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Tinto B, Quellec J, Cêtre-Sossah C, Dicko A, Salinas S, Simonin Y. Rift Valley fever in West Africa: A zoonotic disease with multiple socio-economic consequences. One Health 2023; 17:100583. [PMID: 37664171 PMCID: PMC10474305 DOI: 10.1016/j.onehlt.2023.100583] [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: 02/20/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 09/05/2023] Open
Abstract
Rift Valley fever virus (RVFV) is an arbovirus that causes Rift Valley fever (RVF), a zoonotic disease that mainly affects domestic and wildlife ruminants and humans. The first epidemic in North-Western and West Africa occurred in Senegal and Mauritania in 1987, two countries where RVF is now endemic. Slaughterhouse workers, farmers, herders and veterinarians are at high risk of exposure to RVF. Beyond the health threat, RVF is considered to cause major socio-economic problems, specifically in developing countries where livestock farming and trade are important economic activities. Indeed, the mortality rate linked to RVF infection can reach 95-100% in newborns and young animals. In West Africa, livestock production is a key factor for food production and for national economics. Epizootics caused by RVF can therefore have serious socio-economic consequences by impacting multisectoral economics, the psycho-social health of pastoral communities, and food security. Improving prevention strategies against RVF, including vaccination, enhancing knowledge of RVF and correcting any inappropriate behaviors by populations of endemics areas, as well as better monitoring of RVF ecological factors are effective ways to better foresee and control outbreaks of RVF and its socio-economical side-effects in countries at high risk of occurrence of the disease.
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Affiliation(s)
- Bachirou Tinto
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
- Laboratoire National de Référence des Fièvres Hémorragiques Virale, Centre MURAZ, Institut National de Santé Publique (INSP), Bobo-Dioulasso, Burkina Faso
| | - Jordan Quellec
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
- ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France
| | | | - Amadou Dicko
- Laboratoire central de référence, Institut National de Santé Publique (INSP), Ouagadougou, Burkina Faso
- Ministère de l'Agriculture, des ressources animales et halieutiques du Burkina Faso, Ouagadougou, Burkina Faso
| | - Sara Salinas
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
| | - Yannick Simonin
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
- ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France
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Ebogo‐Belobo JT, Kenmoe S, Abanda NN, Bowo‐Ngandji A, Mbaga DS, Magoudjou‐Pekam JN, Kame‐Ngasse GI, Tchatchouang S, Menkem EZ, Okobalemba EA, Noura EA, Meta‐Djomsi D, Maïdadi‐Foudi M, Kenfack‐Zanguim J, Kenfack‐Momo R, Kengne‐Nde C, Esemu SN, Mbacham WF, Sadeuh‐Mba SA, Ndip L, Njouom R. Contemporary epidemiological data of Rift Valley fever virus in humans, mosquitoes and other animal species in Africa: A systematic review and meta-analysis. Vet Med Sci 2023; 9:2309-2328. [PMID: 37548116 PMCID: PMC10508527 DOI: 10.1002/vms3.1238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/29/2023] [Accepted: 07/21/2023] [Indexed: 08/08/2023] Open
Abstract
Rift Valley fever (RVF) is a severe zoonotic mosquito-borne disease that represents an important threat to human and animal health, with major public health and socioeconomic impacts. This disease is endemic throughout many African countries and the Arabian Peninsula. This systematic review with meta-analysis was conducted to determine the RVF prevalence in humans, mosquitoes and other animal species in Africa. The review also provides contemporary data on RVF case fatality rate (CFR) in humans. In this systematic review with meta-analysis, a comprehensive literature search was conducted on the PubMed, Embase, Web of Science and Global Index Medicus databases from January 2000 to June 2022 to identify relevant studies. Pooled CFR and prevalence estimates were calculated using the random-effects model. Subgroup analysis and sensitivity analysis were performed, and the I2 -statistic was used to investigate a potential source of heterogeneity. A total of 205 articles were included in the final analysis. The overall RVF CFR in humans was found to be 27.5% [95% CI = 8.0-52.5]. The overall pooled prevalence was 7.8% [95% CI = 6.2-9.6] in humans and 9.3% [95% CI = 8.1-10.6] in animals, respectively. The RVF prevalence in individual mosquitoes ranged from 0.0% to 25%. Subgroup analysis showed substantial heterogeneity with respect to geographical regions and human categories. The study shows that there is a correspondingly similar prevalence of RVF in human and animals; however, human CFR is much higher than the observed prevalence. The lack of a surveillance programme and the fact that this virus has subclinical circulation in animals and humans could explain these observations. The implementation of a One Health approach for RVF surveillance and control would be of great interest for human and animal health.
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Affiliation(s)
- Jean Thierry Ebogo‐Belobo
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Sebastien Kenmoe
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Ngu Njei Abanda
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
| | - Arnol Bowo‐Ngandji
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Donatien Serge Mbaga
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | | | - Ginette Irma Kame‐Ngasse
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | | | | | - Efietngab Atembeh Noura
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Dowbiss Meta‐Djomsi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Martin Maïdadi‐Foudi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | - Raoul Kenfack‐Momo
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Cyprien Kengne‐Nde
- Epidemiological Surveillance, Evaluation and Research UnitNational AIDS Control CommitteeYaoundéCameroon
| | | | - Wilfred Fon Mbacham
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Serge Alain Sadeuh‐Mba
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
- Maryland Department of AgricultureSalisbury Animal Health LaboratorySalisburyMarylandUSA
| | - Lucy Ndip
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Richard Njouom
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
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Tober AV, Govender D, Russo IRM, Cable J. The microscopic five of the big five: Managing zoonotic diseases within and beyond African wildlife protected areas. ADVANCES IN PARASITOLOGY 2022; 117:1-46. [PMID: 35878948 DOI: 10.1016/bs.apar.2022.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
African protected areas strive to conserve the continent's great biodiversity with a targeted focus on the flagship 'Big Five' megafauna. Though often not considered, this biodiversity protection also extends to the lesser-known microbes and parasites that are maintained in these diverse ecosystems, often in a silent and endemically stable state. Climate and anthropogenic change, and associated diversity loss, however, are altering these dynamics leading to shifts in ecological interactions and pathogen spill over into new niches and hosts. As many African protected areas are bordered by game and livestock farms, as well as villages, they provide an ideal study system to assess infection dynamics at the human-livestock-wildlife interface. Here we review five zoonotic, multi-host diseases (bovine tuberculosis, brucellosis, Rift Valley fever, schistosomiasis and cryptosporidiosis)-the 'Microscopic Five'-and discuss the biotic and abiotic drivers of parasite transmission using the iconic Kruger National Park, South Africa, as a case study. We identify knowledge gaps regarding the impact of the 'Microscopic Five' on wildlife within parks and highlight the need for more empirical data, particularly for neglected (schistosomiasis) and newly emerging (cryptosporidiosis) diseases, as well as zoonotic disease risk from the rising bush meat trade and game farm industry. As protected areas strive to become further embedded in the socio-economic systems that surround them, providing benefits to local communities, One Health approaches can help maintain the ecological integrity of ecosystems, while protecting local communities and economies from the negative impacts of disease.
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Affiliation(s)
- Anya V Tober
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom.
| | - Danny Govender
- SANParks, Scientific Services, Savanna and Grassland Research Unit, Pretoria, South Africa; Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
| | - Isa-Rita M Russo
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Jo Cable
- School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
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Saeed OS, El-Deeb AH, Gadalla MR, El-Soally SAG, Ahmed HAH. Genetic Characterization of Rift Valley Fever Virus in Insectivorous Bats, Egypt. Vector Borne Zoonotic Dis 2021; 21:1003-1006. [PMID: 34958267 DOI: 10.1089/vbz.2021.0054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: The endemic character of Rift Valley fever (RVF) disease points toward an interepidemic reservoir. Although not yet identified, bats and rodents may be implicated in RVF virus (RVFV) epidemiology. In this study, we investigated the putative role of Egyptian frugivorous and insectivorous bats in RVFV epidemiology in Egypt. Methods: From 2019 to 2021, 200 bats of two different species from six Egyptian governorates were tested for phleboviruses using real-time RT-PCR (rRT-PCR) and sequence analysis. Results: Screening through rRT-PCR showed evidence of the RVFV genome only in insectivorous bats. Partial sequence and phylogenetic analysis based on S and M genome segments showed that these viruses are genetically similar to those circulating (clade A) in livestock and humans during previously reported RVFV outbreaks in 1977/78 and 2003 in Egypt. Conclusions: Our molecular data suggest that the bat Pipistrellus deserti could play a role in RVFV ecology in Egypt.
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Affiliation(s)
- Omar Sayed Saeed
- Department of Virology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt
| | - Ayman Hany El-Deeb
- Department of Virology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt
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Wielgus E, Caron A, Bennitt E, De Garine‐Wichatitsky M, Cain B, Fritz H, Miguel E, Cornélis D, Chamaillé‐Jammes S. Inter‐Group Social Behavior, Contact Patterns and Risk for Pathogen Transmission in Cape Buffalo Populations. J Wildl Manage 2021. [DOI: 10.1002/jwmg.22116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elodie Wielgus
- Department of Natural Sciences Manchester Metropolitan University, All Saints Manchester M15 6BH UK
| | - Alexandre Caron
- Faculdade de Veterinária Universidade Eduardo Mondlane Av. De Moçambique, CP 257 Maputo Mozambique
| | - Emily Bennitt
- Okavango Research Institute University of Botswana Shorobe Road Maun Botswana
| | | | - Bradley Cain
- Department of Natural Sciences Manchester Metropolitan University, All Saints Manchester M15 6BH UK
| | - Herve Fritz
- REHABS, CNRS ‐ Université Lyon 1 ‐ Nelson Mandela University International Research Laboratory George Campus, Madiba Drive George South Africa
| | - Eve Miguel
- Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle Institut de Recherche pour le Développement 911 Avenue Agropolis, 34394 Montpellier cedex 5 France
| | - Daniel Cornélis
- CIRAD, Forêts et Sociétés, F‐34398 Montpellier, France; Forêts et Sociétés Université de Montpellier CIRAD, 34090 Montpellier France
| | - Simon Chamaillé‐Jammes
- CEFE, University of Montpellier, CNRS, EPHE, IRD University Paul Valéry Montpellier 3 Montpellier France
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Sporadic Rift Valley Fever Outbreaks in Humans and Animals in Uganda, October 2017-January 2018. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2021; 2021:8881191. [PMID: 34594384 PMCID: PMC8478567 DOI: 10.1155/2021/8881191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/29/2020] [Accepted: 08/17/2021] [Indexed: 11/17/2022]
Abstract
Introduction Rift Valley fever (RVF) is a mosquito-borne viral zoonosis. The Uganda Ministry of Health received alerts of suspected viral haemorrhagic fever in humans from Kiruhura, Buikwe, Kiboga, and Mityana districts. Laboratory results from Uganda Virus Research Institute indicated that human cases were positive for Rift Valley fever virus (RVFV) by polymerase chain reaction. We investigated to determine the scope of outbreaks, identify exposure factors, and recommend evidence-based control and prevention measures. Methods A suspected case was defined as a person with acute fever onset, negative malaria test result, and at least two of the following symptoms: headache, muscle or joint pain, bleeding, and any gastroenteritis symptom (nausea, vomiting, abdominal pain, diarrhoea) in a resident of Kiruhura, Buikwe, Mityana, and Kiboga districts from 1st October 2017 to 30th January 2018. A confirmed case was defined as a suspected case with laboratory confirmation by either detection of RVF nucleic acid by reverse-transcriptase polymerase chain reaction (RT-PCR) or demonstration of serum IgM or IgG antibodies by ELISA. Community case finding was conducted in all affected districts. In-depth interviews were conducted with human cases that were infected with RVF who included herdsmen and slaughterers/meat handlers to identify exposure factors for RVF infection. A total of 24 human and 362 animal blood samples were tested. Animal blood samples were purposively collected from farms that had reported stormy abortions in livestock and unexplained death of animals after a short illness (107 cattle, 83 goats, and 43 sheep). Convenient sampling for the wildlife (10 zebras, 1 topi, and 1 impala) was conducted to investigate infection in animals from Kiruhura, Buikwe, Mityana, and Kiboga districts. Human blood was tested for anti-RVFV IgM and IgG and animal blood for anti-RVFV IgG. Environmental assessments were conducted during the outbreaks in all the affected districts. Results Sporadic RVF outbreaks occurred from mid-October 2017 to mid-January 2018 affecting humans, domestic animals, and wildlife. Human cases were reported from Kiruhura, Buikwe, Kiboga, and Mityana districts. Of the 24 human blood samples tested, anti-RVFV IgG was detected in 7 (29%) human samples; 1 human sample had detectable IgM only, and 6 had both IgM and IgG. Three of the seven confirmed human cases died among humans. Results from testing animal blood samples obtained from Kiruhura district indicated that 44% (64/146) cattle, 46% (35/76) goats, and 45% (9/20) sheep tested positive for RVF. Among wildlife, (1/10) zebras, (1/1) topi, and (1/1) impala tested positive for RVFV by serological tests. One blood sample from sheep in Kiboga district tested RVFV positive. All the human cases were exposed through contact or consumption of meat from infected animals. Conclusion RVF outbreaks occurred in humans and animals in Kiruhura, Buikwe, Mityana, and Kiboga districts. Human cases were potentially infected through contact with infected animals and their products.
