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Guimapi RA, Klingen I, Tonnang HEZ, Nana P. Linking spatial distribution of Rhipicephalus appendiculatus to climatic variables important for the successful biocontrol by Metarhizium anisopliae in Eastern Africa. Acta Trop 2023; 238:106800. [PMID: 36535510 DOI: 10.1016/j.actatropica.2022.106800] [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: 10/20/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Cattle production is constantly threatened by diseases like East Coast fever, also known as theileriosis, caused by the protozoan parasite Theileria parva which is transmitted by ticks such as the brown ear tick, Rhipicephalus appendiculatus. To reduce the extensive use of chemical acaricides, fungal-based microbial control agents such as Metarhizium anisopliae have been tested and show promising results against R. appendiculatus both in field and in semi-field experiments in Africa. However, no known endeavors to link the spatial distribution of R. appendiculatus to climatic variables important for the successful application of M. anisopliae in selected East African countries exists. This work therefore aims to improve the successful application of M. anisopliae against R. appendiculatus by designing a temperature-dependent model for the efficacy of M. anisopliae against three developmental stages (larvae, nymphs, adults) of R. appendiculatus. Afterward a spatial prediction of potential areas where this entomopathogenic fungus might cause a significant epizootic in R. appendiculatus population in three selected countries (Kenya, Tanzania, Uganda) in Eastern Africa were generated. This can help to determine whether the temperature and rainfall at a local or regional scale might give good conditions for application of M. anisopliae and successful microbial control of R. appendiculatus.
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Affiliation(s)
- Ritter A Guimapi
- Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box, Ås 1433, Norway.
| | - Ingeborg Klingen
- Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box, Ås 1433, Norway
| | - Henri E Z Tonnang
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Paulin Nana
- Advanced School of Agriculture, Forestry, Water Resources and Environment, University of Ebolowa, P.O. Box 786, Ebolowa, Cameroon
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Kopsco HL, Smith RL, Halsey SJ. A Scoping Review of Species Distribution Modeling Methods for Tick Vectors. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.893016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BackgroundGlobally, tick-borne disease is a pervasive and worsening problem that impacts human and domestic animal health, livelihoods, and numerous economies. Species distribution models are useful tools to help address these issues, but many different modeling approaches and environmental data sources exist.ObjectiveWe conducted a scoping review that examined all available research employing species distribution models to predict occurrence and map tick species to understand the diversity of model strategies, environmental predictors, tick data sources, frequency of climate projects of tick ranges, and types of model validation methods.DesignFollowing the PRISMA-ScR checklist, we searched scientific databases for eligible articles, their references, and explored related publications through a graphical tool (www.connectedpapers.com). Two independent reviewers performed article selection and characterization using a priori criteria.ResultsWe describe data collected from 107 peer-reviewed articles that met our inclusion criteria. The literature reflects that tick species distributions have been modeled predominantly in North America and Europe and have mostly modeled the habitat suitability for Ixodes ricinus (n = 23; 21.5%). A wide range of bioclimatic databases and other environmental correlates were utilized among models, but the WorldClim database and its bioclimatic variables 1–19 appeared in 60 (56%) papers. The most frequently chosen modeling approach was MaxEnt, which also appeared in 60 (56%) of papers. Despite the importance of ensemble modeling to reduce bias, only 23 papers (21.5%) employed more than one algorithm, and just six (5.6%) used an ensemble approach that incorporated at least five different modeling methods for comparison. Area under the curve/receiver operating characteristic was the most frequently reported model validation method, utilized in nearly all (98.9%) included studies. Only 21% of papers used future climate scenarios to predict tick range expansion or contraction. Regardless of the representative concentration pathway, six of seven genera were expected to both expand and retract depending on location, while Ornithodoros was predicted to only expand beyond its current range.ConclusionSpecies distribution modeling techniques are useful and widely employed tools for predicting tick habitat suitability and range movement. However, the vast array of methods, data sources, and validation strategies within the SDM literature support the need for standardized protocols for species distribution and ecological niche modeling for tick vectors.
