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Djiman TA, Biguezoton AS, Saegerman C. Tick-Borne Diseases in Sub-Saharan Africa: A Systematic Review of Pathogens, Research Focus, and Implications for Public Health. Pathogens 2024; 13:697. [PMID: 39204297 PMCID: PMC11356977 DOI: 10.3390/pathogens13080697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2024] [Revised: 08/11/2024] [Accepted: 08/12/2024] [Indexed: 09/03/2024] Open
Abstract
Sub-Saharan Africa, with its hot and humid climate, is a conducive zone for tick proliferation. These vectors pose a major challenge to both animal and human health in the region. However, despite the relevance of emerging diseases and evidence of tick-borne disease emergence, very few studies have been dedicated to investigating zoonotic pathogens transmitted by ticks in this area. To raise awareness of the risks of tick-borne zoonotic diseases in sub-Saharan Africa, and to define a direction for future research, this systematic review considers the trends of research on tick-borne bacteria, parasites, and viruses from 2012 to 2023, aiming to highlight the circulation of these pathogens in ticks, cattle, sheep, goats, and humans. For this purpose, three international databases were screened to select 159 papers fitting designed inclusion criteria and used for qualitative analyses. Analysis of these studies revealed a high diversity of tick-borne pathogens in sub-Saharan Africa, with a total of 37 bacterial species, 27 parasite species, and 14 viruses identified. Among these, 27% were zoonotic pathogens, yet only 11 studies investigated their presence in humans. Furthermore, there is growing interest in the investigation of bacteria and parasites in both ticks and ruminants. However, research into viruses is limited and has only received notable interest from 2021 onwards. While studies on the detection of bacteria, including those of medical interest, have focused on ticks, little consideration has been given to these vectors in studies of parasites circulation. Regarding the limited focus on zoonotic pathogens transmitted by ticks, particularly in humans, despite documented cases of emerging zoonoses and the notable 27% proportion reported, further efforts should be made to fill these gaps. Future studies should prioritize the investigation of zoonotic pathogens, especially viruses, which represent the primary emerging threats, by adopting a One Health approach. This will enhance the understanding of their circulation and impact on both human and animal health. In addition, more attention should be given to the risk factors/drivers associated to their emergence as well as the perception of the population at risk of infection from these zoonotic pathogens.
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Affiliation(s)
- Tidjani A. Djiman
- Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animals and Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, 4000 Liège, Belgium;
- Vector-Borne Diseases and Biodiversity Unit (UMaVeB), International Research and Development Centre on Livestock in Sub-humid Areas (CIRDES), Bobo-Dioulasso 454, Burkina Faso;
| | - Abel S. Biguezoton
- Vector-Borne Diseases and Biodiversity Unit (UMaVeB), International Research and Development Centre on Livestock in Sub-humid Areas (CIRDES), Bobo-Dioulasso 454, Burkina Faso;
| | - Claude Saegerman
- Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR-ULiège), Fundamental and Applied Research for Animals and Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, 4000 Liège, Belgium;
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Zhang EY, Kalmath P, Abernathy HA, Giandomenico DA, Nolan MS, Reiskind MH, Boyce RM. Rickettsia africae infections in sub-Saharan Africa: A systematic literature review of epidemiological studies and summary of case reports. Trop Med Int Health 2024; 29:541-583. [PMID: 38813598 PMCID: PMC11216893 DOI: 10.1111/tmi.14002] [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] [Indexed: 05/31/2024]
Abstract
Rickettsia africae is a tick-borne bacteria known to cause African tick bite fever (ATBF). While the disease was first described more than 100 years ago, knowledge of transmission risk factors and disease burden remain poorly described. To better understand the burden of R. africae, this article reviewed and summarized the published literature related to ATBF epidemiology and clinical management. Using a systematic approach, consistent with the PRISMA guidelines, we identified more than 100 eligible articles, including 65 epidemiological studies and 41 case reports. Most reports described R. africae in ticks and livestock, while human studies were less common. Human disease case reports were exclusively among returning travellers from non-endemic areas, which limits our disease knowledge among at-risk populations: people living in endemic regions. Substantial efforts to elucidate the ATBF risk factors and clinical manifestations among local populations are needed to develop effective preventative strategies and facilitate appropriate and timely diagnosis.
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Affiliation(s)
- Elizabeth Y. Zhang
- College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
| | - Prarthana Kalmath
- College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
| | - Haley A. Abernathy
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
| | - Dana A. Giandomenico
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
| | - Melissa S. Nolan
- Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, South Carolina, 29208, USA
| | - Michael H. Reiskind
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, 27695, USA
| | - Ross M. Boyce
- Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
- Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
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Distribution and Prevalence of Anaplasmataceae, Rickettsiaceae and Coxiellaceae in African Ticks: A Systematic Review and Meta-Analysis. Microorganisms 2023; 11:microorganisms11030714. [PMID: 36985288 PMCID: PMC10051480 DOI: 10.3390/microorganisms11030714] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 03/12/2023] Open
Abstract
In Africa, ticks continue to be a major hindrance to the improvement of the livestock industry due to tick-borne pathogens that include Anaplasma, Ehrlichia, Rickettsia and Coxiella species. A systemic review and meta-analysis were conducted here and highlighted the distribution and prevalence of these tick-borne pathogens in African ticks. Relevant publications were searched in five electronic databases and selected using inclusion/exclusion criteria, resulting in 138 and 78 papers included in the qualitative and quantitative analysis, respectively. Most of the studies focused on Rickettsia africae (38 studies), followed by Ehrlichia ruminantium (27 studies), Coxiella burnetii (20 studies) and Anaplasma marginale (17 studies). A meta-analysis of proportions was performed using the random-effects model. The highest prevalence was obtained for Rickettsia spp. (18.39%; 95% CI: 14.23–22.85%), R. africae (13.47%; 95% CI: 2.76–28.69%), R. conorii (11.28%; 95% CI: 1.77–25.89%), A. marginale (12.75%; 95% CI: 4.06–24.35%), E. ruminantium (6.37%; 95% CI: 3.97–9.16%) and E. canis (4.3%; 95% CI: 0.04–12.66%). The prevalence of C. burnetii was low (0%; 95% CI: 0–0.25%), with higher prevalence for Coxiella spp. (27.02%; 95% CI: 10.83–46.03%) and Coxiella-like endosymbionts (70.47%; 95% CI: 27–99.82%). The effect of the tick genera, tick species, country and other variables were identified and highlighted the epidemiology of Rhipicephalus ticks in the heartwater; affinity of each Rickettsia species for different tick genera; dominant distribution of A. marginale, R. africae and Coxiella-like endosymbionts in ticks and a low distribution of C. burnetii in African hard ticks.