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Woodburn DB, Steyl J, Du Plessis EC, Last RD, Reininghaus B, Mitchell EP. Pathological findings in African buffaloes (Syncerus caffer) in South Africa. J S Afr Vet Assoc 2021; 92:e1-e11. [PMID: 34476957 PMCID: PMC8424707 DOI: 10.4102/jsava.v92i0.2117] [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: 09/18/2020] [Revised: 06/04/2021] [Accepted: 06/15/2021] [Indexed: 11/05/2022] Open
Abstract
The African buffalo (Syncerus caffer) is an iconic species of South African megafauna. As the farmed buffalo population expands, the potential impacts on population health and disease transmission warrant investigation. A retrospective study of skin biopsy and necropsy samples from 429 animals was performed to assess the spectrum of conditions seen in buffaloes in South Africa. Determination of the cause of death (or euthanasia) could not be made in 33.1% (136/411) of the necropsy cases submitted due to autolysis or the absence of significant lesions in the samples submitted. Infectious and parasitic diseases accounted for 53.5% (147/275) of adult fatal cases and non-infectious conditions accounted for 34.9% (96/275). Abortions and neonatal deaths made up 11.6% (32/275) of necropsy cases. Rift Valley fever, bovine viral diarrhoea, malignant catarrhal fever, tuberculosis, bacterial pneumonia, anaesthetic deaths, cachexia and hepatotoxic lesions were the most common causes of death. The range of infectious, parasitic and non-infectious diseases to which African buffaloes were susceptible was largely similar to diseases in domestic cattle which supports concerns regarding disease transmission between the two species. The similarity between diseases experienced in both species will assist wildlife veterinarians in the diagnosis and treatment of diseases in captive African buffaloes. The present study likely does not represent accurate disease prevalence data within the source population of buffaloes, and diseases such as anthrax, brucellosis and foot and mouth disease are under-represented in this study. Hepatic ductal plate abnormalities and haemorrhagic septicaemia have not, to our knowledge, been previously reported in African buffaloes.
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Affiliation(s)
- Daniel B Woodburn
- Department of Pathobiology, Zoological Pathology Program, University of Illinois, Illinois.
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Swanepoel H, Crafford J, Quan M. A Scoping Review of Viral Diseases in African Ungulates. Vet Sci 2021; 8:vetsci8020017. [PMID: 33499429 PMCID: PMC7912165 DOI: 10.3390/vetsci8020017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/17/2021] [Accepted: 01/20/2021] [Indexed: 11/25/2022] Open
Abstract
(1) Background: Viral diseases are important as they can cause significant clinical disease in both wild and domestic animals, as well as in humans. They also make up a large proportion of emerging infectious diseases. (2) Methods: A scoping review of peer-reviewed publications was performed and based on the guidelines set out in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. (3) Results: The final set of publications consisted of 145 publications. Thirty-two viruses were identified in the publications and 50 African ungulates were reported/diagnosed with viral infections. Eighteen countries had viruses diagnosed in wild ungulates reported in the literature. (4) Conclusions: A comprehensive review identified several areas where little information was available and recommendations were made. It is recommended that governments and research institutions offer more funding to investigate and report viral diseases of greater clinical and zoonotic significance. A further recommendation is for appropriate One Health approaches to be adopted for investigating, controlling, managing and preventing diseases. Diseases which may threaten the conservation of certain wildlife species also require focused attention. In order to keep track of these diseases, it may be necessary to consider adding a “Wildlife disease and infection” category to the World Organisation for Animal Health-listed diseases.
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Affiliation(s)
- Hendrik Swanepoel
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Disease, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (H.S.); (J.C.)
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
| | - Jan Crafford
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Disease, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (H.S.); (J.C.)
| | - Melvyn Quan
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Disease, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (H.S.); (J.C.)
- Correspondence: ; Tel.: +27-12-529-8142
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Tchouassi DP, Torto B, Sang R, Riginos C, Ezenwa VO. Large herbivore loss has complex effects on mosquito ecology and vector-borne disease risk. Transbound Emerg Dis 2020; 68:2503-2513. [PMID: 33170555 DOI: 10.1111/tbed.13918] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/25/2020] [Accepted: 11/06/2020] [Indexed: 12/15/2022]
Abstract
Loss of biodiversity can affect transmission of infectious diseases in at least two ways: by altering host and vector abundance or by influencing host and vector behaviour. We used a large herbivore exclusion experiment to investigate the effects of wildlife loss on the abundance and feeding behaviour of mosquito vectors and to explore consequences for vector-borne disease transmission. Large herbivore loss affected both mosquito abundance and blood-feeding behaviour. For Aedes mcintoshi, the dominant mosquito species in our study and a primary vector of Rift Valley fever virus (RVFV), abundance decreased with large herbivore loss, while blood feeding on humans increased. Despite an elevated human biting rate in the absence of large herbivores, we estimated that the potential for RVFV transmission to humans doubles in the presence of large herbivores. These results demonstrate that multiple effects of biodiversity loss on vectors can lead to counterintuitive outcomes for human disease risk.
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Affiliation(s)
- David P Tchouassi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Vanessa O Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
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Kroeker AL, Babiuk S, Pickering BS, Richt JA, Wilson WC. Livestock Challenge Models of Rift Valley Fever for Agricultural Vaccine Testing. Front Vet Sci 2020; 7:238. [PMID: 32528981 PMCID: PMC7266933 DOI: 10.3389/fvets.2020.00238] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Since the discovery of Rift Valley Fever virus (RVFV) in Kenya in 1930, the virus has become widespread throughout most of Africa and is characterized by sporadic outbreaks. A mosquito-borne pathogen, RVFV is poised to move beyond the African continent and the Middle East and emerge in Europe and Asia. There is a risk that RVFV could also appear in the Americas, similar to the West Nile virus. In light of this potential threat, multiple studies have been undertaken to establish international surveillance programs and diagnostic tools, develop models of transmission dynamics and risk factors for infection, and to develop a variety of vaccines as countermeasures. Furthermore, considerable efforts to establish reliable challenge models of Rift Valley fever virus have been made and platforms for testing potential vaccines and therapeutics in target species have been established. This review emphasizes the progress and insights from a North American perspective to establish challenge models in target livestock such as cattle, sheep, and goats in comparisons to other researchers' reports. A brief summary of the potential role of wildlife, such as buffalo and white-tailed deer as reservoir species will also be discussed.
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Affiliation(s)
- Andrea Louise Kroeker
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Shawn Babiuk
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Bradley S Pickering
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Juergen A Richt
- Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), Manhattan, KS, United States
| | - William C Wilson
- USDA, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Manhattan, KS, United States
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11
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Kroeker AL, Smid V, Embury-Hyatt C, Collignon B, Pinette M, Babiuk S, Pickering B. Increased Susceptibility of Cattle to Intranasal RVFV Infection. Front Vet Sci 2020; 7:137. [PMID: 32411730 PMCID: PMC7200984 DOI: 10.3389/fvets.2020.00137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 02/24/2020] [Indexed: 11/13/2022] Open
Abstract
Rift Valley Fever virus (RVFV) is a zoonotic mosquito-borne virus that belongs to the Phenuiviridae family. Infections in animal herds cause abortion storms, high mortality rates in neonates, and mild to severe symptoms. Infected animals can also transmit the virus to people, particularly people who live or work in close contact with livestock. There is currently an ongoing effort to produce safe and efficacious veterinary vaccines against RVFV in livestock to protect against both primary infection in animals and zoonotic infections in people. To test the efficacy of these vaccines it is essential to have a reliable challenge model in relevant target species, including ruminants. In this study we evaluated three routes of inoculation (intranasal, intradermal and a combination of routes) in Holstein cattle using an infectious dose of 107 pfu/ml and a virus strain from the 2006-2007 outbreak in Kenya and Sudan. Our results demonstrated that all routes of inoculation were effective at producing viremia in all animals; however, the intranasal route induced the highest levels and longest duration of viremia, the most noticeable clinical signs, and the most widespread infection of tissues. We therefore recommend using the intranasal inoculation for future vaccine and challenge studies.
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Affiliation(s)
- Andrea L Kroeker
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Valerie Smid
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Carissa Embury-Hyatt
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Brad Collignon
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Mathieu Pinette
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Shawn Babiuk
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Bradley Pickering
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada.,College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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Ndengu M, Matope G, Tivapasi M, Pfukenyi DM, Cetre-Sossah C, De Garine-Wichatitsky M. Seroprevalence and associated risk factors of Rift Valley fever in cattle and selected wildlife species at the livestock/wildlife interface areas of Gonarezhou National Park, Zimbabwe. ACTA ACUST UNITED AC 2020; 87:e1-e7. [PMID: 32370521 PMCID: PMC7203192 DOI: 10.4102/ojvr.v87i1.1731] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/05/2019] [Accepted: 07/17/2019] [Indexed: 12/18/2022]
Abstract
A study was conducted to investigate the seroprevalence and associated risk factors of Rift Valley fever (RVF) infection in cattle and some selected wildlife species at selected interface areas at the periphery of the Great Limpopo Transfrontier Conservation Area in Zimbabwe. Three study sites were selected based on the type of livestock–wildlife interface: porous livestock–wildlife interface (unrestricted); non-porous livestock–wildlife interface (restricted by fencing) and livestock–wildlife non-interface (totally absent contact or control). Sera were collected from cattle aged ≥ 2 years representing both female and intact male. Sera were also collected from selected wild ungulates from Mabalauta (porous interface) and Chipinda Pools (non-interface) areas of the Gonarezhou National Park. Sera were tested for antibodies to Rift Valley fever virus (RVFV) using a competitive enzyme-linked immunosorbent assay (ELISA) test. AX2 test was used to assess differences between categories, and p < 0.05 was considered as significant. In cattle, the overall seroprevalence was 1.7% (17/1011) (95% confidence interval [CI]: 1.01–2.7). The porous interface recorded a seroprevalence of 2.3% (95% CI: 1.2–4.3), the non-porous interface recorded a prevalence of 1.8% (95% CI: 0.7–4.3) and the non-interface area recorded a seroprevalence of 0.4% (955 CI: 0.02–2.5), but the difference in seroprevalence according to site was not significant (p > 0.05). All impala and kudu samples tested negative. The overall seroprevalence in buffaloes was 11.7% (95% CI: 6.6–19.5), and there was no significant (p = 0.38) difference between the sites (Mabalauta, 4.4% [95% CI: 0.2–24] vs. Chipinda, 13.6% [95% CI: 7.6–23]). The overall seroprevalence in buffaloes (11.7%, 13/111) was significantly (p < 0.0001) higher than in cattle (1.7%, 17/1011). The results established the presence of RVFV in cattle and selected wildlife and that sylvatic infections may be present in buffalo populations. Further studies are required to investigate if the virus is circulating between cattle and wildlife.
