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Soltan-Alinejad P, Bahrami S, Keshavarzi D, Shahriari-Namadi M, Hosseinpour A, Soltani A. Physicochemical characteristics of larval habitats and biodiversity of mosquitoes in one of the most important metropolises of southern Iran. Heliyon 2023; 9:e22754. [PMID: 38107319 PMCID: PMC10724668 DOI: 10.1016/j.heliyon.2023.e22754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 10/21/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023] Open
Abstract
The present study aimed to investigate the roles of the physicochemical characteristics of larval habitats in biodiversity and other bionomic factors of mosquitoes in Shiraz. The physical parameters of all habitats were recorded separately. The collected mosquito larvae were identified based on morphological characters. The water samples of larval habitats were analyzed for Biochemical Oxygen Demand (BOD, mg/L), Chemical Oxygen Demand (COD, mg/L), pH, alkalinity, turbidity, total hardness (mg/L), Electrical Conductivity (EC, μS/cm), Total Dissolved Solids (TDS, mg/L), Cl2 (mg/L), and water temperature (°C). In addition, three main indices were used for surveying biodiversity. A total of 1229 larvae were collected from April to September 2018 and May to August 2019. Seven medically important mosquito species were identified morphologically. Culex quinquefasciatus and Cx. laticinctus had the highest distribution and abundance. Ecological results showed that the richness and diversity of species were higher and more stable in natural sites than in manmade places. The optimum BOD, COD, alkalinity, TDS, EC, pH, and temperature of water for mosquitoes of the studied areas were 140 mg/L, 360 mg/L, 160 mg/L, 420 mg/L, 840 μS/cm, 8.3, and 24 °C, respectively. Most mosquitoes tended to live in manmade, temporary, and sunny larval habitats with turbid water. The results provided a better understanding of the biology and ecology of mosquitoes as the most important group of disease vectors to humans and animals. Hence, they could be used to apply some safer and more environmentally friendly methods for mosquito control.
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Affiliation(s)
- Parisa Soltan-Alinejad
- Department of Medical Entomology and Vector Control, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Shima Bahrami
- Department of Environmental Health Engineering, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Davood Keshavarzi
- Department of Medical Entomology and Vector Control, School of Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Marziae Shahriari-Namadi
- Department of Medical Entomology and Vector Control, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amin Hosseinpour
- Department of Medical Entomology and Vector Control, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Aboozar Soltani
- Research Center for Health Sciences, Institute of Health, Department of Medical Entomology and Vector Control, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
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Ngoshe YB, Etter E, Gomez-Vazquez JP, Thompson PN. Knowledge, Attitudes, and Practices of Communal Livestock Farmers regarding Animal Health and Zoonoses in Far Northern KwaZulu-Natal, South Africa. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 20:511. [PMID: 36612830 PMCID: PMC9819478 DOI: 10.3390/ijerph20010511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/21/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
The presence of zoonotic diseases adversely affects livestock production and farmers' livelihood in communal areas. A lack of awareness about zoonotic diseases among rural farmers results in economic losses and health risks. The far north-eastern corner of KwaZulu-Natal (KZN) province, South Africa, is home to large numbers of communal livestock farmers who live adjacent to wildlife reserves and international borders. There have been reports of zoonotic and trade-sensitive diseases in the area, but farmers' knowledge, attitudes, and practices (KAP) in this regard are poorly understood. This study investigated the KAPs of communal livestock farmers in far northern KZN regarding livestock and zoonotic diseases found in the livestock-wildlife interface and determined the constraints and challenges faced by communal livestock farmers. A cross-sectional questionnaire survey was conducted among 504 livestock farmers at 45 dip tanks between August and November 2020, using a closed-ended questionnaire. Although the overall level of knowledge regarding animal disease transmission was fairly good (score: 53.2%), 25.4% and 21.4% of farmers had moderate and poor knowledge, respectively, about zoonotic disease transmission and prevention. Over 40% of the farmers were not aware of the zoonotic nature of wildlife and livestock diseases. Older farmers, despite their lower level of education, were more knowledgeable on animal diseases and had better practices in regard to zoonotic disease prevention and management compared to younger ones. The majority of farmers cited the lack of water, insufficient grazing land, stock theft, the restriction of animal movement, and animal diseases as the most significant challenges they faced regarding animal production. The results indicate the need for extension programs that target educating livestock farmers to improve their knowledge of these diseases.
