The African swine fever control zone in South Africa and its current relevance

African swine fever (ASF) has been reported in South Africa since the early 20th century. The disease has been controlled and confined to northern South Africa over the past 80 years by means of a well-defined boundary line, with strict control measures and movement restrictions north of this line. In 2012, the first outbreak of ASF outside the ASF control zone since 1996 occurred. The objective of this study was to evaluate the current relevance of the ASF control line as a demarcation line between endemic ASF (north) areas and ASF-free (south) area and to determine whether there was a need to realign its trajectory, given the recent outbreaks of ASF, global climate changes and urban development since the line’s inception. A study of ASF determinants was conducted in an area 20 km north and 20 km south of the ASF control line, in Limpopo, Mpumalanga, North West and Gauteng provinces between May 2008 and September 2012. The study confirmed that warthogs, warthog burrows and the soft tick reservoir, Ornithodoros moubata, are present south of the ASF control line, but no virus or viral DNA was detected in these ticks. There appears to be an increasing trend in the diurnal maximum temperature and a decrease in humidity along the line, but the impact of these changes is uncertain. No discernible changes in minimum temperatures and average rainfall along the disease control line were observed between 1992 and 2014. Even though the reservoirs were found south of the ASF boundary line, the study concluded that there was no need to realign the trajectory of the ASF disease control line, with the exception of Limpopo Province. However, the provincial surveillance programmes for the reservoir, vector and ASF virus south of this line needs to be maintained and intensified as changing farming practices may favour the spread of ASF virus beyond the control line

Classical swine fever (Hog cholera) : review of aspects relevant to control

Classical swine fever (CSF) has the ability to spread over large distances when human intervention, such as illegal swill feeding facilitates its movement. This was apparent during 2005 when CSF appeared in South Africa (SA) after an absence of 87 years. In this review various newly published developments in terms of the diagnosis of the disease and vaccination are described and applied to situations similar to SA. The role of wildlife such as feral pigs and European wild boar in the dissemination and maintenance of CSF virus are discussed and the dearth of knowledge on the potential of other wild pigs species prevalent on southern Africa noted. The modes of spread and control measures to prevent introduction as well as during outbreaks are discussed.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-1682/issue

Editorial : Foot-and-mouth disease epidemiology, vaccines and vaccination : moving forward

Vaccination has played a major role in foot-and-mouth disease (FMD) control. There are different approaches to the design and implementation of vaccination campaigns, and epidemiological information is paramount in influencing the vaccine and vaccination strategy that best suit each geographic location. FMD-endemic regions typically organize vaccination campaigns as a routine preventive control policy or to mitigate the impact of the disease. The majority of currently used vaccines are formulated with chemically inactivated whole-viral particles and suitable adjuvants such as single and double oil emulsions. The most recent strains circulating in a particular region are typically selected as antigens based on the results of vaccine-matching data and in vitro experiments, however, predictions based on vaccine-matching approaches are usually uncertain without a live virus challenge in natural hosts combined with reliable field data. Vaccine selection and successful vaccination campaigns rely on a deep knowledge of the epidemiology of the region where these vaccines will be used, as well as access to the appropriate diagnostic tools to underpin these campaigns.Instituto de VirologíaFil: Capozzo, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Capozzo, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vosloo, Wilna. Commonwealth Scientific and Industrial Research Organisation (CSIRO) Health and Biosecurity. Transboundary Disease Mitigation. Australian Centre for Disease Preparedness; AustraliaFil: de los Santos, Teresa. United States Department of Agriculture. Agricultural Research Service. Plum Island Animal Disease Center; Estados UnidosFil: Pérez, Andrés M. University of Minnesota. Department of Veterinary Population Medicine; Estados UnidosFil: Perez Filgueira, Daniel Mariano. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Perez Filgueira, Daniel Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The 3A non-structural-protein coding region of the southern African SAT type isolates differs from that of other foot-and-mouth disease viruses

