, Masumu J, Matovu E, Mattioli R, Noyes H, Picado A, Rock KS, Rotureau B, Simo G, Thévenon S, Trindade S, Truc P, Van Reet N. Do Cryptic Reservoirs Threaten Gambiense-Sleeping Sickness Elimination? Trends Parasitol 2018; 34:197-207. [PMID: 29396200 PMCID: PMC5840517 DOI: 10.1016/j.pt.2017.11.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/18/2017] [Accepted: 11/27/2017] [Indexed: 12/22/2022]
Abstract
Trypanosoma brucei gambiense causes human African trypanosomiasis (HAT). Between 1990 and 2015, almost 440000 cases were reported. Large-scale screening of populations at risk, drug donations, and efforts by national and international stakeholders have brought the epidemic under control with <2200 cases in 2016. The World Health Organization (WHO) has set the goals of gambiense-HAT elimination as a public health problem for 2020, and of interruption of transmission to humans for 2030. Latent human infections and possible animal reservoirs may challenge these goals. It remains largely unknown whether, and to what extend, they have an impact on gambiense-HAT transmission. We argue that a better understanding of the contribution of human and putative animal reservoirs to gambiense-HAT epidemiology is mandatory to inform elimination strategies.
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Affiliation(s)
- Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium.
| | - Jean-Mathieu Bart
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France; Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III, Calle Sinesio Delgado 4, 28029 Madrid, Spain
| | - Marleen Boelaert
- Department of Public Health, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Bruno Bucheton
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Giuliano Cecchi
- Sub-regional Office for Eastern Africa, Food and Agriculture Organization of the United Nations, CMC Road, Bole Sub City, Kebele 12/13, P O Box 5536, Addis Ababa, Ethiopia
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, Postfach, 4002 Basel, Switzerland; University of Basel, Switzerland
| | - David Courtin
- Université Paris Descartes, Institut de Recherche pour le Développement, Unité MERIT, Mère et enfant face aux infections tropicales, 4 avenue de l'Observatoire, 75006 Paris, France
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Prof Egas Moniz, 1649-028 Lisboa, Portugal
| | - José-Ramon Franco
- Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, World Health Organization, Via Appia 20, 1202 Geneva, Switzerland
| | - Pascal Grébaut
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Epco Hasker
- Department of Public Health, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Hamidou Ilboudo
- Institut de Recherche sur les Bases Biologiques de la Lutte Intégrée, Centre International de Recherche-Développement sur l'Élevage en zone Subhumide, 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | | | - Mathurin Koffi
- Université Jean Lorougnon Guédé, BP 150 Daloa, Côte d'Ivoire
| | - Veerle Lejon
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Annette MacLeod
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Henry Wellcome Building, 464 Bearsden Road, Glasgow, UK
| | - Justin Masumu
- Département de Parasitologie, Institut National de Recherche Biomédicale, Avenue de la Démocratie, BP 1197 Kinshasa 1, République Démocratique du Congo
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P O Box 7062 Kampala, Uganda
| | - Raffaele Mattioli
- Animal Production and Health Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00153 Rome, Italy
| | - Harry Noyes
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Albert Picado
- Foundation for Innovative New Diagnostics, 9 Chemin des Mines, 1202 Geneva, Switzerland
| | - Kat S Rock
- Zeeman Institute for Systems Biology & Infectious Disease Research, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201 and Department of Parasites and Insect Vectors, Institut Pasteur, 25, rue du Docteur Roux, 75015 Paris, France
| | - Gustave Simo
- Department of Biochemistry, Faculty of Science, University of Dschang, P O Box 67 Dschang, Cameroon
| | - Sophie Thévenon
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France; CIRAD, INTERTRYP, Montpellier, France
| | - Sandra Trindade
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Prof Egas Moniz, 1649-028 Lisboa, Portugal
| | - Philippe Truc
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Nick Van Reet
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
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Ngomtcho SCH, Weber JS, Ngo Bum E, Gbem TT, Kelm S, Achukwi MD. Molecular screening of tsetse flies and cattle reveal different Trypanosoma species including T. grayi and T. theileri in northern Cameroon. Parasit Vectors 2017; 10:631. [PMID: 29287598 PMCID: PMC5747950 DOI: 10.1186/s13071-017-2540-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 11/15/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND African trypanosomes are mainly transmitted through the bite of tsetse flies (Glossina spp.). The present study investigated the occurrence of pathogenic trypanosomes in tsetse flies and cattle in tsetse fly-infested areas of Northern Cameroon. RESULTS Trypanosomes were identified using nested polymerase chain reaction (PCR) analysis of internal transcribed spacer 1 (ITS1) region, both by size estimation and sequencing of PCR products. Apparent density indices recorded in Gamba and Dodeo were 3.1 and 3.6 tsetse flies per trap and day, respectively. Trypanosoma prevalence infection rate for the tsetse fly gut (40%) and proboscis (19%) were recorded. Among the flies where trypanosomes were detected in the gut, 41.7% were positive for T. congolense and 14.6% for T. brucei ssp., whereas in the proboscis 36% harboured T. congolense and 62% contained T. vivax. T. grayi was highly prevalent in tsetse fly gut (58%). The most common mixed infections were the combination of T. congolense and T. grayi. Trypanosome prevalence rate in cattle blood was 6%. Among these, T. vivax represented 26%, T. congolense 35%, T. brucei ssp. 17% and T. theileri 17% of the infections. Surprisingly, in one case T. grayi was found in cattle. The mean packed cell volume (PCV) of cattle positive for trypanosomes was significantly lower (24.1 ± 5.6%; P < 0.05) than that of cattle in which trypanosomes were not detected (27.1 ± 4.9%). Interestingly, the occurrence of T. theileri or T. grayi DNA in cattle also correlated with low PCV at pathological levels. CONCLUSION This molecular epidemiological study of Trypanosoma species in Northern Cameroon revealed active foci of trypanosomes in Dodeo and Gamba. These findings are relevant in assessing the status of trypanosomosis in these regions and will serve as a guide for setting the priorities of the government in the control of the disease.
