Microfilaria in human subcutaneous dirofilariasis: a case report.

Human subcutaneous dirofilariasis, a rare zoonosis is being increasingly reported from various parts of the world. Most of the reported cases have lesions in and around the eye. The adult female dirofilariae release microfilaria into the definitive host's blood. Various mosquitoes that serve as intermediate hosts such as Culex, Aedes and Anopheles take up the microfilariae (mf-L1) while feeding on an infected host. Microfilariae develop in the mosquitoes. The transmission to dogs or other hosts including humans occurs through mosquito bite during subsequent blood meal. Humans may be infected as aberrant (accidental) hosts, mainly by D. repens and D. immitis. D. repens usually resides subcutaneously, while D. immitis frequently ends up in the human lung. In human infections usually just one larva develops, which does not reach sexual maturity. In India, almost all reported cases of dirofilariasis in humans have involvement of face in the form of ocular dirofilariasis with a few reports on subcutaneous dirofilariasis. We report a case of human subcutaneous dirofilariasis, from western India, involving leg and showing microfilaria in tissue indicating presence of gravid female dirofilaria (sexual maturity). To the best of our knowledge, it is among rare cases of subcutaneous dirofilariasis wherein microfilariae have developed in human host.