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Abstract
In early 2014, abortions and death of ruminants were reported on farms in Maputo and Gaza Provinces, Mozambique. Serologic analysis and quantitative and conventional reverse transcription PCR confirmed the presence of Rift Valley fever virus. The viruses belonged to lineage C, which is prevalent among Rift Valley fever viruses in southern Africa.
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Callaby R, Toye P, Jennings A, Thumbi SM, Coetzer JAW, Conradie Van Wyk IC, Hanotte O, Mbole-Kariuki MN, Bronsvoort BMDC, Kruuk LEB, Woolhouse MEJ, Kiara H. Seroprevalence of respiratory viral pathogens of indigenous calves in Western Kenya. Res Vet Sci 2016; 108:120-4. [PMID: 27663380 PMCID: PMC5040193 DOI: 10.1016/j.rvsc.2016.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 08/03/2016] [Accepted: 08/22/2016] [Indexed: 10/24/2022]
Abstract
Most studies of infectious diseases in East African cattle have concentrated on gastro-intestinal parasites and vector-borne diseases. As a result, relatively little is known about viral diseases, except for those that are clinically symptomatic or which affect international trade such as foot and mouth disease, bluetongue and epizootic haemorrhagic disease. Here, we investigate the seroprevalence, distribution and relationship between the viruses involved in respiratory disease, infectious bovine rhinotracheitis virus (IBR), bovine parainfluenza virus Type 3 (PIV3) and bovine viral diarrhoea virus (BVDV) in East African Shorthorn Zebu calves. These viruses contribute to the bovine respiratory disease complex (BRD) which is responsible for major economic losses in cattle from intensive farming systems as a result of pneumonia. We found that calves experience similar risks of infection for IBR, PIV3, and BVDV with a seroprevalence of 20.9%, 20.1% and 19.8% respectively. We confirm that positive associations exist between IBR, PIV3 and BVDV; being seropositive for any one of these three viruses means that an individual is more likely to be seropositive for the other two viruses than expected by chance.
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Affiliation(s)
- R Callaby
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK; James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, UK.
| | - P Toye
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - A Jennings
- The Farm Animal Practice, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK
| | - S M Thumbi
- Paul G Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7079, USA
| | - J A W Coetzer
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private bag X04, Onderstepoort, South Africa
| | - I C Conradie Van Wyk
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private bag X04, Onderstepoort, South Africa
| | - O Hanotte
- School of Life Science, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - M N Mbole-Kariuki
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya; School of Life Science, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - B M de C Bronsvoort
- The Roslin Institute, Easter Bush, University of Edinburgh, Roslin, Midlothian EH25 9RG, UK
| | - L E B Kruuk
- Division of Evolution, Ecology & Genetics, Research School of Biology, The Australian National University, Canberra ACT 0200, Australia; Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - M E J Woolhouse
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - H Kiara
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
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Tuppurainen ESM, Venter EH, Coetzer JAW, Bell-Sakyi L. Lumpy skin disease: attempted propagation in tick cell lines and presence of viral DNA in field ticks collected from naturally-infected cattle. Ticks Tick Borne Dis 2014; 6:134-40. [PMID: 25468765 PMCID: PMC4329317 DOI: 10.1016/j.ttbdis.2014.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/20/2014] [Accepted: 11/03/2014] [Indexed: 11/19/2022]
Abstract
Lumpy skin disease (LSD) is of substantial economic importance for the cattle industry in Africa and the Near and Middle East. Several insect species are thought to transmit the disease mechanically. Recent transmission studies have demonstrated the first evidence for a role of hard (ixodid) ticks as vectors of lumpy skin disease virus (LSDV). The aim of this study was to attempt in vitro growth of the virus in Rhipicephalus spp. tick cell lines and investigate in vivo the presence of the virus in ticks collected from cattle during LSD outbreaks in Egypt and South Africa. No evidence was obtained for replication of LSDV in tick cell lines although the virus was remarkably stable, remaining viable for 35 days at 28 °C in tick cell cultures, in growth medium used for tick cells and in phosphate buffered saline. Viral DNA was detected in two-thirds of the 56 field ticks, making this the first report of the presence of potentially virulent LSDV in ticks collected from naturally infected animals.