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Affiliation(s)
- Sen Claudine Henriette Ngomtcho
- Department of Biological Sciences, University Ngaoundéré, P.O. Box 454, Ngaoundéré, Cameroon
- Ministry of Public Health, Regional Hospital of Ngaoundéré, Ngaoundéré, Cameroon
- Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University Bremen, 28334 Bremen, Germany
| | - Judith Sophie Weber
- Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University Bremen, 28334 Bremen, Germany
| | - Elisabeth Ngo Bum
- Department of Biological Sciences, University Ngaoundéré, P.O. Box 454, Ngaoundéré, Cameroon
| | - Thaddeus Terlumun Gbem
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria
- Department of Biology, Ahmadu Bello University, Zaria, Nigeria
| | - Sørge Kelm
- Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University Bremen, 28334 Bremen, Germany
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N’Djetchi MK, Ilboudo H, Koffi M, Kaboré J, Kaboré JW, Kaba D, Courtin F, Coulibaly B, Fauret P, Kouakou L, Ravel S, Deborggraeve S, Solano P, De Meeûs T, Bucheton B, Jamonneau V. The study of trypanosome species circulating in domestic animals in two human African trypanosomiasis foci of Côte d'Ivoire identifies pigs and cattle as potential reservoirs of Trypanosoma brucei gambiense. PLoS Negl Trop Dis 2017; 11:e0005993. [PMID: 29045405 PMCID: PMC5662240 DOI: 10.1371/journal.pntd.0005993] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 10/30/2017] [Accepted: 09/25/2017] [Indexed: 01/14/2023] Open
Abstract
Background Important control efforts have led to a significant reduction of the prevalence of human African trypanosomiasis (HAT) in Côte d’Ivoire, but the disease is still present in several foci. The existence of an animal reservoir of Trypanosoma brucei gambiense may explain disease persistence in these foci where animal breeding is an important source of income but where the prevalence of animal African trypanosomiasis (AAT) is unknown. The aim of this study was to identify the trypanosome species circulating in domestic animals in both Bonon and Sinfra HAT endemic foci. Methodology/Principal findings 552 domestic animals (goats, pigs, cattle and sheep) were included. Blood samples were tested for trypanosomes by microscopic observation, species-specific PCR for T. brucei sl, T. congolense, T. vivax and subspecies-specific PCR for T. b. gambiense and T. b. gambiense immune trypanolysis (TL). Infection rates varied significantly between animal species and were by far the highest in pigs (30%). T. brucei s.l was the most prevalent trypanosome species (13.7%) followed by T. congolense. No T. b. gambiense was identified by PCR while high TL positivity rates were observed using T. b. gambiense specific variants (up to 27.6% for pigs in the Bonon focus). Conclusion This study shows that domestic animals are highly infected by trypanosomes in the studied foci. This was particularly true for pigs, possibly due to a higher exposure of these animals to tsetse flies. Whereas T. brucei s.l. was the most prevalent species, discordant results were obtained between PCR and TL regarding T. b. gambiense identification. It is therefore crucial to develop better tools to study the epidemiological role of potential animal reservoir for T. b. gambiense. Our study illustrates the importance of “one health” approaches to reach HAT elimination and contribute to AAT control in the studied foci. In Africa, significant efforts to control human African trypanosomiasis (HAT) over the past three decades have drastically reduced the prevalence of the disease and elimination seems today an achievable goal. However, potential animal reservoirs of Trypanosoma brucei gambiense may compromise this ambitious objective. In the Bonon and Sinfra HAT endemic foci in Côte d’Ivoire, no recent data are available about the prevalence of animal African trypanosomiasis (AAT). The aim of this study was to identify trypanosomes circulating in domestic animals in these two HAT foci using serological, parasitological and molecular tools. We showed that T. brucei s.l. and T. congolense were the most prevalent trypanosome species and that pigs and cattle were the most infected animals. Discordant results were observed between the T. b. gambiense specific molecular and serological tools and the presence of an animal reservoir for T. b. gambiense remains unclear. Nevertheless, improved control strategies can be proposed based on this study to reach HAT elimination and contribute to AAT control in the study areas.
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Affiliation(s)
- Martial Kassi N’Djetchi
- Laboratoire des Interactions Hôte-Microorganisme-Environnement et Evolution, Unité de Formation et de Recherche Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Hamidou Ilboudo
- Unité de recherches sur les bases biologiques de la lutte intégrée, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Mathurin Koffi
- Laboratoire des Interactions Hôte-Microorganisme-Environnement et Evolution, Unité de Formation et de Recherche Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Jacques Kaboré
- Unité de recherches sur les bases biologiques de la lutte intégrée, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
- Unité de Formation et de Recherche Sciences et Techniques, Université Nazi Boni, Bobo-Dioulasso, Burkina-Faso
| | - Justin Windingoudi Kaboré
- Unité de recherches sur les bases biologiques de la lutte intégrée, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Dramane Kaba
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Fabrice Courtin
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Bamoro Coulibaly
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Pierre Fauret
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Lingué Kouakou
- Programme National d’Elimination de la Trypanosomose Humaine Africaine, Ministère de la Santé et de l’Hygiène Publique, Abidjan, Côte d’Ivoire
| | - Sophie Ravel
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Stijn Deborggraeve
- Biomedical Sciences Department, Institute of Tropical Medicine, Antwerp, Belgium
| | - Philippe Solano
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Thierry De Meeûs
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Bruno Bucheton
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Vincent Jamonneau
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement (IRD), Montpellier, France
- * E-mail:
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Jacob F, Melachio TT, Njitchouang GR, Gimonneau G, Njiokou F, Abate L, Christen R, Reveillaud J, Geiger A. Intestinal Bacterial Communities of Trypanosome-Infected and Uninfected Glossina palpalis palpalis from Three Human African Trypanomiasis Foci in Cameroon. Front Microbiol 2017; 8:1464. [PMID: 28824591 PMCID: PMC5541443 DOI: 10.3389/fmicb.2017.01464] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/20/2017] [Indexed: 11/27/2022] Open
Abstract
Glossina sp. the tsetse fly that transmits trypanosomes causing the Human or the Animal African Trypanosomiasis (HAT or AAT) can harbor symbiotic bacteria that are known to play a crucial role in the fly's vector competence. We hypothesized that other bacteria could be present, and that some of them could also influence the fly's vector competence. In this context the objectives of our work were: (a) to characterize the bacteria that compose the G. palpalis palpalis midgut bacteriome, (b) to evidence possible bacterial community differences between trypanosome-infected and non-infected fly individuals from a given AAT and HAT focus or from different foci using barcoded Illumina sequencing of the hypervariable V3-V4 region of the 16S rRNA gene. Forty G. p. palpalis flies, either infected by Trypanosoma congolense or uninfected were sampled from three trypanosomiasis foci in Cameroon. A total of 143 OTUs were detected in the midgut samples. Most taxa were identified at the genus level, nearly 50% at the species level; they belonged to 83 genera principally within the phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Prominent representatives included Wigglesworthia (the fly's obligate symbiont), Serratia, and Enterobacter hormaechei. Wolbachia was identified for the first time in G. p. palpalis. The average number of bacterial species per tsetse sample was not significantly different regarding the fly infection status, and the hierarchical analysis based on the differences in bacterial community structure did not provide a clear clustering between infected and non-infected flies. Finally, the most important result was the evidence of the overall very large diversity of intestinal bacteria which, except for Wigglesworthia, were unevenly distributed over the sampled flies regardless of their geographic origin and their trypanosome infection status.