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Kaba T. Geographical distribution of ixodid ticks and tick-borne pathogens of domestic animals in Ethiopia: a systematic review. Parasit Vectors 2022; 15:108. [PMID: 35346354 PMCID: PMC8961985 DOI: 10.1186/s13071-022-05221-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/24/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Ethiopia, ixodid ticks and associated tick-borne pathogens (TBPs) are of great importance from both a veterinary and public health point of view. This review aimed at compiling available published data on the distribution of ixodid tick species and TBPs in the country. METHODS A standard review approach was employed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Published peer-reviewed articles and theses/dissertations reporting on ixodid ticks and TBPs in Ethiopia were searched using different keywords in many electronic databases including PubMed, Scopus, Web of Science, Google Scholar, African Journals OnLine, and institutional repositories. Articles were screened based on inclusion and exclusion criteria using the PRISMA flowchart. Data were retrieved from eligible articles and recorded in a preformed data record sheet. Descriptive statistics were employed to present data using graphs. QGIS (Quantum GIS) software version 3.4.5 was used to show the distribution of ixodid tick species and TBPs. RESULTS Overall, 35 articles that met the inclusion criteria were included in this review. Of these, 24 articles report only on ixodid ticks of domestic animals, six articles report only on TBPs in livestock or ticks, and five articles report on both ticks and TBPs in either animals or ticks. Of these studies, 54% were in the Oromia region, while only 3% of studies were in the Benishangul-Gumuz region. The Gambela region lacked studies on ticks and TBPs. At least 19 ixodid tick species have been recorded from different domestic animals including cattle, small ruminants, donkeys, horses, camels, dogs, and cats. Morphological characterization appears to be the sole method of tick species identification in the country. The distribution and abundance of specific tick species depend on geographical locations and agroecological factors. Sixteen molecularly confirmed TBPs have been identified in animal and tick tissue using molecular methods from only four administrative regions, despite the wide distribution of ticks. Among TBPs, five Anaplasma, two Ehrlichia, two Rickettsia, five Theileria, two Babesia, and one Coxiella species are the major pathogens in both livestock and humans. CONCLUSIONS Many ixodid ticks circulate in a wide geographical zone of Ethiopia. However, the limited reports on TBPs at the country level in general, and the absence of either tick or TBP reports around the border region with neighboring countries in particular, highlights the need for further study.
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Affiliation(s)
- Tamirat Kaba
- Department of Veterinary and Animal Science, College of Agricultural Science, Arba Minch University, Arba Minch, Ethiopia.
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Models for Studying the Distribution of Ticks and Tick-Borne Diseases in Animals: A Systematic Review and a Meta-Analysis with a Focus on Africa. Pathogens 2021; 10:pathogens10070893. [PMID: 34358043 PMCID: PMC8308717 DOI: 10.3390/pathogens10070893] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/30/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022] Open
Abstract
Ticks and tick-borne diseases (TTBD) are constraints to the development of livestock and induce potential human health problems. The worldwide distribution of ticks is not homogenous. Some places are ecologically suitable for ticks but they are not introduced in these areas yet. The absence or low density of hosts is a factor affecting the dissemination of the parasite. To understand the process of introduction and spread of TTBD in different areas, and forecast their presence, scientists developed different models (e.g., predictive models and explicative models). This study aimed to identify models developed by researchers to analyze the TTBD distribution and to assess the performance of these various models with a meta-analysis. A literature search was implemented with PRISMA protocol in two online databases (Scopus and PubMed). The selected articles were classified according to country, type of models and the objective of the modeling. Sensitivity, specificity and accuracy available data of these models were used to evaluate their performance using a meta-analysis. One hundred studies were identified in which seven tick genera were modeled, with Ixodes the most frequently modeled. Additionally, 13 genera of tick-borne pathogens were also modeled, with Borrelia the most frequently modeled. Twenty-three different models were identified and the most frequently used are the generalized linear model representing 26.67% and the maximum entropy model representing 24.17%. A focus on TTBD modeling in Africa showed that, respectively, genus Rhipicephalus and Theileria parva were the most modeled. A meta-analysis on the quality of 20 models revealed that maximum entropy, linear discriminant analysis, and the ecological niche factor analysis models had, respectively, the highest sensitivity, specificity, and area under the curve effect size among all the selected models. Modeling TTBD is highly relevant for predicting their distribution and preventing their adverse effect on animal and human health and the economy. Related results of such analyses are useful to build prevention and/or control programs by veterinary and public health authorities.
