The Fsp region from fusion protein gene of canine distemper virus: high variability?

Abstract

The Canine Distemper is one of the main infectious diseases in domestic dogs. The introduction of live attenuated-viral vaccines has helped to maintain the disease under control. However, in the past few decades it has been observed worldwide a rising number of cases even in vaccinated animals. The canine distemper virus lineages circulating in the world have been described based on the hemagglutinin analyses, due to its high degree of genetic variability. Recently, new studies have reported greater variations in the amino acidic sequence of a region in the fusion protein. In order to determine the variability of the field strains in comparison with the vaccines and strains from other lines, in this dissertation the genomic variability of the Fsp region from the canine distemper virus fusion protein gene is analyzed. With this purpose, a chain-reaction of the polymerase with reverse transcription, capable of amplifying this variable region, was implemented and identified through its nucleotide sequence. These sequences were compared with vaccine strains and with field strains of known lineages. Additionally, a phylogenetic tree was built for this variable region. The results of the nucleotides comparison show that the field strains have more homology to the vaccine strain Onderstepoort and according to phylogeny, it would belong to the America 1 lineage.