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Affiliation(s)
- Franck Jacob
- UMR INTERTRYP, Institut de Recherche pour le Développement-CIRAD, CIRAD TA A-17/GMontpellier, France
| | - Trésor T Melachio
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1Yaounde, Cameroon
| | - Guy R Njitchouang
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1Yaounde, Cameroon
| | - Geoffrey Gimonneau
- UMR INTERTRYP, Institut de Recherche pour le Développement-CIRAD, CIRAD TA A-17/GMontpellier, France
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1Yaounde, Cameroon
| | - Luc Abate
- UMR MIVEGEC, Institut de Recherche pour le Développement 224-Centre National de la Recherche Scientifique 5290Montpellier, France
| | - Richard Christen
- UMR 7138, Systématique Adaptation Evolution, Université de Nice-Sophia AntipolisNice, France
| | - Julie Reveillaud
- Institut National de la Recherche Agronomique, UMR 1309 ASTREMontpellier, France.,CIRAD, UMR ASTREMontpellier, France
| | - Anne Geiger
- UMR INTERTRYP, Institut de Recherche pour le Développement-CIRAD, CIRAD TA A-17/GMontpellier, France
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Tsagmo Ngoune JM, Njiokou F, Loriod B, Kame-Ngasse G, Fernandez-Nunez N, Rioualen C, van Helden J, Geiger A. Transcriptional Profiling of Midguts Prepared from Trypanosoma/T. congolense-Positive Glossina palpalis palpalis Collected from Two Distinct Cameroonian Foci: Coordinated Signatures of the Midguts' Remodeling As T. congolense-Supportive Niches. Front Immunol 2017; 8:876. [PMID: 28804485 PMCID: PMC5532377 DOI: 10.3389/fimmu.2017.00876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/10/2017] [Indexed: 12/11/2022] Open
Abstract
Our previous transcriptomic analysis of Glossina palpalis gambiensis experimentally infected or not with Trypanosoma brucei gambiense aimed to detect differentially expressed genes (DEGs) associated with infection. Specifically, we selected candidate genes governing tsetse fly vector competence that could be used in the context of an anti-vector strategy, to control human and/or animal trypanosomiasis. The present study aimed to verify whether gene expression in field tsetse flies (G. p. palpalis) is modified in response to natural infection by trypanosomes (T. congolense), as reported when insectary-raised flies (G. p. gambiensis) are experimentally infected with T. b. gambiense. This was achieved using the RNA-seq approach, which identified 524 DEGs in infected vs. non-infected tsetse flies, including 285 downregulated genes and 239 upregulated genes (identified using DESeq2). Several of these genes were highly differentially expressed, with log2 fold change values in the vicinity of either +40 or −40. Downregulated genes were primarily involved in transcription/translation processes, whereas encoded upregulated genes governed amino acid and nucleotide biosynthesis pathways. The BioCyc metabolic pathways associated with infection also revealed that downregulated genes were mainly involved in fly immunity processes. Importantly, our study demonstrates that data on the molecular cross-talk between the host and the parasite (as well as the always present fly microbiome) recorded from an experimental biological model has a counterpart in field flies, which in turn validates the use of experimental host/parasite couples.
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Affiliation(s)
- Jean M Tsagmo Ngoune
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.,UMR 177, IRD-CIRAD, CIRAD TA A-17/G, Campus International de Baillarguet, Montpellier, France
| | - Flobert Njiokou
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Béatrice Loriod
- Aix-Marseille University, INSERM, TAGC, Technological Advances for Genomics and Clinics, UMR S 1090, Marseille, France
| | | | - Nicolas Fernandez-Nunez
- Aix-Marseille University, INSERM, TAGC, Technological Advances for Genomics and Clinics, UMR S 1090, Marseille, France
| | - Claire Rioualen
- Aix-Marseille University, INSERM, TAGC, Technological Advances for Genomics and Clinics, UMR S 1090, Marseille, France
| | - Jacques van Helden
- Aix-Marseille University, INSERM, TAGC, Technological Advances for Genomics and Clinics, UMR S 1090, Marseille, France
| | - Anne Geiger
- UMR 177, IRD-CIRAD, CIRAD TA A-17/G, Campus International de Baillarguet, Montpellier, France
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Franco JR, Cecchi G, Priotto G, Paone M, Diarra A, Grout L, Mattioli RC, Argaw D. Monitoring the elimination of human African trypanosomiasis: Update to 2014. PLoS Negl Trop Dis 2017; 11:e0005585. [PMID: 28531222 PMCID: PMC5456402 DOI: 10.1371/journal.pntd.0005585] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 06/02/2017] [Accepted: 04/20/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The World Health Organization (WHO) has targeted the elimination of Human African trypanosomiasis (HAT) 'as a public health problem' by 2020. The selected indicators of elimination should be monitored every two years, and we provide here a comprehensive update to 2014. The monitoring system is underpinned by the Atlas of HAT. RESULTS With 3,797 reported cases in 2014, the corresponding milestone (5,000 cases) was surpassed, and the 2020 global target of 'fewer than 2,000 reported cases per year' seems within reach. The areas where HAT is still a public health problem (i.e. > 1 HAT reported case per 10,000 people per year) have halved in less than a decade, and in 2014 they corresponded to 350 thousand km2. The number and potential coverage of fixed health facilities offering diagnosis and treatment for HAT has expanded, and approximately 1,000 are now operating in 23 endemic countries. The observed trends are supported by sustained surveillance and improved reporting. DISCUSSION HAT elimination appears to be on track. For gambiense HAT, still accounting for the vast majority of reported cases, progress continues unabated in a context of sustained intensity of screening activities. For rhodesiense HAT, a slow-down was observed in the last few years. Looking beyond the 2020 target, innovative tools and approaches will be increasingly needed. Coordination, through the WHO network for HAT elimination, will remain crucial to overcome the foreseeable and unforeseeable challenges that an elimination process will inevitably pose.