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Onyiche TE, Labruna MB, Saito TB. Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.952024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tick-borne rickettsioses are emerging and re-emerging diseases of public health concern caused by over 30 species of Rickettsia. Ticks are obligate hematophagous arthropods with over 700 species of Ixodid ticks known worldwide. The escalating geographical dispersal of tick vectors and concomitant increase in the incidences of tick-borne diseases have fueled interest in the ecology of tick-borne pathogens. This review focuses on aspects of the Rickettsia pathogen, including biology, taxonomy, phylogeny, genetic diversity, epidemiology of the disease, and the role of vertebrate host in the perpetuation of rickettsioses in Africa. Our review also highlights some of the species of Rickettsia that are responsible for disease, the role of tick vectors (both hard and soft ticks) and the species of Rickettsia associated with diverse tick species across the continent. Additionally, this article emphasizes the evolutionary perspective of rickettsiae perpetuation and the possible role of amplifying vertebrate host and other small mammals, domestic animals and wildlife in the epidemiology of Rickettsia species. We also specifically, discussed the role of avian population in the epidemiology of SFG rickettsiae. Furthermore, we highlighted tick-borne rickettsioses among travelers due to African tick-bite fever (ATBF) and the challenges to surveillance of rickettsial infection, and research on rickettsiology in Africa. Our review canvasses the need for more rickettsiologists of African origin based within the continent to further research towards understanding the biology, characterization, and species distribution, including the competent tick vectors involved in their transmission of rickettsiae across the continent in collaboration with established researchers in western countries. We further highlighted the need for proper funding to encourage research despite competing demands for resources across the various sectors. We finalize by discussing the similarities between rickettsial diseases around the world and which steps need to be taken to help foster our understanding on the eco-epidemiology of rickettsioses by bridging the gap between the growing epidemiological data and the molecular characterization of Rickettsia species.
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Abstract
Ticks are hematophagous ectoparasites capable of transmitting multiple human pathogens. Environmental changes have supported the expansion of ticks into new geographical areas that have become the epicenters of tick-borne diseases (TBDs). The spotted fever group (SFG) of Rickettsia frequently infects ticks and causes tick-transmitted rickettsioses in areas of endemicity where ixodid ticks support host transmission during blood feeding. Ticks also serve as a reservoir for SFG Rickettsia. Among the members of SFG Rickettsia, R. rickettsii causes Rocky Mountain spotted fever (RMSF), the most lethal TBD in the United States. Cases of RMSF have been reported for over a century in association with several species of ticks in the United States. However, the isolation of R. rickettsii from ticks has decreased, and recent serological and epidemiological studies suggest that novel species of SFG Rickettsia are responsible for the increased number of cases of RMSF-like rickettsioses in the United States. Recent analyses of rickettsial genomes and advances in genetic and molecular studies of Rickettsia provided insights into the biology of Rickettsia with the identification of conserved and unique putative virulence genes involved in the rickettsial life cycle. Thus, understanding Rickettsia-host-tick interactions mediating successful disease transmission and pathogenesis for SFG rickettsiae remains an active area of research. This review summarizes recent advances in understanding how SFG Rickettsia species coopt and manipulate ticks and mammalian hosts to cause rickettsioses, with a particular emphasis on newly described or emerging SFG Rickettsia species.
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Rauch J, Jochum J, Eisermann P, Gisbrecht J, Völker K, Hunstig F, Mehlhoop U, Muntau B, Tappe D. Inflammatory cytokine profile and T cell responses in African tick bite fever patients. Med Microbiol Immunol 2022; 211:143-152. [PMID: 35543881 PMCID: PMC9092931 DOI: 10.1007/s00430-022-00738-5] [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: 09/22/2021] [Accepted: 04/05/2022] [Indexed: 11/29/2022]
Abstract
African tick bite fever, an acute febrile illness, is caused by the obligate intracellular bacterium Rickettsia africae. Immune responses to rickettsial infections have so far mainly been investigated in vitro with infected endothelial cells as the main target cells, and in mouse models. Patient studies are rare and little is known about the immunology of human infections. In this study, inflammatory mediators and T cell responses were examined in samples from 13 patients with polymerase chain reaction-confirmed R. africae infections at different time points of illness. The Th1-associated cytokines IFNγ and IL-12 were increased in the acute phase of illness, as were levels of the T cell chemoattractant cytokine CXCL-10. In addition, the anti-inflammatory cytokine IL-10 and also IL-22 were elevated. IL-22 but not IFNγ was increasingly produced by CD4+ and CD8+ T cells during illness. Besides IFNγ, IL-22 appears to play a protective role in rickettsial infections.
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Affiliation(s)
- Jessica Rauch
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359, Hamburg, Germany.
| | - Johannes Jochum
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Philip Eisermann
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359, Hamburg, Germany
| | - Jana Gisbrecht
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359, Hamburg, Germany
| | | | | | - Ute Mehlhoop
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359, Hamburg, Germany
| | - Birgit Muntau
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359, Hamburg, Germany
| | - Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359, Hamburg, Germany
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Pillay A, Manyangadze T, Mukaratirwa S. Prevalence of Rickettsia africae in tick vectors collected from mammalian hosts in sub-Saharan Africa: A systematic review and meta-analysis. Ticks Tick Borne Dis 2022; 13:101960. [DOI: 10.1016/j.ttbdis.2022.101960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 04/08/2022] [Accepted: 04/21/2022] [Indexed: 11/29/2022]
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Rasoamalala F, Parany MNJ, Rahajandraibe S, Rakotomanga MN, Ramihangihajason T, Soarimalala V, Boyer S, Rajerison M, Ramasindrazana B. High Rickettsial Diversity in Rodents and Their Ectoparasites From the Central Highlands of Madagascar. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:667-674. [PMID: 34958102 DOI: 10.1093/jme/tjab207] [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: 07/05/2021] [Indexed: 06/14/2023]
Abstract
Rickettsioses are among emerging infectious diseases around the world. In Madagascar, little information is available regarding Rickettsia (Rickettsiales: Rickettsiaceae) diversity and their potential impacts on public health. In fact, molecular screening of ectoparasites of mammals reported the presence of three species, Rickettsia africae, Rickettsia typhi, and Rickettsia felis. The present study aims to investigate the diversity of Rickettsia in small mammals and associated ectoparasites (fleas and ticks) using a molecular approach. In September and December 2016, fieldworks were undertaken in two districts of Madagascar to capture small mammals using standard traps (Tomahawk and Sherman traps) and collect associated ectoparasites. In total, 12 taxa of ectoparasites (5 flea and 7 tick species) were collected from 89 individuals of four species of terrestrial small mammals. Rickettsia spp. were molecularly identified in one specimen of Rattus rattus (Rodentia: Muridae), one specimen of Pulex irritans (Siphonaptera: Pulicidae) as well as four specimens of Ixodes cf. colasbelcouri (Ixodida: Ixodidae). This study showed the presence of three phylogenetically distinct taxa of Rickettsia in small mammals and their ectoparasites. The current study broadens our knowledge on the diversity of Rickettsia in the Central Highlands of Madagascar and highlights for the first time the presence of Ri. felis in R. rattus and in tick, I. cf. colasbelcouri in Madagascar. Additional studies are needed to have exhaustive information on Rickettsia in small mammals and their ectoparasites, to determine their pathogenicity as well as their potential effects on public health in order to update the national policy for the control of emerging infectious diseases in Madagascar.