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Affiliation(s)
- E S M Tuppurainen
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, United Kingdom.
| | - E H Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - J A W Coetzer
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - L Bell-Sakyi
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, United Kingdom
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Fafetine JM, Domingos A, Antunes S, Esteves A, Paweska JT, Coetzer JAW, Rutten VPMG, Neves L. Generation and characterization of monoclonal antibodies against Rift Valley fever virus nucleoprotein. Transbound Emerg Dis 2014; 60 Suppl 2:24-30. [PMID: 24589098 DOI: 10.1111/tbed.12140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Indexed: 11/29/2022]
Abstract
Due to the unpredictable and explosive nature of Rift Valley fever (RVF) outbreaks, rapid and accurate diagnostic assays for low-resource settings are urgently needed. To improve existing diagnostic assays, monoclonal antibodies (MAbs) specific for the nucleocapsid protein of RVF virus (RVFV) were produced and characterized. Four IgG2a MAbs showed specific binding to denatured nucleocapsid protein, both from a recombinant source and from inactivated RVFV, in Western blot analysis and in an enzyme-linked immunosorbent assay (ELISA). Cross-reactivity with genetically related and non-related arboviruses including Bunyamwera and Calovo viruses (Bunyaviridae family), West Nile and Dengue-2 viruses (Flaviviridae family), and Sindbis and Chikungunya viruses (Togaviridae family) was not detected. These MAbs represent a useful tool for the development of rapid diagnostic assays for early recognition of RVF.
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Affiliation(s)
- J M Fafetine
- Veterinary Faculty, Eduardo Mondlane University, Maputo, Mozambique; Biotechnology Center, Eduardo Mondlane University, Maputo, Mozambique
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Lubinga JC, Tuppurainen ESM, Coetzer JAW, Stoltsz WH, Venter EH. Evidence of lumpy skin disease virus over-wintering by transstadial persistence in Amblyomma hebraeum and transovarial persistence in Rhipicephalus decoloratus ticks. Exp Appl Acarol 2014; 62:77-90. [PMID: 23975563 DOI: 10.1007/s10493-013-9721-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/03/2013] [Indexed: 06/02/2023]
Abstract
Lumpy skin disease is a debilitating cattle disease caused by the lumpy skin disease virus (LSDV), belonging to the genus Capripoxvirus. Epidemics of the disease usually occur in summer, when insect activity is high. Limited information is available on how LSDV persists during inter-epidemic periods. Transmission of LSDV by mosquitoes such as Aedes aegypti has been shown to be mechanical, there is no carrier state in cattle and the role of wildlife in the epidemiology of the disease seems to be of minor importance. Recent studies in ticks have shown transstadial persistence of LSDV in Rhipicephalus appendiculatus and Amblyomma hebraeum as well as transovarial persistence of the virus in Rhipicephalus decoloratus, R. appendiculatus and A. hebraeum. The over-wintering of ticks off the host as part of their life cycles is well known: A. hebraeum and R. appendiculatus over-winter, for example, on the ground as engorged nymphs/unfed (emergent) adults while R. decoloratus over-winters on the ground as engorged females. In this study, transstadial and transovarial persistence of LSDV from experimentally infected A. hebraeum nymphs and R. decoloratus females after exposure to cold temperatures of 5 °C at night and 20 °C during the day for 2 months was reported. This observation suggests possible over-wintering of the virus in these tick species.