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Affiliation(s)
- Masimba Ndengu
- Department of Clinical Veterinary Studies, Faculty of Veterinary Science, University of Zimbabwe, Harare.
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13
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Gortázar Schmidt C, Michel V, Miranda Chueca MÁ, Roberts HC, Sihvonen LH, Stahl K, Velarde A, trop A, Winckler C, Cetre‐Sossah C, Chevalier V, de Vos C, Gubbins S, Antoniou S, Broglia A, Dhollander S, Van der Stede Y. Rift Valley Fever: risk of persistence, spread and impact in Mayotte (France). EFSA J 2020; 18:e06093. [PMID: 32874301 PMCID: PMC7448016 DOI: 10.2903/j.efsa.2020.6093] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Rift Valley fever (RVF) is a vector-borne disease transmitted by different mosquito species, especially Aedes and Culex genus, to animals and humans. In November 2018, RVF re-emerged in Mayotte (France) after 11 years. Up to the end of October 2019, 126 outbreaks in animals and 143 human cases were reported. RVF mortality was 0.01%, and the number of abortions reported in polymerase chain reaction (PCR)-positive ruminants was fivefold greater than the previous 7 years. Milk loss production in 2019 compared to 2015-2018 was estimated to be 18%, corresponding to an economic loss of around €191,000 in all of Mayotte. The tropical climate in Mayotte provides conditions for the presence of mosquitoes during the whole year, and illegal introductions of animals represent a continuous risk of (re)introduction of RVF. The probability of RVF virus (RVFV) persisting in Mayotte for 5 or more years was estimated to be < 10% but could be much lower if vertical transmission in vectors does not occur. Persistence of RVF by vertical transmission in Mayotte and Réunion appears to be of minor relevance compared to other pathways of re-introduction (i.e. animal movement). However, there is a high uncertainty since there is limited information about the vertical transmission of some of the major species of vectors of RVFV in Mayotte and Réunion. The only identified pathways for the risk of spread of RVF from Mayotte to other countries were by infected vectors transported in airplanes or by wind currents. For the former, the risk of introduction of RVF to continental France was estimated to 4 × 10-6 epidemic per year (median value; 95% CI: 2 × 10-8; 0.0007), and 0.001 epidemic per year to Réunion (95% CI: 4 × 10-6; 0.16). For the latter pathway, mosquitoes dispersing on the wind from Mayotte between January and April 2019 could have reached the Comoros Islands, Madagascar, Mozambique and, possibly, Tanzania. However, these countries are already endemic for RVF, and an incursion of RVFV-infected mosquitoes would have negligible impact.
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14
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Van den Bergh C, Venter EH, Swanepoel R, Hanekom CC, Thompson PN. Neutralizing antibodies against Rift Valley fever virus in wild antelope in far northern KwaZulu-Natal, South Africa, indicate recent virus circulation. Transbound Emerg Dis 2020; 67:1356-1363. [PMID: 31943795 DOI: 10.1111/tbed.13479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 11/03/2019] [Accepted: 01/09/2020] [Indexed: 11/29/2022]
Abstract
Rift Valley fever (RVF) is a zoonotic viral disease of domestic ruminants in Africa and the Arabian Peninsula caused by a mosquito-borne Phlebovirus. Outbreaks in livestock and humans occur after heavy rains favour breeding of vectors, and the virus is thought to survive dry seasons in the eggs of floodwater-breeding aedine mosquitoes. We recently found high seroconversion rates to RVF virus (RVFV) in cattle and goats, in the absence of outbreaks, in far northern KwaZulu-Natal (KZN), South Africa. Here, we report the prevalence of, and factors associated with, neutralizing antibodies to RVFV in 326 sera collected opportunistically from nyala (Tragelaphus angasii) and impala (Aepyceros melampus) culled during 2016-2018 in two nature reserves in the same area. The overall seroprevalence of RVFV, determined using the serum neutralization test, was 35.0% (114/326; 95%CI: 29.8%-40.4%) and tended to be higher in Ndumo Game Reserve (11/20; 55.0%; 95%CI: 31.5%-76.9%) than in Tembe Elephant Park (103/306; 33.6%; 95%CI: 28.4%-39.3%) (p = .087). The presence of antibodies in juveniles (6/21; 28.6%; 95%CI: 11.3%-52.2%) and sub-adults (13/65; 20.0%; 95%CI: 11.1%-37.8%) confirmed that infections had occurred at least until 2016, well after the 2008-2011 RVF outbreaks in South Africa. Odds of seropositivity was higher in adults than in sub-adults (OR = 3.98; 95%CI: 1.83-8.67; p = .001), in males than in females (OR = 2.66; 95%CI: 1.51-4.68; p = .001) and in animals collected ≤2 km from a swamp or floodplain compared with those collected further away (OR = 3.30; 95%CI: 1.70-6.38; p < .001). Under similar ecological conditions, domestic and wild ruminants may play a similar role in maintenance of RVFV circulation and either or both may serve as the mammalian host in a vector-host reservoir system. The study confirms the recent circulation of RVFV in the tropical coastal plain of northern KZN, providing the basis for investigation of factors affecting virus circulation and the role of wildlife in RVF epidemiology.
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Affiliation(s)
- Carien Van den Bergh
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Estelle H Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.,College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
| | - Robert Swanepoel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | | | - Peter N Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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15
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Abstract
Rift Valley fever (RVF) is a mosquito-borne viral disease, principally of ruminants, that is endemic to Africa. The causative Phlebovirus, Rift Valley fever virus (RVFV), has a broad host range and, as such, also infects humans to cause primarily a self-limiting febrile illness. A small number of human cases will also develop severe complications, including haemorrhagic fever, encephalitis and visual impairment. In parts of Africa, it is a major disease of domestic ruminants, causing epidemics of abortion and mortality. It infects and can be transmitted by a broad range of mosquitos, with those of the genus Aedes and Culex thought to be the major vectors. Therefore, the virus has the potential to become established beyond Africa, including in Australia, where competent vector hosts are endemic. Vaccines for humans have not yet been developed to the commercial stage. This review examines the threat of this virus, with particular reference to Australia, and assesses gaps in our knowledge that may benefit from research focus.
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16
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Adesiyun AA, Knobel DL, Thompson PN, Wentzel J, Kolo FB, Kolo AO, Conan A, Simpson GJG. Sero-Epidemiological Study of Selected Zoonotic and Abortifacient Pathogens in Cattle at a Wildlife-Livestock Interface in South Africa. Vector Borne Zoonotic Dis 2019; 20:258-267. [PMID: 31841655 DOI: 10.1089/vbz.2019.2519] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A cross sectional sero-epidemiological study was conducted on cattle in a communal farming area adjacent to Kruger National Park at a wildlife-livestock interface in South Africa. A total of 184 cattle were screened for exposure to 5 abortifacient or zoonotic pathogens, namely Coxiella burnetii, Toxoplasma gondii, Chlamydophila abortus, Neospora caninum, and Rift Valley fever virus (RVFV) using enzyme-linked immunosorbent assays. In addition, the virus neutralization test was used to confirm the presence of antibodies to RVFV. The seroprevalence of C. burnetii, T. gondii, C. abortus, N. caninum, and RVFV antibodies was 38.0%, 32.6%, 20.7%, 1.6%, and 0.5%, respectively, and varied between locations (p < 0.001). Seroprevalence of C. burnetii and T. gondii was highly clustered by location (intraclass correlation coefficient [ICC] = 0.57), and that of C. abortus moderately so (ICC = 0.11). Seroprevalence was not associated with sex or age for any pathogen, except for C. abortus, for which seroprevalence was positively associated with age (p = 0.01). The predominant mixed infections were C. burnetii and T. gondii (15.2%) and C. burnetii, T. gondii, and C. abortus (13.0%). The serological detection of the five abortifacient pathogens in cattle indicates the potential for economic losses to livestock farmers, health impacts to domestic animals, transmission across the livestock-wildlife interface, and the risk of zoonotic transmission. This is the first documentation of T. gondii infection in cattle in South Africa, while exposure to C. burnetii, C. abortus, and N. caninum infections is being reported for the first time in cattle in a wildlife-livestock interface in the country.
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Affiliation(s)
- Abiodun A Adesiyun
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Department of Basic Veterinary Sciences, Faculty of Medical Sciences, University of the West Indies, St Augustine, Trinidad and Tobago
| | - Darryn L Knobel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, Basseterre, St. Kitts and Nevis
| | - Peter N Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Jeanette Wentzel
- Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Hans Hoheisen Wildlife Research Station, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Francis B Kolo
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Agatha O Kolo
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Anne Conan
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, Basseterre, St. Kitts and Nevis
| | - Gregory J G Simpson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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17
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Abstract
In association with a study investigating the apparent decline of African buffalos (Syncerus caffer) in Ruaha National Park, Tanzania, 40 buffalos were screened for selected diseases. Bovine tuberculosis was detected in 23%, and exposure to Brucella abortus and Rift Valley fever virus in 18% and 8%, respectively, of buffalos tested.
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Lubisi BA, Ndouvhada PN, Neiffer D, Penrith ML, Sibanda DR, Bastos A. Seroprevalence of Rift valley fever in South African domestic and wild suids (1999-2016). Transbound Emerg Dis 2019; 67:811-821. [PMID: 31655018 DOI: 10.1111/tbed.13402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 09/26/2019] [Accepted: 10/03/2019] [Indexed: 01/09/2023]
Abstract
Rift valley fever (RVF) is a vector-borne viral disease of domestic ruminants, camels and man, characterized by widespread abortions and neonatal deaths in animals, and flu-like symptoms, which can progress to hepatitis and encephalitis in humans. The disease is endemic in Africa, Saudi Arabia and Yemen, and outbreaks occur after periods of high rainfall, or in environments supporting the proliferation of RVF virus (RVFV)-infected mosquito vectors. The domestic and wild animal maintenance hosts of RVFV, which may serve as sources of virus during inter-epidemic periods (IEPs) and contribute to occurrence of sporadic outbreaks, remain unknown, although reports indicate that the African buffalo (Syncerus caffer) may play a role. Due to the close proximity of the habitats of domestic pigs and warthogs to those of known domestic and wild ruminant RVFV maintenance hosts respectively, our study investigated their possible role in the epidemiology of RVF in South Africa by evaluating RVFV exposure and seroconversion in suids. A total of 107 warthog and 3,984 domestic pig sera from 2 and all 9 provinces of South Africa, respectively, were screened for presence of RVFV neutralizing antibodies using the virus neutralization test (VNT). Sero-positivity rates of 1.87% (95% CI: 0.01%-6.9%) and 0.68% (95% CI: 0.49%-1.04%) were observed for warthogs and domestic pigs, respectively, but true prevalence rates, taking test sensitivity and specificity into account, were lower for both groups. There was a strong association between the results of the two groups (χ2 = 0.75, p = .38), and differences in prevalence between the epidemic and IEPs were non-significant for all suid samples tested (p > .05). This study, which provides the first evidence of probable exposure and infection of South African domestic pigs and warthogs to RVFV, indicates that further investigations are warranted, to fully clarify the role of suids in the epidemiology of RVF.