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Affiliation(s)
| | - Mamionah N J Parany
- Plague Unit, Institut Pasteur de Madagascar, BP, 1274, Antananarivo, 101, Madagascar
| | | | - Malala N Rakotomanga
- Medical Entomology Unit, Institut Pasteur de Madagascar, BP, 1274, Antananarivo, 101, Madagascar
| | - Tojo Ramihangihajason
- Medical Entomology Unit, Institut Pasteur de Madagascar, BP, 1274, Antananarivo, 101, Madagascar
| | | | - Sébastien Boyer
- Medical and Veterinary Entomology Unit, Institut Pasteur de Cambogde, 5 Boulevard Monivong, Phnom Penh, Cambodia
| | - Minoarisoa Rajerison
- Plague Unit, Institut Pasteur de Madagascar, BP, 1274, Antananarivo, 101, Madagascar
| | - Beza Ramasindrazana
- Plague Unit, Institut Pasteur de Madagascar, BP, 1274, Antananarivo, 101, Madagascar
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Molecular Evidence for Flea-Borne Rickettsiosis in Febrile Patients from Madagascar. Pathogens 2021; 10:pathogens10111482. [PMID: 34832637 PMCID: PMC8621948 DOI: 10.3390/pathogens10111482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/02/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
Rickettsiae may cause febrile infections in humans in tropical and subtropical regions. From Madagascar, no molecular data on the role of rickettsioses in febrile patients are available. Blood samples from patients presenting with fever in the area of the capital Antananarivo were screened for the presence of rickettsial DNA. EDTA (ethylenediaminetetraacetic acid) blood from 1020 patients presenting with pyrexia > 38.5 °C was analyzed by gltA-specific qPCR. Positive samples were confirmed by ompB-specific qPCR. From confirmed samples, the gltA amplicons were sequenced and subjected to phylogenetic analysis. From five gltA-reactive samples, two were confirmed by ompB-specific qPCR. The gltA sequence in the sample taken from a 38-year-old female showed 100% homology with R. typhi. The other sample taken from a 1.5-year-old infant was 100% homologous to R. felis. Tick-borne rickettsiae were not identified. The overall rate of febrile patients with molecular evidence for a rickettsial infection from the Madagascan study site was 0.2% (2/1020 patients). Flea-borne rickettsiosis is a rare but neglected cause of infection in Madagascar. Accurate diagnosis may prompt adequate antimicrobial treatment.
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Serology- and Blood-PCR-Based Screening for Schistosomiasis in Pregnant Women in Madagascar-A Cross-Sectional Study and Test Comparison Approach. Pathogens 2021; 10:pathogens10060722. [PMID: 34201231 PMCID: PMC8229283 DOI: 10.3390/pathogens10060722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/24/2021] [Accepted: 06/05/2021] [Indexed: 12/17/2022] Open
Abstract
This work was conducted as a cross sectional study to define the disease burden of schistosomiasis in pregnant Madagascan women and to evaluate serological and molecular diagnostic assays. A total of 1154 residual EDTA blood samples from pregnant Madagascan women were assessed. The nucleic acid extractions were subjected to in-house real-time PCRs specifically targeting S. mansoni complex, S. haematobium complex, and African Schistosoma spp. on genus level, while the EDTA plasma samples were analyzed using Schistosoma-specific IgG and IgM commercial ELISA and immunofluorescence assays. The analyses indicated an overall prevalence of schistosomiasis in Madagascan pregnant women of 40.4%, with only minor regional differences and differences between serology- and blood PCR-based surveillance. The S. mansoni specific real-time PCR showed superior sensitivity of 74% (specificity 80%) compared with the genus-specific real-time PCR (sensitivity 13%, specificity 100%) in blood. The laborious immunofluorescence (sensitivity IgM 49%, IgG 87%, specificity IgM 85%, IgG 96%) scored only slightly better than the automatable ELISA (sensitivity IgM 38%, IgG 88%, specificity IgM 78%, IgG 91%). Infections with S. mansoni were detected only. The high prevalence of schistosomiasis recorded here among pregnant women in Madagascar calls for actions in order to reduce the disease burden.
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Katswara T, Mukaratirwa S. Knowledge, attitudes and practices on African tick bite fever of rural livestock communities living in a livestock-wildlife interface area in the Eastern Cape Province of South Africa. BMC Infect Dis 2021; 21:497. [PMID: 34049499 PMCID: PMC8161941 DOI: 10.1186/s12879-021-06174-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 05/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND African tick bite fever (ATBF) caused by Rickettsia africae and transmitted by Amblyomma spp. ticks is one of the zoonotic tick-borne fevers from the spotted fever group (SFG) of rickettsiae, which is an emerging global health concern. There is paucity of information regarding the occurrence and awareness of the disease in endemic rural livestock farming communities living in livestock-wildlife interface areas in South Africa. METHODS The purpose of the study was to assess the level of knowledge, attitudes and practices on ticks and ATBF infection from a community living in livestock-wildlife interface areas in South Africa. A focus group discussion (FGD) was carried out followed by verbal administration of a standardized semi-structured questionnaire a month later to 38 rural livestock farmers (23 from Caquba area and 15 from Lucingweni area where A. hebraeum was absent). An FGD was conducted in Caquba (situated at the livestock-wildlife interface where Amblyomma hebraeum was prevalent on cattle and infected with Rickettsia africae) in the O.R. Tambo district of the Eastern Cape province of South Africa. RESULTS Results from the FGD and questionnaire survey showed that participants from the two rural communities were not aware of ATBF and were not aware that ticks are vectors of the disease. Respondents from Caquba reported of having frequent exposure to tick bites (91.3%, 21/23) specifically from the anthropophilic A. hebrauem which they were able to identify as Qwelagqibe in IsiXhosa (their vernacular). Thirteen out of 15 (86.7%) of respondents from Lucingweni reported that they had never been bitten by ticks, which corresponded with the absence of A. hebraeum from their locality as evidenced from results of a concurrent study on prevalence of ticks on livestock in the area. Both communities confirmed to being "very concerned" of tick bites and we presume this was more related to the localized wounds from the bites than to the diseases transmitted by the ticks. CONCLUSIONS We recommend future studies encompassing seroprevalence of ATBF in Caquba and other communities at risk in South Africa including establishing surveillance systems to monitor the seasonal infection rates in ticks, cattle and humans.
