Dirofilaria hongkongensis - A first report of potential zoonotic dirofilariosis infection in dogs from Tamil Nadu.

Dirofilariosisis, is a mosquito borne anthropo-zoonotic disease caused by the filarial nematodes of the genus Dirofilaria. The current paper reports a species of Dirofilaria, which has not been recorded in Tamil Nadu, in addition to differentiating it from the existing species of Dirofilaria spp. through morphological and molecular techniques. Micrometry of the microfilaria detected by Knott's technique as well as in Giemsa stained blood smears revealed that the length was on an average 280 μm to 310 μm whereas the width was 5 to 8 μm. The microfilariae were unsheathed with blunt heads and tapering tails. For molecular confirmation, the blood sample was subjected to genomic DNA isolation. PCR amplification using specific primers for D. hongkongensis was carried out using thermal cycler with the isolated genomic DNA as template. Molecular analyses revealed the band size of about 230 bp which confirmed the presence of D. hongkongensis. Phylogenetic analysis was done using UPGMA and MLM method. Dirofilaria is recognized as a zoonotic entity throughout the world, and dirofilariasis should be considered an emerging zoonosis in southern India. The control of ubiquitous mosquito population is essential to prevent the transmission of microfilaria from animals to arthropods and from arthropods to humans.