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Affiliation(s)
- Yusuf Bitrus Ngoshe
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Eric Etter
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
- ASTRE, University of Montpellier, CIRAD, INRA, F-34000 Montpellier, France
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), F-97170 Petit-Bourg, France
| | - Jose Pablo Gomez-Vazquez
- Center for Disease Modelling and Surveillance (CADMS), University of California, Davis, CA 95616, USA
| | - Peter N. Thompson
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
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Gerken KN, Ndenga BA, Owuor KO, Winter CA, Seetah K, LaBeaud AD. Leveraging livestock movements to urban slaughterhouses for wide-spread Rift Valley fever virus surveillance in Western Kenya. One Health 2022; 15:100457. [PMID: 36532672 PMCID: PMC9754961 DOI: 10.1016/j.onehlt.2022.100457] [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: 07/12/2022] [Revised: 11/11/2022] [Accepted: 11/12/2022] [Indexed: 11/16/2022] Open
Abstract
Rift Valley fever virus (RVFV) is an economically devastating, zoonotic arbovirus endemic across Africa with potential to cause severe disease in livestock and humans. Viral spread is primarily driven by movement of domestic ruminants and there is a high potential for transboundary spread. Despite influx of livestock to urban areas in response to the high demand for meat and animal products, RVFV has not been detected in any urban center. The objectives of this study were to determine the feasibility of assessing risk of RVFV introduction to urban Kisumu, Kenya, by testing slaughtered livestock for RVFV exposure and mapping livestock origins. Blood was collected from cattle, sheep, and goats directly after slaughter and tested for anti-RVFV IgG antibodies. Slaughterhouse businessmen responded to a questionnaire on their individual animals' origin, marketplace, and transport means. Thereafter, we mapped livestock flow from origin to slaughterhouse using participatory methods in focus group discussions with stakeholders. Qualitative data on route choice and deviations were spatially integrated into the map. A total of 304 blood samples were collected from slaughtered livestock in October and November 2021. Most (99%) of animals were purchased from 28 different markets across eight counties in Western Kenya. The overall RVFV seroprevalence was 9% (19% cattle, 3% in sheep, and 7% in goats). Migori County bordering Tanzania had the highest county-level seroprevalence (34%) and 80% of all seropositive cattle were purchased at the Suba Kuria market in Migori County. Road quality and animal health influenced stakeholders' decisions for choice of transport means. Overall, this proof-of-concept study offers a sampling framework for RVFV that can be locally implemented and rapidly deployed in response to regional risk. This system can be used in conjunction with participatory maps to improve active livestock surveillance and monitoring of RVFV in Western Kenya, and these methods could be extrapolated to other urban centers or livestock diseases.
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Affiliation(s)
- Keli Nicole Gerken
- Department of Pediatrics, Division of Infectious Disease, Stanford University School of Medicine, Stanford, CA, USA,Corresponding author at: LaBeaud Research Lab, Stanford University School of Medicine, Biomedical Innovation BMI Building, 2 Floor, Room 2400, 1291 Welch Road, Stanford, CA -, USA.
| | | | - Kevin Omondi Owuor
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Krish Seetah
- Department of Anthropology, Stanford University, USA
| | - Angelle Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Disease, Stanford University School of Medicine, Stanford, CA, USA
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de Glanville WA, Nyarobi JM, Kibona T, Halliday JEB, Thomas KM, Allan KJ, Johnson PCD, Davis A, Lankester F, Claxton JR, Rostal MK, Carter RW, de Jong RMF, Rubach MP, Crump JA, Mmbaga BT, Nyasebwa OM, Swai ES, Willett B, Cleaveland S. Inter-epidemic Rift Valley fever virus infection incidence and risks for zoonotic spillover in northern Tanzania. PLoS Negl Trop Dis 2022; 16:e0010871. [PMID: 36306281 PMCID: PMC9665400 DOI: 10.1371/journal.pntd.0010871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 11/15/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne pathogen that has caused epidemics involving people and animals across Africa and the Arabian Peninsula. A number of studies have found evidence for the circulation of RVFV among livestock between these epidemics but the population-level incidence of infection during this inter-epidemic period (IEP) is rarely reported. General force of infection (FOI) models were applied to age-adjusted cross-sectional serological data to reconstruct the annual FOI and population-level incidence of RVFV infection among cattle, goats, and sheep in northern Tanzania from 2009 through 2015, a period without reported Rift Valley fever (RVF) cases in people or animals. To evaluate the potential for zoonotic RVFV spillover during this period, the relationship between village-level livestock RVFV FOI and human RVFV seropositivity was quantified using multi-level logistic regression. The predicted average annual incidence was 72 (95% Credible Interval [CrI] 63, 81) RVFV infections per 10,000 animals and 96 (95% CrI 81, 113), 79 (95% CrI 62, 98), and 39 (95% CrI 28, 52) per 10,000 cattle, sheep, and goats, respectively. There was variation in transmission intensity between study villages, with the highest estimated village-level FOI 2.49% (95% CrI 1.89, 3.23) and the lowest 0.12% (95% CrI 0.02, 0.43). The human RVFV seroprevalence was 8.2% (95% Confidence Interval 6.2, 10.9). Human seropositivity was strongly associated with the village-level FOI in livestock, with the odds of seropositivity in an individual person increasing by around 1.2 times (95% CrI 1.1, 1.3) for each additional annual RVFV seroconversion per 1,000 animals. A history of raw milk consumption was also positively associated with human seropositivity. RVFV has circulated at apparently low levels among livestock in northern Tanzania in the period since the last reported epidemic. Although our data do not allow us to confirm human RVFV infections during the IEP, a strong association between human seropositivity and the FOI in cattle, goats, and sheep supports the hypothesis that RVFV circulation among livestock during the IEP poses a risk for undetected zoonotic spillover in northern Tanzania. We provide further evidence for the likely role of raw milk consumption in RVFV transmission from animals to people.