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Affiliation(s)
- Tandiwe Katswara
- School of Life Sciences, Biological Sciences Section, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa
| | - Samson Mukaratirwa
- School of Life Sciences, Biological Sciences Section, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa.
- One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis.
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Jiang J, Farris CM, Yeh KB, Richards AL. International Rickettsia Disease Surveillance: An Example of Cooperative Research to Increase Laboratory Capability and Capacity for Risk Assessment of Rickettsial Outbreaks Worldwide. Front Med (Lausanne) 2021; 8:622015. [PMID: 33738293 PMCID: PMC7960665 DOI: 10.3389/fmed.2021.622015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/20/2021] [Indexed: 01/30/2023] Open
Abstract
Cooperative research that addresses infectious disease surveillance and outbreak investigations relies heavily on availability and effective use of appropriate diagnostic tools, including serological and molecular assays, as exemplified by the current COVID-19 pandemic. In this paper, we stress the importance of using these assays to support collaborative epidemiological studies to assess risk of rickettsial disease outbreaks among international partner countries. Workforce development, mentorship, and training are important components in building laboratory capability and capacity to assess risk of and mitigate emerging disease outbreaks. International partnerships that fund cooperative research through mentoring and on-the-job training are successful examples for enhancing infectious disease surveillance. Cooperative research studies between the Naval Medical Research Center's Rickettsial Diseases Research Program (RDRP) and 17 institutes from nine countries among five continents were conducted to address the presence of and the risk for endemic rickettsial diseases. To establish serological and molecular assays in the collaborative institutes, initial training and continued material, and technical support were provided by RDRP. The laboratory methods used in the research studies to detect and identify the rickettsial infections included (1) group-specific IgM and IgG serological assays and (2) molecular assays. Twenty-six cooperative research projects performed between 2008 and 2020 enhanced the capability and capacity of 17 research institutes to estimate risk of rickettsial diseases. These international collaborative studies have led to the recognition and/or confirmation of rickettsial diseases within each of the partner countries. In addition, with the identification of specific pathogen and non-pathogen Rickettsia species, a more accurate risk assessment could be made in surveillance studies using environmental samples. The discoveries from these projects reinforced international cooperation benefiting not only the partner countries but also the scientific community at large through presentations (n = 40) at international scientific meetings and peer-reviewed publications (n = 18). The cooperative research studies conducted in multiple international institutes led to the incorporation of new SOPs and trainings for laboratory procedures; biosafety, biosurety, and biosecurity methods; performance of rickettsia-specific assays; and the identification of known and unknown rickettsial agents through the introduction of new serologic and molecular assays that complemented traditional microbiology methods.
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Affiliation(s)
- Ju Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Christina M. Farris
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States
| | | | - Allen L. Richards
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Ehlers J, Krüger A, Rakotondranary SJ, Ratovonamana RY, Poppert S, Ganzhorn JU, Tappe D. Molecular detection of Rickettsia spp., Borrelia spp., Bartonella spp. and Yersinia pestis in ectoparasites of endemic and domestic animals in southwest Madagascar. Acta Trop 2020; 205:105339. [PMID: 31935354 DOI: 10.1016/j.actatropica.2020.105339] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/16/2022]
Abstract
Little is known about the presence of vector-borne bacteria in southwest Madagascar. Anthropogenic alteration of natural habitats represents an important driver for the emergence of new diseases. Especially the involvement of livestock and the involuntary maintaining of invasive synanthropic animals (particularly rats) facilitate disease transmission from wildlife to humans and associated animals and vice versa. The dissemination or acquisition of ectoparasites is most likely in regions where human/wildlife contact is increasing. Little is known about the presence of vector-borne bacteria in southwest Madagascar. In 2016 and 2017, ectoparasites were collected from various introduced (cattle and goats, cats, dogs and chicken, rats and mice) and native animal species (mouse lemurs [Microcebus griseorufus], Grandidier's mongooses [Galidictis grandidieri], bastard big-footed mice [Macrotarsomys bastardi], greater hedgehog tenrecs [Setifer setosus] and lesser hedgehog tenrecs [Echinops telfairi]) in the northern portion of Tsimanampetsotsa National Park and the adjacent littoral region. Thirteen species of blood-feeding ectoparasites (235 individuals of ticks [5 species], 414 lice [4 spp.] and 389 fleas [4 spp.]) were investigated for the presence and identity of rickettsiae, borreliae, bartonellae and Yersinia pestis using PCR techniques. Rickettsia spp. were detected in every single ectoparasite species (Amblyomma variegatum, A. chabaudi, Rhipicephalus microplus, Haemaphysalis simplex, Argas echinops, Ctenocephalides felis, Echidnophaga gallinacea, Pulex irritans, Xenopsylla cheopis, Haematopinus quadripertusus, Linognathus africanus, L. vituli, Lemurpediculus verruculosus). Lice and ticks were found harboring rickettsiae identified as Rickettsia africae, while Rickettsia felis-like bacteria were associated with fleas. Borrelia spp. were detected in 5% of H. simplex and 1% of R. microplus ticks. Bartonella spp. were detected in 40% of H. quadripertusus pools and in 5% of L. verruculosus pools. Y. pestis was detected in X. cheopis and E. gallinacea fleas collected from a rat. This study presents the detection of a broad spectrum of vector-borne bacteria including potential pathogens, and an unexpected finding of Y. pestis far off the known plague foci in Madagascar.