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Bakkes DK, Ropiquet A, Chitimia-Dobler L, Matloa DE, Apanaskevich DA, Horak IG, Mans BJ, Matthee CA. Adaptive radiation and speciation in Rhipicephalus ticks: A medley of novel hosts, nested predator-prey food webs, off-host periods and dispersal along temperature variation gradients. Mol Phylogenet Evol 2021; 162:107178. [PMID: 33892098 DOI: 10.1016/j.ympev.2021.107178] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 03/18/2021] [Accepted: 04/13/2021] [Indexed: 01/22/2023]
Abstract
Rhipicephalus are a species-diverse genus of ticks, mainly distributed in the Afrotropics with some species in the Palearctic and Oriental regions. Current taxonomic consensus comprise nine informal species groups/lineages based on immature morphology. This work integrates biogeographic, ecological and molecular lines of evidence to better understand Rhipicephalus evolution. Phylogenetic analysis based on four genes (12S, 16S, 28S-D2 and COI) recovered five distinct clades with nine descendant clades that are generally congruent with current taxonomy, with some exceptions. Historical biogeography is inferred from molecular divergence times, ancestral distribution areas, host-use and climate niches of four phylogenetically significant bioclimatic variables (isothermality, annual, seasonal and diurnal temperature range). Novel hosts enabled host-linked dispersal events into new environments, and ticks exploited new hosts through nested predator-prey connections in food webs. Diversification was further induced by climate niche partitioning along gradients in temperature range during off-host periods. Ancestral climate niche estimates corroborated dispersal events by indicating hypothetical ancestors moved into environments with different annual and seasonal temperature ranges along latitudinal gradients. Host size for immature and adult life stages was important for dispersal and subsequent diversification rates. Clades that utilise large, mobile hosts (ungulates and carnivores) early in development have wider geographic ranges but slower diversification rates, and those utilising small, less mobile hosts (rodents, lagomorphs and afroinsectivores) early in development have smaller ranges but higher diversification rates. These findings suggest diversification is driven by a complex set of factors linked to both host-associations (host size, ranges and mobility) and climate niche partitioning along annual and seasonal temperature range gradients that vary with latitude. Moreover, competitive interactions can reinforce these processes and drive speciation. Off-host periods facilitate adaptive radiation by enabling host switches along nested predator-prey connections in food webs, but at the cost of environmental exposure that partitions niches among dispersing progenitors, disrupting geneflow and driving diversification. As such, the evolution and ecological niches of Rhipicephalus are characterised by trade-offs between on- and off-host periods, and these trade-offs interact with nested predator-prey connections in food webs, host-use at different life stages, as well as gradients in annual and seasonal temperature ranges to drive adaptive radiation and speciation.
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Affiliation(s)
- Deon K Bakkes
- Gertrud Theiler Tick Museum - Epidemiology, Parasites and Vectors, Agricultural Research Council - Onderstepoort Veterinary Research, Pretoria 0110, South Africa; Evolutionary Genomics Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
| | - Anne Ropiquet
- Evolutionary Genomics Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa; Middlesex University, Department of Natural Sciences- Faculty of Science and Technology, London NW4 4BT, United Kingdom
| | | | - Dikeledi E Matloa
- Gertrud Theiler Tick Museum - Epidemiology, Parasites and Vectors, Agricultural Research Council - Onderstepoort Veterinary Research, Pretoria 0110, South Africa
| | - Dmitry A Apanaskevich
- United States National Tick Collection, the James H. Oliver, Jr. Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA 30460-8042, USA; Biology Department, Georgia Southern University, Statesboro, GA 30460, USA; Zoological Institute, Russian Academy of Sciences, St. Petersburg 199034, Russia
| | - Ivan G Horak
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Ben J Mans
- Gertrud Theiler Tick Museum - Epidemiology, Parasites and Vectors, Agricultural Research Council - Onderstepoort Veterinary Research, Pretoria 0110, South Africa; Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa; Department of Life and Consumer Sciences, University of South Africa, South Africa
| | - Conrad A Matthee
- Evolutionary Genomics Group, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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Obara I, Githaka N, Nijhof A, Krücken J, Nanteza A, Odongo D, Lubembe D, Atimnedi P, Mijele D, Njeri A, Mwaura S, Owido G, Ahmed J, Clausen PH, Bishop RP. The Rhipicephalus appendiculatus tick vector of Theileria parva is absent from cape buffalo (Syncerus caffer) populations and associated ecosystems in northern Uganda. Parasitol Res 2020; 119:2363-2367. [PMID: 32500369 PMCID: PMC7308261 DOI: 10.1007/s00436-020-06728-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 05/25/2020] [Indexed: 12/02/2022]