The 3A non-structural protein of foot-and-mouth disease viruses is a relatively conserved protein comprising 153 amino acids. Recent studies have demonstrated correlation between mutations in the 3A non-structural-protein-coding region, including a 10-amino acid deletion, and attenuation of the viruses in cattle. Although the 3A coding region of several type A, O and C isolates has previously been described, nucleotide sequence data of the 3A coding region of the South African Types (SAT) 1, 2 and 3 viruses are limited. Therefore, the 3A non-structural-coding region of different SAT serotypes was determined, analysed and compared to that of European, South American and Asian isolates. The 3A regions of the SAT isolates investigated differed markedly from that of types A, O, C and Asia-1, but were similar within the group.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Emergency foot-and-mouth disease vaccines a Malaysia 97 and A₂₂ Iraq 64 offer good protection against heterologous challenge with a variant serotype a ASIA/G-IX/SEA-97 lineage virus

The continuous emergence of foot-and-mouth disease virus (FMDV) serotype A variants in South East Asia is of concern for international FMDV antigen banks, especially when in vitro tests predict a low antigenic match. A vaccination-challenge study was performed by using two emergency FMDV vaccines with A22 Iraq 64 (A22 IRQ) and A Malaysia 97 (A MAY 97) strains, against challenge with a variant strain of FMDV A/Asia/G-IX/SEA-97 lineage at 7- and 21-day post-vaccination (dpv). At 7 dpv, three of five female calves vaccinated with A MAY 97 and four of five vaccinated with A22 IRQ did not show lesions on the feet and were considered protected, while at 21 dpv all five calves were protected with each vaccine, indicating equal efficacy of both vaccine strains. Calves were protected despite relatively low heterologous neutralizing antibody titers to the challenge virus at the time of challenge. All the calves developed antibodies to the non-structural proteins, most likely due to the direct intradermolingual (IDL) inoculation. Only one calf from the A MAY 97-7 group had infectious virus in the serum 1–3-day post-challenge (dpc), while no virus could be isolated from the serum of cattle challenged on 21 dpv. The virus could be isolated from the oral swabs of all calves, 1–7 dpc with viral RNA detected 1–10 dpc. Nasal swabs were positive for virus 1–6 dpc in a small number of calves. The time between vaccination and infection did not have an impact on the number of animals with persistent infection, with almost all the animals showing viral RNA in their oro-pharyngeal fluid (probang) samples up to 35 dpc. Despite the poor in vitro matching data and field reports of vaccine failures, this study suggests that these vaccine strains should be effective against this new A/Asia/G/SEA-97 variant, provided they are formulated with a high antigen dose.</p

Investigation into the epidemiology of African swine fever virus at the wildlife - domestic interface of the Gorongosa National Park, Central Mozambique

An epidemiological study of African swine fever (ASF) was conducted between March 2006 and September 2007 in a rural area adjacent to the Gorongosa National park (GNP) located in the Central Mozambique. Domestic pigs and warthogs were sampled to determine the prevalence of antibodies against ASF virus and the salivary antigens of Ornithodoros spp. ticks, while ticks collected from pig pens were tested for the presence of ASFV. In addition, 310 framers were interviewed to gain a better understanding of the pig value chain and potential practices that could impact on the spread of the virus. The sero-prevalence to ASFV was 12.6% on farms and 9.1% in pigs, while it reached 75% in warthogs. Approximately 33% of pigs and 78% of warthogs showed antibodies against salivary antigens of ticks. The differences in sero-prevalence between farms close to the GNP, where there is greater chance for the sylvatic cycle to cause outbreaks, and farms located in the rest of the district, where pig to pig transmission is more likely to occur, were marginally significant. Ornithodoros spp. ticks were found in only 2 of 20 pig pens outside the GNP, and both pens had ticks testing positive for ASFV DNA. Interviews carried out among farmers indicated that biosecurity measures were mostly absent. Herd sizes were small with pigs kept in a free-ranging husbandry system (65%). Only 1.6% of farmers slaughtered on their premises, but 51% acknowledged allowing visitors into their farms to purchase pigs. ASF outbreaks seemed to have a severe economic impact with nearly 36% of farmers ceasing pig farming for at least 1 year after a suspected ASF outbreak. This study provides the first evidence of the existence of a sylvatic cycle in Mozambique and confirms the presence of a permanent source of virus for the domestic pig value chain.Wellcome Trust (Project number 210183. 183 AHDW03/04).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-16822017-08-30hb201