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Amblyomma hebraeum is the predominant tick species on goats in the Mnisi Community Area of Mpumalanga Province South Africa and is co-infected with Ehrlichia ruminantium and Rickettsia africae. Parasit Vectors 2020; 13:172. [PMID: 32312285 PMCID: PMC7171862 DOI: 10.1186/s13071-020-04059-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 04/01/2020] [Indexed: 12/16/2022] Open
Abstract
Background In sub-Saharan Africa, Amblyomma ticks are vectors of heartwater disease in domestic ruminants, caused by the rickettsial pathogen Ehrlichia ruminantium. Immature tick stages often bite humans, whereby they act as vectors of tick-bite fever caused by Rickettsia africae. Moreover, Amblyomma ticks cause damage to livestock due to their feeding behaviour. In South Africa, we studied the abundance of Amblyomma hebraeum ticks on goats of emerging farmers in Mpumalanga Province. A selected number of A. hebraeum nymphs and adult ticks was tested for co-infection with E. ruminantium and R. africae. Methods A total of 630 indigenous goats, belonging to farmers in the Mnisi Community area, were examined for ticks in 2013 and 2014. All ticks were identified, and a selected number was tested by PCR with reverse line blot hybridisation. Results In total, 13,132 ticks were collected from goats distributed over 17 different households. Amblyomma hebraeum was the predominant species, followed by R. microplus. Rhipicephalus appendiculatus, R. simus and R. zambeziensis were also identified. Amblyomma hebraeum was present throughout the year, with peak activity of adults in summer (November) and nymphs in winter (July). The ratio between adults and nymphs ranged from 1:2.7 in summer to 1:55.1 in winter. The mean prevalence of infection for E. ruminantium by PCR/RLB in adult ticks was 17.4% (31/178), whereas 15.7% (28/178) were infected with R. africae. In pooled nymphs, 28.4% were infected with E. ruminantium and 38.8% carried R. africae infection. Co-infections of E. ruminantium and R. africae in adult and pooled nymphal ticks were 3.9% (7/178) and 10% (14.9), respectively. Lameness of goats due to predilection of ticks for the interdigital space of their feet was observed in 89% of the households. Conclusions Goats act as important alternative hosts for cattle ticks, which underscored the necessity to include goats in control programs. It is suggested to use acaricide-impregnated leg-bands as a sustainable method to kill ticks and prevent lameness in goats. The challenge of goats by considerable numbers of E. ruminantium-infected ticks is a major obstacle for upgrading the indigenous goat breeds. Humans may be at risk to contract tick-bite fever in this area.![]()
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Schafbauer T, Dreyfus A, Hogan B, Rakotozandrindrainy R, Poppert S, Straubinger RK. Seroprevalence of Leptospira spp. Infection in Cattle from Central and Northern Madagascar. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16112014. [PMID: 31174244 PMCID: PMC6603958 DOI: 10.3390/ijerph16112014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/03/2019] [Accepted: 06/05/2019] [Indexed: 12/25/2022]
Abstract
Leptospirosis is a zoonotic disease of global importance, especially in tropical countries. The current Leptospira spp. seroprevalence in cattle from central and northern Madagascar is unknown. Thus, the aim of this study was to determine the seroprevalence resulting from infections with pathogenic Leptospira spp. in zebu cattle from these areas. Serum samples from 194 animals were tested by microscopic agglutination test (MAT) using a panel of 12 serovars as antigens. Samples with a titer of ≥1:100 were considered positive. The overall seroprevalence was 59.3% (95% CI; 52.0–66.2%) with titers ranging from 1:100 to 1:1600. Among the seropositive animals, the most frequent antibody reactions were against serovar L. Tarassovi (serogroup L. Tarassovi) with 40.2% (33.3–47.5%), followed by L. Hardjo (L. Sejroe) with 13.9% (9.5–19.8%), L. Grippotyphosa (L. Grippotyphosa) with 9.8% (6.2–15.1%), L. Pomona (L. Pomona) with 7.7% (4.5–12.7%) and L. Autumnalis (L. Autumnalis) with 5.2% (2.6–9.5%). Less than 5% of the samples reacted positively against the remaining serovars. These results indicate a very high exposure of Malagasy cattle to Leptospira spp. which, consequently, poses a definite risk for people working with cattle acquiring this zoonotic infection.
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Affiliation(s)
- Theresa Schafbauer
- Bacteriology and Mycology, Institute for Infectious Diseases and Zoonoses, Department of Veterinary Sciences, Faculty of Veterinary Medicine, LMU Munich, Veterinaerstr. 13, 80539 Munich, Germany.
| | - Anou Dreyfus
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.
- Faculty of Medicine, University Basel, 4056 Basel, Switzerland.
| | - Benedikt Hogan
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany.
| | - Raphael Rakotozandrindrainy
- Department of Microbiology and Parasitology, University of Antananarivo, BP 566, Antananarivo 101, Madagascar.
| | - Sven Poppert
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.
- Faculty of Medicine, University Basel, 4056 Basel, Switzerland.
| | - Reinhard K Straubinger
- Bacteriology and Mycology, Institute for Infectious Diseases and Zoonoses, Department of Veterinary Sciences, Faculty of Veterinary Medicine, LMU Munich, Veterinaerstr. 13, 80539 Munich, Germany.
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Rauch J, Muntau B, Eggert P, Tappe D. Rickettsia typhi as Cause of Fatal Encephalitic Typhus in Hospitalized Patients, Hamburg, Germany, 1940-1944. Emerg Infect Dis 2019; 24:1982-1987. [PMID: 30334722 PMCID: PMC6200005 DOI: 10.3201/eid2411.171373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We evaluated formalin-fixed paraffin-embedded tissue specimens from 7 patients who died with encephalitic typhus in Hamburg, Germany, during World War II. The archived specimens included only central nervous system tissues >70 years old that had been stored at room temperature. We demonstrated successful detection of Rickettsia typhi DNA by a nested qPCR specific to prsA in 2 patients. These results indicate that R. typhi infections contributed to typhus outbreaks during World War II. Immunohistochemical analyses of brain tissue specimens of R. typhi DNA-positive and -negative specimens showed perivascular B-cell accumulation. Around blood vessels, nodular cell accumulations consisted of CD4-positive and CD8-positive T cells and CD68-positive microglia and macrophages; neutrophils were found rarely. These findings are similar to those of previously reported R. prowazekii tissue specimen testing. Because R. typhi and R. prowazekii infections can be clinically and histopathologically similar, molecular analyses should be performed to distinguish the 2 pathogens.
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Rauch J, Eisermann P, Noack B, Mehlhoop U, Muntau B, Schäfer J, Tappe D. Typhus Group Rickettsiosis, Germany, 2010-2017 1. Emerg Infect Dis 2019; 24:1213-1220. [PMID: 29912688 PMCID: PMC6038764 DOI: 10.3201/eid2407.180093] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Typhus group rickettsiosis is caused by the vectorborne bacteria Rickettsia typhi and R. prowazekii. R. typhi, which causes murine typhus, the less severe endemic form of typhus, is transmitted by fleas; R. prowazekii, which causes the severe epidemic form of typhus, is transmitted by body lice. To examine the immunology of human infection with typhus group rickettsiae, we retrospectively reviewed clinical signs and symptoms, laboratory changes, and travel destinations of 28 patients who had typhus group rickettsiosis diagnosed by the German Reference Center for Tropical Pathogens, Hamburg, Germany, during 2010-2017. Immunofluorescence assays of follow-up serum samples indicated simultaneous seroconversion of IgM, IgA, and IgG or concurrence in the first serum sample. Cytokine levels peaked during the second week of infection, coinciding with organ dysfunction and seroconversion. For 3 patients, R. typhi was detected by species-specific nested quantitative PCR. For all 28 patients, R. typhi was the most likely causative pathogen.
