Cytological diagnosis of filarial infection in an endemic area where screening and prophylaxis is in place

Abstract

Filariasis has a worldwide distribution. However, the disease is often overlooked or misdiagnosed because of its unusual presentations and there may be false-negative results in endemic areas. This study was carried out to assess the role of cytology in the demonstration of filarial parasites in an area where screening and prophylaxis are in place. This study was carried out in Wardha district in central India, which is endemic for filarial infection. A total of 9182 smears of cases undergoing cytological evaluation were routinely screened at the time of reporting for the presence of adult filarial worm, microfilarial larvae or their fertilized and unfertilized eggs, irrespective of their original clinical diagnosis. Microfilariae were found incidentally in fine needle aspiration (FNA) smears of patients presenting with other clinical conditions. Smears of seven cases were found to be positive for microfilaria. Four cases presented with subcutaneous nodules in the upper arm, two cases were seen incidentally in axillary lymph node aspirates and microfilariae were found in the pleural fluid in one case. Another case was suspected to have breast cancer, but aspirates from the axillary area showed lymphatic obstruction considered to be due to filariasis. FNA cytology is an inexpensive, simple and easy procedure for detecting microfilariae. Detection of microfilariae may not be common even in endemic areas as screening and prophylaxis is routinely performed, and patients may show atypical presentations such as subcutaneous nodules. We believe that careful screening of FNAs, especially those from subcutaneous swellings, as well as serous fluids, is very important in a filariasis-endemic zone.