Fowl pox virus: a minireview

Among the genus Avipoxvirus (APV) of the family Poxviridae, Fowlpox virus (FWPV) is of the highest economic importance associated with a severe drop in egg production, retarded growth of younger birds, and sometimes heavy mortality. Despite its worldwide prevalence, the status of fowlpox infection varies in different geographical regions due to differences in climate, vector population, vaccination status, management, and employed hygienic practices. The disease is frequently seen in all production systems, ranging from backyard to commercial poultry flocks due to insufficient vaccination coverage, strain differences or the emergence of novel variants. FWPV can either produce cutaneous lesions (hypertrophy/hyperplasia of epidermal cells) or can affect mucous membranes of the upper respiratory tract or digestive system (diphtheritic form). The host specificity has been considered broader than previously thought: (a) ‘fowlpox-like viruses’ being mainly isolated from Galliformes, (b) ‘canarypox-like viruses’ from Passeriformes and (c) viruses of Psittaciformes. Currently, fowlpox is considered an evolving disease in the poultry industry with several incidences documented in vaccinated chicken flocks worldwide. Limited reports are available on the antigenic, genetic, and biological characterisation of FWPV and other APVs. Complete genome sequencing of different APVs is necessary to understand its molecular epidemiology which would help to solve the complex paradigm of its host range. In the recent past, FWPV has been used as a vector to produce recombinant veterinary vaccines. This review has briefed the aetiology, epidemiology, pathogenesis, clinical signs, prevention, and control strategies related to fowlpox infection.