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Affiliation(s)
- William A. de Glanville
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- University of Global Health Equity, Kigali, Rwanda
- * E-mail: (WAdG); (SC)
| | - James M. Nyarobi
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Tito Kibona
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Jo E. B. Halliday
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kate M. Thomas
- Centre for International Health, University of Otago, Dunedin, New Zealand
- Kilimanjaro Clinical Research Institute, Moshi, United Republic of Tanzania
| | - Kathryn J. Allan
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Paul C. D. Johnson
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alicia Davis
- School of Social and Political Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Felix Lankester
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, United States of America
- Global Animal Health Tanzania, Arusha, Tanzania
| | - John R. Claxton
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Melinda K. Rostal
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- EcoHealth Alliance, New York, New York, United States of America
| | - Ryan W. Carter
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Rosanne M. F. de Jong
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew P. Rubach
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Programme in Emerging Infectious Diseases, Duke-National University of Singapore, Singapore
| | - John A. Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
| | - Blandina T. Mmbaga
- Kilimanjaro Clinical Research Institute, Moshi, United Republic of Tanzania
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
| | - Obed M. Nyasebwa
- Ministry of Livestock and Fisheries, Dodoma, United Republic of Tanzania
| | - Emanuel S. Swai
- Ministry of Livestock and Fisheries, Dodoma, United Republic of Tanzania
| | - Brian Willett
- MRC University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Sarah Cleaveland
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (WAdG); (SC)
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An unusually long Rift valley fever inter-epizootic period in Zambia: Evidence for enzootic virus circulation and risk for disease outbreak. PLoS Negl Trop Dis 2022; 16:e0010420. [PMID: 35653390 PMCID: PMC9197056 DOI: 10.1371/journal.pntd.0010420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 06/14/2022] [Accepted: 04/14/2022] [Indexed: 11/19/2022] Open
Abstract
Rift valley fever (RVF) is a mosquito-borne disease of animals and humans. Although RVF outbreaks are usually reported at 5-15-year intervals in sub-Saharan Africa, Zambia has experienced an unusually long inter-epizootic/-epidemic period of more than three decades. However, serological evidence of RVF virus (RVFV) infection in domestic ruminants during this period underscores the need for comprehensive investigation of the mechanisms of virus perpetuation and disease emergence. Mosquitoes (n = 16,778) captured from eight of the ten provinces of Zambia between April 2014 and May 2019 were pooled (n = 961) and screened for RVFV genome by a pan-phlebo RT-PCR assay. Aedes mosquito pools (n = 85) were further screened by nested RT-PCR assay. Sera from sheep (n = 13), goats (n = 259) and wild ungulates (n = 285) were screened for RVFV antibodies by ELISA while genome detection in pooled sera (n = 276) from domestic (n = 248) and wild ungulates (n = 37) was performed by real-time RT-PCR assay. To examine the association between the long inter-epizootic period and climatic variables, we examined El Niño-Southern Oscillation indices, precipitation anomalies, and normalized difference vegetation index. We then derived RVF risk maps by exploring climatic variables that would favor emergence of primary RVFV vectors. While no RVFV genome could be detected in pooled mosquito and serum samples, seroprevalence was significantly high (OR = 8.13, 95% CI [4.63–14.25]) in wild ungulates (33.7%; 96/285) compared to domestic ruminants (5.6%; 16/272). Retrospective analysis of RVF epizootics in Zambia showed a positive correlation between anomalous precipitation (La Niña) and disease emergence. On risk mapping, whilst northern and eastern parts of the country were at high risk, domestic ruminant population density was low (< 21 animals/km2) in these areas compared to low risk areas (>21 animals/km2). Besides evidence of silent circulation of RVFV and the risk of disease emergence in some areas, wildlife may play a role in the maintenance of RVFV in Zambia. Rift valley fever (RVF) is an important mosquito borne disease of humans and ruminants. RVF is endemic in sub-Saharan Africa where disease outbreaks are frequently reported in humans and animals. For RVF outbreaks to occur, there has to be presence of the host (animals or humans) and favorable climatic conditions that favor emergence of RVF virus vectors (mosquitoes). Understanding this complex interaction enables us to predict future disease outbreaks and map RVF high risk areas. Above normal rainfall and floods will usually trigger RVF outbreaks. In this study, we conducted surveillance for RVF in mosquitoes, domestic and wild ruminants. We then examined climatic conditions that may have been responsible for past RVF outbreaks and the unusually (>30 years) long inter-epizootic period. Finally, we derived RVF risk maps for Zambia using a combination of climatic variables. We found evidence of RVF infection in both wild and domestic ruminants while there was a positive correlation between past RVF outbreaks and above-normal rainfall. On risk mapping, we found favorable conditions (i.e. high rainfall and risk of flooding) for RVF emergence in northern and eastern parts of the country. Studies like this are important in planning surveillance and disease control programs.
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Serological Evidence of Antibodies to Rift Valley Fever Virus in Wild and Domestic Animals in Bauchi State, Nigeria. Vet Med Int 2022; 2022:6559193. [PMID: 35340539 PMCID: PMC8942677 DOI: 10.1155/2022/6559193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 01/18/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
Rift Valley fever (RVF) is an arthropod-borne zoonotic disease responsible for severe outbreaks in livestock and humans with concomitant economic losses in many countries in sub-Saharan Africa. The study, therefore, investigated the seroprevalence of the Rift Valley fever virus (RVFV) among wild and domestic animals. Blood samples were collected between 2013 and 2015 from 106 wild animals, 300 cattle (Bos indicus), and 200 horses (Equus caballus), respectively, in Yankari Game Reserve (YGR) and Sumu Wildlife Park (SWP) in Bauchi state, Nigeria. Harvested sera from blood were evaluated for the presence of anti-RVFV IgM/IgG antibodies. The overall seroprevalence in cattle was 11.3% (p = 0.677; 95% CI: 0.624–0.730) and in wildlife was 8.5% (p = 0.006; 95% CI: 0.00–0.60). The diversity of wildlife species sampled indicated seropositivity of 36.0% in waterbuck (Kobus ellipsiprymus), 25.0% in elephant (Loxodonta africana), 12.5% in eland (Taurotragus oryx), and 8.3% in wildebeest (Connochaetes taurinus). Whereas, samples from zebra (Equus quagga crawshayi), kudu (Tragelaphus strepsiceros), and hartebeest (Alcelaphus buselaphus caama) did not show detectable antibodies to RVFV, and seroprevalence in female (15.0%) wildlife species was higher than in males (4.5%) (p = 0.061). Classification of cattle into breed and sex showed no significant difference in seropositivity. Seropositivity of 12.0% was observed in White Fulani, 12.1% in Red Bororo, and 7.8% in Sokoto Gudali breeds of cattle (p = 0.677). Whereas, seropositivity of 13.6% was observed in females and 6.4% observed in males (p = 0.068). This study indicated the presence of antibodies to RVFV among some wild animals and cattle in the absence of a reported outbreak in the study area. The circulation of RVFV in the study area may pose a significant health risk to livestock, wildlife, and humans. Therefore, surveillance for RVFV should be intensified targeting mosquito vectors and humans in Bauchi state, Nigeria.
