[en] The Capripoxvirus genus is comprised of sheeppovirus (SPV), goatpox virus (GPV) and lumpy skin disease virus (LSDV). The three separate diseases caused by capripoxviruses (CaPVs) in sheep, goat and cattle are most economically significant in large areas in Africa and Asia. CaPVs are generally considered to be host specific leading to outbreaks in the preferential host, even if experimental infections have shown that most strains can cause disease in more than one species. Sheeppox and goatpox exhibit similar clinical signs that can be confused with other exanthemas, i.e. orf. Lumpy skin disease is a subacute to acute cattle disease. The CaPVs are serologically impossible to differentiate. Specific identification of the genus inside the Poxviridae family relies mainly on molecular tools rather than on classical serology. In the last few years, restriction fragment pattern analysis, cross-hybridisation and more recently the complete genome sequencing of the three viruses showed that grouping of isolates correlated with the animal species from which the viruses were isolated: SPV, GPV and LSDV are phylogenetically distinguishable through conserved genes responsible for hostrange. For taxonomy and evolutionary studies we have worked on a non-essential gene for the virus growth encoding an homologue of a G protein-coupled chemokine receptor (GPCR) described by Cao et al (1995) on the genome of Kenya sheep isolate (KS1). The Q2/3L gene, known to be located in the terminal genomic region, is likely to affect the viral virulence. This poxvirus-encoded gene affects the host immune response to viral infection because of its homology to mammalian chemokine receptors. We describe here its suitability for host range phylogenetic grouping. The sequence analysis of the Q2/3L gene of KS1 vaccine strain led to the design of PCR primers to study the relationship among 23 CaPVs strains (including 13 virulent sheep isolates and 1 sheep vaccine strain, 5 goat isolates and 1 goat vaccine strain, and 3 bovine isolates and 1 bovine vaccine strain; 5 strain sequences were obtained from genbank). Alignment analysis of both the nucleotide and deduced amino acid sequence showed that one deletion was associated to the sheep strains and another to the cattle strains while these were absent from the goat strains. A representative phylogenetic analysis using the neighbour-joining method showed 3 tight genetic clusters suggesting a co-adaptation of the strains and their original host. Surprisingly, the KS1 strain was closer to the LSDV strain cluster and the goat vaccine was closer to the sheep group. These vaccine strains may in fact originate from bovine and sheep respectively. In the case of KS-1, the similarity with LSDV genome was recently evidenced. These results suggest that the genomic mutations that occurred in the GPCR gene account for viral adaptation to combat the immune system in a specific host. This gene provides one starting point for the understanding of the genetic basis of the CaPVs host range specificity. A particularly valuable application of the delineated primers would be their direct use for disease epidemio-surveillance and differential diagnosis

[en] Because of their close relationship, specific identification of the CaPVs genus inside the Poxviridae family relies mainly on molecular tools rather than on classical serology. We describe the suitability of the G protein-coupled chemokine receptor (GPCR), for host range phylogenetic grouping. The analysis of 26 CaPVs shows 3 tight genetic clusters consisting of goatpox virus (GPV), lumpy skin disease virus (LSDV), and sheeppox virus (SPV). (author)

[en] The Genus Capripoxvirus (CaPV) of the Poxviridae family comprises sheep poxvirus (SPPV), goat poxvirus (GTPV) and lumpy skin disease virus (LSDV) which are responsible for economically important diseases affecting sheep, goats and cattle respectively. To date, there have been no molecular criteria upon which to base strain designation. The complexity of CaPVs host specificity shows the need to develop more reliable tools for CaPVs identification than the current method which is based on the host origin. Previous reports, based on partial or full genome sequencing indicated that CaP viruses are genetically distinct from each other and can be grouped as three different species: SPPV, GTPV and LSDV. In contributing to the creation of more stringent data for geno-typing CaPVs, we have analysed the RPO30 gene of several isolates. The phylogenetic reconstructions have shown that the viruses can be segregated into three different lineages according to their host origins: the SPPV, the GTPV and the LSDV lineages. In addition, a 21-nucleotides deletion found in all individuals within only the SPPV group was exploited to design a classical PCR method to differentiate SPPV from GTPV. This test allows the rapid differential diagnosis of diseases caused by either SPPV or GTPV strains. (author)