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Affiliation(s)
- J C Lubinga
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstpoort, Pretoria, 0110, South Africa,
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Thumbi SM, Bronsvoort MBM, Kiara H, Toye PG, Poole J, Ndila M, Conradie I, Jennings A, Handel IG, Coetzer JAW, Steyl J, Hanotte O, Woolhouse MEJ. Mortality in East African shorthorn zebu cattle under one year: predictors of infectious-disease mortality. BMC Vet Res 2013; 9:175. [PMID: 24010500 PMCID: PMC3848692 DOI: 10.1186/1746-6148-9-175] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 08/23/2013] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Infectious livestock diseases remain a major threat to attaining food security and are a source of economic and livelihood losses for people dependent on livestock for their livelihood. Knowledge of the vital infectious diseases that account for the majority of deaths is crucial in determining disease control strategies and in the allocation of limited funds available for disease control. Here we have estimated the mortality rates in zebu cattle raised in a smallholder mixed farming system during their first year of life, identified the periods of increased risk of death and the risk factors for calf mortality, and through analysis of post-mortem data, determined the aetiologies of calf mortality in this population. A longitudinal cohort study of 548 zebu cattle was conducted between 2007 and 2010. Each calf was followed during its first year of life or until lost from the study. Calves were randomly selected from 20 sub-locations and recruited within a week of birth from different farms over a 45 km radius area centered on Busia in the Western part of Kenya. The data comprised of 481.1 calf years of observation. Clinical examinations, sample collection and analysis were carried out at 5 week intervals, from birth until one year old. Cox proportional hazard models with frailty terms were used for the statistical analysis of risk factors. A standardized post-mortem examination was conducted on all animals that died during the study and appropriate samples collected. RESULTS The all-cause mortality rate was estimated at 16.1 (13.0-19.2; 95% CI) per 100 calf years at risk. The Cox models identified high infection intensity with Theileria spp., the most lethal of which causes East Coast Fever disease, infection with Trypanosome spp., and helminth infections as measured by Strongyle spp. eggs per gram of faeces as the three important infections statistically associated with infectious disease mortality in these calves. Analysis of post-mortem data identified East Coast Fever as the main cause of death accounting for 40% of all deaths, haemonchosis 12% and heartwater disease 7%. CONCLUSION The findings demonstrate the impact of endemic parasitic diseases in indigenous animals expected to be well adapted against disease pressures. Additionally, agreement between results of Cox models using data from simple diagnostic procedures and results from post-mortem analysis underline the potential use such diagnostic data to reduce calf mortality. The control strategies for the identified infectious diseases have been discussed.
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Affiliation(s)
- Samuel M Thumbi
- Centre for Infectious Diseases, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090, USA
- Kenya Medical Research Institute/CDC Public Health and Research Collaboration, P.O BOX, 1578, Kisumu 40100, Kenya
| | - Mark BMdec Bronsvoort
- The Roslin Institute, Easter Bush, University of Edinburgh, Roslin, Midlothian, EH25 9RG, Edinburgh, UK
| | - Henry Kiara
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - PG Toye
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Jane Poole
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Mary Ndila
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Ilana Conradie
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private bag X04, Onderstepoort, South Africa
| | - Amy Jennings
- The Roslin Institute, Easter Bush, University of Edinburgh, Roslin, Midlothian, EH25 9RG, Edinburgh, UK
| | - Ian G Handel
- The Roslin Institute, Easter Bush, University of Edinburgh, Roslin, Midlothian, EH25 9RG, Edinburgh, UK
| | - JAW Coetzer
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private bag X04, Onderstepoort, South Africa
| | - Johan Steyl
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private bag X04, Onderstepoort, South Africa
| | - Olivier Hanotte
- University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Mark EJ Woolhouse
- Centre for Infectious Diseases, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
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Lubinga JC, Tuppurainen ESM, Stoltsz WH, Ebersohn K, Coetzer JAW, Venter EH. Detection of lumpy skin disease virus in saliva of ticks fed on lumpy skin disease virus-infected cattle. Exp Appl Acarol 2013; 61:129-38. [PMID: 23456606 DOI: 10.1007/s10493-013-9679-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 02/11/2013] [Indexed: 06/01/2023]
Abstract
Lumpy skin disease is an economically important disease of cattle that is caused by the lumpy skin disease virus (LSDV), which belongs to the genus Capripoxvirus. It is endemic in Africa and outbreaks have also been reported in the Middle-East. Transmission has mostly been associated with blood-feeding insects but recently, the authors have demonstrated mechanical transmission by Rhipicephalus appendiculatus as well as mechanical/intrastadial and transstadial transmission by Amblyomma hebraeum. Saliva is the medium of transmission of pathogens transmitted by biting arthropods and, simultaneously, it potentiates infection in the vertebrate host. This study aimed to detect LSDV in saliva of A. hebraeum and R. appendiculatus adult ticks fed, as nymphs or as adults, on LSDV-infected animals, thereby also demonstrating transstadial or mechanical/intrastadial passage of the virus in these ticks. Saliva samples were tested for LSDV by real-time PCR and virus isolation. Supernatants obtained from virus isolation were further tested by real-time PCR to confirm that the cytopathic effects observed were due to LSDV. Lumpy skin disease virus was detected, for the first time, in saliva samples of both A. hebraeum and R. appendiculatus ticks. At the same time, mechanical/intrastadial and transstadial passage of the virus was demonstrated and confirmed in R. appendiculatus and A. hebraeum.
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Affiliation(s)
- J C Lubinga
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private bag X04 Onderstepoort, Pretoria 0110, South Africa.
