Subcutaneous dirofilariasis caused by Dirofilaria (Nochtiella) repens in Sri Lanka: A potential risk of transmitting human dirofilariasis

OBJECTIVE Dirofilariasis is a parasitic infection caused by filarial nematodes belonging to the genus Dirofilaria. Human dirofilariasis due to Dirofilaria repens has been widely reported from European countries. Sri Lanka is the most affected country in Asia with an infection rate of almost 60% in dog population. However, human infection of D. repens remains undiagnosed and many of the cases are not scientifically documented. Therefore, the objective of the present investigation is to document the presence of dirofilariasis infections in humans. METHOD A 1 year and 10 months old boy from Ragama, Gampaha District, Western Province of Sri Lanka, was presented to a private hospital with a painless, non-pruritic and ill-defined subcutaneous nodule on his right hypochondrial region of the anterior abdominal wall for 1 week. On examination, there was a non-tender swelling measuring 2 cm × 2 cm in the anterior abdominal wall, with surrounding mild redness. The patient was referred for ultrasound confirmation. RESULTS The ultrasound scan revealed a hypoechoic nodular lesion measuring 11 mm × 6 mm in the anterior abdominal wall. Parasitological examination on the excised nodule confirmed the presence of D. repens measuring 10.5 cm in length having characteristic cuticle with longitudinal ridges. CONCLUSION It is essential to record the human infections and increase the awareness about this infection, diagnostic tests and vector controlling measures, in order to reduce the disease prevalence through suppressing vector densities, proper diagnosis and patient care.