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van den Bergh C, Thompson PN, Swanepoel R, Almeida APG, Paweska JT, Jansen van Vuren P, Wilson WC, Kemp A, Venter EH. Detection of Rift Valley Fever Virus in Aedes (Aedimorphus) durbanensis, South Africa. Pathogens 2022; 11:pathogens11020125. [PMID: 35215069 PMCID: PMC8879006 DOI: 10.3390/pathogens11020125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/10/2022] [Accepted: 01/18/2022] [Indexed: 12/10/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne, zoonotic phlebovirus-causing disease in domestic ruminants and humans in Africa, the Arabian Peninsula and some Indian Ocean islands. Outbreaks, characterized by abortion storms and a high morbidity rate in newborn animals, occur after heavy and prolonged rainfalls favouring the breeding of mosquitoes. However, the identity of the important mosquito vectors of RVFV is poorly known in most areas. Mosquitoes collected in the Ndumo area of tropical north-eastern KwaZulu-Natal (KZN), South Africa, were tested for RVFV nucleic acid using RT-PCR. The virus was detected in a single pool of unfed Aedes (Aedimorphus) durbanensis, indicating that this seasonally abundant mosquito species could serve as a vector in this area of endemic RVFV circulation. Phylogenetic analysis indicated the identified virus is closely related to two isolates from the earliest outbreaks, which occurred in central South Africa more than 60 years ago, indicating long-term endemicity in the region. Further research is required to understand the eco-epidemiology of RVFV and the vectors responsible for its circulation in the eastern tropical coastal region of southern Africa.
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Affiliation(s)
- Carien van den Bergh
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; (R.S.); (E.H.V.)
- Correspondence: ; Tel.: +27-(0)82-300-7406
| | - Peter N. Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria 0002, South Africa;
| | - Robert Swanepoel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; (R.S.); (E.H.V.)
| | - Antonio P. G. Almeida
- Unidade de Parasitologia Medica, Global Health and Tropical Medicine, Universidade Nova Lisboa, 1365-008 Lisboa, Portugal;
| | - Janusz T. Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa; (J.T.P.); (P.J.v.V.); (A.K.)
- Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Petrus Jansen van Vuren
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa; (J.T.P.); (P.J.v.V.); (A.K.)
- Australian Centre for Disease Preparedness, CSIRO-Health and Biosecurity, Geelong, VIC 3220, Australia
| | - William C. Wilson
- National Bio and Agro-Defense Facility, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS 66502, USA;
| | - Alan Kemp
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa; (J.T.P.); (P.J.v.V.); (A.K.)
| | - Estelle H. Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; (R.S.); (E.H.V.)
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia
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Pawęska JT, Msimang V, Kgaladi J, Hellferscee O, Weyer J, Jansen van Vuren P. Rift Valley Fever Virus Seroprevalence among Humans, Northern KwaZulu-Natal Province, South Africa, 2018-2019. Emerg Infect Dis 2021; 27:3159-3162. [PMID: 34808090 PMCID: PMC8632195 DOI: 10.3201/eid2712.210643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We detected Rift Valley fever virus (RVFV) IgM and IgG in human serum samples collected during 2018–2019 in northern KwaZulu-Natal Province, South Africa. Our results show recent RVFV circulation and likely RVFV endemicity in this tropical coastal plain region of South Africa in the absence of apparent clinical disease.
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Obaidat MM, Graziano JC, Morales-Betoulle M, Brown SM, Chiang CF, Klena JD. Rift Valley Fever and Crimean-Congo Hemorrhagic Fever Viruses in Ruminants, Jordan. Emerg Infect Dis 2021; 27:653-655. [PMID: 33496248 PMCID: PMC7853544 DOI: 10.3201/eid2702.203713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The epidemiology of Rift Valley fever virus (RVFV) and Crimean-Congo hemorrhagic fever virus (CCHFV) in Jordan is unknown. Our investigation showed 3% of 989 tested dairy cattle, sheep, and goats were RVFV seropositive and 14% were CCHFV seropositive. Ongoing surveillance is needed to assess risk to humans and protect public health.
