Yemen and Vietnam capripoxviruses demonstrate a distinct host preference for goats compared with sheep

Abstract

Sheeppox and goatpox are caused by viruses that are members of the genus Capripoxvirus, and globally result in significant production losses. To improve the understanding of disease pathogenesis and evaluate host species preferences, sheep and goats were inoculated either with a capripoxvirus isolate from Yemen or from a recent outbreak in Vietnam. Blood, swabs and tissues were collected at various time points following experimental challenge and assessed for viral DNA content using real-time PCR and infectivity using virus isolation. The Yemen isolate was considerably more pathogenic in goats with 100 % mortality and morbidity compared with sheep with 0 % mortality and 100 % morbidity. The Vietnam isolate was also more pathogenic in goats with 100 % morbidity and an estimated 33 % mortality rate compared with mild morbidity and a 0 % mortality rate in sheep. Higher viral titres were observed in nasal, oral and conjunctival swabs from goats inoculated with either the Yemen or Vietnam isolate compared with those collected from sheep. Although the highest viral titres were detected in primary and secondary skin lesions in sheep and goats, the severity of clinical disease observed in each species varied according to the inoculum used. Whereas both the Yemen and Vietnam isolates clearly caused more severe disease in goats, the Yemen isolate was also moderately pathogenic in sheep. The Vietnam isolate, in contrast, caused only very mild disease in sheep. Limited DNA sequencing revealed ORF 074 of the Vietnam isolate to be identical to that of several goatpox virus isolates from China, suggesting a possible Chinese origin.

Goat pox virus isolated from an outbreak at Akola, Maharashtra (India) phylogenetically related to Chinese strain

“…Capripox viruses (CaPVs) usually have no host preference as they infect both sheep and goats (Rao and Bandopadhyay 2000). However, sheep pox (SPPV) and goat pox viruses (GTPV) are considered as different entity in India (Hosamani et al 2004a;Bhanuprakash et al 2006b) and recently confirmed in other countries (Babiuk et al 2009). Goat pox is often a great threat to goats and sheep and characterized by pyrexia and generalized pock lesions with lymphadenopathy causing high mortality (50-100%) and morbidity up to 100% (Bhanuprakash et al 2006a;Babiuk et al 2008) and not distinguishable from sheep pox serologically but possible by molecular technique (Hosamani et al 2004a).…”

Capripoxvirus G-protein-coupled chemokine receptor: a host-range gene suitable for virus animal origin discrimination

“…Though mixed flocks often comprise sheep and goats, outbreaks of sheep or goat pox can be confined to only sheep or goats, respectively, or can involve both species. The host preference for goat poxviruses was recently demonstrated experimentally (Babiuk et al, 2009); however, the breed of the sheep and goat used might account for this difference. There is at least one confirmed isolation of an LSDV isolate from a sheep, the Kenyan O-240 isolate (KS-1) (Davies, 1976(Davies, , 1982Kitching et al, 1987).…”

Genetic diversity of fusion gene (ORF 117), an analogue of vaccinia virus A27L gene of capripox virus isolates

“…Capripox viruses (CaPV) are difficult to be distinguished by serological methods , but possible by molecular tools [2] and they usually have no host preference [3]. CaPV isolates are shown to have differential host preference demonstrated by experimental challenge studies and virus isolation [4] and considered as different entities within the Indian subcontinent [5]. Capripox is enzootic in Southwest and Central Asia, Northern and Central Africa and Indian subcontinent [1] and pose potential economic threat to the small ruminant industry [6].…”