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Two of the 22 presently recognised African swine fever (ASF) virus p72 genotypes are genetically homogeneous and are associated with domestic pig cycles. Of these, genotype VIII comprises just two p72 variants, designated 'a' and 'b' in this study, and is confined four or less viruses with a maximum circulation period of three years. A combined p72-CVR analysis resulted in eight discrete lineages corresponding to eight unique p72-CVR combinations. One of these, b-F, appears to have arisen by convergent evolution or through an intra-genotypic recombination event, as the individual p72 and CVR gene phylogenies are incongruent. This raises the possibility of intra-genotypic recombination in ASF viruses for the first time. However, given the repetitive nature of the CVR region, convergent evolution cannot be excluded and may be the more likely explanation.

Outbreaks of African swine fever (ASF) have been reported from many countries, particularly in Sub-Saharan Africa, but until 2007 the disease had never been reported from the Republic of Mauritius. This is the first report describing field epidemiological and laboratory investigations into the outbreak of the lethal pig disease on the island. The official index case displayed clinical and necropsy signs suggestive of ASF. Serological and agent identification methods used to confirm and investigate the outbreak yielded negative and a few positive results respectively. Phylogenetic analysis based on DNA sequencing clustered the outbreak strain within genotype II viruses. The outbreak was controlled by modified stamping out and risk assessment revealed the possibility of disease endemicity in the country.

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Two hundred and thirty-nine cattle from Gauteng Province in South Africa were tested for various pathogens causing reproductive diseases including bovine viral diarrhoea/mucosal disease (BVD/MD) virus, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus, Neospora caninum and Brucella abortus using various tests. For BVD/MD virus, 49.37 % tested positive, 74.47 % for IBR/IPV virus, 8.96 % for Neospora caninum and 3.8 % for Brucella abortus. The result for Brucella abortus is higher than the national average, possibly due to the small sample size. A high seroprevalence of antibodies to both BVD/MD virus and IBR/IPV virus was evident. These 2 viruses should be considered, in addition to Brucella abortus, when trying to establish causes of abortion in cattle. The clinical significance of Neospora caninum as a cause of abortion in Gauteng needs further investigation. One hundred and forty-three bulls were tested for Campylobacter fetus and Trichomonas fetus, and a low prevalence of 1.4 % and 2.1 % respectively was found in this study. The clinical implications of these findings are discussed.

Rift Valley fever (RVF) is a re-emerging zoonotic disease responsible for major losses in livestock production, with negative impact on the livelihoods of both commercial and resource-poor farmers in sub-Sahara African countries. The disease remains a threat in countries where its mosquito vector thrives. Outbreaks of RVF usually follow weather conditions which favour increase in mosquito populations. Such outbreaks are usually cyclical, occurring every 10–15 years. Recent outbreaks of the disease in South Africa have occurred unpredictably and with increased frequency. In 2008, outbreaks were reported in Mpumalanga, Limpopo and Gauteng provinces, followed by 2009 outbreaks in KwaZulu-Natal, Mpumalanga and Northern Cape provinces and in 2010 in the Eastern Cape, Northern Cape, Western Cape, North West, Free State and Mpumalanga provinces. By August 2010, 232 confirmed infections had been reported in humans, with 26 confirmed deaths.To investigate the evolutionary dynamics of RVF viruses (RVFVs) circulating in South Africa, we undertook complete genome sequence analysis of isolates from animals at discrete foci of the 2008–2010 outbreaks. The genome sequences of these viruses were compared with those of the viruses from earlier outbreaks in South Africa and in other countries. The data indicate that one 2009 and all the 2008 isolates from South Africa and Madagascar (M49/08) cluster in Lineage C or Kenya-1. The remaining of the 2009 and 2010 isolates cluster within Lineage H, except isolate M259_RSA_09, which is a probable segment M reassortant. This information will be useful to agencies involved in the control and management of Rift Valley fever in South Africa and the neighbouring countries.

The laboratory diagnosis of African horse sickness (AHS) is important for: (a) demonstrating freedom from infection in a population, animals or products for trade (b) assessing the efficiency of eradication policies; (c) laboratory confirmation of clinical diagnosis; (d) estimating the prevalence of AHS infection; and (e) assessing postvaccination immune status of individual animals or populations. Although serological techniques play a secondary role in the confirmation of clinical cases, their use is very important for all the other purposes due to their high throughput, ease of use and good cost-benefit ratio. The main objective of this study was to support the validation of AHS VP7 Blocking ELISA up to the Stage 3 of the World Animal Health Organization (OIE) assay validation pathway. To achieve this, a collaborative ring trial, which included all OIE Reference Laboratories and other AHS-specialist diagnostic centres, was conducted in order to assess the diagnostic performance characteristics of the VP7 Blocking ELISA. In this trial, a panel of sera of different epidemiological origin and infection status was used. Through this comprehensive evaluation we can conclude that the VP7 Blocking ELISA satisfies the OIE requirements of reproducibility. The VP7 Blocking ELISA, in its commercial version is ready to enter Stage 4 of the validation pathway (Programme Implementation). Specifically, this will require testing the diagnostic performance of the assay using contemporary serum samples collected during control campaigns in endemic countries.