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Affiliation(s)
- Baratang Alison Lubisi
- Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort, South Africa.,Department of Zoology & Entomology, Mammal Research Institute, University of Pretoria, Hatfield, South Africa
| | - Phumudzo Nomicia Ndouvhada
- Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort, South Africa.,Department of Agriculture and Animal Health, College of Agriculture and Environmental Sciences, University of South Africa, Roodepoort, South Africa
| | - Donald Neiffer
- Wildlife Health Sciences, National Zoological Park, Smithsonian Conservation Biology Institute, Washington, DC, USA
| | - Mary Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Donald-Ray Sibanda
- Department of Agriculture and Animal Health, College of Agriculture and Environmental Sciences, University of South Africa, Roodepoort, South Africa
| | - Armanda Bastos
- Department of Zoology & Entomology, Mammal Research Institute, University of Pretoria, Hatfield, South Africa.,Centre for Veterinary Wildlife Studies, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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19
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Gorsich EE, Beechler BR, van Bodegom PM, Govender D, Guarido MM, Venter M, Schrama M. A comparative assessment of adult mosquito trapping methods to estimate spatial patterns of abundance and community composition in southern Africa. Parasit Vectors 2019; 12:462. [PMID: 31578155 PMCID: PMC6775653 DOI: 10.1186/s13071-019-3733-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/25/2019] [Indexed: 12/31/2022] Open
Abstract
Background Assessing adult mosquito populations is an important component of disease surveillance programs and ecosystem health assessments. Inference from adult trapping datasets involves comparing populations across space and time, but comparisons based on different trapping methods may be biased if traps have different efficiencies or sample different subsets of the mosquito community. Methods We compared four widely-used trapping methods for adult mosquito data collection in Kruger National Park (KNP), South Africa: Centers for Disease Control miniature light trap (CDC), Biogents Sentinel trap (BG), Biogents gravid Aedes trap (GAT) and a net trap. We quantified how trap choice and sampling effort influence inferences on the regional distribution of mosquito abundance, richness and community composition. Results The CDC and net traps together collected 96% (47% and 49% individually) of the 955 female mosquitoes sampled and 100% (85% and 78% individually) of the 40 species or species complexes identified. The CDC and net trap also identified similar regional patterns of community composition. However, inference on the regional patterns of abundance differed between these traps because mosquito abundance in the net trap was influenced by variation in weather conditions. The BG and GAT traps collected significantly fewer mosquitoes, limiting regional comparisons of abundance and community composition. Conclusions This study represents the first systematic assessment of trapping methods in natural savanna ecosystems in southern Africa. We recommend the CDC trap or the net trap for future monitoring and surveillance programs.
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Affiliation(s)
- Erin E Gorsich
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands. .,School of Life Sciences, University of Warwick, Coventry, UK. .,The Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, University of Warwick, Coventry, UK.
| | - Brianna R Beechler
- College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
| | - Peter M van Bodegom
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | | | - Milehna M Guarido
- Zoonotic Arbo- and Respiratory Virus Program, Centre for Viral Zoonoses, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Marietjie Venter
- Zoonotic Arbo- and Respiratory Virus Program, Centre for Viral Zoonoses, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Maarten Schrama
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
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20
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van den Bergh C, Venter EH, Swanepoel R, Thompson PN. High seroconversion rate to Rift Valley fever virus in cattle and goats in far northern KwaZulu-Natal, South Africa, in the absence of reported outbreaks. PLoS Negl Trop Dis 2019; 13:e0007296. [PMID: 31050673 PMCID: PMC6519843 DOI: 10.1371/journal.pntd.0007296] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 05/15/2019] [Accepted: 03/12/2019] [Indexed: 11/19/2022] Open
Abstract
Background Rift Valley fever (RVF) is a mosquito-borne zoonotic disease characterized in South Africa by large epidemics amongst ruminant livestock at very long, irregular intervals, mainly in the central interior. However, the presence and patterns of occurrence of the virus in the eastern parts of the country are poorly known. This study aimed to detect the presence of RVF virus (RVFV) in cattle and goats in far northern KwaZulu-Natal province and to estimate the prevalence of antibodies to the virus and the incidence rate of seroconversion. Methodology Cross-sectional studies were performed in communally farmed cattle (n = 423) and goats (n = 104), followed by longitudinal follow-up of seronegative livestock (n = 253) 14 times over 24 months, representing 160.3 animal-years at risk. Exposure to RVFV was assessed using an IgG sandwich ELISA and a serum neutralization test (SNT) and seroconversion was assessed using SNT. Incidence density was estimated and compared using multivariable Poisson models and hazard of seroconversion was estimated over time. Principal findings Initial overall seroprevalence was 34.0% (95%CI: 29.5–38.8%) in cattle and 31.7% (95%CI: 22.9–41.6%) in goats, varying by locality from 18–54%. Seroconversions to RVFV based on SNT were detected throughout the year, with the incidence rate peaking during the high rainfall months of January to March, and differed considerably between years. Overall seroconversion rate in cattle was 0.59 per animal-year (95% CI: 0.46–0.75) and in goats it was 0.41 per animal-year (95% CI: 0.25–0.64), varying significantly over short distances. Conclusions/Significance The high seroprevalence in all age groups and evidence of year-round viral circulation provide evidence for a hyperendemic situation in the study area. This is the first study to directly estimate infection rate of RVFV in livestock in an endemic area in the absence of reported outbreaks and provides the basis for further investigation of factors affecting viral circulation and mechanisms for virus survival during interepidemic periods. Rift Valley fever (RVF) is a mosquito-transmitted viral disease that may cause large epidemics in domestic livestock and in humans. Although currently largely confined to Africa, it is of international concern due to its ability to spread and become established in areas where suitable mosquito vectors occur. Outbreaks occur sporadically, associated with conditions favourable for proliferation of mosquito populations, such as high rainfall and flooding, yet their location and timing remain difficult to predict. In other areas there is evidence that RVF virus is endemic and may circulate without causing outbreaks. However, the location and extent of such areas is poorly known, as is the transmission dynamics of the virus in those areas. In this paper, we report the existence of such an area of endemic RVF virus transmission on the tropical coastal plain of South Africa bordering Mozambique, where we found a high rate of exposure of domestic cattle and goats to the naturally circulating virus over a two-year period, with no outbreaks being reported. Research in such areas will help us to assess the potential for spread of the virus to other areas and also to better understand the behaviour of the virus during periods between epidemics.
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Affiliation(s)
- Carien van den Bergh
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
| | - Estelle H. Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
| | - Robert Swanepoel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
| | - Peter N. Thompson
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
- * E-mail:
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21
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Msimang V, Thompson PN, Jansen van Vuren P, Tempia S, Cordel C, Kgaladi J, Khosa J, Burt FJ, Liang J, Rostal MK, Karesh WB, Paweska JT. Rift Valley Fever Virus Exposure amongst Farmers, Farm Workers, and Veterinary Professionals in Central South Africa. Viruses 2019; 11:v11020140. [PMID: 30736488 PMCID: PMC6409972 DOI: 10.3390/v11020140] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 12/21/2022] Open
Abstract
Rift Valley fever (RVF) is a re-emerging arboviral disease of public health and veterinary importance in Africa and the Arabian Peninsula. Major RVF epidemics were documented in South Africa in 1950⁻1951, 1974⁻1975, and 2010⁻2011. The number of individuals infected during these outbreaks has, however, not been accurately estimated. A total of 823 people in close occupational contact with livestock were interviewed and sampled over a six-month period in 2015⁻2016 within a 40,000 km² study area encompassing parts of the Free State and Northern Cape provinces that were affected during the 2010⁻2011 outbreak. Seroprevalence of RVF virus (RVFV) was 9.1% (95% Confidence Interval (CI95%): 7.2⁻11.5%) in people working or residing on livestock or game farms and 8.0% in veterinary professionals. The highest seroprevalence (SP = 15.4%; CI95%: 11.4⁻20.3%) was detected in older age groups (≥40 years old) that had experienced more than one known large epidemic compared to the younger participants (SP = 4.3%; CI95%: 2.6⁻7.3%). The highest seroprevalence was in addition found in people who injected animals, collected blood samples (Odds ratio (OR) = 2.3; CI95%: 1.0⁻5.3), slaughtered animals (OR = 3.9; CI95%: 1.2⁻12.9) and consumed meat from an animal found dead (OR = 3.1; CI95%: 1.5⁻6.6), or worked on farms with dams for water storage (OR = 2.7; CI95%: 1.0⁻6.9). We estimated the number of historical RVFV infections of farm staff in the study area to be most likely 3849 and 95% credible interval between 2635 and 5374 based on seroprevalence of 9.1% and national census data. We conclude that human RVF cases were highly underdiagnosed and heterogeneously distributed. Improving precautions during injection, sample collection, slaughtering, and meat processing for consumption, and using personal protective equipment during outbreaks, could lower the risk of RVFV infection.
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Affiliation(s)
- Veerle Msimang
- Epidemiology Section, Department of Animal Production Studies; Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham 2192, South Africa.
| | - Peter N Thompson
- Epidemiology Section, Department of Animal Production Studies; Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
| | - Petrus Jansen van Vuren
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham 2192, South Africa.
| | - Stefano Tempia
- MassGenics, Duluth, GA 30026, USA.
- Influenza Division, Centers for Disease Control and Prevention, Pretoria 0001, South Africa; Influenza Division and Centers for Disease Control and Prevention, Atlanta, GA 30301, USA.
| | | | - Joe Kgaladi
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham 2192, South Africa.
| | - Jimmy Khosa
- National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham 2192, South Africa.
| | - Felicity J Burt
- Division of Virology, National Health Laboratory Service and Faculty of Health Sciences, University of the Free State, Bloemfontein 9300, South Africa.
| | | | | | | | - Janusz T Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham 2192, South Africa.
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22
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Rostal MK, Liang JE, Zimmermann D, Bengis R, Paweska J, Karesh WB. Rift Valley Fever: Does Wildlife Play a Role? ILAR J 2018; 58:359-370. [PMID: 28985319 DOI: 10.1093/ilar/ilx023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 07/12/2017] [Indexed: 12/18/2022] Open
Abstract
Rift Valley fever (RVF) virus (RVFV) is an emerging vector-borne pathogen that causes sporadic epizootics and epidemics with multi-year, apparently quiescent, inter-epidemic periods. The epidemiology and ecology of the virus during these inter-epidemic periods is poorly understood. There is evidence for low-level circulation of the virus in livestock and wild ruminants; however, as of yet there is no evidence to identify a specific mammalian reservoir host. Using a systematic approach, this review synthesizes results from serosurveys, attempts at viral detection, and experimental infection of wildlife. These data demonstrate there is a gap in research conducted on RVF in wild ruminants. Specifically, there is very little published data on the pathogenicity of an RVFV infection in various wildlife species, validation of diagnostic assays for exposure to RVFV and understanding of epizootic or endemic disease dynamics in wild ruminants. We recommend that future research on RVFV incorporate a more systematic approach to understand the low-level cycling of the virus during inter-epidemic periods in both wild and domestic ruminant species.