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Pedarrieu A, El Mellouli F, Khallouki H, Zro K, Sebbar G, Sghaier S, Madani H, Bouayed N, Lo MM, Diop M, Ould El Mamy AB, Barry Y, Dakouo M, Traore A, Gagara H, Souley MM, Acha S, Mapaco L, Chang’a J, Nyakilinga D, Lubisi BA, Tshabalala T, Filippone C, Heraud JM, Chamassy SB, Achiraffi A, Keck N, Grard G, Mohammed KAA, Alrizqi AM, Cetre-Sossah C. External quality assessment of Rift Valley fever diagnosis in countries at risk of the disease: African, Indian Ocean and Middle-East regions. PLoS One 2021; 16:e0251263. [PMID: 34010292 PMCID: PMC8133482 DOI: 10.1371/journal.pone.0251263] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/23/2021] [Indexed: 12/14/2022] Open
Abstract
Rift Valley fever virus (RVFV), an arbovirus belonging to the Phlebovirus genus of the Phenuiviridae family, causes the zoonotic and mosquito-borne RVF. The virus, which primarily affects livestock (ruminants and camels) and humans, is at the origin of recent major outbreaks across the African continent (Mauritania, Libya, Sudan), and in the South-Western Indian Ocean (SWIO) islands (Mayotte). In order to be better prepared for upcoming outbreaks, to predict its introduction in RVFV unscathed countries, and to run efficient surveillance programmes, the priority is harmonising and improving the diagnostic capacity of endemic countries and/or countries considered to be at risk of RVF. A serological inter-laboratory proficiency test (PT) was implemented to assess the capacity of veterinary laboratories to detect antibodies against RVFV. A total of 18 laboratories in 13 countries in the Middle East, North Africa, South Africa, and the Indian Ocean participated in the initiative. Two commercial kits and two in-house serological assays for the detection of RVFV specific IgG antibodies were tested. Sixteen of the 18 participating laboratories (88.9%) used commercial kits, the analytical performance of test sensitivity and specificity based on the seroneutralisation test considered as the reference was 100%. The results obtained by the laboratories which used the in-house assay were correct in only one of the two criteria (either sensitivity or specificity). In conclusion, most of the laboratories performed well in detecting RVFV specific IgG antibodies and can therefore be considered to be prepared. Three laboratories in three countries need to improve their detection capacities. Our study demonstrates the importance of conducting regular proficiency tests to evaluate the level of preparedness of countries and of building a network of competent laboratories in terms of laboratory diagnosis to better face future emerging diseases in emergency conditions.
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Affiliation(s)
- Aurélie Pedarrieu
- ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, F-34398 Montpellier Cedex, France
| | - Fatiha El Mellouli
- Laboratoire Régional d’Analyses et de Recherches de Casablanca, Office National de la Sécurité Sanitaire des aliments), Nouaceur, Casablanca, Morocco
| | - Hanane Khallouki
- Laboratoire Régional d’Analyses et de Recherches de Casablanca, Office National de la Sécurité Sanitaire des aliments), Nouaceur, Casablanca, Morocco
| | | | | | - Soufien Sghaier
- Département de Virologie, Institut de la Recherche Vétérinaire de Tunisie (IRVT), Université de Tunis El Manar, Tunis, Tunisia
| | - Hafsa Madani
- Laboratoire Central Vétérinaire d’Alger, Institut National de Médecine Vétérinaire (INMV), Mohammadia, Algeria
| | - Nadera Bouayed
- Laboratoire Central Vétérinaire d’Alger, Institut National de Médecine Vétérinaire (INMV), Mohammadia, Algeria
| | - Modou Moustapha Lo
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar, Senegal
| | - Mariame Diop
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar, Senegal
| | | | - Yahya Barry
- Office National de Recherches et de Développement de l’Elevage (ONARDEL), Nouakchott, Mauritania
| | | | | | - Haladou Gagara
- Laboratoire Central de l’Elevage (LABOCEL), Niamey, Niger
| | | | - Sara Acha
- Agrarian Research Institute of Mozambique, Directorate of Aninal Science, Central Veterinary Laboratory, Maputo, Mozambique
| | - Laurenco Mapaco
- Agrarian Research Institute of Mozambique, Directorate of Aninal Science, Central Veterinary Laboratory, Maputo, Mozambique
| | - Jelly Chang’a
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Denis Nyakilinga
- Centre for Infectious Diseases and Biotechnology, Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Baratang A. Lubisi
- Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVR), Onderstepoort, South Africa
| | - Thabisile Tshabalala
- Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVR), Onderstepoort, South Africa
| | - Claudia Filippone
- Institut Pasteur de Madagascar, Unité de Virologie, Antananarivo, Madagascar
| | - Jean Michel Heraud
- Institut Pasteur de Madagascar, Unité de Virologie, Antananarivo, Madagascar
| | | | - Abdou Achiraffi
- Laboratoire vétérinaire et d’analyses départemental (LVAD976), Mayotte, France
| | - Nicolas Keck
- Laboratoire Départemental Vétérinaire (LDV34), Montpellier, France
| | - Gilda Grard
- Centre National de Référence sur les arboviruses (CNR Arbovirus), Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France
- Unité des Virus Émergents (UVE: Aix-Marseille Univ-IRD 190-Inserm 1207-IHU Méditerranée Infection), Marseille, France
| | | | - Abdulwahed Mohammed Alrizqi
- The Ministry of Environment, Water and Agriculture (MEWA), Jazan Veterinary Diagnostic Laboratory, Jizan, Kingdom of Saudi Arabia
| | - Catherine Cetre-Sossah
- ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, F-97490 Sainte-Clotilde, La Réunion, France
- * E-mail:
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11
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Odendaal L, Davis AS, Venter EH. Insights into the Pathogenesis of Viral Haemorrhagic Fever Based on Virus Tropism and Tissue Lesions of Natural Rift Valley Fever. Viruses 2021; 13:v13040709. [PMID: 33923863 PMCID: PMC8073615 DOI: 10.3390/v13040709] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/26/2021] [Accepted: 04/02/2021] [Indexed: 12/20/2022] Open
Abstract
Rift Valley fever phlebovirus (RVFV) infects humans and a wide range of ungulates and historically has caused devastating epidemics in Africa and the Arabian Peninsula. Lesions of naturally infected cases of Rift Valley fever (RVF) have only been described in detail in sheep with a few reports concerning cattle and humans. The most frequently observed lesion in both ruminants and humans is randomly distributed necrosis, particularly in the liver. Lesions supportive of vascular endothelial injury are also present and include mild hydropericardium, hydrothorax and ascites; marked pulmonary congestion and oedema; lymph node congestion and oedema; and haemorrhages in many tissues. Although a complete understanding of RVF pathogenesis is still lacking, antigen-presenting cells in the skin are likely the early targets of the virus. Following suppression of type I IFN production and necrosis of dermal cells, RVFV spreads systemically, resulting in infection and necrosis of other cells in a variety of organs. Failure of both the innate and adaptive immune responses to control infection is exacerbated by apoptosis of lymphocytes. An excessive pro-inflammatory cytokine and chemokine response leads to microcirculatory dysfunction. Additionally, impairment of the coagulation system results in widespread haemorrhages. Fatal outcomes result from multiorgan failure, oedema in many organs (including the lungs and brain), hypotension, and circulatory shock. Here, we summarize current understanding of RVF cellular tropism as informed by lesions caused by natural infections. We specifically examine how extant knowledge informs current understanding regarding pathogenesis of the haemorrhagic fever form of RVF, identifying opportunities for future research.
