Sequence Analysis of VP2 Gene of the Parvoviruses Isolated from Fecal Samples of Domestic Cats in Tehran, Iran

Abstract

Panleukopenia is a viral enteritis of high mortality rate in Feline population. It is caused by a small single-stranded DNA virus, belonging to the Family Parvoviridae, called Feline Panleukopenia Virus (FPV). Parvoviruses are capable of adapting to new hosts and can simply mutate like RNA viruses, resulting in the emergence of different strains with antigenic changes. Unlike the original Canine Parvovirus (CPV) type 2, the antigenic variants (CPV-2a, CPV-2b, CPV-2c) earned the ability to replicate in cat hosts either with clinical signs or without any symptoms. Cats may be able to shed Parvoviruses for a long time and can serve as an important reservoir. Co-infection with FPV and CPV-2 variants has been also reported. These characteristics make the cat an important host for Parvoviruses. Since no molecular study has reported on Parvoviruses infected cats in Iran, a decision was made to study these strains of Parvovirus. Twenty-eight fecal samples were collected from kittens under 6 months of age, both male and female and different breeds which had leukemia. PCR was performed on each sample and 26 samples tested positive for Parvoviruses. Randomly, the PCR products of eight samples were sequenced and their phylogenetic tree was generated. Analysis of the results revealed that all eight samples are FPV and it appears that FPV is more clonal than the CPV-2 variants in Iran. Amino acid residue 232 from the VP2 gene of FPVs has been changed from isoleucine to valine, which has only been reported in CPV-2 and its variants. It seems that some FPVs of Iran are changing to the CPV-2 variants. Hence, it is expected that in the future, the CPV-2 variants will be observed in cats.