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Affiliation(s)
- Melinda K Rostal
- Melinda K. Rostal, DVM, MPH, is a senior research scientist at EcoHealth Alliance in New York City, New York. Janice E. Liang is a research assistant at EcoHealth Alliance in New York City, New York. David Zimmermann, BVSc, MSc, is a veterinarian with South African National Parks in Kimberley, South Africa. Roy Bengis, BVSc, MSc, PhD, is a veterinarian who sits on the World Organisation for Animal Health (OIE) Working Group on Wildlife and in Port Alfred, South Africa. Janusz Paweska, Prof., DVSc, dr hab., is the head of the Center for Emerging and Zoonotic Diseases at the National Institute for Communicable Diseases of the National Health Laboratory Service in Sandringham, South Africa. William B. Karesh is the Executive Vice President for Health and Policy at EcoHealth Alliance in New York City, New York
| | - Janice E Liang
- Melinda K. Rostal, DVM, MPH, is a senior research scientist at EcoHealth Alliance in New York City, New York. Janice E. Liang is a research assistant at EcoHealth Alliance in New York City, New York. David Zimmermann, BVSc, MSc, is a veterinarian with South African National Parks in Kimberley, South Africa. Roy Bengis, BVSc, MSc, PhD, is a veterinarian who sits on the World Organisation for Animal Health (OIE) Working Group on Wildlife and in Port Alfred, South Africa. Janusz Paweska, Prof., DVSc, dr hab., is the head of the Center for Emerging and Zoonotic Diseases at the National Institute for Communicable Diseases of the National Health Laboratory Service in Sandringham, South Africa. William B. Karesh is the Executive Vice President for Health and Policy at EcoHealth Alliance in New York City, New York
| | - David Zimmermann
- Melinda K. Rostal, DVM, MPH, is a senior research scientist at EcoHealth Alliance in New York City, New York. Janice E. Liang is a research assistant at EcoHealth Alliance in New York City, New York. David Zimmermann, BVSc, MSc, is a veterinarian with South African National Parks in Kimberley, South Africa. Roy Bengis, BVSc, MSc, PhD, is a veterinarian who sits on the World Organisation for Animal Health (OIE) Working Group on Wildlife and in Port Alfred, South Africa. Janusz Paweska, Prof., DVSc, dr hab., is the head of the Center for Emerging and Zoonotic Diseases at the National Institute for Communicable Diseases of the National Health Laboratory Service in Sandringham, South Africa. William B. Karesh is the Executive Vice President for Health and Policy at EcoHealth Alliance in New York City, New York
| | - Roy Bengis
- Melinda K. Rostal, DVM, MPH, is a senior research scientist at EcoHealth Alliance in New York City, New York. Janice E. Liang is a research assistant at EcoHealth Alliance in New York City, New York. David Zimmermann, BVSc, MSc, is a veterinarian with South African National Parks in Kimberley, South Africa. Roy Bengis, BVSc, MSc, PhD, is a veterinarian who sits on the World Organisation for Animal Health (OIE) Working Group on Wildlife and in Port Alfred, South Africa. Janusz Paweska, Prof., DVSc, dr hab., is the head of the Center for Emerging and Zoonotic Diseases at the National Institute for Communicable Diseases of the National Health Laboratory Service in Sandringham, South Africa. William B. Karesh is the Executive Vice President for Health and Policy at EcoHealth Alliance in New York City, New York
| | - Janusz Paweska
- Melinda K. Rostal, DVM, MPH, is a senior research scientist at EcoHealth Alliance in New York City, New York. Janice E. Liang is a research assistant at EcoHealth Alliance in New York City, New York. David Zimmermann, BVSc, MSc, is a veterinarian with South African National Parks in Kimberley, South Africa. Roy Bengis, BVSc, MSc, PhD, is a veterinarian who sits on the World Organisation for Animal Health (OIE) Working Group on Wildlife and in Port Alfred, South Africa. Janusz Paweska, Prof., DVSc, dr hab., is the head of the Center for Emerging and Zoonotic Diseases at the National Institute for Communicable Diseases of the National Health Laboratory Service in Sandringham, South Africa. William B. Karesh is the Executive Vice President for Health and Policy at EcoHealth Alliance in New York City, New York
| | - William B Karesh
- Melinda K. Rostal, DVM, MPH, is a senior research scientist at EcoHealth Alliance in New York City, New York. Janice E. Liang is a research assistant at EcoHealth Alliance in New York City, New York. David Zimmermann, BVSc, MSc, is a veterinarian with South African National Parks in Kimberley, South Africa. Roy Bengis, BVSc, MSc, PhD, is a veterinarian who sits on the World Organisation for Animal Health (OIE) Working Group on Wildlife and in Port Alfred, South Africa. Janusz Paweska, Prof., DVSc, dr hab., is the head of the Center for Emerging and Zoonotic Diseases at the National Institute for Communicable Diseases of the National Health Laboratory Service in Sandringham, South Africa. William B. Karesh is the Executive Vice President for Health and Policy at EcoHealth Alliance in New York City, New York
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Association between Rift Valley fever virus seroprevalences in livestock and humans and their respective intra-cluster correlation coefficients, Tana River County, Kenya. Epidemiol Infect 2018; 147:e67. [PMID: 30516123 PMCID: PMC6518590 DOI: 10.1017/s0950268818003242] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We implemented a cross-sectional study in Tana River County, Kenya, a Rift Valley fever (RVF)-endemic area, to quantify the strength of association between RVF virus (RVFv) seroprevalences in livestock and humans, and their respective intra-cluster correlation coefficients (ICCs). The study involved 1932 livestock from 152 households and 552 humans from 170 households. Serum samples were collected and screened for anti-RVFv immunoglobulin G (IgG) antibodies using inhibition IgG enzyme-linked immunosorbent assay (ELISA). Data collected were analysed using generalised linear mixed effects models, with herd/household and village being fitted as random variables. The overall RVFv seroprevalences in livestock and humans were 25.41% (95% confidence interval (CI) 23.49–27.42%) and 21.20% (17.86–24.85%), respectively. The presence of at least one seropositive animal in a household was associated with an increased odds of exposure in people of 2.23 (95% CI 1.03–4.84). The ICCs associated with RVF virus seroprevalence in livestock were 0.30 (95% CI 0.19–0.44) and 0.22 (95% CI 0.12–0.38) within and between herds, respectively. These findings suggest that there is a greater variability of RVF virus exposure between than within herds. We discuss ways of using these ICC estimates in observational surveys for RVF in endemic areas and postulate that the design of the sentinel herd surveillance should consider patterns of RVF clustering to enhance its effectiveness as an early warning system for RVF epidemics.
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24
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Tavalire HF, Beechler BR, Buss PE, Gorsich EE, Hoal EG, le Roex N, Spaan JM, Spaan RS, van Helden PD, Ezenwa VO, Jolles AE. Context-dependent costs and benefits of tuberculosis resistance traits in a wild mammalian host. Ecol Evol 2018; 8:12712-12726. [PMID: 30619576 PMCID: PMC6308860 DOI: 10.1002/ece3.4699] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/02/2018] [Accepted: 10/12/2018] [Indexed: 12/24/2022] Open
Abstract
Disease acts as a powerful driver of evolution in natural host populations, yet individuals in a population often vary in their susceptibility to infection. Energetic trade-offs between immune and reproductive investment lead to the evolution of distinct life history strategies, driven by the relative fitness costs and benefits of resisting infection. However, examples quantifying the cost of resistance outside of the laboratory are rare. Here, we observe two distinct forms of resistance to bovine tuberculosis (bTB), an important zoonotic pathogen, in a free-ranging African buffalo (Syncerus caffer) population. We characterize these phenotypes as "infection resistance," in which hosts delay or prevent infection, and "proliferation resistance," in which the host limits the spread of lesions caused by the pathogen after infection has occurred. We found weak evidence that infection resistance to bTB may be heritable in this buffalo population (h 2 = 0.10) and comes at the cost of reduced body condition and marginally reduced survival once infected, but also associates with an overall higher reproductive rate. Infection-resistant animals thus appear to follow a "fast" pace-of-life syndrome, in that they reproduce more quickly but die upon infection. In contrast, proliferation resistance had no apparent costs and was associated with measures of positive host health-such as having a higher body condition and reproductive rate. This study quantifies striking phenotypic variation in pathogen resistance and provides evidence for a link between life history variation and a disease resistance trait in a wild mammalian host population.
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Affiliation(s)
- Hannah F. Tavalire
- Department of Integrative BiologyOregon State UniversityCorvallisOregon
- The Institute of Ecology and EvolutionUniversity of OregonEugeneOregon
- Present address:
Prevention Science InstituteUniversity of OregonEugeneOregon
- Present address:
Institute of Ecology and EvolutionUniversity of OregonEugeneOregon
| | | | | | - Erin E. Gorsich
- College of Veterinary MedicineOregon State UniversityCorvallisOregon
- Present address:
Erin E. Gorsich, Zeeman Institute: Systems Biology and Infectious Disease Epidemiology Research (SBIDER)University of WarwickCoventryUK
- Present address:
School of Life SciencesUniversity of WarwickCoventryUK
| | - Eileen G. Hoal
- South African Medical Research Council, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health SciencesStellenbosch UniversityTygerbergSouth Africa
| | - Nikki le Roex
- South African Medical Research Council, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health SciencesStellenbosch UniversityTygerbergSouth Africa
| | - Johannie M. Spaan
- Department of Integrative BiologyOregon State UniversityCorvallisOregon
| | - Robert S. Spaan
- Department of Fisheries and WildlifeOregon State UniversityCorvallisOregon
| | - Paul D. van Helden
- South African Medical Research Council, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health SciencesStellenbosch UniversityTygerbergSouth Africa
| | - Vanessa O. Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary MedicineUniversity of GeorgiaAthensGeorgia
| | - Anna E. Jolles
- Department of Integrative BiologyOregon State UniversityCorvallisOregon
- College of Veterinary MedicineOregon State UniversityCorvallisOregon
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25
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Molecular aspects of Rift Valley fever virus and the emergence of reassortants. Virus Genes 2018; 55:1-11. [PMID: 30426314 DOI: 10.1007/s11262-018-1611-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 11/03/2018] [Indexed: 10/27/2022]
Abstract
Rift Valley fever phlebovirus (RVFV) is a mosquito-transmitted pathogen endemic to sub-Saharan Africa and the Arabian Peninsula. RVFV is a threat to both animal and human health and has costly economic consequences mainly related to livestock production and trade. Competent hosts and vectors for RVFV are widespread, existing outside of endemic countries including the USA. Thus, the possibility of RVFV spreading to the USA or other countries worldwide is of significant concern. RVFV (genus Phlebovirus) is comprised of an enveloped virion containing a three-segmented, negative-stranded RNA genome that is able to undergo genetic reassortment. Reassortment has the potential to produce viruses that are more pathogenic, easily transmissible, and that have wider vector or host range. This is especially concerning because of the wide use of live attenuated vaccine strains throughout endemic countries. This review focuses on the molecular aspects of RVFV, genetic diversity of RVFV strains, and RVFV reassortment.
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26
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Tshilenge GM, Dundon WG, De Nardi M, Mulumba Mfumu LK, Rweyemamu M, Kayembe-Ntumba JM, Masumu J. Seroprevalence of Rift Valley fever virus in cattle in the Democratic Republic of the Congo. Trop Anim Health Prod 2018; 51:537-543. [PMID: 30350160 DOI: 10.1007/s11250-018-1721-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 09/30/2018] [Indexed: 01/08/2023]
Abstract
This study aimed at assessing the serological and virological status of Rift Valley fever virus (RVFV) in cattle from four climatically diverse zones of the Democratic Republic of the Congo (DRC). A total of 1675 sera samples collected between 2014 and 2015 from cattle without clinical manifestation of RVF infection were tested using competitive and capture enzyme ELISA to detect both IgG and IgM. RT-PCR was used for the detection of nucleic acid of RVFV. Out of the 1675 cattle sera tested, 203 were found to be IgG-positive, giving an overall true seroprevalence of 12.37% (95% CI 10.86-14.05). This seroprevalence varied between the four zones with a seroprevalence of 16.16% (95% CI 12.86-20.12), 14.70% (95% CI 11.72-18.29), 10.82% (95% CI 7.19-14.19), and 7.34% (95% CI 5.13-10.41) recorded in cattle sampled in the mountainous, humid savannah, dry savannah, and forest zones, respectively (p < 0.05, χ2 = 17.26). A higher true seroprevalence of 14.58% (95% CI 9.3-22.13) was found in animals aged 1 year compared to 10.43% (95% CI 8.12-13.30) and 13.16% (95% CI 11.19-15.42) in groups aged between 2-3 and > 3 years, respectively, although the difference was not statistically significant (p > 0.05, χ2 = 2.95). Similarly, no statistically significant difference (p > 0.05, χ2 = 0.04) was found between the sexes of the animals. Among the IgG-positive samples screened for anti-RVFV IgM, only 1.47% (3/203) was IgM-positive. One of the IgM-positive samples was positive by RT-PCR. These findings reveal country-wide distribution of RVF in the DRC for the first time.
