Intraspecies variation of Brugia spp. in cat reservoirs using complete ITS sequences.

The internal transcribed spacer (ITS) region was used to study the intraspecies variation of Brugia spp. in cat reservoirs. Blood specimens from seven naturally infected cats were collected from two different geographical brugian-endemic areas in Thailand. The DNAPAR tree of these Brugia spp. was constructed using a maximum likelihood approach based on ITS nucleotide sequences and was compared to those of Brugia malayi, Brugia pahangi, and Dirofilaria immitis that were previously reported in GenBank. The phylogenetic trees inferred from ITS1, ITS2, and complete ITS sequences indicated that B. malayi and B. pahangi were separated into two clades, and subgroups were generated within each clade. The data revealed that ITS2 sequences were less informative than ITS1 for studying intraspecies variation of Brugia spp. Our results are primary data for intraspecies variation of B. malayi and B. pahangi in cat reservoirs. The information could be applicable for studying the molecular epidemiology and the dynamic nature of the parasites.