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Affiliation(s)
- José R. Franco
- World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Sub-regional Office for Eastern Africa, Addis Ababa, Ethiopia
| | - Gerardo Priotto
- World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Abdoulaye Diarra
- World Health Organization, Regional Office for Africa, Communicable Disease Unit, Brazzaville, Congo
| | - Lise Grout
- World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
| | - Raffaele C. Mattioli
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Daniel Argaw
- World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
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Wicker LV, Canfield PJ, Higgins DP. Potential Pathogens Reported in Species of the Family Viverridae and Their Implications for Human and Animal Health. Zoonoses Public Health 2017; 64:75-93. [PMID: 27359248 PMCID: PMC7165938 DOI: 10.1111/zph.12290] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Indexed: 12/28/2022]
Abstract
The Viverridae is a family of nocturnal carnivores including civets, genets and African linsangs. While a list of known organisms isolated from a species is an essential tool for population management, this review represents the first attempt to collate published reports of organisms isolated from viverrids. A wide range of organisms, including 11 viruses, eight bacterial species, one internal arthropod species, representatives from eight genera of protozoan, 21 genera of nematode, seven genera of cestode, eight genera of trematode and six genera of external arthropod (mites, ticks and louse), have been reported in literature spanning over a century of research. Many of these are capable of infecting multiple hosts, including humans. This is of concern given the anthropogenic factors that bring humans and domestic species into close contact with viverrids, facilitating transmission and spillover of organisms between groups. These factors include trade in viverrids for human consumption, captive management in zoos, rescue centres or on commercial breeding farms, and the increasing overlap of free-ranging viverrid distribution and human settlement.
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Affiliation(s)
- L. V. Wicker
- Faculty of Veterinary ScienceThe University of SydneySydneyNSW2006Australia
- Save Vietnam's WildlifeCuc Phuong National ParkNinh BinhVietnam
| | - P. J. Canfield
- Faculty of Veterinary ScienceThe University of SydneySydneyNSW2006Australia
| | - D. P. Higgins
- Faculty of Veterinary ScienceThe University of SydneySydneyNSW2006Australia
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Grébaut P, Girardin K, Fédérico V, Bousquet F. Simulating the elimination of sleeping sickness with an agent-based model. Parasite 2016; 23:63. [PMID: 28008825 PMCID: PMC5188770 DOI: 10.1051/parasite/2016066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/29/2016] [Indexed: 11/14/2022] Open
Abstract
Although Human African Trypanosomiasis is largely considered to be in the process of extinction today, the persistence of human and animal reservoirs, as well as the vector, necessitates a laborious elimination process. In this context, modeling could be an effective tool to evaluate the ability of different public health interventions to control the disease. Using the Cormas® system, we developed HATSim, an agent-based model capable of simulating the possible endemic evolutions of sleeping sickness and the ability of National Control Programs to eliminate the disease. This model takes into account the analysis of epidemiological, entomological, and ecological data from field studies conducted during the last decade, making it possible to predict the evolution of the disease within this area over a 5-year span. In this article, we first present HATSim according to the Overview, Design concepts, and Details (ODD) protocol that is classically used to describe agent-based models, then, in a second part, we present predictive results concerning the evolution of Human African Trypanosomiasis in the village of Lambi (Cameroon), in order to illustrate the interest of such a tool. Our results are consistent with what was observed in the field by the Cameroonian National Control Program (CNCP). Our simulations also revealed that regular screening can be sufficient, although vector control applied to all areas with human activities could be significantly more efficient. Our results indicate that the current model can already help decision-makers in planning the elimination of the disease in foci.
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Affiliation(s)
- Pascal Grébaut
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UMR177 IRD/CIRAD INTERTRYP, TA A17 G, Campus International de Baillarguet 34398
Montpellier Cedex 5 France
| | - Killian Girardin
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Faculté des Sciences, Université Montpellier 2 Place Eugène Bataillon 34095
Montpellier Cedex 5 France
| | | | - François Bousquet
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UR GREEN, CIRAD, Campus International de Baillarguet 34398
Montpellier Cedex 5 France
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Odongo S, Delespaux V, Ngotho M, Bekkele SM, Magez S. Comparative evaluation of the nested ITS PCR against the 18S PCR-RFLP in a survey of bovine trypanosomiasis in Kwale County, Kenya. J Vet Diagn Invest 2016; 28:589-94. [PMID: 27423733 DOI: 10.1177/1040638716659100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We compared the nested internal transcribed spacer (ITS) PCR and the 18S PCR-RFLP (restriction-fragment length polymorphism) pan-trypanosome assays in a cross-sectional survey of bovine trypanosomiasis in 358 cattle in Kwale County, Kenya. The prevalence of trypanosomiasis as determined by the nested ITS PCR was 19.6% (70/358) and by 18S PCR-RFLP was 16.8% (60/358). Of the pathogenic trypanosomes detected, the prevalence of Trypanosoma congolense and Trypanosoma vivax was greater than that of Trypanosoma simiae The nested ITS PCR detected 83 parasite events, whereas the 18S PCR-RFLP detected 64; however, overall frequencies of infections and the parasite events detected did not differ between the assays (χ(2) = 0.8, df = 1, p > 0.05 and χ(2) = 2.5, df = 1, p > 0.05, respectively). The kappa statistic (0.8) showed good agreement between the tests. The nested ITS PCR and the 18S PCR-RFLP had comparable sensitivity, although the nested ITS PCR was better at detecting mixed infections (χ(2) = 5.4, df = 1, p < 0.05).
