Characterization of Fowlpox Virus

The complex cytoplasmic DNA virus known as the fowlpox virus (FWPV) is a member of the avipoxvirus genus, Subfamily Chordopoxvirinae, and Family Poxviridae. The large genome size of FWPV makes it a potential vector for the creation of vaccines against a range of serious veterinary and human ailments. It also allows for multiple gene insertion and the generation of abortive infection in mammalian cells. The virus, which causes fowlpox in chickens and turkeys, is mainly transmitted to poultry through aerosols or biting insects. Fowlpox is a highly contagious disease that affects both domestic and wild birds, causing cutaneous and/or diphtheritic illnesses. To control the illness, strict hygiene practices and immunization with FWPV attenuated strains or antigenically similar pigeon pox virus vaccines are employed. Recent years have seen an increase in fowlpox outbreaks in chicken flocks, primarily due to the introduction of novel forms of FWPV. It is believed that the pathogenic characteristics of these strains are enhanced by the integration of reticuloendotheliosis virus sequences of variable lengths into the FWPV genome. The standard laboratory diagnosis of FPV involves histopathological analysis, electron microscopy, virus isolation on chorioallantoic membrane (CAM) of embryonated chicken eggs or cell cultures, and serologic techniques. For quick and consistent diagnosis, polymerase chain reaction (PCR) has proven to be the most sensitive method. PCR is used in concert with restriction endonuclease enzyme analysis (REA) to identify, differentiate, and characterize the molecular makeup of isolates of the fowlpox virus. Sequencing of the amplified fragments is then done.

Presence of avipoxvirus DNA in avian dermal squamous cell carcinoma

Dermal squamous cell carcinoma (DSCC; avian keratoacanthoma) is a neoplastic skin lesion of broiler chickens of unknown aetiology. In previous studies, the possibility of the involvement of pox viruses in the cause of DSCC was considered. In this work, a sensitive and specific nested polymerase chain reaction (PCR) protocol was developed that could amplify a 419 base pair DNA fragment of fowlpox virus with a detection limit of less than one infectious unit. Fowlpox virus DNA was always detected in skin samples with fowlpox lesions while it was not detected in samples of unrelated diseases such as cowpox, Marek's disease or infectious laryngotracheitis. Some macroscopically normal skin samples from vaccinated and non-vaccinated birds also produced PCR-positive results, corroborating previous studies on the possibility that a latent or chronic form of fowlpox occurs. Fowlpox virus DNA was consistently detected from DSCC skin lesions, and this finding is discussed.