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Affiliation(s)
- Lieza Odendaal
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria 0002, South Africa
- Correspondence: (L.O.); (A.S.D.)
| | - A Sally Davis
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria 0002, South Africa
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
- Correspondence: (L.O.); (A.S.D.)
| | - Estelle H Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0002, South Africa;
- College of Public Health Medical and Veterinary Sciences, Discipline Veterinary Science, James Cook University, Townsville, QLD 4811, Australia
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12
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Wichgers Schreur PJ, Vloet RPM, Kant J, van Keulen L, Gonzales JL, Visser TM, Koenraadt CJM, Vogels CBF, Kortekaas J. Reproducing the Rift Valley fever virus mosquito-lamb-mosquito transmission cycle. Sci Rep 2021; 11:1477. [PMID: 33446733 PMCID: PMC7809480 DOI: 10.1038/s41598-020-79267-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/30/2020] [Indexed: 01/25/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus that is pathogenic to ruminants and humans. The virus is endemic to Africa and the Arabian Peninsula where outbreaks are characterized by abortion storms and mortality of newborns, particularly in sheep herds. Vector competence experiments in laboratory settings have suggested that over 50 mosquito species are capable of transmitting RVFV. Transmission of mosquito-borne viruses in the field is however influenced by numerous factors, including population densities, blood feeding behavior, extrinsic incubation period, longevity of vectors, and viremia levels in vertebrate hosts. Animal models to study these important aspects of RVFV transmission are currently lacking. In the present work, RVFV was transmitted to European (Texel-swifter cross-breed) lambs by laboratory-reared Aedes aegypti mosquitoes that were infected either by membrane feeding on a virus-spiked blood meal or by feeding on lambs that developed viremia after intravenous inoculation of RVFV. Feeding of mosquitoes on viremic lambs resulted in strikingly higher infection rates as compared to membrane feeding. Subsequent transmission of RVFV from lamb to lamb by infected mosquitoes was highly efficient in both models. The animal models described here can be used to study mosquito-mediated transmission of RVFV among the major natural target species and to evaluate the efficacy of vaccines against mosquito-mediated RVFV infection.
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Affiliation(s)
| | | | - Jet Kant
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | | | - Jose L Gonzales
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Tessa M Visser
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | | | - Chantal B F Vogels
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Jeroen Kortekaas
- Wageningen Bioveterinary Research, Lelystad, The Netherlands. .,Laboratory of Virology, Wageningen University & Research, Wageningen, The Netherlands.
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13
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Sero-prevalence of West Nile virus and Rift Valley fever virus infections among cattle under extensive production system in South Omo area, southern Ethiopia. Trop Anim Health Prod 2021; 53:92. [PMID: 33415465 DOI: 10.1007/s11250-020-02506-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/03/2020] [Indexed: 12/20/2022]
Abstract
West Nile fever (WNF) and Rift Valley fever (RVF) are emerging and re-emerging zoonotic diseases of veterinary and public health importance in Africa. Despite the existence of potential vectors and a wide range of hosts, the transmission of these diseases in domestic animals has not been well documented in the South Omo area of Ethiopia. This study aimed to estimate the sero-prevalence of IgG antibodies produced against West Nile virus (WNV) and Rift Valley fever virus (RVFV) infections among cattle in the South Omo area. Between May and June 2019, blood samples were collected from 397 cattle and screened for IgG antibodies against WNV and RVFV infections using enzyme-linked immunosorbent assay (ELISA). The overall sero-prevalence of IgG antibody to WNV infection was 4.8% (95% CI: 2.67-6.88%), while it was 5.0% to RVFV infection (95% CI: 2.87-7.18). Compared to 1-3 years old cattle, those in the age group ≥ 7 years had significantly higher odds of being positive for WNV (AOR = 6.82; 95% CI: 1.72-26.99) and RVFV (AOR = 4.38; 95% CI: 1.08-17.88) infections. The occurrence of WNV and RVFV infections in cattle population in the present study area indicates the risk of transmission to humans. Strengthening the surveillance system and conducting further studies to identify active cases in domestic and wild animals as well as in humans is crucial to reduce the risk of possible outbreaks.