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Affiliation(s)
- Georges Mbuyi Tshilenge
- Faculty of Veterinary Medicine, University of Kinshasa, University Street, P.O. Box 117, Kinshasa XI, Democratic Republic of the Congo. .,Central Veterinary Laboratory, Wangata Street, Gombe, P.O. Box 8842, Kinshasa, Democratic Republic of the Congo.
| | - William G Dundon
- Animal Production and Health Laboratory, Joint FAO/AIEA, Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Application, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, 1400, Vienna, Austria
| | | | - Leopold K Mulumba Mfumu
- Faculty of Veterinary Medicine, University of Kinshasa, University Street, P.O. Box 117, Kinshasa XI, Democratic Republic of the Congo
| | - Mark Rweyemamu
- Southern African Centre for Infectious Disease Surveillance, Sokoïne University of Agriculture, Chuo Kikuu, P.O. Box 3297, Morogoro, Tanzania
| | - Jean-Marie Kayembe-Ntumba
- Faculty of Medicine, University of Kinshasa, University Street, P.O. Box 117, Kinshasa XI, Democratic Republic of the Congo
| | - Justin Masumu
- Central Veterinary Laboratory, Wangata Street, Gombe, P.O. Box 8842, Kinshasa, Democratic Republic of the Congo.,Faculty of Veterinary Medicine, National Pedagogic University, Matadi/Liberation Street, Ngaliema, P.O. Box 8815, Kinshasa, Democratic Republic of the Congo.,National Institute for Biomedical Research, 5345 Huilerie Street, Gombe, Kinshasa, Democratic Republic of the Congo
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27
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Lo Iacono G, Cunningham AA, Bett B, Grace D, Redding DW, Wood JLN. Environmental limits of Rift Valley fever revealed using ecoepidemiological mechanistic models. Proc Natl Acad Sci U S A 2018; 115:E7448-E7456. [PMID: 30021855 PMCID: PMC6077718 DOI: 10.1073/pnas.1803264115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vector-borne diseases (VBDs) of humans and domestic animals are a significant component of the global burden of disease and a key driver of poverty. The transmission cycles of VBDs are often strongly mediated by the ecological requirements of the vectors, resulting in complex transmission dynamics, including intermittent epidemics and an unclear link between environmental conditions and disease persistence. An important broader concern is the extent to which theoretical models are reliable at forecasting VBDs; infection dynamics can be complex, and the resulting systems are highly unstable. Here, we examine these problems in detail using a case study of Rift Valley fever (RVF), a high-burden disease endemic to Africa. We develop an ecoepidemiological, compartmental, mathematical model coupled to the dynamics of ambient temperature and water availability and apply it to a realistic setting using empirical environmental data from Kenya. Importantly, we identify the range of seasonally varying ambient temperatures and water-body availability that leads to either the extinction of mosquito populations and/or RVF (nonpersistent regimens) or the establishment of long-term mosquito populations and consequently, the endemicity of the RVF infection (persistent regimens). Instabilities arise when the range of the environmental variables overlaps with the threshold of persistence. The model captures the intermittent nature of RVF occurrence, which is explained as low-level circulation under the threshold of detection, with intermittent emergence sometimes after long periods. Using the approach developed here opens up the ability to improve predictions of the emergence and behaviors of epidemics of many other important VBDs.
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Affiliation(s)
- Giovanni Lo Iacono
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
- Public Health England, Didcot, Oxford OX11 0RQ, United Kingdom
- School of Veterinary Medicine, University of Surrey, Guildford GU2 7AL, United Kingdom
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, London NW1 4RY, United Kingdom
| | - Bernard Bett
- Animal and Human Health Program, International Livestock Research Institute, Nairobi, 00100 Kenya
| | - Delia Grace
- Animal and Human Health Program, International Livestock Research Institute, Nairobi, 00100 Kenya
| | - David W Redding
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - James L N Wood
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Cambridge CB3 0ES, United Kingdom
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28
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Seroprevalence and Virus Activity of Rift Valley Fever in Cattle in Eastern Region of Democratic Republic of the Congo. J Vet Med 2018; 2018:4956378. [PMID: 30050953 PMCID: PMC6046122 DOI: 10.1155/2018/4956378] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/08/2018] [Accepted: 05/17/2018] [Indexed: 11/17/2022] Open
Abstract
Rift Valley fever (RVF) is a zoonotic disease that is characterized by periodic and severe outbreaks in humans and animals. Published information on the occurrence of RVF in domestic animals is very scarce in the Democratic Republic of the Congo (DRC). To assess possible circulation of Rift Valley fever virus (RVFV) in cattle in the eastern province of DRC, 450 sera collected from cattle in North Kivu, South Kivu, and Ituri provinces were analyzed using the enzyme-linked immunosorbent assay (ELISA), for the detection of viral Immunoglobulin (Ig) G and M, and reverse transcriptase polymerase chain reaction (RT-PCR), for detection of viral RVF RNA. A cumulative anti-RVF IgG prevalence of 6.22% (95% CI 4.25–8.97) was recorded from the three provinces sampled. In North Kivu and Ituri provinces the anti-RVF IgG prevalence was 12.67% [95% CI 7.80–19.07] and 6% [95% CI 2.78–11.08], respectively, while all the sera collected from South Kivu province were negative for anti-RVF IgG antibodies. Anti-RVF IgM prevalence of 1.8% was obtained among sampled animals in the three provinces. None of the positive anti-RVF IgM samples (n=8) was positive for viral RVFV RNA using RT-PCR. Our findings suggest that RVFV is widely distributed among cattle in eastern province of DRC particularly in North Kivu and Ituri provinces although the epidemiological factors supporting this virus circulation remain unknown in these areas.
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29
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Walsh MG, Mor SM. Interspecific network centrality, host range and early-life development are associated with wildlife hosts of Rift Valley fever virus. Transbound Emerg Dis 2018; 65:1568-1575. [PMID: 29756406 DOI: 10.1111/tbed.12903] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Indexed: 11/29/2022]
Abstract
Rift Valley fever virus (RVFV) is responsible for a substantive disease burden in pastoralist communities and the agricultural sector in the African continent and Arabian Peninsula. Enzootic, epizootic and zoonotic RVFV transmission dynamics remain ill-defined, particularly due to a poor understanding of the role of mammalian hosts in the epidemiology and infection ecology of this arbovirus. Using a piecewise structural equation model, this study sought to identify associations between biological and ecological characteristics of mammalian species and documented RVFV infection to highlight species-level traits that may influence wildlife host status. Interspecific network centrality, size of species home range and reproductive life-history traits were all associated with being an RVFV host. The identification of these species-level characteristics may help to provide ecological context for the role of wildlife amplification hosts in the epidemiology of spillover to livestock and humans and may also help to identify specific points of vulnerability at the wildlife-livestock interface.
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Affiliation(s)
- M G Walsh
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead, NSW, Australia.,Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia
| | - S M Mor
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead, NSW, Australia.,Faculty of Science, School of Veterinary Science, University of Sydney, Camperdown, NSW, Australia
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30
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van Hooft P, Dougherty ER, Getz WM, Greyling BJ, Zwaan BJ, Bastos ADS. Genetic responsiveness of African buffalo to environmental stressors: A role for epigenetics in balancing autosomal and sex chromosome interactions? PLoS One 2018; 13:e0191481. [PMID: 29415077 PMCID: PMC5802885 DOI: 10.1371/journal.pone.0191481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 01/05/2018] [Indexed: 02/04/2023] Open
Abstract
In the African buffalo (Syncerus caffer) population of the Kruger National Park (South Africa) a primary sex-ratio distorter and a primary sex-ratio suppressor have been shown to occur on the Y chromosome. A subsequent autosomal microsatellite study indicated that two types of deleterious alleles with a negative effect on male body condition, but a positive effect on relative fitness when averaged across sexes and generations, occur genome-wide and at high frequencies in the same population. One type negatively affects body condition of both sexes, while the other acts antagonistically: it negatively affects male but positively affects female body condition. Here we show that high frequencies of male-deleterious alleles are attributable to Y-chromosomal distorter-suppressor pair activity and that these alleles are suppressed in individuals born after three dry pre-birth years, likely through epigenetic modification. Epigenetic suppression was indicated by statistical interactions between pre-birth rainfall, a proxy for parental body condition, and the phenotypic effect of homozygosity/heterozygosity status of microsatellites linked to male-deleterious alleles, while a role for the Y-chromosomal distorter-suppressor pair was indicated by between-sex genetic differences among pre-dispersal calves. We argue that suppression of male-deleterious alleles results in negative frequency-dependent selection of the Y distorter and suppressor; a prerequisite for a stable polymorphism of the Y distorter-suppressor pair. The Y distorter seems to be responsible for positive selection of male-deleterious alleles during resource-rich periods and the Y suppressor for positive selection of these alleles during resource-poor periods. Male-deleterious alleles were also associated with susceptibility to bovine tuberculosis, indicating that Kruger buffalo are sensitive to stressors such as diseases and droughts. We anticipate that future genetic studies on African buffalo will provide important new insights into gene fitness and epigenetic modification in the context of sex-ratio distortion and infectious disease dynamics.
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Affiliation(s)
- Pim van Hooft
- Resource Ecology Group, Wageningen University, Wageningen, The Netherlands
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Hatfield, South Africa
- * E-mail:
| | - Eric R. Dougherty
- Department of Environmental Science Policy & Management, University of California, Berkeley, California, United States of America
| | - Wayne M. Getz
- Department of Environmental Science Policy & Management, University of California, Berkeley, California, United States of America
- School of Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Barend J. Greyling
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Hatfield, South Africa
- Agricultural Research Council, Irene, South Africa
| | - Bas J. Zwaan
- Laboratory of Genetics, Wageningen University, Wageningen, The Netherlands
| | - Armanda D. S. Bastos
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Hatfield, South Africa
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31
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Beechler BR, Jolles AE, Budischak SA, Corstjens PLAM, Ezenwa VO, Smith M, Spaan RS, van Dam GJ, Steinauer ML. Host immunity, nutrition and coinfection alter longitudinal infection patterns of schistosomes in a free ranging African buffalo population. PLoS Negl Trop Dis 2017; 11:e0006122. [PMID: 29253882 PMCID: PMC5755937 DOI: 10.1371/journal.pntd.0006122] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 01/05/2018] [Accepted: 11/20/2017] [Indexed: 11/19/2022] Open
Abstract
Schistosomes are trematode parasites of global importance, causing infections in millions of people, livestock, and wildlife. Most studies on schistosomiasis, involve human subjects; as such, there is a paucity of longitudinal studies investigating parasite dynamics in the absence of intervention. As a consequence, despite decades of research on schistosomiasis, our understanding of its ecology in natural host populations is centered around how environmental exposure and acquired immunity influence acquisition of parasites, while very little is known about the influence of host physiology, coinfection and clearance in the absence of drug treatment. We used a 4-year study in free-ranging African buffalo to investigate natural schistosome dynamics. We asked (i) what are the spatial and temporal patterns of schistosome infections; (ii) how do parasite burdens vary over time within individual hosts; and (iii) what host factors (immunological, physiological, co-infection) and environmental factors (season, location) explain patterns of schistosome acquisition and loss in buffalo? Schistosome infections were common among buffalo. Microgeographic structure explained some variation in parasite burdens among hosts, indicating transmission hotspots. Overall, parasite burdens ratcheted up over time; however, gains in schistosome abundance in the dry season were partially offset by losses in the wet season, with some hosts demonstrating complete clearance of infection. Variation among buffalo in schistosome loss was associated with immunologic and nutritional factors, as well as co-infection by the gastrointestinal helminth Cooperia fuelleborni. Our results demonstrate that schistosome infections are surprisingly dynamic in a free-living mammalian host population, and point to a role for host factors in driving variation in parasite clearance, but not parasite acquisition which is driven by seasonal changes and spatial habitat utilization. Our study illustrates the power of longitudinal studies for discovering mechanisms underlying parasite dynamics in individual animals and populations.