Abstract
Rhipicephalus appendiculatus is the major tick vector of Theileria parva, an apicomplexan protozoan parasite that causes the most economically important and lethal disease of cattle in East and central Africa. The African cape buffalo (Syncerus caffer) is the major wildlife host of T. parva from southern Uganda and Kenya to southern Africa. We show herein that R. appendiculatus appears to be absent from the two largest national parks in northern Uganda. Syncerus caffer is common in both of these national parks, specifically Murchison falls (MFNP) and Kidepo Valley (KVNP). We re-confirmed the previously reported absence of T. parva in buffalo sampled in the two northern parks based on RLB data using a nested PCR based on the T. parva p104 gene. By contrast, T. parva-infected R. appendiculatus ticks and parasite-infected buffalo were present in Lake Mburo (LMNP) in South central Uganda. This suggests that the distribution of R. appendiculatus, which is predicted to include the higher rainfall regions of northern Uganda, may be limited by additional, as yet unknown factors.
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Affiliation(s)
- I Obara
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany.
| | - N Githaka
- International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - A Nijhof
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - J Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - A Nanteza
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - D Odongo
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - D Lubembe
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - P Atimnedi
- Uganda Wildlife Authority, Kampala, Uganda
| | - D Mijele
- Kenya Wildlife Service, Nairobi, Kenya
| | - A Njeri
- International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - S Mwaura
- International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - G Owido
- International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - J Ahmed
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - P H Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - R P Bishop
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, WA, USA
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Raboloko OO, Ramabu SS, Guerrini L, Jori F. Seroprevalence of Selected Tick Borne Pathogens and Diversity and Abundance of Ixodid Ticks (Acari: Ixodidae) at the Wildlife-Livestock Interface in Northern Botswana. Front Vet Sci 2020; 7:187. [PMID: 32432129 PMCID: PMC7214809 DOI: 10.3389/fvets.2020.00187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/23/2020] [Indexed: 11/30/2022] Open
Abstract
Ticks and tick borne diseases (TBDs) undermine livestock production with considerable economic losses to livestock producers in endemic areas worldwide. Despite the impact of ticks and TBDs in livestock production, there is a paucity of information on ticks and diseases they transmit in Botswana. To address this gap, a cross-sectional study was conducted to determine (i) the seroprevalence of selected tick borne (TB) pathogens and (ii) the diversity and abundance of ixodid ticks among 301 cattle foraging around two protected areas in northern Botswana, differing by the presence or absence of a physical barrier (fence) separating wildlife and livestock. Competitive inhibition enzyme linked immuno-sorbent assay (cELISA) was used to test for Anaplasma spp. infection and Indirect Fluorescence Antibody Test (IFAT) was used to test for Theileria parva, Babesia bovis, and B. bigemina. Ticks were identified morphologically at either genus or species level. Seroprevalence of cattle was found to be 90% for Anaplasma spp., followed by 38.6% for Babesia spp. and 2.4% for T. parva. Except for Babesia spp., comparisons of the seroprevalence of the selected haemoparasites between the two wildlife-livestock interface areas were not significantly different. The overall prevalence of ticks was found to be 73.4% with Amblyomma variegatum being the most abundant (53.1%) followed by Rhipicephalus evertsi evertsi (31.7%) and R. (B.) decoloratus (7.7%). Except for Babesia spp., comparisons of the seroprevalence of the selected haemoparasites between the two study areas were not significantly different while comparisons of the burden of tick infestation between the study sites revealed significant difference for A. variegatum and R. evertsi evertsi with both tick infestations higher where there is no barrier. Our work provided baseline data on TBD pathogens and tick infestation in cattle populations exposed to different levels of contact with adjacent buffalo populations. The presence of a veterinary fence did not significantly influence the seroprevalence of the selected TBD pathogens (except for Babesia spp.) but seemed to reduce tick burdens in cattle. Findings from this study can be used for guiding future epidemiological study designs to improve our understanding of ticks and TBDs dynamics in northern Botswana.