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Affiliation(s)
- Steven Odongo
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium (Odongo, Bekkele, Magez)Structural Biology Research Center (SBRC), Vlaams Instituut voor Biotechnologie (VIB), Brussels, Belgium (Odongo, Bekkele, Magez)Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, Kampala, Uganda (Odongo)Interuniversity Programme Molecular Biology, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (Delespaux)Department of Animal Health and Production, Mount Kenya University, Thika, Kenya (Ngotho)
| | - Vincent Delespaux
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium (Odongo, Bekkele, Magez)Structural Biology Research Center (SBRC), Vlaams Instituut voor Biotechnologie (VIB), Brussels, Belgium (Odongo, Bekkele, Magez)Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, Kampala, Uganda (Odongo)Interuniversity Programme Molecular Biology, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (Delespaux)Department of Animal Health and Production, Mount Kenya University, Thika, Kenya (Ngotho)
| | - Maina Ngotho
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium (Odongo, Bekkele, Magez)Structural Biology Research Center (SBRC), Vlaams Instituut voor Biotechnologie (VIB), Brussels, Belgium (Odongo, Bekkele, Magez)Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, Kampala, Uganda (Odongo)Interuniversity Programme Molecular Biology, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (Delespaux)Department of Animal Health and Production, Mount Kenya University, Thika, Kenya (Ngotho)
| | - Serkalem Mindaye Bekkele
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium (Odongo, Bekkele, Magez)Structural Biology Research Center (SBRC), Vlaams Instituut voor Biotechnologie (VIB), Brussels, Belgium (Odongo, Bekkele, Magez)Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, Kampala, Uganda (Odongo)Interuniversity Programme Molecular Biology, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (Delespaux)Department of Animal Health and Production, Mount Kenya University, Thika, Kenya (Ngotho)
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium (Odongo, Bekkele, Magez)Structural Biology Research Center (SBRC), Vlaams Instituut voor Biotechnologie (VIB), Brussels, Belgium (Odongo, Bekkele, Magez)Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, Kampala, Uganda (Odongo)Interuniversity Programme Molecular Biology, Faculty of Science and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium (Delespaux)Department of Animal Health and Production, Mount Kenya University, Thika, Kenya (Ngotho)
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Khatri-Chhetri R, Wang HC, Chen CC, Shih HC, Liao HC, Sun CM, Khatri-Chhetri N, Wu HY, Pei KJC. Surveillance of ticks and associated pathogens in free-ranging Formosan pangolins (Manis pentadactyla pentadactyla). Ticks Tick Borne Dis 2016; 7:1238-1244. [PMID: 27426438 DOI: 10.1016/j.ttbdis.2016.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 07/09/2016] [Accepted: 07/09/2016] [Indexed: 10/21/2022]
Abstract
Chinese pangolins are critically endangered insectivorous mammals distributed in several South and Southeast Asian countries. In recent years, there has been an increase in spread of tick-borne diseases in both humans and animals worldwide. Currently, limited information is available on ticks and associated pathogens infesting pangolins. The objective of the present study was to survey ticks and associated pathogens in the Formosan pangolin population in Southeastern Taiwan. Free-ranging Formosan pangolins captured during ecological survey were examined for the presence of ticks. DNA extracted from these ticks was used to identify the tick species and also to detect the tick-borne pathogens, by molecular methods. In the present study, we found 25% (13/52) of pangolins captured during 2012-2014 infested with ixodid ticks. A total of 21 ticks were collected and 3 species were identified: Haemaphysalis hystricis (14/21), Haemaphysalis formosensis (2/21) and Amblyomma testudinarium (5/21). We detected four different tick-borne pathogens, where one was identical to Anaplasma sp. strain An.H1446 while others showed close resemblance to Rickettsia conorii subsp. caspia A-167, Ehrlichia sp. TC251-2 and Cytauxzoon spp., respectively. The present study is the first survey of ticks infesting the free-ranging Chinese pangolins and pathogens harboured by these ticks. This information is important to know the diversity of ticks and tick-borne pathogens, and its conservation significance to pangolins and other sympatric wildlife. Important future step should be regular surveillance of ticks and tick-borne diseases at human-domestic animals-wildlife interface, which can provide a useful insight into the dynamics of these pathogens and can help control and prevent outbreak of zoonoses.
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Affiliation(s)
- Rupak Khatri-Chhetri
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Taiwan
| | - Hsi-Chieh Wang
- Diagnostic and Vaccine Development, Centers for Disease Control, Taiwan
| | - Chen-Chih Chen
- Institute of Wildlife Conservation, College of Veterinary Medicine, National Pingtung University of Science and Technology, Taiwan
| | - Han-Chun Shih
- Diagnostic and Vaccine Development, Centers for Disease Control, Taiwan
| | - Hsien-Chun Liao
- Diagnostic and Vaccine Development, Centers for Disease Control, Taiwan
| | - Ching-Min Sun
- Institute of Bioresources, College of Agriculture, National Pingtung University of Science and Technology, Taiwan
| | - Nabin Khatri-Chhetri
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Taiwan
| | - Hung-Yi Wu
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Taiwan.
| | - Kurtis Jai-Chyi Pei
- Institute of Wildlife Conservation, College of Veterinary Medicine, National Pingtung University of Science and Technology, Taiwan; Pingtung Rescue Center for Endangered Wild Animals, National Pingtung University of Science and Technology, Taiwan.
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Wamwiri FN, Changasi RE. Tsetse Flies (Glossina) as Vectors of Human African Trypanosomiasis: A Review. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6201350. [PMID: 27034944 PMCID: PMC4789378 DOI: 10.1155/2016/6201350] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/02/2016] [Accepted: 02/04/2016] [Indexed: 11/18/2022]
Abstract
Human African Trypanosomiasis (HAT) transmitted by the tsetse fly continues to be a public health issue, despite more than a century of research. There are two types of the disease, the chronic gambiense and the acute rhodesiense-HAT. Fly abundance and distribution have been affected by changes in land-use patterns and climate. However, disease transmission still continues. Here, we review some aspects of HAT ecoepidemiology in the context of altered infestation patterns and maintenance of the transmission cycle as well as emerging options in disease and vector control.