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Affiliation(s)
- Brianna R. Beechler
- College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States of America
| | - Anna E. Jolles
- College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States of America
- Department of Integrative Biology, Oregon State University, Corvallis, OR, United States of America
| | - Sarah A. Budischak
- Odum School of Ecology, University of Georgia, Athens, GA, United States of America
| | - Paul L. A. M. Corstjens
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Vanessa O. Ezenwa
- Odum School of Ecology, University of Georgia, Athens, GA, United States of America
- College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Mireya Smith
- College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Robert S. Spaan
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Michelle L. Steinauer
- College of Osteopathic Medicine of the PNW, Western University of Health Sciences, Lebanon, OR, United States of America
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Redding DW, Tiedt S, Lo Iacono G, Bett B, Jones KE. Spatial, seasonal and climatic predictive models of Rift Valley fever disease across Africa. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160165. [PMID: 28584173 PMCID: PMC5468690 DOI: 10.1098/rstb.2016.0165] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2017] [Indexed: 02/06/2023] Open
Abstract
Understanding the emergence and subsequent spread of human infectious diseases is a critical global challenge, especially for high-impact zoonotic and vector-borne diseases. Global climate and land-use change are likely to alter host and vector distributions, but understanding the impact of these changes on the burden of infectious diseases is difficult. Here, we use a Bayesian spatial model to investigate environmental drivers of one of the most important diseases in Africa, Rift Valley fever (RVF). The model uses a hierarchical approach to determine how environmental drivers vary both spatially and seasonally, and incorporates the effects of key climatic oscillations, to produce a continental risk map of RVF in livestock (as a proxy for human RVF risk). We find RVF risk has a distinct seasonal spatial pattern influenced by climatic variation, with the majority of cases occurring in South Africa and Kenya in the first half of an El Niño year. Irrigation, rainfall and human population density were the main drivers of RVF cases, independent of seasonal, climatic or spatial variation. By accounting more subtly for the patterns in RVF data, we better determine the importance of underlying environmental drivers, and also make space- and time-sensitive predictions to better direct future surveillance resources.This article is part of the themed issue 'One Health for a changing world: zoonoses, ecosystems and human well-being'.
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Affiliation(s)
- David W Redding
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Sonia Tiedt
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Gianni Lo Iacono
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
- Environmental Change, Public Health England, Didcot OX11 0RQ, UK
| | - Bernard Bett
- International Livestock Research Institute, PO Box 30709-00100, Nairobi, Kenya
| | - Kate E Jones
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK
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Lumley S, Horton DL, Hernandez-Triana LLM, Johnson N, Fooks AR, Hewson R. Rift Valley fever virus: strategies for maintenance, survival and vertical transmission in mosquitoes. J Gen Virol 2017; 98:875-887. [PMID: 28555542 DOI: 10.1099/jgv.0.000765] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne arbovirus causing severe disease in humans and ruminants. Spread of RVFV out of Africa has raised concerns that it could emerge in Europe or the USA. Virus persistence is dependent on successful infection of, replication in, and transmission to susceptible vertebrate and invertebrate hosts, modulated by virus-host and vector-virus interactions. The principal accepted theory for the long-term maintenance of RVFV involves vertical transmission (VT) of virus to mosquito progeny, with the virus surviving long inter-epizootic periods within the egg. This VT hypothesis, however, is yet to be comprehensively proven. Here, evidence for and against the VT of RVFV is reviewed along with the identification of factors limiting its detection in natural and experimental data. The observations of VT for other arboviruses in the genera Alphavirus, Flavivirus and Orthobunyavirus are discussed within the context of RVFV. The review concludes that VT of RVFV is likely but that current data are insufficient to irrefutably prove this hypothesis.
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Affiliation(s)
- Sarah Lumley
- Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK.,School of Veterinary Medicine, University of Surrey, Guildford, UK.,Virology and Pathogenesis Group, Microbiology Services Division, Public Health England, Wiltshire, UK
| | - Daniel L Horton
- School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - Luis L M Hernandez-Triana
- Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK
| | - Nicholas Johnson
- School of Veterinary Medicine, University of Surrey, Guildford, UK.,Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK
| | - Anthony R Fooks
- Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK.,Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Liverpool, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
| | - Roger Hewson
- Virology and Pathogenesis Group, Microbiology Services Division, Public Health England, Wiltshire, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
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Couch CE, Movius MA, Jolles AE, Gorman ME, Rigas JD, Beechler BR. Serum biochemistry panels in African buffalo: Defining reference intervals and assessing variability across season, age and sex. PLoS One 2017; 12:e0176830. [PMID: 28472180 PMCID: PMC5417560 DOI: 10.1371/journal.pone.0176830] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 04/18/2017] [Indexed: 11/18/2022] Open
Abstract
Serum biochemical parameters can be utilized to evaluate the physiological status of an animal, and relate it to the animal's health. In order to accurately interpret individual animal biochemical results, species-specific reference intervals (RI) must be established. Reference intervals for biochemical parameters differ between species, and physiological differences including reproductive status, nutritional resource availability, disease status, and age affect parameters within the same species. The objectives of this study were to (1) establish RI for biochemical parameters in managed African buffalo (Syncerus caffer), (2) assess the effects of age, sex, pregnancy, and season on serum biochemistry values, and (3) compare serum biochemistry values from a managed herd to a free-ranging buffalo herd and to values previously published for captive (zoo) buffalo. Season profoundly affected all biochemistry parameters, possibly due to changes in nutrition and disease exposure. Age also affected all biochemical parameters except gamma glutamyl transferase and magnesium, consistent with patterns seen in cattle. Sex and reproductive status had no detectable effects on the parameters that were measured. The biochemical profiles of managed buffalo were distinct from those observed in the free-ranging herd and captive buffalo. Biochemical differences between buffalo from captive, managed, and free-ranging populations may be related to nutritional restriction or lack of predation in the context of management or captivity. The reference intervals provided in this study, in addition to the seasonal and age-related patterns observed, provide a foundation for health investigations that may inform management strategies in this ecologically and economically important species.
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Affiliation(s)
- Claire E. Couch
- Oregon State University, Department of Integrative Biology, Corvallis, Oregon, United States of America
| | - Morgan A. Movius
- Oregon State University, College of Veterinary Medicine, Corvallis, Oregon, United States of America
| | - Anna E. Jolles
- Oregon State University, Department of Integrative Biology, Corvallis, Oregon, United States of America
- Oregon State University, College of Veterinary Medicine, Corvallis, Oregon, United States of America
| | - M. Elena Gorman
- Oregon State University, College of Veterinary Medicine, Corvallis, Oregon, United States of America
| | - Johanna D. Rigas
- Utah State University, School of Veterinary Medicine, Logan, Utah, United States of America
| | - Brianna R. Beechler
- Oregon State University, College of Veterinary Medicine, Corvallis, Oregon, United States of America
- * E-mail:
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Glanzmann B, Möller M, le Roex N, Tromp G, Hoal EG, van Helden PD. The complete genome sequence of the African buffalo (Syncerus caffer). BMC Genomics 2016; 17:1001. [PMID: 27927182 PMCID: PMC5142436 DOI: 10.1186/s12864-016-3364-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 12/02/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The African buffalo (Syncerus caffer) is an important role player in the savannah ecosystem. It has become a species of relevance because of its role as a wildlife maintenance host for an array of infectious and zoonotic diseases some of which include corridor disease, foot-and-mouth disease and bovine tuberculosis. To date, no complete genome sequence for S. caffer had been available for study and the genomes of other species such as the domestic cow (Bos taurus) had been used as a proxy for any genetics analysis conducted on this species. Here, the high coverage genome sequence of the African buffalo (S. caffer) is presented. RESULTS A total of 19,765 genes were predicted and 19,296 genes could be successfully annotated to S. caffer while 469 genes remained unannotated. Moreover, in order to extend a detailed annotation of S. caffer, gene clusters were constructed using twelve additional mammalian genomes. The S. caffer genome contains 10,988 gene clusters, of which 62 are shared exclusively between B. taurus and S. caffer. CONCLUSIONS This study provides a unique genomic perspective for the S. caffer, allowing for the identification of novel variants that may play a role in the natural history and physiological adaptations.
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Affiliation(s)
- Brigitte Glanzmann
- SA MRC Centre for TB Research, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
| | - Marlo Möller
- SA MRC Centre for TB Research, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nikki le Roex
- SA MRC Centre for TB Research, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Gerard Tromp
- SA MRC Centre for TB Research, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Eileen G Hoal
- SA MRC Centre for TB Research, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Paul D van Helden
- SA MRC Centre for TB Research, DST/NRF Centre of Excellence for Biomedical TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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36
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Tran A, Trevennec C, Lutwama J, Sserugga J, Gély M, Pittiglio C, Pinto J, Chevalier V. Development and Assessment of a Geographic Knowledge-Based Model for Mapping Suitable Areas for Rift Valley Fever Transmission in Eastern Africa. PLoS Negl Trop Dis 2016; 10:e0004999. [PMID: 27631374 PMCID: PMC5025187 DOI: 10.1371/journal.pntd.0004999] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 08/22/2016] [Indexed: 11/18/2022] Open
Abstract
Rift Valley fever (RVF), a mosquito-borne disease affecting ruminants and humans, is one of the most important viral zoonoses in Africa. The objective of the present study was to develop a geographic knowledge-based method to map the areas suitable for RVF amplification and RVF spread in four East African countries, namely, Kenya, Tanzania, Uganda and Ethiopia, and to assess the predictive accuracy of the model using livestock outbreak data from Kenya and Tanzania. Risk factors and their relative importance regarding RVF amplification and spread were identified from a literature review. A numerical weight was calculated for each risk factor using an analytical hierarchy process. The corresponding geographic data were collected, standardized and combined based on a weighted linear combination to produce maps of the suitability for RVF transmission. The accuracy of the resulting maps was assessed using RVF outbreak locations in livestock reported in Kenya and Tanzania between 1998 and 2012 and the ROC curve analysis. Our results confirmed the capacity of the geographic information system-based multi-criteria evaluation method to synthesize available scientific knowledge and to accurately map (AUC = 0.786; 95% CI [0.730-0.842]) the spatial heterogeneity of RVF suitability in East Africa. This approach provides users with a straightforward and easy update of the maps according to data availability or the further development of scientific knowledge.
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Affiliation(s)
- Annelise Tran
- CIRAD, UPR AGIRs, Ste-Clotilde, Reunion Island
- CIRAD, UMR TETIS, Ste-Clotilde, Reunion Island
| | - Carlène Trevennec
- Food and Agriculture Organization of the United Nations, Rome, Italy
| | | | - Joseph Sserugga
- Uganda Ministry of Agriculture, Animal Industry and Fisheries, Entebbe, Uganda
| | | | - Claudia Pittiglio
- Food and Agriculture Organization of the United Nations, Rome, Italy
| | - Julio Pinto
- Food and Agriculture Organization of the United Nations, Rome, Italy
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37
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Capobianco Dondona A, Aschenborn O, Pinoni C, Di Gialleonardo L, Maseke A, Bortone G, Polci A, Scacchia M, Molini U, Monaco F. Rift Valley Fever Virus among Wild Ruminants, Etosha National Park, Namibia, 2011. Emerg Infect Dis 2016; 22:128-30. [PMID: 26692385 PMCID: PMC4696689 DOI: 10.3201/eid2201.150725] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
After a May 2011 outbreak of Rift Valley fever among livestock northeast of Etosha National Park, Namibia, wild ruminants in the park were tested for the virus. Antibodies were detected in springbok, wildebeest, and black-faced impala, and viral RNA was detected in springbok. Seroprevalence was high, and immune response was long lasting.
