Isolation and Molecular Biological Characterization of Fowlpox Virus from Specimen of Cutaneous Nodular Lesions from Chickens in Several Regions of Tanzania

Aim: To investigate molecular and evolutionary characteristics of genes of fowlpox virus (FWPV) isolates from chickens in Tanzania.

Study Design: Experimental.

Place and Duration of Study: Faculty of Veterinary Medicine, Sokoine University of Agriculture, Morogoro, Tanzania; between November 2011 and October 2013.

Methodology: Samples of cutaneous nodular lesions were collected from featherless parts of chickens (n = 154) suspected to have fowl pox in 14 regions of Tanzania followed by virus isolation, DNA extraction, polymerase chain reaction (PCR) amplification of the P4b gene, gel electrophoresis of PCR products, purification of PCR products, sequencing of purified PCR products and finally analysis of sequence data using standard procedures.

Results: The disease was confirmed in 12 regions, out of 154 investigated samples 66 (42.86%) were found to contain FWPV, indicating that the 66 chickens from which the samples were collected had fowl pox as a result FWPV infection. Sequence analysis revealed that the Tanzanian FWPV isolates were 99.65 – 100% identical to each other and 99 – 100% identical to several published sequences of FWPV isolates from various countries in different continents of the world, including Europe and Asia. Phylogenetic analysis revealed that all Tanzanian isolates belong to clade A, subclade A1.

Conclusion: Based on the findings of this study it is concluded that currently fowl pox is prevalent in several regions of Tanzania, caused by FWPVs which are genetically and phylogenetically closely related. However, these findings do not rule out the possibility of existence of genetic divergence among FWPVs currently prevalent in Tanzania. In order to rule out or detect genetic divergence (if any) among FWPVs currently prevalent in the country, other studies aimed at investigating molecular and evolutionary characteristics of genes in other genomic regions are highly recommended.