A Survey of Bancroftian Filariasis by Detecting Microfilaria and Circulating Antigenaemia in Biase Cross River State, Nigeria

Abstract

The estimation of filariasis prevalence in Biase Local Government has previously relied upon clinical evaluation and examination of night blood smears. However, night blood smears examination fail to detect the infection in individuals having low parasitaemia and cryptic filarial infection. The present study was undertaken to evaluate the prevalence of filarialsis in nine wards of Biase local government by immunochromatographic test (ICT). Methods : Clinical examination was performed according to WHO criteria to classify filarial disease. Night blood smears collected between 21.00 to 00.00h were examined to detect microfilaria (MF). For estimation of circulating filarial antigen (CFA) by Binax Now filarialsis, 2ml of blood was collected from each individual by venepuncture at any time of the day. Results : A total of 425 participants made up of 260 males and 165 females were examined randomly from the community with particular emphasis on those with suspected cases of infection such as elephantiasis of the leg. The result shows that 56 (13.2 percent) of subjects had microfilaria of wuchereria bancrofti from night samples collected, while 207 (48,7 percent) of the population studied had positive result with ICT cards. There was a statistically significant difference in the prevalence of W. bancrofti microfilaria and circulating filarial antigenaemia by method of detection(X2=11.004, Plt;0.05).We found out that there was no correlation between the two methods of detection of filarial infection (r=0.967, Pgt;0.05). Interpretation and conclusion : The study emphasizes the use of CFA estimation being a more sensitive and specific diagnostic tool for the evaluation of the true prevalence of the disease. The high CFA prevalence in the study area necessitates intervention measures to check its transmission.