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38
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Lwande OW, Paul GO, Chiyo PI, Ng'ang'a E, Otieno V, Obanda V, Evander M. Spatio-temporal variation in prevalence of Rift Valley fever: a post-epidemic serum survey in cattle and wildlife in Kenya. Infect Ecol Epidemiol 2015; 5:30106. [PMID: 26679561 PMCID: PMC4683986 DOI: 10.3402/iee.v5.30106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 11/14/2015] [Accepted: 11/17/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Rift Valley fever (RVF) is a fatal arthropod-borne zoonotic disease of livestock and humans. Since the identification of RVF in Kenya in the 1930s, repeated epizootics and epidemics coinciding with El Niño events have occurred in several locations in Africa and Saudi Arabia, causing mass deaths of livestock and humans. RVF is of great interest worldwide because of its negative effect on international livestock trade and its potential to spread globally. The latter is due to the increasing incidence of extreme climatic phenomena caused by global warming, as well as to the increase in global trade and international travel. How RVF is maintained and sustained between epidemics and epizootics is not clearly understood, but it has been speculated that wildlife reservoirs and trans-ovarian transmission in the vector may be important. Several studies have examined the role of wildlife and livestock in isolation or in a limited geographical location within the one country over a short time (usually less than a year). In this study, we examined the seroprevalence of anti-RVF antibodies in cattle and several wildlife species from several locations in Kenya over an inter-epidemic period spanning up to 7 years. METHODS A serological survey of immunoglobulin G (IgG) antibodies to RVF using competitive ELISA was undertaken on 297 serum samples from different wildlife species at various locations in Kenya. The samples were collected between 2008 and 2015. Serum was also collected in 2014 from 177 cattle from Ol Pejeta Conservancy; 113 of the cattle were in close contact with wildlife and the other 64 were kept separate from buffalo and large game by an electric fence. RESULTS The seroprevalence of RVF virus (RVFV) antibody was 11.6% in wildlife species during the study period. Cattle that could come in contact with wildlife and large game were all negative for RVFV. The seroprevalence was relatively high in elephants, rhinoceros, and buffalo, but there were no antibodies in zebras, baboons, vervet monkeys, or wildebeest. CONCLUSIONS Diverse species in conservation areas are exposed to RVFV. RVFV exposure in buffalo may indicate distribution of the virus over wide geographical areas beyond known RVFV foci in Kenya. This finding calls for thorough studies on the epizootology of RVFV in specific wildlife species and locations.
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Affiliation(s)
- Olivia Wesula Lwande
- Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden
- Consortium for Epidemiology and Ecology (CEER-Africa), Minnesota, USA; ;
| | - George Omondi Paul
- Consortium for Epidemiology and Ecology (CEER-Africa), Minnesota, USA
- Department of Veterinary Population Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Patrick I Chiyo
- Consortium for Epidemiology and Ecology (CEER-Africa), Minnesota, USA
- Department of Biology, Duke University, Durham, NC, USA
| | - Eliud Ng'ang'a
- Department of Medical Laboratory Sciences, Mount Kenya University, Thika, Kenya
| | - Viola Otieno
- IGAD Climate Prediction and Application Center (ICPAC), Nairobi, Kenya
| | - Vincent Obanda
- Consortium for Epidemiology and Ecology (CEER-Africa), Minnesota, USA
- Department of Veterinary Services, Kenya Wildlife Service, Nairobi, Kenya
| | - Magnus Evander
- Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden
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Beechler BR, Manore CA, Reininghaus B, O'Neal D, Gorsich EE, Ezenwa VO, Jolles AE. Enemies and turncoats: bovine tuberculosis exposes pathogenic potential of Rift Valley fever virus in a common host, African buffalo (Syncerus caffer). Proc Biol Sci 2015; 282:rspb.2014.2942. [PMID: 25788592 DOI: 10.1098/rspb.2014.2942] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The ubiquity and importance of parasite co-infections in populations of free-living animals is beginning to be recognized, but few studies have demonstrated differential fitness effects of single infection versus co-infection in free-living populations. We investigated interactions between the emerging bacterial disease bovine tuberculosis (BTB) and the previously existing viral disease Rift Valley fever (RVF) in a competent reservoir host, African buffalo, combining data from a natural outbreak of RVF in captive buffalo at a buffalo breeding facility in 2008 with data collected from a neighbouring free-living herd of African buffalo in Kruger National Park. RVF infection was twice as likely in individual BTB+ buffalo as in BTB- buffalo, which, according to a mathematical model, may increase RVF outbreak size at the population level. In addition, co-infection was associated with a far higher rate of fetal abortion than other infection states. Immune interactions between BTB and RVF may underlie both of these interactions, since animals with BTB had decreased innate immunity and increased pro-inflammatory immune responses. This study is one of the first to demonstrate how the consequences of emerging infections extend beyond direct effects on host health, potentially altering the dynamics and fitness effects of infectious diseases that had previously existed in the ecosystem on free-ranging wildlife populations.
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Affiliation(s)
- B R Beechler
- College of Veterinary Medicine, Oregon State University, Dryden Hall, Corvallis, OR, USA
| | - C A Manore
- Center for Computational Science, Tulane University, Tulane, LA, USA
| | - B Reininghaus
- Mpumalanga State Veterinary Services, Nelspruit, Mpumalanga, South Africa
| | - D O'Neal
- Odum School of Ecology and Department of Infectious Disease, University of Georgia, Athens, GA, USA
| | - E E Gorsich
- Environmental Sciences, Oregon State University, OR, USA
| | - V O Ezenwa
- Odum School of Ecology and Department of Infectious Disease, University of Georgia, Athens, GA, USA
| | - A E Jolles
- College of Veterinary Medicine, Oregon State University, Dryden Hall, Corvallis, OR, USA
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40
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Jori F, Alexander KA, Mokopasetso M, Munstermann S, Moagabo K, Paweska JT. Serological Evidence of Rift Valley Fever Virus Circulation in Domestic Cattle and African Buffalo in Northern Botswana (2010-2011). Front Vet Sci 2015; 2:63. [PMID: 26664990 PMCID: PMC4672236 DOI: 10.3389/fvets.2015.00063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 11/09/2015] [Indexed: 11/24/2022] Open
Abstract
Rift Valley fever (RVF) is endemic in many countries in Sub-Saharan Africa and is responsible for severe outbreaks in livestock characterized by a sudden onset of abortions and high neonatal mortality. During the last decade, several outbreaks have occurred in Southern Africa, with a very limited number of cases reported in Botswana. To date, published information on the occurrence of RVF in wild and domestic animals from Botswana is very scarce and outdated, despite being critical to national and regional disease control. To address this gap, 863 cattle and 150 buffalo sampled at the interface between livestock areas and the Chobe National Park (CNP) and the Okavango Delta (OD) were screened for the presence of RVF virus (RVFV) neutralizing antibodies. Antibodies were detected in 5.7% (n = 863), 95% confidence intervals (CI) (4.3–7.5%) of cattle and 12.7% (n = 150), 95% CI (7.8–19.5%) of buffalo samples. The overall prevalence was significantly higher (p = 0.0016) for buffalo [12.7%] than for cattle [5.7%]. Equally, when comparing RVF seroprevalence in both wildlife areas for all pooled bovid species, it was significantly higher in CNP than in OD (9.5 vs. 4%, respectively; p = 0.0004). Our data provide the first evidence of wide circulation of RVFV in both buffalo and cattle populations in Northern Botswana and highlight the need for further epidemiological and ecological investigations on RVF at the wildlife–livestock–human interface in this region.
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Affiliation(s)
- Ferran Jori
- Integrated Animal Risk Management Unit, CIRAD, Campus International de Baillarguet , Montpellier , France ; Department of Animal Science and Production, Botswana College of Agriculture , Gaborone , Botswana
| | - Kathleen A Alexander
- Department of Fish and Wildlife Conservation, Virginia Tech , Blacksburg, VA , USA ; CARACAL, Center for African Resources: Communities, Animals, and Land Use , Kasane , Botswana
| | - Mokganedi Mokopasetso
- FAO-ECTAD Regional Office , Gaborone , Botswana ; Botswana Vaccine Institute , Gaborone , Botswana
| | - Suzanne Munstermann
- FAO-ECTAD Regional Office , Gaborone , Botswana ; World Organization for Animal Health (OIE) , Paris , France
| | | | - Janusz T Paweska
- Center for Emerging and Zoonotic Diseases, National Institute of Communicable Diseases of the National Health Laboratory Service , Johannesburg , South Africa ; Faculty of Health Sciences, University of the Witwatersrand , Johannesburg , South Africa
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Jolles AE, Beechler BR, Dolan BP. Beyond mice and men: environmental change, immunity and infections in wild ungulates. Parasite Immunol 2015; 37:255-66. [PMID: 25354672 PMCID: PMC4414670 DOI: 10.1111/pim.12153] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/16/2014] [Indexed: 02/06/2023]
Abstract
In the face of rapid environmental change, anticipating shifts in microparasite and macroparasite dynamics, including emergence events, is an enormous challenge. We argue that immunological studies in natural populations are pivotal to meeting this challenge: many components of environmental change--shifts in biotic assemblages, altered climate patterns and reduced environmental predictability--may affect host immunity. We suggest that wild ungulates can serve as model systems aiding the discovery of immunological mechanisms that link environmental change with parasite transmission dynamics. Our review of eco-immunological studies in wild ungulates reveals progress in understanding how co-infections affect immunity and parasite transmission and how environmental and genetic factors interact to shape immunity. Changes in bioavailability of micronutrients have been linked to immunity and health in wild ungulates. Although physiological stress in response to environmental change has been assessed, downstream effects on immunity have not been studied. Moreover, the taxonomic range of ungulates studied is limited to bovids (bighorn sheep, Soay sheep, chamois, musk oxen, bison, African buffalo) and a few cervids (red deer, black-tailed deer). We discuss areas where future studies in ungulates could lead to significant contributions in understanding the patterns of immunity and infection in natural populations and across species.
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Affiliation(s)
- Anna E. Jolles
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR 97331
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331
| | - Brianna R. Beechler
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR 97331
| | - Brian P. Dolan
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR 97331
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Manore CA, Beechler BR. Inter-epidemic and between-season persistence of rift valley fever: vertical transmission or cryptic cycling? Transbound Emerg Dis 2013; 62:13-23. [PMID: 23551913 DOI: 10.1111/tbed.12082] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Indexed: 11/29/2022]
Abstract
Rift Valley fever (RVF) is an emerging zoonotic mosquito-borne infectious disease that has been identified as a risk for spread to other continents and can cause mass livestock mortality. In equatorial Africa, outbreaks of RVF are associated with high rainfall, when vector populations are at their highest. It is, however, unclear how RVF virus persists during the inter-epidemic periods and between seasons. Understanding inter-epidemic persistence as well as the role of vectors and hosts is paramount to creating effective management programmes for RVF control. We created a mathematical model for the spread of RVF and used the model to explore different scenarios of persistence including vertical transmission and alternate wildlife hosts, with a case study on buffalo in Kruger National Park, South Africa. Our results suggest that RVF persistence is a delicate balance between numerous species of susceptible hosts, mosquito species, vertical transmission and environmental stochasticity. Further investigations should not focus on a single species, but should instead consider a myriad of susceptible host species when seeking to understand disease dynamics.
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Affiliation(s)
- C A Manore
- Department of Mathematics, Tulane University, New Orleans, LA, USA; Center for Computational Science, Tulane University, New Orleans, LA, USA
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