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de Clare Bronsvoort BM, Thumbi SM, Poole EJ, Kiara H, Auguet OT, Handel IG, Jennings A, Conradie I, Mbole-Kariuki MN, Toye PG, Hanotte O, Coetzer JAW, Woolhouse MEJ. Design and descriptive epidemiology of the Infectious Diseases of East African Livestock (IDEAL) project, a longitudinal calf cohort study in western Kenya. BMC Vet Res 2013; 9:171. [PMID: 24000820 PMCID: PMC3847666 DOI: 10.1186/1746-6148-9-171] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 08/23/2013] [Indexed: 11/29/2022] Open
Abstract
Background There is a widely recognised lack of baseline epidemiological data on the dynamics and impacts of infectious cattle diseases in east Africa. The Infectious Diseases of East African Livestock (IDEAL) project is an epidemiological study of cattle health in western Kenya with the aim of providing baseline epidemiological data, investigating the impact of different infections on key responses such as growth, mortality and morbidity, the additive and/or multiplicative effects of co-infections, and the influence of management and genetic factors. A longitudinal cohort study of newborn calves was conducted in western Kenya between 2007-2009. Calves were randomly selected from all those reported in a 2 stage clustered sampling strategy. Calves were recruited between 3 and 7 days old. A team of veterinarians and animal health assistants carried out 5-weekly, clinical and postmortem visits. Blood and tissue samples were collected in association with all visits and screened using a range of laboratory based diagnostic methods for over 100 different pathogens or infectious exposures. Results The study followed the 548 calves over the first 51 weeks of life or until death and when they were reported clinically ill. The cohort experienced a high all cause mortality rate of 16% with at least 13% of these due to infectious diseases. Only 307 (6%) of routine visits were classified as clinical episodes, with a further 216 reported by farmers. 54% of calves reached one year without a reported clinical episode. Mortality was mainly to east coast fever, haemonchosis, and heartwater. Over 50 pathogens were detected in this population with exposure to a further 6 viruses and bacteria. Conclusion The IDEAL study has demonstrated that it is possible to mount population based longitudinal animal studies. The results quantify for the first time in an animal population the high diversity of pathogens a population may have to deal with and the levels of co-infections with key pathogens such as Theileria parva. This study highlights the need to develop new systems based approaches to study pathogens in their natural settings to understand the impacts of co-infections on clinical outcomes and to develop new evidence based interventions that are relevant.
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Lubinga JC, Tuppurainen ESM, Mahlare R, Coetzer JAW, Stoltsz WH, Venter EH. Evidence of transstadial and mechanical transmission of lumpy skin disease virus by Amblyomma hebraeum ticks. Transbound Emerg Dis 2013; 62:174-82. [PMID: 23702314 DOI: 10.1111/tbed.12102] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Indexed: 11/29/2022]
Abstract
Lumpy skin disease (LSD) is an economically important disease caused by LSD virus (LSDV), a Capripoxvirus, characterized by fever and circumscribed skin lesions. It is suspected to be transmitted mechanically by biting flies. To assess the vector potential of Amblyomma hebraeum in transmission of LSDV, mechanical/intrastadial and transstadial modes of transmission of the virus by this tick species were investigated. Two cattle were artificially infected as sources (donors) of infection to ticks. Ticks were infected as either nymphs or adults. Male A. hebraeum ticks were partially fed on donor animals and transferred to recipient animals to test for mechanical/intrastadial transmission. Nymphal A. hebraeum were fed to repletion on donor animals. The emergent adult ticks were placed on recipient animals to test for transstadial transmission of the virus. Successful transmission of LSDV infection was determined in recipient animals by monitoring development of clinical signs, testing of blood for the presence of LSDV by real-time PCR, virus isolation and the serum neutralization test. This report provides further evidence of mechanical/intrastadial and, for the first time, transstadial transmission of LSDV by A. hebraeum. These findings implicate A. hebraeum as a possible maintenance host in the epidemiology of the disease.