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Affiliation(s)
- Obuile O Raboloko
- Veterinary Sciences, Botswana University of Agriculture and Natural Resources, Gaborone, Botswana.,Department of Veterinary Services, Ministry of Agriculture, Gaborone, Botswana
| | - Solomon S Ramabu
- Veterinary Sciences, Botswana University of Agriculture and Natural Resources, Gaborone, Botswana.,Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, United States
| | - Laure Guerrini
- UMR Animal, Health, Territories, Risks and Ecosystems (ASTRE), CIRAD-INRA- Uni. Montpellier, Campus International de Baillarguet, Montpellier, France.,CIRAD, UMR ASTRE, RP-PCP, Harare, Zimbabwe
| | - Ferran Jori
- Veterinary Sciences, Botswana University of Agriculture and Natural Resources, Gaborone, Botswana.,UMR Animal, Health, Territories, Risks and Ecosystems (ASTRE), CIRAD-INRA- Uni. Montpellier, Campus International de Baillarguet, Montpellier, France
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Okely M, Anan R, Gad-Allah S, Samy AM. Mapping the environmental suitability of etiological agent and tick vectors of Crimean-Congo hemorrhagic fever. Acta Trop 2020; 203:105319. [PMID: 31874130 DOI: 10.1016/j.actatropica.2019.105319] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 11/30/2022]
Abstract
Crimean-Congo hemorrhagic fever (CCHF) is one of the most important public health threats in many regions across Africa, Europe, and Asia. This study used ecological niche modeling analyses to map the environmental suitability of both CCHF virus (CCHFV), and its tick vectors (Amblyomma variegatum, Dermacentor marginatus, Hyalomma marginatum, Hyalomma rufipes, Hyalomma truncatum, Rhipicephalus appendiculatus, and Rhipicephalus evertsi evertsi) in the Old World countries. The CCHFV was anticipated to occur with high environmental suitability across southern and central Europe, northwestern Africa, central Asia, and western Mediterranean region. Ecological niche models of tick vectors anticipated diverse patterns based on the tick species in question; D. marginatus and H. marginatum showed high environmental suitability in southern and central Europe, and North Africa. The remaining vector species were anticipated to occur in Africa. All models were statistically robust and performed better than random (P < 0.001). Finally, we tested the niche similarities between CCHFV and diverse tick vectors and could not reject the null hypotheses of niche similarity in all vector-virus combinations (P > 0.05) except the combinations of CCHFV with A. variegatum, R. evertsi evertsi and R. appendiculatus (P < 0.05).
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Affiliation(s)
- Mohammed Okely
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt.
| | - Rabia Anan
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
| | - Sohair Gad-Allah
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
| | - Abdallah M Samy
- Entomology Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt.
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Amzati GS, Djikeng A, Odongo DO, Nimpaye H, Sibeko KP, Muhigwa JBB, Madder M, Kirschvink N, Marcotty T. Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa. Parasit Vectors 2019; 12:588. [PMID: 31842995 PMCID: PMC6915983 DOI: 10.1186/s13071-019-3848-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 12/10/2019] [Indexed: 02/07/2023] Open
Abstract
Background Theileria parva causes East Coast fever (ECF), one of the most economically important tick-borne diseases of cattle in sub-Saharan Africa. A live immunisation approach using the infection and treatment method (ITM) provides a strong long-term strain-restricted immunity. However, it typically induces a tick-transmissible carrier state in cattle and may lead to spread of antigenically distinct parasites. Thus, understanding the genetic composition of T. parva is needed prior to the use of the ITM vaccine in new areas. This study examined the sequence diversity and the evolutionary and biogeographical dynamics of T. parva within the African Great Lakes region to better understand the epidemiology of ECF and to assure vaccine safety. Genetic analyses were performed using sequences of two antigen-coding genes, Tp1 and Tp2, generated among 119 T. parva samples collected from cattle in four agro-ecological zones of DRC and Burundi. Results The results provided evidence of nucleotide and amino acid polymorphisms in both antigens, resulting in 11 and 10 distinct nucleotide alleles, that predicted 6 and 9 protein variants in Tp1 and Tp2, respectively. Theileria parva samples showed high variation within populations and a moderate biogeographical sub-structuring due to the widespread major genotypes. The diversity was greater in samples from lowlands and midlands areas compared to those from highlands and other African countries. The evolutionary dynamics modelling revealed a signal of selective evolution which was not preferentially detected within the epitope-coding regions, suggesting that the observed polymorphism could be more related to gene flow rather than recent host immune-based selection. Most alleles isolated in the Great Lakes region were closely related to the components of the trivalent Muguga vaccine. Conclusions Our findings suggest that the extensive sequence diversity of T. parva and its biogeographical distribution mainly depend on host migration and agro-ecological conditions driving tick population dynamics. Such patterns are likely to contribute to the epidemic and unstable endemic situations of ECF in the region. However, the fact that ubiquitous alleles are genetically similar to the components of the Muguga vaccine together with the limited geographical clustering may justify testing the existing trivalent vaccine for cross-immunity in the region.