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Affiliation(s)
- Florence Njeri Wamwiri
- Kenya Agricultural and Livestock Research Organisation, Biotechnology Research Institute, P.O. Box 362, Muguga 00902, Kenya
| | - Robert Emojong Changasi
- Kenya Agricultural and Livestock Research Organisation, Biotechnology Research Institute, P.O. Box 362, Muguga 00902, Kenya
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Biteau N, Asencio C, Izotte J, Rousseau B, Fèvre M, Pillay D, Baltz T. Trypanosoma brucei gambiense Infections in Mice Lead to Tropism to the Reproductive Organs, and Horizontal and Vertical Transmission. PLoS Negl Trop Dis 2016; 10:e0004350. [PMID: 26735855 PMCID: PMC4703293 DOI: 10.1371/journal.pntd.0004350] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/11/2015] [Indexed: 01/06/2023] Open
Abstract
Trypanosoma brucei gambiense, transmitted by the tsetse fly, is the main causative agent of Human African trypanosomosis in West Africa and poses a significant health risk to 70 million people. Disease progression varies depending on host immunity, but usually begins with a haemo-lymphatic phase, followed by parasite invasion of the central nervous system. In the current study, the tropism of T. b. gambiense 1135, causing a low level chronic ‘silent’ infection, was monitored in a murine model using bioluminescence imaging and PCR. A tropism to the reproductive organs, in addition to the central nervous system, after 12–18 months of infection was observed. Bioluminescent analysis of healthy females crossed with infected males showed that 50%, 62.5% and 37.5% of the female mice were subsequently positive for parasites in their ovaries, uteri and brain respectively. Although PCR confirmed the presence of parasites in the uterus of one of these mice, the blood of all mice was negative by PCR and LAMP. Subsequently, bioluminescent imaging of the offspring of infected female mice crossed with healthy males indicated parasites were present in the reproductive organs of both male (80%) and female (60%) offspring. These findings imply that transmission of T. b. gambiense 1135 occurs horizontally, most probably via sexual contact, and vertically in a murine model, which raises the possibility of a similar transmission in humans. This has wide reaching implications. Firstly, the observations made in this study are likely to be valid for wild animals acting as a reservoir for T. b. gambiense. Also, the reproductive organs may act as a refuge for parasites during drug treatment in a similar manner to the central nervous system. This could leave patients at risk of a relapse, ultimately allowing them to act as a reservoir for subsequent transmission by tsetse and possibly, horizontally and vertically. Human African trypanosomosis (HAT) caused by Trypanosoma brucei gambiense is a serious disease threatening 70 million people in West Africa. The parasite is transmitted by the tsetse fly, and initially multiplies in the bloodstream of the mammalian host, before progressing to the central nervous system. Using a strain of T. b. gambiense transfected with a gene for luminescent detection that causes a chronic infection with very low parasitaemia, we found that the parasite is capable of entering the reproductive organs of both male and female mice. Subsequently, crossing infected male mice with healthy females resulted in some female mice becoming infected. Furthermore, female mice infected directly with T. b. gambiense parasites and crossed with healthy males, produced offspring which were also shown to be positive for parasites. These experiments demonstrated that T. b. gambiense 1135 is transmitted both horizontally, most probably by sexual contact, and vertically in mice. If these alternate modes of transmission are analogous to the situation in humans, this has drastic implications for future control measures of HAT as parasites may avoid the immune system and treatment by accumulating in the reproductive organs as well as the CNS.
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Affiliation(s)
- Nicolas Biteau
- Microbiologie Fondamentale et Pathogénicité, UMR 5234, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France
| | - Corinne Asencio
- Microbiologie Fondamentale et Pathogénicité, UMR 5234, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France
| | - Julien Izotte
- Microbiologie Fondamentale et Pathogénicité, UMR 5234, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France
| | | | - Muriel Fèvre
- Animalerie A2, Université de Bordeaux, Bordeaux, France
| | - Davita Pillay
- Microbiologie Fondamentale et Pathogénicité, UMR 5234, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France
- * E-mail:
| | - Théo Baltz
- Microbiologie Fondamentale et Pathogénicité, UMR 5234, Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Bordeaux, France
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Simo G, Rayaisse JB. Challenges facing the elimination of sleeping sickness in west and central Africa: sustainable control of animal trypanosomiasis as an indispensable approach to achieve the goal. Parasit Vectors 2015; 8:640. [PMID: 26671582 PMCID: PMC4681034 DOI: 10.1186/s13071-015-1254-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/10/2015] [Indexed: 11/10/2022] Open
Abstract
African trypanosomiases are infectious diseases caused by trypanosomes. African animal trypanosomiasis (AAT) remains an important threat for livestock production in some affected areas whereas human African trypanosomiasis (HAT) is targeted for elimination in 2020. In West and Central Africa, it has been shown that the parasites causing these diseases can coexist in the same tsetse fly or the same animal. In such complex settings, the control of these diseases must be put in the general context of trypanosomiasis control or "one health" concept where the coordination of control operations will be beneficial for both diseases. In this context, implementing control activities on AAT will help to sustain HAT control. It will also have a positive impact on animal health and economic development of the regions. The training of inhabitants on how to implement and sustain vector control tools will enable a long-term sustainability of control operations that will lead to the elimination of HAT and AAT.
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Affiliation(s)
- Gustave Simo
- Department of Biochemistry, Molecular Parasitology and Entomology Unit, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon.
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45
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Rock KS, Torr SJ, Lumbala C, Keeling MJ. Quantitative evaluation of the strategy to eliminate human African trypanosomiasis in the Democratic Republic of Congo. Parasit Vectors 2015; 8:532. [PMID: 26490248 PMCID: PMC4618948 DOI: 10.1186/s13071-015-1131-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/02/2015] [Indexed: 12/03/2022] Open
Abstract
Background The virulent vector-borne disease, Gambian human African trypanosomiasis (HAT), is one of several diseases targeted for elimination by the World Health Organization. This article utilises human case data from a high-endemicity region of the Democratic Republic of Congo in conjunction with a suite of novel mechanistic mathematical models to address the effectiveness of on-going active screening and treatment programmes and compute the likely time to elimination as a public health problem (i.e. <1 case per 10,000 per year). Methods The model variants address uncertainties surrounding transmission of HAT infection including heterogeneous risk of exposure to tsetse bites, non-participation of certain groups during active screening campaigns and potential animal reservoirs of infection. Results Model fitting indicates that variation in human risk of tsetse bites and participation in active screening play a key role in transmission of this disease, whilst the existence of animal reservoirs remains unclear. Active screening campaigns in this region are calculated to have been effective, reducing the incidence of new human infections by 52–53 % over a 15-year period (1998–2012). However, projections of disease dynamics in this region indicate that the elimination goal may not be met until later this century (2059–2092) under the current intervention strategy. Conclusions Improvements to active detection, such as screening those who have not previously participated and raising overall screening levels, as well as beginning widespread vector control in the area have the potential to ensure successful and timely elimination. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1131-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kat S Rock
- Life Sciences, Warwick University, Coventry, CV4 7AL, UK. .,WIDER, Warwick University, Coventry, CV4 7AL, UK.