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Affiliation(s)
- J C Lubinga
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa; Department of Veterinary and Tsetse Control Services, Provincial Veterinary Office, Kasama, Zambia
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Fafetine J, Neves L, Thompson PN, Paweska JT, Rutten VPMG, Coetzer JAW. Serological evidence of Rift Valley fever virus circulation in sheep and goats in Zambézia Province, Mozambique. PLoS Negl Trop Dis 2013; 7:e2065. [PMID: 23469300 PMCID: PMC3585041 DOI: 10.1371/journal.pntd.0002065] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 01/04/2013] [Indexed: 11/18/2022] Open
Abstract
Rift Valley fever (RVF) is endemic in most parts of Africa and has also been reported to occur in the Arabian Peninsula. It is responsible for significant morbidity and mortality, particularly in livestock, but also in humans. During the last two decades several outbreaks of RVF have been reported in countries in Southern Africa. In contrast to other countries, no clinical disease has been reported in Mozambique during this period. In a serological study conducted in 2007 in five districts of Zambézia Province, Mozambique, of a total of 654 small ruminants sampled (277 sheep and 377 goats), 35.8% of sheep sera and 21.2% of goat sera were positive for RVF virus (RVFV) antibodies in a virus neutralization test (VN) and in an IgG enzyme-linked immunosorbent assay (ELISA). In 2010, a cross-sectional survey was conducted in 313 sheep and 449 goats in two districts of the same province. This study revealed an overall seropositivity rate of 9.2% in sheep and 11.6% in goat and an increased likelihood of being seropositive in older animals (OR = 7.3; p<0.001) using an IgG ELISA. 29 out of 240 animals assessed for RVF specific IgM by ELISA were positive, suggesting recent exposure to RVFV. However, a longitudinal study carried out between September 2010 and April 2011 in a cohort of 125 of these animals (74 sheep and 51 goats) failed to demonstrate seroconversion. The results of the study indicate that RVFV circulates sub-clinically in domestic small ruminants in Zambézia Province.
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Affiliation(s)
- José Fafetine
- Veterinary Faculty, Eduardo Mondlane University, Maputo, Mozambique.
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Toye PG, Batten CA, Kiara H, Henstock MR, Edwards L, Thumbi S, Poole EJ, Handel IG, Bronsvoort BMD, Hanotte O, Coetzer JAW, Woolhouse MEJ, Oura CAL. Bluetongue and epizootic haemorrhagic disease virus in local breeds of cattle in Kenya. Res Vet Sci 2012; 94:769-73. [PMID: 23261160 PMCID: PMC3632752 DOI: 10.1016/j.rvsc.2012.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 11/02/2012] [Accepted: 11/17/2012] [Indexed: 11/16/2022]
Abstract
The presence of bluetongue virus (BTV) and Epizootic Haemorrhagic Disease virus (EHDV) in indigenous calves in western Kenya was investigated. Serum was analysed for BTV and EHDV antibodies. The population seroprevalences for BTV and EHDV for calves at 51 weeks of age were estimated to be 0.942 (95% CI 0.902–0.970) and 0.637 (95% CI 0.562–0.710), respectively, indicating high levels of circulating BTV and EHDV. The odds ratio of being positive for BTV if EHDV positive was estimated to be 2.57 (95% CI 1.37–4.76). When 99 calves were tested for BTV and EHDV RNA by real-time RT-PCR, 88.9% and 63.6% were positive, respectively. Comparison of the serology and real-time RT-PCR results revealed an unexpectedly large number of calves that were negative by serology but positive by real-time RT-PCR for EHDV. Eight samples positive for BTV RNA were serotyped using 24 serotype-specific real-time RT-PCR assays. Nine BTV serotypes were detected, indicating that the cattle were infected with a heterogeneous population of BTVs. The results show that BTV and EHDV are highly prevalent, with cattle being infected from an early age.
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Affiliation(s)
- P G Toye
- The International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
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Tuppurainen ESM, Stoltsz WH, Troskie M, Wallace DB, Oura CAL, Mellor PS, Coetzer JAW, Venter EH. A potential role for ixodid (hard) tick vectors in the transmission of lumpy skin disease virus in cattle. Transbound Emerg Dis 2010; 58:93-104. [PMID: 21114790 DOI: 10.1111/j.1865-1682.2010.01184.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Lumpy skin disease (LSD) is an economically important cattle disease. The disease is endemic in many African countries, but outbreaks have also been reported in Madagascar and the Middle East. The aim of this study was to investigate the potential role of ixodid (hard) ticks in the transmission of the disease. Cattle were infected with a virulent, South African field isolate of lumpy skin disease virus (LSDV). Three common African tick species (genera Rhipicephalus, Amblyomma and Rhipicephalus (Boophilus)) in different life cycle stages were fed on the infected animals during the viraemic stage and on skin lesions. Post-feeding, the partially fed male ticks were transferred to the skin of non-infected 'recipient' animals, while females were allowed to lay eggs that were then tested using the polymerase chain reaction (PCR) method and virus isolation. Nymphs were allowed to develop for 2-3 weeks after which time they were tested. The non-infected 'recipient' cattle were closely monitored, both skin and blood samples were tested using PCR and virus isolation, and serum samples were tested by the serum neutralization test. This is the first report showing molecular evidence of potential transmission of LSDV by ixodid ticks. The study showed evidence of transstadial and transovarial transmission of LSDV by R. (B.) decoloratus ticks and mechanical or intrastadial transmission by R. appendiculatus and A. hebraeum ticks.