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14
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Rostal MK, Cleaveland S, Cordel C, van Staden L, Matthews L, Anyamba A, Karesh WB, Paweska JT, Haydon DT, Ross N. Farm-Level Risk Factors of Increased Abortion and Mortality in Domestic Ruminants during the 2010 Rift Valley Fever Outbreak in Central South Africa. Pathogens 2020; 9:E914. [PMID: 33158214 PMCID: PMC7694248 DOI: 10.3390/pathogens9110914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/25/2020] [Accepted: 10/30/2020] [Indexed: 11/28/2022] Open
Abstract
(1) Background: Rift Valley fever (RVF) outbreaks in domestic ruminants have severe socio-economic impacts. Climate-based continental predictions providing early warnings to regions at risk for RVF outbreaks are not of a high enough resolution for ruminant owners to assess their individual risk. (2) Methods: We analyzed risk factors for RVF occurrence and severity at the farm level using the number of domestic ruminant deaths and abortions reported by farmers in central South Africa during the 2010 RVF outbreaks using a Bayesian multinomial hurdle framework. (3) Results: We found strong support that the proportion of days with precipitation, the number of water sources, and the proportion of goats in the herd were positively associated with increased severity of RVF (the numbers of deaths and abortions). We did not find an association between any risk factors and whether RVF was reported on farms. (4) Conclusions: At the farm level we identified risk factors of RVF severity; however, there was little support for risk factors of RVF occurrence. The identification of farm-level risk factors for Rift Valley fever virus (RVFV) occurrence would support and potentially improve current prediction methods and would provide animal owners with critical information needed in order to assess their herd's risk of RVFV infection.
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Affiliation(s)
- Melinda K. Rostal
- EcoHealth Alliance, New York, NY 10018, USA; (W.B.K.); (N.R.)
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; (S.C.); (L.M.); (D.T.H.)
| | - Sarah Cleaveland
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; (S.C.); (L.M.); (D.T.H.)
| | - Claudia Cordel
- ExecuVet PTY LTD., Bloemfontein 9301, Free State, South Africa; (C.C.); (L.v.S.)
| | - Lara van Staden
- ExecuVet PTY LTD., Bloemfontein 9301, Free State, South Africa; (C.C.); (L.v.S.)
| | - Louise Matthews
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; (S.C.); (L.M.); (D.T.H.)
| | - Assaf Anyamba
- Universities Space Research Association, Columbia, MD 21046, USA;
- NASA Goddard Space Flight Center, Biospheric Sciences Laboratory, Greenbelt, MD 20771, USA
| | | | - Janusz T. Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg 2192, South Africa;
| | - Daniel T. Haydon
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK; (S.C.); (L.M.); (D.T.H.)
| | - Noam Ross
- EcoHealth Alliance, New York, NY 10018, USA; (W.B.K.); (N.R.)
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15
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Odendaal L, Clift SJ, Fosgate GT, Davis AS. Ovine Fetal and Placental Lesions and Cellular Tropism in Natural Rift Valley Fever Virus Infections. Vet Pathol 2020; 57:791-806. [PMID: 32885745 DOI: 10.1177/0300985820954549] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Infection with Rift Valley fever phlebovirus (RVFV) causes abortion storms and a wide variety of outcomes for both ewes and fetuses. Sheep fetuses and placenta specimens were examined during the 2010-2011 River Valley fever (RVF) outbreak in South Africa. A total of 72 fetuses were studied of which 58 were confirmed positive for RVF. Placenta specimens were available for 35 cases. Macroscopic lesions in fetuses were nonspecific and included marked edema and occasional hemorrhages in visceral organs. Microscopically, multifocal hepatic necrosis was present in 48 of 58 cases, and apoptotic bodies, foci of liquefactive hepatic necrosis (primary foci), and eosinophilic intranuclear inclusions in hepatocytes were useful diagnostic features. Lymphocytolysis was present in all lymphoid organs examined with the exception of thymus and Peyer's patches, and pyknosis or karyorrhexis was often present in renal glomeruli. The most significant histologic lesion in the placenta was necrosis of trophoblasts and endothelial cells in the cotyledonary and intercotyledonary chorioallantois. Immunolabeling for RVFV was most consistent in trophoblasts of the cotyledon or caruncle. Other antigen-positive cells included hepatocytes, renal tubular epithelial, juxtaglomerular and extraglomerular mesangial cells, vascular smooth muscle, endothelial and adrenocortical cells, cardiomyocytes, Purkinje fibers, and macrophages. Fetal organ samples for diagnosis must minimally include liver, kidney, and spleen. From the placenta, the minimum recommended specimens for histopathology include the cotyledonary units and caruncles from the endometrium, if available. The diagnostic investigation of abortion in endemic areas should always include routine testing for RVFV, and a diagnosis during interepidemic periods might be missed if only limited specimens are available for examination.