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Affiliation(s)
- Gaston S Amzati
- Research Unit of Veterinary Epidemiology and Biostatistics, Faculty of Agricultural and Environmental Sciences, Université Evangélique en Afrique, PO Box 3323, Bukavu, Democratic Republic of the Congo. .,Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium. .,Biosciences Eastern and Central Africa - International Livestock Research Institute (BecA-ILRI) Hub, PO Box 30709-00100, Nairobi, Kenya.
| | - Appolinaire Djikeng
- Biosciences Eastern and Central Africa - International Livestock Research Institute (BecA-ILRI) Hub, PO Box 30709-00100, Nairobi, Kenya.,Centre for Tropical Livestock Genetics and Health (CTLGH), The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - David O Odongo
- Biosciences Eastern and Central Africa - International Livestock Research Institute (BecA-ILRI) Hub, PO Box 30709-00100, Nairobi, Kenya.,School of Biological Sciences, University of Nairobi, PO Box 30197-00100, Nairobi, Kenya
| | - Herman Nimpaye
- Faculty of Medicine, University of Burundi, PO Box 1550, Bujumbura, Burundi
| | - Kgomotso P Sibeko
- Vector and Vector-Borne Disease Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, P/Bag X04, Onderstepoort, Gauteng, 0110, South Africa
| | - Jean-Berckmans B Muhigwa
- Research Unit of Veterinary Epidemiology and Biostatistics, Faculty of Agricultural and Environmental Sciences, Université Evangélique en Afrique, PO Box 3323, Bukavu, Democratic Republic of the Congo
| | - Maxime Madder
- Vector and Vector-Borne Disease Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, P/Bag X04, Onderstepoort, Gauteng, 0110, South Africa
| | - Nathalie Kirschvink
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium
| | - Tanguy Marcotty
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium
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Amzati GS, Pelle R, Muhigwa JBB, Kanduma EG, Djikeng A, Madder M, Kirschvink N, Marcotty T. Mitochondrial phylogeography and population structure of the cattle tick Rhipicephalus appendiculatus in the African Great Lakes region. Parasit Vectors 2018; 11:329. [PMID: 29855375 PMCID: PMC5984310 DOI: 10.1186/s13071-018-2904-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/16/2018] [Indexed: 12/02/2022] Open
Abstract
Background The ixodid tick Rhipicephalus appendiculatus is the main vector of Theileria parva, wich causes the highly fatal cattle disease East Coast fever (ECF) in sub-Saharan Africa. Rhipicephalus appendiculatus populations differ in their ecology, diapause behaviour and vector competence. Thus, their expansion in new areas may change the genetic structure and consequently affect the vector-pathogen system and disease outcomes. In this study we investigated the genetic distribution of R. appendiculatus across agro-ecological zones (AEZs) in the African Great Lakes region to better understand the epidemiology of ECF and elucidate R. appendiculatus evolutionary history and biogeographical colonization in Africa. Methods Sequencing was performed on two mitochondrial genes (cox1 and 12S rRNA) of 218 ticks collected from cattle across six AEZs along an altitudinal gradient in the Democratic Republic of Congo, Rwanda, Burundi and Tanzania. Phylogenetic relationships between tick populations were determined and evolutionary population dynamics models were assessed by mismach distribution. Results Population genetic analysis yielded 22 cox1 and 9 12S haplotypes in a total of 209 and 126 nucleotide sequences, respectively. Phylogenetic algorithms grouped these haplotypes for both genes into two major clades (lineages A and B). We observed significant genetic variation segregating the two lineages and low structure among populations with high degree of migration. The observed high gene flow indicates population admixture between AEZs. However, reduced number of migrants was observed between lowlands and highlands. Mismatch analysis detected a signature of rapid demographic and range expansion of lineage A. The star-like pattern of isolated and published haplotypes indicates that the two lineages evolve independently and have been subjected to expansion across Africa. Conclusions Two sympatric