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Tappe D, Booken N, Böer-Auer A, Rauch J, Schmiedel S, Reich K. Histology and Serum Cytokine Responses in an Imported Rickettsia slovaca Infection, Germany. Am J Trop Med Hyg 2018; 98:248-251. [PMID: 29141745 DOI: 10.4269/ajtmh.17-0392] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Rickettsia slovaca, a spotted fever group rickettsial pathogen, causes a syndrome consisting of scalp eschar and neck lymphadenopathy following tick bite. We analyzed the histologic skin reaction in the eschar, showing a prominent eosinophilic infiltration, as well as the presence of B lymphocytes and CD4- and CD8-positive T cells. Examination of the serum cytokine responses over time demonstrated an initial proinflammatory cytokine elevation followed by normalization.
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Affiliation(s)
- Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | | | - Jessica Rauch
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefan Schmiedel
- Division of Infectious Diseases and Tropical Medicine, University Medical Center Hamburg Eppendorf, Hamburg, Germany
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Cherry CC, Denison AM, Kato CY, Thornton K, Paddock CD. Diagnosis of Spotted Fever Group Rickettsioses in U.S. Travelers Returning from Africa, 2007-2016. Am J Trop Med Hyg 2018; 99:136-142. [PMID: 29848404 DOI: 10.4269/ajtmh.17-0882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Spotted fever group rickettsioses (SFGRs), such as African tick bite fever (ATBF), are among the most commonly diagnosed diseases for ill travelers returning from southern Africa. We summarized demographic, clinical, and diagnostic features of imported SFGR cases in U.S. travelers returning from Africa who had laboratory specimens submitted to the Centers for Disease Control and Prevention. Diagnosis of SFGR was performed by indirect immunofluorescence antibody assay, immunohistochemical staining, polymerase chain reaction (PCR), or culture. Cases were defined as probable SFGR, confirmed SFGR, or confirmed ATBF. Clinical and epidemiological categorical variables were described as counts and proportions; continuous variables were described using geometric mean titers, median, and range. One hundred and twenty-seven patients satisfied laboratory criteria for confirmed or probable SFGR. Fever was the most common symptom (N = 88; 69%), followed by ≥ 1 eschars (N = 70; 55%). Paired serums were submitted for 36 patients (28%); 12 patients (33%) had nonreactive initial serum sample but converted to a titer ≥ 64 with the convalescent sample. Twenty-seven patients (21%) had infection with Rickettsia africae based on PCR analysis of eschar swab (N = 8) or biopsy (N = 23). Fifteen patients had eschar biopsy or swab samples and serum sample(s) submitted together; 9 (60%) had PCR-positive eschar results and nonreactive acute serology. Health-care providers should consider SFGR when evaluating patients for a febrile illness with eschar and compatible foreign travel history. Polymerase chain reaction testing of eschar biopsies or swabs provides a confirmed diagnosis in early stages of disease; eschar swabs or biopsies are an underutilized diagnostic technique.
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Affiliation(s)
- Cara C Cherry
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Amy M Denison
- Infectious Diseases Pathology Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Cecilia Y Kato
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Katrina Thornton
- Epidemiology Elective Program, Center for Surveillance, Epidemiology, and Laboratory Services, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Christopher D Paddock
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
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Vanegas A, Keller C, Krüger A, Manchang TK, Hagen RM, Frickmann H, Veit A, Achukwi MD, Krücken J, Poppert S. Molecular detection of spotted fever group rickettsiae in ticks from Cameroon. Ticks Tick Borne Dis 2018; 9:1049-1056. [PMID: 29636236 DOI: 10.1016/j.ttbdis.2018.03.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
Abstract
In western and eastern Africa, rickettsioses are one cause of fever in humans. Little is known regarding the presence of Rickettsia sp. in northern Cameroon. The present work was conducted in order to identify potential tick-borne spotted fever group Rickettsia in the Adamawa region of northern Cameroon, which may contribute filling some of the knowledge gaps of these pathogens. Ticks were collected from cattle in the municipal slaughterhouse of Ngaoundere in the Adamawa region of northern Cameroon. After morphological identification of tick species, extracted DNA was analyzed by PCR targeting the rickettsial ompB gene and the intergenic spacers dksA-xerC, mppA-purC and rpmE-tRNAfMet. Of the 316 adult ticks collected, 149 (47.1%) were Amblyomma variegatum, 92 (29%) Rhipicephalus spp. and 75 (23.7%) Hyalomma spp. Through the use of conventional PCR assays for the rickettsial ompB gene, rickettsial DNA was detected in 104 (32.9%) samples (85 Amblyomma sp., 14 Hyalomma spp. and 5 Rhipicephalus spp.). The ompB gene and the three intergenic were sequenced for 10 ticks in order to determine the rickettsial species. Rickettsia africae was detected in Amblyomma variegatum, Rickettsia aeschlimannii in Hyalomma rufipes and Hyalomma truncatum, Rickettsia sibirica in H. truncatum, Rickettsia massiliae in Rhipicephalus lunulatus and Candidatus Rickettsia barbariae in R. lunulatus. To the best of the author's knowledge, this report represents the first molecular evidence of rickettsial infection in ticks in the Adamawa region of northern Cameroon, which suggests a possible exposure of the human population in this region.
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Affiliation(s)
- Andrea Vanegas
- Department of Dermatology, Bundeswehr Hospital Hamburg, Lesserstr. 180, 22049 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
| | - Christian Keller
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
| | - Andreas Krüger
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
| | - Tanyi K Manchang
- Veterinary Research Laboratory, Institute of Agricultural Research for Development, Wakwa Regional Center, B.P. 65 Ngaoundere, Cameroon.
| | - Ralf M Hagen
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
| | - Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
| | - Alexandra Veit
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
| | - Mbunkah D Achukwi
- Veterinary Research Laboratory, Institute of Agricultural Research for Development, Wakwa Regional Center, B.P. 65 Ngaoundere, Cameroon.