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Affiliation(s)
| | - W H Stoltsz
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - M Troskie
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - D B Wallace
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - C A L Oura
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - P S Mellor
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - J A W Coetzer
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - E H Venter
- Institute for Animal Health, Pirbright, Surrey, UK Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa Onderstepoort Veterinary Institute, Onderstepoort, South Africa
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Swan GE, Coetzer JAW, Terblanche HM. Integrating global animal health, public health and tropical animal health issues into the veterinary curriculum: a South African/African perspective. REV SCI TECH OIE 2010; 28:727-38. [PMID: 20128484 DOI: 10.20506/rst.28.2.1916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The globalisation of trade and food, the increased volume and speed of international travel, climate change, and the related escalation of emerging and re-emerging infectious diseases mean that countries are now more interconnected and interdependent than ever before. Africa is beleaguered by a range of endemic infectious and parasitic tropical diseases which, due to its diverse wildlife populations and indigenous livestock, can serve as a reservoir of high-impact or transboundary diseases and play a role in the emergence of disease, particularly at the wildlife, domestic animal and human interfaces. It is therefore essential to integrate animal and public health issues into the veterinary curriculum. Veterinary training in most parts of sub-Saharan Africa has focused on producing veterinarians to serve the livestock sector although socio-economic changes and privatisation of Veterinary Services have caused curriculum adjustments, as have globalisation and the increased risk of the spread of transboundary diseases. In South Africa, undergraduate veterinary training is more clinically oriented than in other regions. Animal and public health issues are covered in the curriculum, although their global relevance is not emphasised. The authors describe the undergraduate veterinary curriculum and summarise post-graduate programmes in South Africa. They also discuss a more comprehensive core-elective approach to the current curriculum and the need to adapt to new challenges facing the profession. Finally, they examine the potential use of innovative technology in undergraduate and post-graduate training and professional development, the importance of regional and international collaboration and the accreditation and recognition of veterinary training.
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Affiliation(s)
- G E Swan
- Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
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14
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Van den Bossche P, Coetzer JAW. Climate change and animal health in Africa. REV SCI TECH OIE 2008; 27:551-562. [PMID: 18819677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Climate change is expected to have direct and indirect impacts on African livestock. Direct impacts include increased ambient temperature, floods and droughts. Indirect impacts are the result of reduced availability of water and forage and changes in the environment that promote the spread of contagious diseases through increased contact between animals, or increased survival or availability of the agent or its intermediate host. The distribution and prevalence of vector-borne diseases may be the most significant effect of climate change. The potential vulnerability of the livestock industry will depend on its ability to adapt to such changes. Enhancing this adaptive capacity presents a practical way of coping with climate change. Adaptive capacity could be increased by enabling the African livestock owner to cope better with animal health problems through appropriate policy measures and institutional support. Developing an effective and sustainable animal health service, associated surveillance and emergency preparedness systems and sustainable disease control and prevention programmes is perhaps the most important strategy for dealing with climate change in many African countries.
