Naturally acquired concomitant infections of bancroftian filariasis and human plasmodia in Orissa.

Blood smears collected from fever cases for detection of malaria parasites during daytime showed concomitant infections of Wuchereria bancrofti from 1989 to 1991 in Bisra PHC of district Sundargarh, Orissa. Of the total 51,448 blood smears examined, 18,444 (35.84%) were positive for malaria parasites which comprised 3401 (18.44%) Plasmodium vivax, 14,524 (78.75%) P. falciparum, 156 (0.84%) P. malariae and 363 (1.97%) mixed plasmodial infections. Only 240 (0.46%) cases were positive for W. bancrofti, of which 160 (66.67%) were frank microfilariae (mf) cases, while 80 (33.33%) showed concomitant infections with malaria parasites. Filariasis was less prevalent in lower age-groups. Malaria incidence in people below thirty years was higher compared to older people, on the contrary, mf incidence was more in people above 15 yrs or more age. Microfilariae density was within 1-7 parasites per 10 microliters blood. About 90% mf cases were within the range of 1-4 per 10 microliters blood. Mean malaria parasitaemia in concomitant infection cases was 9574 per microliters blood (median 5955; range 35 to 49,500). Presence of diurnal microfilaraemia needs further investigation.