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In areas where foot-and-mouth disease (FMD) is endemic in wildlife hosts, such as the Kruger National Park (KNP) in South Africa, control measures are in place that ensure that potentially infected antelope and buffalo do not come into close contact with domestic animals. In South Africa several SAT-1 outbreaks occurred nearly simultaneously in cattle and impala between 1971-1981. Phylogenetic analysis based on partial 1D gene nucleotide sequencing indicated that several of these outbreaks were linked and it is probable that disease spread from the intermediary impala antelope host to cattle in close proximity. Evidence was found for the involvement of viruses from a single KNP genotype in precipitating outbreaks in impala over a 10-year period. In addition, several unrelated outbreaks affecting cattle and impala occurred within a single year. Characterisation of outbreak strains from Botswana similarly revealed that a single genotype affected different species over a 10-year period and that transboundary spread of SAT-1 virus occurred on at least one occasion. This retrospective analysis of outbreak strains has clearly demonstrated that FMD control policies that address the role of antelope as intermediaries in disease transmission are crucial as these wildlife species play an important role in disease dissemination.

African buffalo were introduced into a wildlife conservancy in the southeast of Zimbabwe in an effortto increase the conservancy's economic viability, which is primarily based on eco-tourism. The buffalo were infected with SAT serotypes (SAT-1, SAT-2 and SAT-3) of foot and mouth disease (FMD) virus, and in order to isolate the conservancy and prevent the transmission of FMD to adjacent populations of domestic livestock, the conservancy was surrounded by a double-fence system, 1.8 m in height. The intention was to prevent the movement of both wildlife and domestic animals across the perimeter. However, two years after the buffalo were introduced, FMD occurred in cattle farmed just outside of the conservancy. Using serological and molecular diagnostic tests, epidemiological investigations showed that it was most likely that antelope (impala or kudu), infected through contact with the buffalo herd within the conservancy, had jumped over the fence and transmitted the virus to the cattle.

Two main reasons prompted the authors to write this paper. First, outbreaks of foot and mouth disease (FMD) have occurred repeatedly in Mali and neighbouring countries during the last decade. Secondly, there is a pressing need for control strategies, since the first molecular epidemiological studies of FMD virus in West Africa have demonstrated that FMD transmission across national boundaries is common in this region. The authors discuss the FMD outbreaks that occurred during the period of 1980 to 1996, which were reported to the Central Livestock Office in Mali by field veterinarians. The outbreaks in 1980 and 1982 were confined to the regions of Kayes and Gao, respectively. Between 1991 and 1992, outbreaks occurred in Segou, Sikasso and Bamako. In 1996, FMD outbreaks were reported in cattle populations throughout Mali, except in Kidal in the Sahara desert, where temperatures reach 45 degrees C. High mortality was reported in young animals, while morbidity approached 100% in adult cattle.

VP1 gene nucleotide sequences of 51 SAT3-type foot-and-mouth disease (FMD) viruses from seven southern and eastern African countries were used to infer a gene phylogeny. Results obtained by phylogenetic analysis of the homologous 405 nt region corresponding to the C-terminal 128 amino acids of 1D and adjacent 7 amino acids of 2A indicate that there are six distinct virus lineages evolving independently in different geographical localities in accordance with the FMD topotype concept. Topotypes I-IV occur in southern Africa, whilst topotypes V and VI are unique to East Africa. Viruses of different topotypes differ from each other at 20% or more of the nucleotide sites, specified in this study. Despite the limited geographical distribution of this serotype, the level of intratypic variation is intermediate between that of SAT1 and SAT2, both of which are widely distributed in sub-Saharan Africa. Within SAT3, 37.3% and 47.4% of sites were completely conserved on nucleotide and amino acid levels, respectively. The locality-specific grouping of viruses permits accurate determination of the sources of outbreaks, whilst the high levels of variation within the immunodominant 1D protein has implications for the control of the disease through vaccination.

The complete 1D genome region encoding the immunogenic and phylogenetically informative VP1 gene was genetically characterized for 23 South African Territories (SAT)-1 viruses causing foot-and-mouth (FMD) disease outbreaks in the West African region between 1975 and 1981. The results indicate that two independent outbreaks occurred, the first involved two West African countries, namely Niger and Nigeria, whilst the second affected Nigeria alone. In the former epizootic, virus circulation spanned a period of 2 years, whilst in the latter virus was recovered from the field over a 3 year period. Comparison of the West African viruses with SAT-1 viruses from other regions on the continent revealed that the two West African lineages identified in this study are regionally distinct. Furthermore, variation in VP1 gene length was identified in SAT-1 viruses for the first time, further emphasizing the uniqueness of these pathogens in West Africa. This first retrospective analysis in which the molecular epidemiology of SAT-1 viruses in West Africa is reported, provides a useful measure of the regional variation of these viruses and is an essential first step in the establishment of a West African sequence database that will be a useful reference for future outbreak eventualities.

Six of the seven serotypes of foot and mouth disease (FMD) virus (i.e. all but Asia 1) are prevalent in Africa although there are marked regional differences in distribution. Three of these serotypes are unique to Africa, namely the three South African Territories (SAT) serotypes. Serotype C may also now be confined to Africa because it has not been reported elsewhere recently. In southern Africa at least, the SAT serotypes have an intimate and probably ancient association with African buffalo (Syncerus caffer) that is instrumental in their maintenance. Within each of the six prevalent serotypes, with the possible exception of C, there are a number of different lineages with more or less defined distributions (i.e. topotypes) that in some cases are sufficiently immunologically different from one another to require specific vaccines to ensure efficient control. This immunological diversity in prevalent serotypes and topotypes, in addition to uncontrolled animal movement in most parts of the continent, render FMD difficult to control in present circumstances. This fact, together with poorly developed intercontinental trade in animals and animal products has resulted in the control of FMD being afforded a low priority in most parts of the continent, although the northern and southern regions of the continent are an exception. As a consequence, eradication of FMD from Africa as a whole is not a prospect within the foreseeable future. In southern Africa, the use of fencing and other means to strictly control the movement of wildlife and livestock as well as judicious application of vaccine has resulted in countries of the region being able to access beef and other livestock markets in Europe and elsewhere in the developed world. Significant marketing of livestock and livestock products from Africa outside the continent is unlikely to be achieved unless similar approaches can be developed for other regions of Africa. This will result in continuing under-exploitation of a valuable resource in the arid and semi-arid regions of Africa, with increasing marginalisation of human populations living there.