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Affiliation(s)
- Lieza Odendaal
- 56410University of Pretoria, Onderstepoort, Pretoria, South Africa
| | - Sarah J Clift
- 56410University of Pretoria, Onderstepoort, Pretoria, South Africa
| | | | - A Sally Davis
- 56410University of Pretoria, Onderstepoort, Pretoria, South Africa.,5308Kansas State University, Manhattan, KS, USA
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16
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Durand B, Lo Modou M, Tran A, Ba A, Sow F, Belkhiria J, Fall AG, Biteye B, Grosbois V, Chevalier V. Rift Valley fever in northern Senegal: A modelling approach to analyse the processes underlying virus circulation recurrence. PLoS Negl Trop Dis 2020; 14:e0008009. [PMID: 32479505 PMCID: PMC7289439 DOI: 10.1371/journal.pntd.0008009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/11/2020] [Accepted: 04/22/2020] [Indexed: 01/12/2023] Open
Abstract
Rift Valley fever (RVF) is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. To investigate the mechanisms that explain RVF recurrent circulation, we modelled a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics, and nomadic herd movements recorded in Younoufere area. To calibrate the model, serological surveys were performed in 2015–2016 on both resident and nomadic domestic herds in the same area. Mosquito population dynamics were obtained from a published model trained in the same region. Model comparison techniques were used to compare five different scenarios of virus introduction by nomadic herds associated or not with vertical transmission in Aedes vexans. Our serological results confirmed a long lasting RVF endemicity in resident herds (IgG seroprevalence rate of 15.3%, n = 222), and provided the first estimation of RVF IgG seroprevalence in nomadic herds in West Africa (12.4%, n = 660). Multivariate analysis of serological data suggested an amplification of the transmission cycle during the rainy season with a peak of circulation at the end of that season. The best scenario of virus introduction combined yearly introductions of RVFV from 2008 to 2015 (the study period) by nomadic herds, with a proportion of viraemic individuals predicted to be larger in animals arriving during the 2nd half of the rainy season (3.4%). This result is coherent with the IgM prevalence rate (4%) found in nomadic herds sampled during the 2nd half of the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, our model demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal. Rift Valley fever (RVF) is one of the most important vector borne disease in Africa, seriously affecting the health of domestic ruminants and humans and leading to severe economic consequences. This disease is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. Two non-exclusive mechanisms may support this endemicity: recurrent introductions of the virus by nomadic animals, and vertical transmission of the virus (i.e. from infected female mosquito to eggs) in local Aedes populations. The authors followed resident and nomadic domestic herds for 1 year. They used the data thus obtained to model a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics. They found that the best scenario explaining RVF remanence combined yearly introductions of RVFV by nomadic herds, with a viraemic proportion predicted to be larger in animals arriving during the 2nd half of the rainy season, which is consistent with an amplification of virus circulation in the area during the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, their results demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal.
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Affiliation(s)
- Benoit Durand
- Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, Maisons-Alfort, France
- * E-mail: (BD); (VC)
| | | | - Annelise Tran
- CIRAD, UMR TETIS, Sainte-Clotilde, Réunion, France
- CIRAD, UMR ASTRE, Montpellier, France
- Université Montpellier, Montpellier, France
| | - Aminata Ba
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Fafa Sow
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Jaber Belkhiria
- Center for Animal Disease Modeling and Surveillance, Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, California, United States of America
| | | | - Biram Biteye
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | | | - Véronique Chevalier
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Phnom Penh, Cambodia
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- * E-mail: (BD); (VC)
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17
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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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18
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Systematic Review of Important Viral Diseases in Africa in Light of the 'One Health' Concept. Pathogens 2020; 9:pathogens9040301. [PMID: 32325980 PMCID: PMC7238228 DOI: 10.3390/pathogens9040301] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 12/19/2022] Open
Abstract
Emerging and re-emerging viral diseases are of great public health concern. The recent emergence of Severe Acute Respiratory Syndrome (SARS) related coronavirus (SARS-CoV-2) in December 2019 in China, which causes COVID-19 disease in humans, and its current spread to several countries, leading to the first pandemic in history to be caused by a coronavirus, highlights the significance of zoonotic viral diseases. Rift Valley fever, rabies, West Nile, chikungunya, dengue, yellow fever, Crimean-Congo hemorrhagic fever, Ebola, and influenza viruses among many other viruses have been reported from different African countries. The paucity of information, lack of knowledge, limited resources, and climate change, coupled with cultural traditions make the African continent a hotspot for vector-borne and zoonotic viral diseases, which may spread globally. Currently, there is no information available on the status of virus diseases in Africa. This systematic review highlights the available information about viral diseases, including zoonotic and vector-borne diseases, reported in Africa. The findings will help us understand the trend of emerging and re-emerging virus diseases within the African continent. The findings recommend active surveillance of viral diseases and strict implementation of One Health measures in Africa to improve human public health and reduce the possibility of potential pandemics due to zoonotic viruses.
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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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20
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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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Rissmann M, Stoek F, Pickin MJ, Groschup MH. Mechanisms of inter-epidemic maintenance of Rift Valley fever phlebovirus. Antiviral Res 2019; 174:104692. [PMID: 31870761 DOI: 10.1016/j.antiviral.2019.104692] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 09/26/2019] [Accepted: 12/11/2019] [Indexed: 12/31/2022]
Abstract
Rift Valley fever phlebovirus (RVFV) is an arthropod-borne virus that has caused substantial epidemics throughout Africa and in the Arabian Peninsula. The virus can cause severe disease in livestock and humans and therefore the control and prevention of viral outbreaks is of utmost importance. The epidemiology of RVFV has some particular characteristics. Unexpected and significant epidemics have been observed in spatially and temporally divergent patterns across the African continent. Sudden epidemics in previously unaffected areas are followed by periods of long-term apparent absence of virus and sudden, unpredictable reoccurrence in disparate regions. Therefore, the elucidation of underlying mechanisms of viral maintenance is one of the largest gaps in the knowledge of RVFV ecology. It remains unknown whether the virus needs to be reintroduced before RVF outbreaks can occur, or if unperceived viral circulation in local vertebrates or mosquitoes is sufficient for maintenance of the virus. To gain insight into these knowledge gaps, we here review existing data that describe potential mechanisms of RVFV maintenance, as well as molecular and serological studies in endemic and non-endemic areas that provide evidence of an inter- or pre-epidemic virus presence. Basic and country-specific mechanisms of RVFV introduction into non-endemic countries are summarized and an overview of studies using mathematical modeling of RVFV persistence is given.
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Affiliation(s)
- Melanie Rissmann
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Suedufer 10, 17489, Greifswald-Insel Riems, Germany
| | - Franziska Stoek
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Suedufer 10, 17489, Greifswald-Insel Riems, Germany
| | - Matthew J Pickin
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Suedufer 10, 17489, Greifswald-Insel Riems, Germany
| | - Martin H Groschup
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, Suedufer 10, 17489, Greifswald-Insel Riems, Germany.
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22
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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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