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von Ostertag-Str. 7-13, 14163 Berlin, Germany.
| | - Sven Poppert
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
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Orientia tsutsugamushi Is Highly Susceptible to the RNA Polymerase Switch Region Inhibitor Corallopyronin A In Vitro and In Vivo. Antimicrob Agents Chemother 2018; 62:AAC.01732-17. [PMID: 29358295 DOI: 10.1128/aac.01732-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/12/2018] [Indexed: 01/19/2023] Open
Abstract
Scrub typhus is a potentially lethal infection caused by the obligate intracellular bacterium Orientia tsutsugamushi Reports on the emergence of doxycycline-resistant strains highlight the urgent need to develop novel antiinfectives against scrub typhus. Corallopyronin A (CorA) is a novel α-pyrone compound synthesized by the myxobacterium Corallococcus coralloides that was characterized as a noncompetitive inhibitor of the switch region of the bacterial RNA polymerase (RNAP). We investigated the antimicrobial action of CorA against the human-pathogenic Karp strain of O. tsutsugamushiin vitro and in vivo The MIC of CorA against O. tsutsugamushi was remarkably low (0.0078 μg/ml), 16-fold lower than that against Rickettsia typhi In the lethal intraperitoneal O. tsutsugamushi mouse infection model, a minimum daily dose of 100 μg CorA protected 100% of infected mice. Two days of treatment were sufficient to confer protection. In contrast to BALB/c mice, SCID mice succumbed to the infection despite treatment with CorA or tetracycline, suggesting that antimicrobial treatment required synergistic action of the adaptive immune response. Similar to tetracycline, CorA did not prevent latent infection of O. tsutsugamushiin vivo However, latency was not caused by acquisition of antimicrobial resistance, since O. tsutsugamushi reisolated from latently infected BALB/c mice remained fully susceptible to CorA. No mutations were found in the CorA-binding regions of the β and β' RNAP subunit genes rpoB and rpoC Inhibition of the RNAP switch region of O. tsutsugamushi by CorA is therefore a novel and highly potent target for antimicrobial therapy for scrub typhus.
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Presence of Borrelia spp. DNA in ticks, but absence of Borrelia spp. and of Leptospira spp. DNA in blood of fever patients in Madagascar. Acta Trop 2018; 177:127-134. [PMID: 28986249 DOI: 10.1016/j.actatropica.2017.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 09/25/2017] [Accepted: 10/02/2017] [Indexed: 02/02/2023]
Abstract
The occurrence of tick-borne relapsing fever and leptospirosis in humans in Madagascar remains unclear despite the presence of their potential vectors and reservoir hosts. We screened 255 Amblyomma variegatum ticks and 148 Rhipicephalus microplus ticks from Zebu cattle in Madagascar for Borrelia-specific DNA. Borrelia spp. DNA was detected in 21 Amblyomma variegatum ticks and 2 Rhipicephalus microplus ticks. One Borrelia found in one Rhipicephalus microplus showed close relationship to Borrelia theileri based on genetic distance and phylogenetic analyses on 16S rRNA and flaB sequences. The borreliae from Amblyomma variegatum could not be identified due to very low quantities of present DNA reflected by high cycle threshold values in real-time-PCR. It is uncertain whether these low numbers of Borrelia spp. are sufficient for transmission of infection from ticks to humans. In order to determine whether spirochaete infections are relevant in humans, blood samples of 1009 patients from the highlands of Madagascar with fever of unknown origin were screened for Borrelia spp. - and in addition for Leptospira spp. - by real-time PCR. No target DNA was detected, indicating a limited relevance of these pathogens for humans in the highlands of Madagascar.
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Are brucellosis, Q fever and melioidosis potential causes of febrile illness in Madagascar? Acta Trop 2017; 172:255-262. [PMID: 28502643 DOI: 10.1016/j.actatropica.2017.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 12/18/2022]
Abstract
Brucellosis, Q fever and melioidosis are zoonoses, which can lead to pyrexia. These diseases are often under-ascertained and underreported because of their unspecific clinical signs and symptoms, insufficient awareness by physicians and public health officers and limited diagnostic capabilities, especially in low-resource countries. Therefore, the presence of Brucella spp., Coxiella burnetii and Burkholderia pseudomallei was investigated in Malagasy patients exhibiting febrile illness. In addition, we analyzed zebu cattle and their ticks as potential reservoirs for Brucella and C. burnetii, respectively. Specific quantitative real-time PCR assays (qPCRs) were performed on 1020 blood samples drawn from febrile patients. In total, 15 samples (1.5%) were Brucella-positive, mainly originating from patients without travel history, while DNA from C. burnetii and Bu. pseudomallei was not detected. Anti-C. burnetii antibodies were found in four out of 201 zebu serum samples (2%), whereas anti-Brucella antibodies could not be detected. Brucella DNA was detected in a single zebu sample. Three out of 330 ticks analyzed (1%) were positively tested for C. burnetii DNA but with high Ct values in the qPCR assay. Our data suggest that zebus as well as Amblyomma and Boophilus ticks have to be considered as a natural reservoir or vector for C. burnetii, but the risk of cattle-to-human transmission is low. Since bovine brucellosis does not seem to contribute to human infections in Madagascar, other transmission routes have to be assumed.
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GFPuv-Expressing Recombinant Rickettsia typhi: a Useful Tool for the Study of Pathogenesis and CD8 + T Cell Immunology in R. typhi Infection. Infect Immun 2017; 85:IAI.00156-17. [PMID: 28289147 PMCID: PMC5442613 DOI: 10.1128/iai.00156-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 03/06/2017] [Indexed: 11/20/2022] Open
Abstract
Rickettsia typhi is the causative agent of endemic typhus, a disease with increasing incidence worldwide that can be fatal. Because of its obligate intracellular life style, genetic manipulation of the pathogen is difficult. Nonetheless, in recent years, genetic manipulation tools have been successfully applied to rickettsiae. We describe here for the first time the transformation of R. typhi with the pRAM18dRGA plasmid that originally derives from Rickettsia amblyommatis and encodes the expression of GFPuv (green fluorescent protein with maximal fluorescence when excited by UV light). Transformed R. typhi (R. typhiGFPuv) bacteria are viable, replicate with kinetics similar to those of wild-type R. typhi in cell culture, and stably maintain the plasmid and GFPuv expression under antibiotic treatment in vitro and in vivo during infection of mice. CB17 SCID mice infected with R. typhiGFPuv succumb to the infection with kinetics similar to those for animals infected with wild-type R. typhi and develop comparable pathology and bacterial loads in the organs, demonstrating that the plasmid does not influence pathogenicity. In the spleen and liver of infected CB17 SCID mice, the bacteria are detectable by immunofluorescence microscopy in neutrophils and macrophages by histological staining. Finally, we show for the first time that transformed rickettsiae can be used for the detection of CD8+ T cell responses. GFP-specific restimulation of spleen cells from R. typhiGFPuv-infected BALB/c mice elicits gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and interleukin 2 (IL-2) secretion by CD8+ T cells. Thus, R. typhiGFPuv bacteria are a novel, potent tool to study infection with the pathogen in vitro and in vivo and the immune response to these bacteria.
