Fowlpox virus

Abstract

Poxviruses are ubiquitous in nature and dispersed globally among domestic and wild birds. A total of 230 species have been reported with poxvirus infection from terrestrial and marine environment. Fowlpox virus (FPV) is a major economically important virus especially in the layer birds which cause drop in egg production and heavy mortality. It belongs to genus Avipoxvirus (APV), subfamily Chordopoxvirinae, of the family Poxviridae. The genus Avipoxvirus (APV) consists of a cluster of poxvirus that infects fowl, turkey, pigeon and many wild birds. However, their pathogenicity, host specificity and degree of relationship may vary. The cutaneous or diphtheritic form or both occurred in naturally infected birds. Host specificity is considered one of the important criteria for differentiation of APVs. Till now the precise figure of existing strains and variants of APV is not clearly defined due to emergence of new strains from different avian species. Nowadays, the turkey and pigeon pox also gained much economic importance due to their virulence nature. Even though the APV is strongly host specific, there are several reports on FPV infection on turkey that reveals the fact that FAV is emerging pathogen of turkey. The FPV is highly infectious for chickens and turkeys, rarely for pigeons and not for ducks and canaries. The turkey pox virus is virulent to ducks. In the current scenario, the disease has emerged as a new risk to poultry industry and several incidences also documented in vaccinated poultry flocks worldwide. The pathogenicity of the field FPV strains is higher than vaccine strains and studies reveal that these field FPV strains are integrated with reticuloendotheliosis provirus in their genome. Due to altered genome, the pathogenicity of the field FPV is higher and could not be protected by vaccine virus.