Molecular characterization of Orf virus in goats in Gabon, Central Africa

Abstract

Background: Orf or contagious ecthyma is a zoonotic viral infection with a potential serious health threat for the small ruminants industry as well as humans. It is currently emerging in new territories.

Results: Eight suspected clinical cases of pustular dermatitis in goats occurred in the rural area of Tebe, in south-eastern Gabon, in January 2013. The orf virus (ORFV) was detected by high-throughput sequencing on sera, buccal swabs and scab pool samples. It was confirmed in six out of eight sick goats by using specific PCR targeting the major envelope protein (B2L) and the orf virus interferon resistance (VIR) genes. Phylogenetic analysis revealed that the Gabonese strain and South Korean strains evolved from a common ancestor, suggesting an Asian origin of the ORFV' Gabonese strain.

Conclusions: This study provides the molecular detection of the ORFV strain involved in the cases of pustular dermatitis in goats and highlights its circulation in Gabon.

Keywords: Goats; High-throughput sequencing; Orf virus; PCR.

Fig. 1

Geographic location and typical clinical signs of the ORFV infection in goats. Expanded map of Gabon showing the geographic location of confirmed cases of orf infection among goats, south-eastern Gabon (red circle) (a), proliferative lesions of ORFV infection around the lips and nostrils of goats (b, c), proliferative lesions on the udders (d)

Fig. 2

Phylogenetic tree based on nucleotide sequences of the B2L gene (a) and VIR gene (b) analysis. The tree was visualized with FigTree 1.3.1. Bayesian posterior probabilities values are shown to the right of the branches. ORFV sequences obtained in this study are shown in red. In Fig. 2a, a branch has been shortened and condensed for clarity and represented as dashed branch