| | - Steve J Torr
- WIDER, Warwick University, Coventry, CV4 7AL, UK.,Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Crispin Lumbala
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of Congo
| | - Matt J Keeling
- Life Sciences, Warwick University, Coventry, CV4 7AL, UK.,WIDER, Warwick University, Coventry, CV4 7AL, UK.,Mathematics Institute, Warwick University, Coventry, CV4 7AL, UK
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46
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Simo G, Fongho P, Farikou O, Ndjeuto-Tchouli PIN, Tchouomene-Labou J, Njiokou F, Asonganyi T. Trypanosome infection rates in tsetse flies in the "silent" sleeping sickness focus of Bafia in the Centre Region in Cameroon. Parasit Vectors 2015; 8:528. [PMID: 26458386 PMCID: PMC4603914 DOI: 10.1186/s13071-015-1156-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 10/07/2015] [Indexed: 11/27/2022] Open
Abstract
Background The Bafia sleeping sickness focus of Cameroon is considered as “silent” with no case reported for about 20 years despite medical surveys performed during the last decades. In this focus, all epidemiological factors that can contribute to trypanosomes transmission are present. To update our knowledge on the current risks of Human and Animal African trypanosomiases, different trypanosome species were identified in midguts of tsetse flies captured in the Bafia focus. Methods Tsetse flies were trapped using pyramidal traps. Each tsetse fly was identified and live flies were dissected and their midguts collected. DNA was extracted from each midgut and thereafter, blood meals and different trypanosome species were identified with molecular tools. The biological data were transported onto maps in order to have their distribution. Results Of the 98 traps set up, 461 Glossina palpalis palpalis were captured; 322 (69.8 %) tsetse flies were dissected and 49 (15.2 %) teneral flies identified. The average apparent density of tsetse flies per day was 1.18. Of the 35 (10.9 %) blood meals collected, 82 % were taken on pigs and 17.6 % on humans. Eighty two (25.5 %) trypanosome infections were identified: 56 (17.4 %) T. congolense savannah, 17 (5.3 %) T. congolense forest, 5 (1.6 %) T. vivax and 4 (1.2 %) T. brucei s.l. No infection of T. simiae and T. b. gambiense was identified. Sixty seven (81.7 %) infections were single and 15 (18.3 %) mixed involving one triple infection (T. congolense forest, T. brucei and T. vivax) and 14 double infections: 11 T. congolense forest and T. congolense savannah, two T. congolense savannah and T. brucei, and one of T. brucei and T. vivax. The generated maps show the distribution of tsetse flies and trypanosome infections across the focus. Conclusion This study has shown that animal trypanosomes remain an important problem in this region. Meanwhile, it is very likely that HAT does not seem anymore to be a public health problem in this focus. The generated maps enabled us to define high risk transmission areas for AAT, and where disease control must be focused in order to improve animal health as well as the quantity of animal proteins.
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Affiliation(s)
- Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon.
| | - Pierre Fongho
- Faculty of Science, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon.
| | - Oumarou Farikou
- Ministry of Livestock, Fisheries and Animal Industries, Special Mission for TseTse Flies Eradication, PO Box 263, Ngaoundéré, Cameroon.
| | | | | | - Flobert Njiokou
- Faculty of Science, University of Yaoundé I, PO Box 812, Yaoundé, Cameroon.
| | - Tazoacha Asonganyi
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon.
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47
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Stone CM, Chitnis N. Implications of Heterogeneous Biting Exposure and Animal Hosts on Trypanosomiasis brucei gambiense Transmission and Control. PLoS Comput Biol 2015; 11:e1004514. [PMID: 26426854 PMCID: PMC4591123 DOI: 10.1371/journal.pcbi.1004514] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 08/24/2015] [Indexed: 11/29/2022] Open
Abstract
The gambiense form of sleeping sickness is a neglected tropical disease, which is presumed to be anthroponotic. However, the parasite persists in human populations at levels of considerable rarity and as such the existence of animal reservoirs has been posited. Clarifying the impact of animal host reservoirs on the feasibility of interrupting sleeping sickness transmission through interventions is a matter of urgency. We developed a mathematical model allowing for heterogeneous exposure of humans to tsetse, with animal populations that differed in their ability to transmit infections, to investigate the effectiveness of two established techniques, screening and treatment of at-risk populations, and vector control. Importantly, under both assumptions, an integrated approach of human screening and vector control was supported in high transmission areas. However, increasing the intensity of vector control was more likely to eliminate transmission, while increasing the intensity of human screening reduced the time to elimination. Non-human animal hosts played important, but different roles in HAT transmission, depending on whether or not they contributed as reservoirs. If they did not serve as reservoirs, sensitivity analyses suggested their attractiveness may instead function as a sink for tsetse bites. These outcomes highlight the importance of understanding the ecological and environmental context of sleeping sickness in optimizing integrated interventions, particularly for moderate and low transmission intensity settings. Sleeping sickness, a disease that strikes predominantly poor populations in sub-Saharan Africa, has been targeted for elimination as a public health problem. Despite decades of control operations the disease remains enigmatic and is capable of persisting in populations at low levels of prevalence. Two mechanisms are investigated here that could allow persistence at such levels. Heterogeneous exposure of humans to tsetse is modelled as a subset of humans commuting to areas of high vectorial capacity. Additionally, non-human animals may act as reservoir species. We developed, parameterized, and investigated a model of sleeping sickness transmission to gain insight into the impact of these assumptions on the prospects of elimination using screening and treatment of humans and vector control. Supplemental use of vector control increased the probability of elimination and decreased the duration until elimination was achieved. This was more pronounced when animals did contribute to transmission, or when coverage and compliance of humans with screening operations was lower, for instance due to an inability to reach the humans at greatest risk of exposure. These results can provide insights to public health officials as to when to consider supplementing human treatment with additional measures, and thereby improve the prospects of elimination of this disease.
