Characterisation of a SAT-1 outbreak of foot-and-mouth disease in captive African buffalo (Syncerus caffer): Clinical symptoms, genetic characterisation and phylogenetic comparison of outbreak isolates

Vosloo, Wilna; Klerk, L.-M. de; Boshoff, C. I.; Botha, B.; Dwarka, Rahana; Keet, D.F.; Haydon, Daniel T.

doi:10.1016/j.vetmic.2006.11.002

Cited by 32 publications

(36 citation statements)

References 28 publications

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“…There are unequivocal cases of extensive vesicles and debilitating FMD in buffalo (44,45). The reasons for these discrepancies in disease severity are unclear, and the occurrence of vesicles may depend on the interplay between virus, host, and environmental factors.…”

Section: Discussionmentioning

confidence: 99%

Differential Persistence of Foot-and-Mouth Disease Virus in African Buffalo Is Related to Virus Virulence

Maree

Klerk-Lorist²,

Gubbins

et al. 2016

J Virol

103

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d ABSTRACTFoot-and-mouth disease (FMD) virus (FMDV) circulates as multiple serotypes and strains in many regions of endemicity. In particular, the three Southern African Territories (SAT) serotypes are maintained effectively in their wildlife reservoir, the African buffalo, and individuals may harbor multiple SAT serotypes for extended periods in the pharyngeal region. However, the exact site and mechanism for persistence remain unclear. FMD in buffaloes offers a unique opportunity to study FMDV persistence, as transmission from carrier ruminants has convincingly been demonstrated for only this species. Following coinfection of naive African buffaloes with isolates of three SAT serotypes from field buffaloes, palatine tonsil swabs were the sample of choice for recovering infectious FMDV up to 400 days postinfection (dpi). Postmortem examination identified infectious virus for up to 185 dpi and viral genomes for up to 400 dpi in lymphoid tissues of the head and neck, focused mainly in germinal centers. Interestingly, viral persistence in vivo was not homogenous, and the SAT-1 isolate persisted longer than the SAT-2 and SAT-3 isolates. Coinfection and passage of these SAT isolates in goat and buffalo cell lines demonstrated a direct correlation between persistence and cell-killing capacity. These data suggest that FMDV persistence occurs in the germinal centers of lymphoid tissue but that the duration of persistence is related to virus replication and cell-killing capacity. IMPORTANCEFoot-and-mouth disease virus (FMDV) causes a highly contagious acute vesicular disease in domestic livestock and wildlife species. African buffaloes (Syncerus caffer) are the primary carrier hosts of FMDV in African savannah ecosystems, where the disease is endemic. We have shown that the virus persists for up to 400 days in buffaloes and that there is competition between viruses during mixed infections. There was similar competition in cell culture: viruses that killed cells quickly persisted more efficiently in passaged cell cultures. These results may provide a mechanism for the dominance of particular viruses in an ecosystem.

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Section: Discussionmentioning

confidence: 99%

Differential Persistence of Foot-and-Mouth Disease Virus in African Buffalo Is Related to Virus Virulence

Maree

Klerk-Lorist²,

Gubbins

et al. 2016

J Virol

103

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“…3) over 4 months, which is rapid compared to two previous studies of genetic change in buffaloes. Vosloo et al (1996) showed a substitution rate of 1.64 % per year over a similar genetic region for a SAT-2 virus in carrier buffaloes and Vosloo et al (2007) estimated a rate of 1.1 % per year in an outbreak of SAT-1 in buffalo that also led to the establishment of a carrier state. It is not known whether FMDV might evolve faster in cattle than buffaloes, or whether the faster rate of change observed in this study might have arisen as a result of vaccine induced selection pressure.…”

Section: Discussionmentioning

confidence: 99%

“…Antigenic variants can be selected for in immune or partially immune hosts (Gebauer, De la Torre, Gomes, Maten, Barahona, Tiraboshi, Bergman, De Mello & Domingo 1988), although Diez, Mateu & Domingo (1989) reported that antigenic variants may accumulate over time even in the absence of antibody selection. Studies have shown that cattle and buffalo carriers (subclinically infected animals) may be a significant source of genetic variation (Salt, Samuel & Kitching 1996;Vosloo, Bastos, Kirkbride, Esterhuysen, Janse van Rensburg, Bengis, Keet & Thomson 1996;Vosloo, De Klerk, Boshoff, Botha, Dwarka, Keet & Haydon 2007). In particular, capsid protein VP1, encoded by the 1D gene, greatly contributes to the antigenicity of FMDV Mateu, Camarero, Giralt, Andreu & Domingo 1995) due to the existence of an immuno-dominant site, located between beta-strands G and H (the G-H loop) of VP1 which also acts as the cell receptor recognition site (Kitson, McCahon & Belsham 1990).…”

