Laboratory capacity for diagnosis of foot-and-mouth disease in Eastern Africa: implications for the progressive control pathway (original) (raw)
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Rapid, sensitive and effective diagnostic tools for foot-and-mouth disease virus in Africa
Onderstepoort J Vet Res, 2014
Speed is paramount in the diagnosis of highly infectious diseases, such as foot-and-mouth disease (FMD), as well as for emerging diseases; however, simplicity is required if a test is to be deployed in the field. Recent developments in molecular biology have enabled the specific detection of FMD virus (FMDV) by reverse-transcription loop-mediated isothermal amplification (RT-LAMP), real-time reverse-transcription polymerase chain reaction (RT-qPCR) and sequencing. RT-LAMP enables amplification of the FMDV RNA-dependent RNA polymerase 3D(pol) gene at 63 °C (in the presence of a primer mixture and both reverse transcriptase and Bst DNA polymerase) for 1 h, whilst RT-qPCR amplifies the same gene in approximately 2 h 30 min. In this study, we compared the sensitivity and effectiveness of RT-LAMP against RT-qPCR for the detection of the FMDV 3D(pol) gene in 179 oesophageal-pharyngeal scraping samples (collected by probang) obtained from clinically healthy cattle and buffalo in Malawi, M...
Foot and mouth disease control strategies in Africa
Preventive Veterinary Medicine, 1984
Foot and mouth disease control strategies in Africa are complicated by special features of the disease and its control which are peculiar to Africa. Six of the seven serotypes of foot and mouth disease virus are known to occur in Africa and within each serotype wide antigenic variations have been demonstrated. This among other factors has necessitated constant changes in vaccine viruses. Recent serological studies indicated the possibility of rationalising the selection of vaccine viruses to a few baseline strains. Detailed epidemiological studies are lacking in view of the limited laboratory facilities. The necessity for a network of national diagnostic laboratories coordinated through an international regional FMD reference centre in Africa is stressed. The role of animal movements of different forms and wildlife mammals in virus dissemination is discussed. Examples of effective FMD control programmes in Northern, Eastern and Southern Africa are described. It is stressed that a greater effort will be required in regional coordination of FMD control programmes.
Challenges and prospects for the control of foot-and-mouth disease: an African perspective
Veterinary Medicine: Research and Reports, 2014
The epidemiology of foot-and-mouth disease (FMD) in Africa is unique in the sense that six of the seven serotypes of FMD viruses (Southern African Territories [SAT] 1, SAT2, SAT3, A, O, and C), with the exception of Asia-1, have occurred in the last decade. Due to underreporting of FMD, the current strains circulating throughout sub-Saharan Africa are in many cases unknown. For SAT1, SAT2, and serotype A viruses, the genetic diversity is reflected in antigenic variation, and indications are that vaccine strains may be needed for each topotype. This has serious implications for control using vaccines and for choice of strains to include in regional antigen banks. The epidemiology is further complicated by the fact that SAT1, SAT2, and SAT3 viruses are maintained and spread by wildlife, persistently infecting African buffalo in particular. Although the precise mechanism of transmission of FMD from buffalo to cattle is not well understood, it is facilitated by direct contact between these two species. Once cattle are infected they may maintain SAT infections without the further involvement of buffalo. No single strategy for control of FMD in Africa is applicable. Decision on the most effective regional control strategy should focus on an ecosystem approach, identification of primary endemic areas, animal husbandry practices, climate, and animal movement. Within each ecosystem, human behavior could be integrated in disease control planning. Different regions in sub-Saharan Africa are at different developmental stages and are thus facing unique challenges and priorities in terms of veterinary disease control. Many science-based options targeting improved vaccinology, diagnostics, and other control measures have been described. This review therefore aims to emphasize, on one hand, the progress that has been achieved in the development of new technologies, including research towards improved tailored vaccines, appropriate vaccine strain selection, vaccine potency, and diagnostics, and how it relates to the conditions in Africa. On the other hand, we focus on the unique epidemiological, ecological, livestock farming and marketing, socioeconomic, and governance issues that constrain effective FMD control. Any such new technologies should have the availability of safe livestock products for trade as the ultimate goal.