R. appendiculatus lineages occur in the Great Lakes region. Lineage A, the most diverse and ubiquitous, has experienced rapid population growth and range expansion in all AEZs probably through cattle movement, whereas lineage B, the less abundant, has probably established a founder population from recent colonization events and its occurrence decreases with altitude. These two lineages are sympatric in central and eastern Africa and allopatric in southern Africa. The observed colonization pattern may strongly affect the transmission system and may explain ECF endemic instability in the tick distribution fringes. Electronic supplementary material The online version of this article (10.1186/s13071-018-2904-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gaston S Amzati
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium. .,Research Unit of Veterinary Epidemiology and Biostatistics, Faculty of Agricultural and Environmental Sciences, Université Evangélique en Afrique, P.O. Box 3323, Bukavu, Democratic Republic of the Congo. .,Biosciences eastern and central Africa - International Livestock Research Institute (BecA-ILRI) hub, P.O. Box 30709-00100, Nairobi, Kenya.
| | - Roger Pelle
- Biosciences eastern and central Africa - International Livestock Research Institute (BecA-ILRI) hub, P.O. Box 30709-00100, Nairobi, Kenya
| | - Jean-Berckmans B Muhigwa
- Research Unit of Veterinary Epidemiology and Biostatistics, Faculty of Agricultural and Environmental Sciences, Université Evangélique en Afrique, P.O. Box 3323, Bukavu, Democratic Republic of the Congo
| | - Esther G Kanduma
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Appolinaire Djikeng
- Biosciences eastern and central Africa - International Livestock Research Institute (BecA-ILRI) hub, P.O. Box 30709-00100, Nairobi, Kenya.,Present address: Centre for Tropical Livestock Genetics and Health (CTLGH), The University of Edinburgh, Easter Bush, Midlothian, Scotland, EH25 9RG, UK
| | - Maxime Madder
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, P/Bag X04, Onderstepoort, 0110, South Africa
| | - Nathalie Kirschvink
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium
| | - Tanguy Marcotty
- Unit of Integrated Veterinary Research, Department of Veterinary Medicine, Faculty of Sciences, Namur Research Institute for Life Sciences (NARILIS), University of Namur (UNamur), Rue de Bruxelles 61, 5000, Namur, Belgium
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Vectors and vector-borne pathogens of dogs in Nigeria: a meta-analysis of their prevalence and distribution from data published between 1975 and 2016. VETERINARY PARASITOLOGY- REGIONAL STUDIES AND REPORTS 2018; 12:69-77. [PMID: 31014812 DOI: 10.1016/j.vprsr.2018.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 01/24/2018] [Accepted: 02/11/2018] [Indexed: 11/23/2022]
Abstract
Knowledge of vectors and the pathogens they transmit is essential for veterinarians and public health workers to ensure successful diagnosis, treatment and public health protection. In the present study, the guideline for Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) was employed to determine the prevalence and distribution of vectors and vector-borne pathogens (VBPs) of dogs across Nigeria in a meta-analysis of data published between 1975 and 2016. Pooled prevalence estimate (PPE) was determined by the random-effects model while heterogeneity was evaluated using Cochran's Q-test. A total of 2897 cases of vectors and VBPs were reported from 9880 dogs in 28 studies across 15 Nigerian states. Overall PPE was 29.3% (95% CI: 28.4, 30.2) and ranged between 4.4% (95% CI: 2.3, 7.6) and 59.1% (95% CI: 55.7, 62.5) across sub-groups. Rhipicephalus sanquineus (Prev: 25.3%, 95% CI: 23.7, 27.0) and Hepatozoon canis (Prev: 16.9%, 95% CI: 13.9, 20.3) were the most prevalent vector and VBP respectively. Vectors and VBPs of zoonotic and veterinary importance were prevalent in Nigerian dogs and were distributed across the six regions. Vector control, adequate hygiene and sanitation as well as appropriate policies on pet ownership and implementation of control measures will help control these pathogens and curtail the risk of transmission to humans in Nigeria.
