Persistent infection of African buffalo (Syncerus caffer) with SAT-type foot-and-mouth disease viruses: rate of fixation of mutations, antigenic change and interspecies transmission

Vosloo, Wilna; Bastos, Armanda D.S.; Kirkbride, E.; Esterhuysen, J. J.; Rensburg, D Janse van; Bengis, Roy G.; Keet, D.F.; Thomson, G.R.

doi:10.1099/0022-1317-77-7-1457

Cited by 110 publications

(92 citation statements)

References 34 publications

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“…This may not be reflected in the amino acid sequences. This much variation appears greater than published estimates for SAT2 in buffalo of 1.64% nucleotide substitutions per year (40). Here there are several genotypes, with many intermediate strains, which begins to give an impression of the evolutionary changes of these persistent viruses and the immunological pressure they are under (17).…”

Section: Discussioncontrasting

confidence: 39%

Molecular Epidemiology of Foot-and-Mouth Disease Viruses in the Adamawa Province of Cameroon

et al. 2004

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Foot-and-mouth disease virus (FMDV) causes a highly contagious viral disease of even-toed ungulates and is one of the most important economic diseases of livestock. Most studies of FMDV are done in countries where control measures are being implemented. In contrast, in areas such as sub-Saharan Africa, where FMDV is endemic and new strains are likely to emerge, there are only sporadic submissions to the World Reference Laboratory, Pirbright, United Kingdom. This paper describes the molecular epidemiology of FMDV in the Adamawa province of Cameroon based on a population sample of cattle herds. Serotypes SAT2 and A were isolated in the cross-sectional study. SAT2 isolates were all similar, with phylogenetic distances of <6%, and were most closely related to published sequences of isolates from Eritrea and Saudi Arabia. Serotype A isolates were more variable, with phylogenetic distances of 0 to 11%, and were most closely related to historic isolates from Cameroon. Use of a population-based sample gives a representative sample of virus diversity and will improve our understanding of the evolution of FMDV and its epidemiology. A supplementary study of pigs passing through the railhead collection yard at Ngaoundere detected a serotype O virus. A third pilot longitudinal study monitored viral persistence in three cattle herds over 12 months, and serotype O and A viruses were recovered from a herd 12 months after it was first recorded as being infected with SAT2 virus. The pig type O isolate was not closely related to that recovered from the cattle, suggesting that the pigs had not introduced the O virus into the cattle herds.

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Section: Discussioncontrasting

confidence: 39%

Molecular Epidemiology of Foot-and-Mouth Disease Viruses in the Adamawa Province of Cameroon

et al. 2004

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“…A daily rate of 0.00003 nucleotides per site per day, would lead to a 1% turnover in capsid nucleotides per year-which is well in the 0.5-1.5% per year range previously reported (Haydon et al, 2001 andVosloo et al, 1996). In this case, almost half these substitutions resulted in amino acid changes, so antigenic change is likely.…”

Section: Openup (July 2007)mentioning

confidence: 54%

“…SAT type viruses undergo high levels of mutation over time in persistently infected buffalo and these changes can lead to significant antigenic changes (Vosloo et al, 1996).…”

Section: Openup (July 2007)mentioning

confidence: 99%

“…Thereafter virus disappears from all secretions and excretions except for the pharynx where low-level viral replication persists in less or equal than 60% of individuals and virus can only be isolated from probangs (oropharyngeal scrapings) . During persistence, the SAT viruses undergo high rates of mutations, giving rise to new genetic and antigenic variants (Vosloo et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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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

Vosloo

Klerk

Boshoff

et al. 2007

Veterinary Microbiology

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African buffalo (Syncerus caffer) play an important role in the maintenance of the SAT types of foot-and-mouth disease (FMD) in southern Africa. These long-term carriers mostly become sub-clinically infected, maintaining the disease and posing a threat to other susceptible wildlife and domestic species. During an unrelated bovine tuberculosis experiment using captive buffalo in the Kruger National Park (KNP), an outbreak of SAT-1 occurred and was further investigated. The clinical signs were recorded and all animals demonstrated significant weight loss and lymphopenia that lasted 100 days. In openUP (July 2007) addition, the mean cell volume and mean cell haemoglobin values were significantly higher than before the outbreak started. Virus was isolated from several buffalo over a period of 167 days post infection and the molecular clock estimated to be 3 × 10 −5 nucleotide substitutions per site per day. Seven amino acid changes occurred of which four occurred in hypervariable regions previously described for SAT-1. The genetic relationship of the outbreak virus was compared to buffalo viruses previously obtained from the KNP but the phylogeny was largely unresolved, therefore the relationship of this outbreak strain to others isolated from the KNP remains unclear.

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“…Another unique feature of FMD epidemiology in Africa is the presence of the three Southern African Territories (SAT) serotypes, i.e. SAT1, SAT2 and SAT3, with multiple genetics and antigenic variants in different geographical regions, defined as topotypes [9,[13][14][15][16]. All three SAT serotypes are main-tained within the African buffalo populations [9,13].…”

Section: Introductionmentioning

confidence: 99%

Intra-serotype SAT2 chimeric foot-and-mouth disease vaccine protects cattle against FMDV challenge

Maree

Nsamba

Mutowembwa

et al. 2015

Vaccine

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The genetic diversity of the three Southern African Territories (SAT) types of foot-and-mouth disease virus (FMDV) reflects high antigenic variation, and indications are that vaccines targeting each SATspecific topotype may be needed. This has serious implications for control of FMD using vaccines as well as the choice of strains to include in regional antigen banks. Here, we investigated an intra-serotype chimeric virus, vSAT2 ZIM14 -SAT2, which was engineered by replacing the surface-exposed capsid-coding region (1B-1D/2A) of a SAT2 genome-length clone, pSAT2, with that of the field isolate, SAT2/ZIM/14/90. The chimeric FMDV produced by this technique was viable, grew to high titres and stably maintained the 1B-1D/2A sequence upon passage. Chemically inactivated, oil adjuvanted vaccines of both the chimeric and parental immunogens were used to vaccinate cattle. The serological response to vaccination showed the production of strong neutralizing antibody titres that correlated with protection against homologous FMDV challenge. We also predicted a good likelihood that cattle vaccinated with an intra-serotype chimeric vaccine would be protected against challenge with viruses that caused recent outbreaks in southern Africa. These results provide support that chimeric vaccines containing the external capsid of field isolates induce protective immune responses in FMD host species similar to the parental vaccine.

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Persistent infection of African buffalo (Syncerus caffer) with SAT-type foot-and-mouth disease viruses: rate of fixation of mutations, antigenic change and interspecies transmission

Cited by 110 publications

References 34 publications

Molecular Epidemiology of Foot-and-Mouth Disease Viruses in the Adamawa Province of Cameroon

Molecular Epidemiology of Foot-and-Mouth Disease Viruses in the Adamawa Province of Cameroon

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

Intra-serotype SAT2 chimeric foot-and-mouth disease vaccine protects cattle against FMDV challenge

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