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Molecular and serological evidence of flea-associated typhus group and spotted fever group rickettsial infections in Madagascar. Parasit Vectors 2017; 10:125. [PMID: 28259176 PMCID: PMC5336680 DOI: 10.1186/s13071-017-2061-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/24/2017] [Indexed: 12/25/2022] Open
Abstract
Background Rickettsiae are obligate intracellular bacteria responsible for many febrile syndromes around the world, including in sub-Saharan Africa. Vectors of these pathogens include ticks, lice, mites and fleas. In order to assess exposure to flea-associated Rickettsia species in Madagascar, human and small mammal samples from an urban and a rural area, and their associated fleas were tested. Results Anti-typhus group (TGR)- and anti-spotted fever group rickettsiae (SFGR)-specific IgG were detected in 24 (39%) and 21 (34%) of 62 human serum samples, respectively, using indirect ELISAs, with six individuals seropositive for both. Only two (2%) Rattus rattus out of 86 small mammals presented antibodies against TGR. Out of 117 fleas collected from small mammals, Rickettsia typhi, a TGR, was detected in 26 Xenopsylla cheopis (24%) collected from rodents of an urban area (n = 107), while two of these urban X. cheopis (2%) were positive for Rickettsia felis, a SFGR. R. felis DNA was also detected in eight (31%) out of 26 Pulex irritans fleas. Conclusions The general population in Madagascar are exposed to rickettsiae, and two flea-associated Rickettsia pathogens, R. typhi and R. felis, are present near or in homes. Although our results are from a single district, they demonstrate that rickettsiae should be considered as potential agents of undifferentiated fever in Madagascar.
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Papp S, Rauch J, Kuehl S, Richardt U, Keller C, Osterloh A. Comparative evaluation of two Rickettsia typhi-specific quantitative real-time PCRs for research and diagnostic purposes. Med Microbiol Immunol 2016; 206:41-51. [PMID: 27696011 DOI: 10.1007/s00430-016-0480-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 09/21/2016] [Indexed: 01/03/2023]
Abstract
Rickettsioses are caused by intracellular bacteria of the family of Rickettsiaceae. Rickettsia (R.) typhi is the causative agent of endemic typhus. The disease occurs worldwide and is one of the most prevalent rickettsioses. Rickettsial diseases, however, are generally underdiagnosed which is mainly due to the lack of sensitive and specific methods. In addition, methods for quantitative detection of the bacteria for research purposes are rare. We established two qPCRs for the detection of R. typhi by amplification of the outer membrane protein B (ompB) and parvulin-type PPIase (prsA) genes. Both qPCRs are specific and exclusively recognize R. typhi but no other rickettsiae including the closest relative, R. prowazekii. The prsA-based qPCR revealed to be much more sensitive than the amplification of ompB and provided highly reproducible results in the detection of R. typhi in organs of infected mice. Furthermore, as a nested PCR the prsA qPCR was applicable for the detection of R. typhi in human blood samples. Collectively, the prsA-based qPCR represents a reliable method for the quantitative detection of R. typhi for research purposes and is a promising candidate for differential diagnosis.
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Affiliation(s)
- Stefanie Papp
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Jessica Rauch
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Svenja Kuehl
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Ulricke Richardt
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Christian Keller
- Institute for Virology, University Medical Center Gießen and Marburg, 35032, Marburg, Germany
| | - Anke Osterloh
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany.
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Tomassone L, De Meneghi D, Adakal H, Rodighiero P, Pressi G, Grego E. Detection of Rickettsia aeschlimannii and Rickettsia africae in ixodid ticks from Burkina Faso and Somali Region of Ethiopia by new real-time PCR assays. Ticks Tick Borne Dis 2016; 7:1082-1088. [PMID: 27641952 DOI: 10.1016/j.ttbdis.2016.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/09/2016] [Accepted: 09/10/2016] [Indexed: 11/16/2022]
Abstract
In the framework of cooperation for development projects in Burkina Faso and Ethiopia, we collected ixodid ticks from cattle, small ruminants and camels. We optimized new TaqMan Probe real-time PCR assays to detect Rickettsia aeschlimannii and Rickettsia africae OmpA gene in the collected samples. Rickettsia africae was identified in 75.0% Amblyomma variegatum (95%CI: 56.6-88.5), while R. aeschlimannii in 24.0% Hyalomma truncatum (95%CI: 9.4-45.1) and 50.0% H. rufipes (95%CI: 29.9-70.0) collected from cattle in different provinces throughout Burkina Faso. Ticks from the Libaan zone, Somali Region of Ethiopia, were also infected by R. africae (28.5% prevalence in Amblyomma gemma, 95%CI: 14.7-46.0) and R. aeschlimannii (27.0% H. truncatum, 95%CI: 5.0-62.9; 88.3% H. rufipes, 95%CI: 60.5-99.3). All tested ticks were adults. The developed diagnostic tools were highly sensitive and enabled us to rapidly classify R. aeschlimannii and R. africae, which were identified in Burkina Faso and in the Somali Region of Ethiopia for the first time. Further studies are needed to assess the zoonotic risk and prevalence of infection in local human populations, who have high contact rates with ticks and their animal hosts.
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Affiliation(s)
- L Tomassone
- Dipartimento Scienze Veterinarie, Università degli Studi di Torino, Largo Braccini 2, 10095 Grugliasco, Torino, Italy.
| | - D De Meneghi
- Dipartimento Scienze Veterinarie, Università degli Studi di Torino, Largo Braccini 2, 10095 Grugliasco, Torino, Italy
| | - H Adakal
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide - CIRDES, Bobo Dioulasso, Burkina Faso; present affiliation: Département Sciences et Techniques de l'Elevage, Université Dan Dicko Dankoulodo de Maradi, Niger
| | - P Rodighiero
- Comitato di Collaborazione Medica, via Cirié 32/e, Torino, Italy; present affiliation: Associazione Veterinaria di Cooperazione con i Paesi in Via di Sviluppo - AVEC PVS, Via Laffait 13, Donnas, Aosta, Italy
| | - G Pressi
- Comitato di Collaborazione Medica, via Cirié 32/e, Torino, Italy; present affiliation: Associazione Veterinaria di Cooperazione con i Paesi in Via di Sviluppo - AVEC PVS, Via Laffait 13, Donnas, Aosta, Italy
| | - E Grego
- Dipartimento Scienze Veterinarie, Università degli Studi di Torino, Largo Braccini 2, 10095 Grugliasco, Torino, Italy
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