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Githaka N, Konnai S, Bishop R, Odongo D, Lekolool I, Kariuki E, Gakuya F, Kamau L, Isezaki M, Murata S, Ohashi K. Identification and sequence characterization of novel Theileria genotypes from the waterbuck (Kobus defassa) in a Theileria parva-endemic area in Kenya. Vet Parasitol 2014; 202:180-93. [PMID: 24690249 DOI: 10.1016/j.vetpar.2014.02.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 02/19/2014] [Accepted: 02/24/2014] [Indexed: 10/25/2022]
Abstract
Waterbuck (Kobus defassa), an ungulate species endemic to the Eastern African savannah, is suspected of being a wildlife reservoir for tick-transmitted parasites infective to livestock. Waterbuck is infested by large numbers of Rhipicephalus appendiculatus, the tick vector for Theileria parva, and previous data suggests that the species may be a source of T. parva transmission to cattle. In the present study, a total of 86 cattle and 26 waterbuck blood samples were obtained from Marula, a site in Kenya endemic for East Coast fever (ECF) where the primary wildlife reservoir of T. parva the Cape buffalo (Syncerus caffer) is also common. To investigate for the presence of cattle-infective Theileria parasites, DNA specimens extracted from the blood samples were subjected to two diagnostic assays; a nested PCR based on the p104 gene that is specific for T. parva, and a reverse line blot (RLB) incorporating 13 oligonucleotide probes including all of the Theileria spp. so far described from livestock and wildlife in Kenya. Neither assay provided evidence of T. parva or Theileria sp. (buffalo) infection in the waterbuck DNA samples. By contrast, majority of the cattle samples (67.4%) were positive for T. parva using a nested PCR assay. The RLB assay, including a generic probe for the genus Theileria, indicated that 25/26 (96%) of the waterbuck samples were positive for Theileria, while none of the 11 Theileria species-specific probes hybridized with the waterbuck-derived PCR products. Phylogenetic analysis of 18S ribosomal RNA (18S rRNA) and internal transcribed spacer (ITS) sequences within the RLB-positive waterbuck samples revealed the occurrence of three Theileria genotypes of unknown identity designated A, B and C. Group A clustered with Theileria equi, a pathogenic Theileria species and a causative agent of equine piroplasmosis in domestic equids. However, DNA from this group failed to hybridize with the T. equi oligonucleotide present on the RLB filter probe, suggesting the occurrence of novel taxa in these animals. This was confirmed by DNA sequencing that revealed heterogeneity between the waterbuck isolates and previously reported T. equi genotypes. Group B parasites clustered closely with Theileria luwenshuni, a highly pathogenic parasite of sheep and goats reported from China. Group C was closely related to Theileria ovis, an apparently benign parasite of sheep. Together, these findings provided no evidence that waterbuck plays a role in the transmission of T. parva. However, novel Theileria genotypes detected in this bovid species may be of veterinary importance.
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Affiliation(s)
- Naftaly Githaka
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan
| | - Satoru Konnai
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan
| | - Richard Bishop
- International Livestock Research Institute, ILRI, P.O. Box 30709-00100, Nairobi, Kenya
| | - David Odongo
- International Livestock Research Institute, ILRI, P.O. Box 30709-00100, Nairobi, Kenya; School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Isaac Lekolool
- Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
| | - Edward Kariuki
- Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
| | - Francis Gakuya
- Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
| | - Lucy Kamau
- Department of Zoological Sciences, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
| | - Masayoshi Isezaki
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan
| | - Shiro Murata
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan
| | - Kazuhiko Ohashi
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan.
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Pfäffle M, Littwin N, Muders SV, Petney TN. The ecology of tick-borne diseases. Int J Parasitol 2013; 43:1059-77. [DOI: 10.1016/j.ijpara.2013.06.009] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 12/30/2022]
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