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Affiliation(s)
- Chris M. Stone
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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48
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Abstract
Over the past 17 years, the number of reported cases of human African trypanosomiasis (HAT) has declined by over 90%, a significant result since the disease was highlighted as a public health problem by the WHO in 1995. However, if the goal of eliminating HAT by 2020 is to be achieved, then new treatments need to be identified and developed. A plethora of compound collections has been screened against Trypanosoma brucei spp, the etiological agents of HAT, resulting in three compounds progressing to clinical development. However, due to the high attrition rates in drug discovery, it is essential that research continues to identify novel molecules. Failure to do so, will result in the absence of molecules in the pipeline to fall back on should the current clinical trials be unsuccessful. This could seriously compromise control efforts to date, resulting in a resurgence in the number of HAT cases.
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Affiliation(s)
- Amy J Jones
- a Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, Brisbane, 4111, Australia
| | - Vicky M Avery
- a Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, Brisbane, 4111, Australia
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49
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Tirados I, Esterhuizen J, Kovacic V, Mangwiro TNC, Vale GA, Hastings I, Solano P, Lehane MJ, Torr SJ. Tsetse Control and Gambian Sleeping Sickness; Implications for Control Strategy. PLoS Negl Trop Dis 2015; 9:e0003822. [PMID: 26267814 PMCID: PMC4580652 DOI: 10.1371/journal.pntd.0003822] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 05/10/2015] [Indexed: 11/19/2022] Open
Abstract
Background Gambian sleeping sickness (human African trypanosomiasis, HAT) outbreaks are brought under control by case detection and treatment although it is recognised that this typically only reaches about 75% of the population. Vector control is capable of completely interrupting HAT transmission but is not used because it is considered too expensive and difficult to organise in resource-poor settings. We conducted a full scale field trial of a refined vector control technology to determine its utility in control of Gambian HAT. Methods and Findings The major vector of Gambian HAT is the tsetse fly Glossina fuscipes which lives in the humid zone immediately adjacent to water bodies. From a series of preliminary trials we determined the number of tiny targets required to reduce G. fuscipes populations by more than 90%. Using these data for model calibration we predicted we needed a target density of 20 per linear km of river in riverine savannah to achieve >90% tsetse control. We then carried out a full scale, 500 km2 field trial covering two HAT foci in Northern Uganda to determine the efficacy of tiny targets (overall target density 5.7/km2). In 12 months, tsetse populations declined by more than 90%. As a guide we used a published HAT transmission model and calculated that a 72% reduction in tsetse population is required to stop transmission in those settings. Interpretation The Ugandan census suggests population density in the HAT foci is approximately 500 per km2. The estimated cost for a single round of active case detection (excluding treatment), covering 80% of the population, is US$433,333 (WHO figures). One year of vector control organised within the country, which can completely stop HAT transmission, would cost US$42,700. The case for adding this method of vector control to case detection and treatment is strong. We outline how such a component could be organised. Sleeping sickness is controlled by case detection and treatment but this often only reaches less than 75% of the population. Vector control is capable of completely interrupting HAT transmission but is not used because of expense. We conducted a full scale field trial of a refined vector control technology. From preliminary trials we determined the number of insecticidal tiny targets required to control tsetse populations by more than 90%. We then carried out a full scale, 500 km2 field trial covering two HAT foci in Northern Uganda (overall target density 5.7/km2). In 12 months tsetse populations declined by more than 90%. A mathematical model suggested that a 72% reduction in tsetse population is required to stop transmission in those settings. The Ugandan census suggests population density in the HAT foci is approximately 500 per km2. The estimated cost for a single round of active case detection (excluding treatment), covering 80% of the population, is US$433,333 (WHO figures). One year of vector control organised within country, which can completely stop HAT transmission, would cost US$42,700. The case for adding this new method of vector control to case detection and treatment is strong. We outline how such a component could be organised.
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Affiliation(s)
- Inaki Tirados
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Vanja Kovacic
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - T. N. Clement Mangwiro
- Bindura University of Science Education, Department of Animal Science, Bindura, Zimbabwe
| | - Glyn A. Vale
- Southern African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
| | - Ian Hastings
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Philippe Solano
- Institut de Recherche pour le Developpement (IRD), UMR IRD-CIRAD 177 INTERTRYP CIRDES 01, Bobo-Dioulasso, Burkina Faso
| | - Michael J. Lehane
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
| | - Steve J. Torr
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
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50
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Cordon-Obras C, Rodriguez YF, Fernandez-Martinez A, Cano J, Ndong-Mabale N, Ncogo-Ada P, Ndongo-Asumu P, Aparicio P, Navarro M, Benito A, Bart JM. Molecular evidence of a Trypanosoma brucei gambiense sylvatic cycle in the human african trypanosomiasis foci of Equatorial Guinea. Front Microbiol 2015; 6:765. [PMID: 26257727 PMCID: PMC4513237 DOI: 10.3389/fmicb.2015.00765] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/13/2015] [Indexed: 11/13/2022] Open
Abstract
Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense) by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of gambiense trypanosomiasis.
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Affiliation(s)
- Carlos Cordon-Obras
- Consejo Superior de Investigaciones Científicas, Instituto de Parasitologia y Biomedicina Lopez Neyra Granada, Spain
| | | | | | - Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Nicolas Ndong-Mabale
- Centro de Referencia para el Control de Endemias, Instituto de Salud Carlos III Malabo, Equatorial Guinea
| | - Policarpo Ncogo-Ada
- Centro de Referencia para el Control de Endemias, Instituto de Salud Carlos III Malabo, Equatorial Guinea
| | - Pedro Ndongo-Asumu
- Centro de Referencia para el Control de Endemias, Instituto de Salud Carlos III Malabo, Equatorial Guinea
| | - Pilar Aparicio
- Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III Madrid, Spain
| | - Miguel Navarro
- Consejo Superior de Investigaciones Científicas, Instituto de Parasitologia y Biomedicina Lopez Neyra Granada, Spain
| | - Agustin Benito
- Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III Madrid, Spain
| | - Jean-Mathieu Bart
- Consejo Superior de Investigaciones Científicas, Instituto de Parasitologia y Biomedicina Lopez Neyra Granada, Spain ; Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III Madrid, Spain
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