Ethiopian Veterinary Journal
Foot and mouth disease (FMD) is consistently ranked as the most economically important viral disease, and ranks among the top five important livestock diseases in Ethiopia. The status of FMD is barrier for the international trade of livestock and livestock products; thus, continuous epidemiological studies are necessary to develop efficient control strategies. This study determined the seroprevalence of FMD, associated risk factors for its occurrence, and FMD serotypes in the Adama and Boset districts of the East Shewa zone of Oromia Regional State, Ethiopia. A total of 305 blood samples were randomly collected from cattle and subjected to a 3ABC enzyme-linked immune-sorbent assay (ELISA) to detect antibodies against non-structural proteins of FMD virus (FMDV) and Solid-Phase Competitive ELISA for FMDV serotype identification. Evaluation of the associated risk factors was conducted using a multivariable logistic regression model. In this study, an overall seroprevalence of 28.2% (95...
2021
Multiple serotypes and topotypes of foot-and-mouth disease virus (FMDV) circulate in endemic areas, posing considerable impacts locally. In addition, introductions into new areas are of great concern. Indeed, in recent years, multiple FMDV outbreaks, caused by topotypes that have escaped from their original areas, have been recorded in various parts of the world. In both cases, rapid and accurate diagnosis, including the identification of the serotype and topotype causing the given outbreaks, plays an important role in the implementation of the most effective and appropriate measures to control the spread of the disease. In the present study, we describe the performance of a range of diagnostic and typing tools for FMDV on a panel of vesicular samples collected in northern Tanzania (East Africa, EA) during 2012–2018. Specifically, we tested these samples with a real-time RT-PCR targeting 3D sequence for pan-FMDV detection; an FMDV monoclonal antibody-based antigen (Ag) detection and...
Journal of Agricultural Science
Endemic foot-and-mouth disease (FMD) presents a global economic challenge to the livestock industry. The progressive control pathway for FMD (PCP-FMD) specifies successive steps through which a country/region can reduce FMD virus circulation and impact. These steps are reliant on understanding and obtaining knowledge on FMD epidemiology, to inform development of appropriate disease interventions like vaccination and quarantine programs. Currently, Uganda and Tanzania are in the early stages of the PCP-FMD. This review was undertaken to determine FMDV serotype distribution in Uganda and Tanzania between 2003 and 2015. The paper also presents the vaccine strains used in both countries for the same period viz avis the circulating topotypes. The review highlights four (O, A, SAT 1 and SAT 2) and five (O, A, SAT 1, SAT 2 and SAT 3) serotypes that occurred in Uganda and Tanzania respectively in the thirteen year period. Observations revealed that reported circulating serotypes O and A in ...
A Five-Year Retrospective Study of Foot-and-Mouth Disease Outbreaks in Southern Africa, 2014 to 2018
Veterinary Medicine International, 2021
Foot-and-mouth disease (FMD) virus (FMDv), like other ribonucleic acid (RNA) genome viruses, has a tendency to mutate rapidly. As such, available vaccines may not confer enough cross-protection against incursion of new lineages and sublineages. This paper is a retrospective study to determine the topotypes/lineages that caused previous FMD outbreaks in 6 southern African countries and the efficacy of the current vaccines to protect cattle against them. A total of 453 bovine epithelial tissue samples from 33 FMD outbreaks that occurred in these countries from 2014 to 2018 were investigated for the presence of FMDv. The genetic diversity of the identified Southern African Type (SAT)-FMD viruses was determined by comparing sequences from outbreaks and historical prototype sequences. Of the 453 samples investigated, 176 were positive for four FMDv serotypes. Out of the 176 FMD positive cases there were 105 SAT2 samples, 32 SAT1 samples, 21 SAT3 samples, and 18 serotype O samples. Phylog...
2016
Foot-and-mouth disease (FMD) is a viral disease of Ungulates; both Artiodactyla and Perissodactyla. The mortality rates are low in adult animals but it affects milk yield and international trade. In endemic countries, diagnosis can be based on clinical signs. But these are shared by other vesicular diseases, so a laboratory is needed to confirm the disease. In Uganda the commonly used assays for the laboratory diagnosis of FMD are NSP ELISA and RT-PCR. Serology using ELISA techniques may fail to distinguish between vaccinated and new infection so compromising its sensitivity. The gel passed PCR is involves a lot of advance sample treatment increasing errors due to carry over which also compromises its sensitivity. This work reports comparative the detection of foot-and-mouth virus by NSP ELISA and RTPCR with real time PCR which was taken as the gold standard. The assays were compared in terms of sensitivity, specificity and disease prevalence and likelihood ratios. A total of 176 ca...