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Affiliation(s)
- P Van den Bossche
- Institute of Tropical Medicine, Animal Health Department, Antwerp, Belgium
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15
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Fafetine JM, Tijhaar E, Paweska JT, Neves LCBG, Hendriks J, Swanepoel R, Coetzer JAW, Egberink HF, Rutten VPMG. Cloning and expression of Rift Valley fever virus nucleocapsid (N) protein and evaluation of a N-protein based indirect ELISA for the detection of specific IgG and IgM antibodies in domestic ruminants. Vet Microbiol 2007; 121:29-38. [PMID: 17187944 DOI: 10.1016/j.vetmic.2006.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 11/13/2006] [Accepted: 11/15/2006] [Indexed: 10/23/2022]
Abstract
Serodiagnosis of Rift Valley fever (RVF) currently relies on the use of live or inactivated whole virus as antigens. The recombinant nucleocapsid (N) protein of RVF virus was tested for diagnostic applicability in an indirect enzyme-linked immunosorbent assay (I-ELISA), using sera from experimentally infected sheep (n=128), vaccinated sheep (n=240), and field-collected sera from sheep (n=251), goats (n=362) and cattle (n=100). The N-protein based I-ELISA performed at least as good as VN and HI tests. In goat the diagnostic sensitivity (D-Sn) and specificity (D-Sp) of the I-ELISA was 100% when using the anti-species IgG conjugate. Using protein G as a detection system, the D-Sn and D-Sp in goats were 99.4% and 99.5%, in sheep field sera both 100%, in cattle 100% and 98.3%, respectively. The I-ELISA based on recombinant N-protein has the potential to complement the traditional assays for serodiagnosis of RVF. Advantages of the N-protein are its safety, stability and cost-effectiveness in use and production.
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Affiliation(s)
- José Manuel Fafetine
- Veterinary Faculty, Eduardo Mondlane University, Maputo, Mozambique, C. Postal 257, Mozambique.
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Tuppurainen ESM, Venter EH, Coetzer JAW. The detection of lumpy skin disease virus in samples of experimentally infected cattle using different diagnostic techniques. ACTA ACUST UNITED AC 2005; 72:153-64. [PMID: 16137133 DOI: 10.4102/ojvr.v72i2.213] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Lumpy skin disease (LSD) is a disease of cattle, primarily in Africa and Madagascar and rarely in the Middle East. It is caused by a capripoxvirus that belongs to the family Poxviridae. The disease is of economic importance in endemic areas. Effective control of LSD requires accurate and rapid laboratory techniques to confirm a tentative clinical diagnosis. Comparative studies on different diagnostic tests used at different stages of the disease have not been done. The aim of this study was to compare several of these tests. Six seronegative bulls, between 11 and 20 months of age, were infected intravenously and kept in an insect-free facility. The course of the infection was monitored. During a 3-month period blood samples and skin biopsies were collected for virus isolation and polymerase chain reaction (PCR). Skin biopsies were also examined using transmission electron microscopy (TEM). The incubation period in infected animals varied from 4-5 days. The length of the viraemic period did not correlate with the severity of clinical disease. Viraemia was detected from 1-12 days using virus isolation and from 4-11 days using the PCR, which is longer than has previously been reported. Virus was isolated from skin biopsies until Day 39 post infection (p.i.) and PCR could demonstrate viral DNA until Day 92 p.i. Transmission electron microscopy of negatively stained skin biopsies detected LSD virus only in one of the four bulls that developed skin lesions until Day 33 p.i. The PCR was a fast and sensitive method to demonstrate viral DNA in blood and skin samples. It could detect viral nucleic acid in skin lesions 53 days longer than virus isolation. Virus isolation from blood and skin samples was sensitive and reliable, but as a single test it may be too time-consuming to use although this depends on how rapidly the diagnosis must be confirmed. In conclusion, this study showed the PCR to be superior in detecting LSD virus from blood and skin samples. However, virus isolation is still required when the infectivity of the LSD virus is to be determined.
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Affiliation(s)
- E S M Tuppurainen
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria Private Bag X04, Onderstepoort, 0110, South Africa.
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Howell PG, Groenewald D, Visage CW, Bosman AM, Coetzer JAW, Guthrie AJ. The classification of seven serotypes of equine encephalosis virus and the prevalence of homologous antibody in horses in South Africa. Onderstepoort J Vet Res 2002; 69:79-93. [PMID: 12092781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Selected isolates of equine encephalosis virus were shown to have comparable viral protein profiles and to represent seven distinct serotypes, based on cross-neutralization tests. Serotype-specific virus-neutralizing antibody in serum samples from horses confirmed the widespread occurrence of infection. The distribution and prevalence of individual serotypes however, varied considerably. Localised foci with an increased seasonal seroconversion in groups of horses to a specific serotype and the detection of an ongoing low level of infection from other serotypes within the population, confirmed the independent persistence of the viruses in a maintenance cycle. The identification of donors with antibody resulting from infection with multiple serotypes indicated a low level of cross-protection in horses to natural reinfection.
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Affiliation(s)
- P G Howell
- Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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