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confidence: 99%

Molecular characterization of SAT-2 foot-and-mouth disease virus isolates obtained from cattle during a four-month period in 2001 in Limpopo Province, South Africa

Phologane¹,

Dwarka²,

Haydon³

et al. 2008

Onderstepoort J Vet Res

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Foot-and-mouth disease (FMD) is an acute, highly contagious viral infection of domestic and wild cloven-hoofed animals. The virus is a single-stranded RNA virus that has a high rate of nucleotide mutation and amino acid substitution. In southern Africa the South African Territories (SAT) 1-3 serotypes of FMD virus are maintained by large numbers of African buffaloes (Syncerus caffer), which provide a potential source of infection for domestic livestock and wild animals. During February 2001, an outbreak of SAT-2 was recorded in cattle in the FMD control zone of South Africa, adjacent to the Kruger National Park (KNP). They had not been vaccinated against the disease since they form the buffer between the vaccination and free zones but in the face of the outbreak, they were vaccinated as part of the control measures to contain the disease. The virus was, however, isolated from some of them on several occasions up to May 2001. These isolates were characterized to determine the rate of genetic change in the main antigenic determinant, the 1D/2A gene. Nucleotide substitutions at 12 different sites were identified of which five led to amino acid changes. Three of these occurred in known antigenic sites, viz. the GH-loop and C-terminal part of the protein, and two of these have previously been shown to be subject to positive selection. Likelihood models indicated that the ratio of non-synonymous to synonymous changes among the outbreak sequences recovered from cattle was four times higher than among comparable sequences isolated from wildlife, suggesting that the virus may be under greater selective pressure during rapid transmission events.

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“…Buffalo calves play an important role in the dynamics of the disease, because they are the most infectious individuals (Gainaru et al, 1986). They become susceptible to FMD in the period after their maternal antibodies wane and before their natural immunity develop, which coincides with the age three to eight months (Bastos et al, 2000;Vosloo et al, 2007). The maintenance of FMD by wildlife makes the eradication of the virus impossible without the destruction of large numbers of African buffaloes -a solution that is both ecologically and morally untenable (Thomson et al, 2003a).…”

Section: Transmission Cycle Of Foot-and-mouth Disease In South Africamentioning

confidence: 99%

The landscape epidemiology of foot-and-mouth disease in South Africa: A spatially explicit multi-agent simulation

Dion

VanSchalkwyk

Lambin

2011

Ecological Modelling

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a b s t r a c tThis study aimed at understanding how landscape heterogeneity influences outbreaks of contagious diseases in southern Africa. Landscape attributes influence patterns of movement and behaviour of animal hosts, virus spread and survival, as well as land use practices. A multi-agent simulation was developed to represent the spatial and temporal dynamics of pathogens between human-livestock and wildlife interfaces at the fringe of large wildlife conservation areas. The model represents the three main elements associated with epidemics -populations, space, and time -to simulate direct contacts between wildlife and livestock. The dynamics of these populations emerge from interactions between agents and the landscape. The model was calibrated to represent the transmission of foot-and-mouth disease through direct contact at the border of the Kruger National Park in South Africa. In the region, African buffaloes (Syncerus caffer) act as reservoirs of the virus and spread the infection to domestic cattle bordering the park. We tested the sensitivity of various factors influencing contact rate between buffaloes and cattle, and thus the risk of foot-and-mouth disease transmission. Results show that cattle-buffalo contacts mostly depend on the range of displacements of cattle and buffaloes, as influenced by the landscape configuration, and on the number of fence breakages multiplied by the time between breakage and repair. Contacts take place not only close to water-points but also in grazing areas, within an area up to 6 km from the fence.

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Characterisation of a SAT-1 outbreak of foot-and-mouth disease in captive African buffalo (Syncerus caffer): Clinical symptoms, genetic characterisation and phylogenetic comparison of outbreak isolates

Cited by 32 publications

References 28 publications

Differential Persistence of Foot-and-Mouth Disease Virus in African Buffalo Is Related to Virus Virulence

Differential Persistence of Foot-and-Mouth Disease Virus in African Buffalo Is Related to Virus Virulence

Molecular characterization of SAT-2 foot-and-mouth disease virus isolates obtained from cattle during a four-month period in 2001 in Limpopo Province, South Africa

The landscape epidemiology of foot-and-mouth disease in South Africa: A spatially explicit multi-agent simulation

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