Prospects of human malaria and Bancroftian filariasis infections in the Lower Rufiji Basin, Tanzania II. Bancroftian filariasis.

Surveys for human bancroftian filariasis infections were conducted in the Lower Rufiji Basin, Tanzania, before and after the long rains in 1981. A multipurpose water resources development project has been planned in the area. A microfilarial rate of 18.1%, a mean microfilarial count of 80 microfilariae per 100 microliters blood were observed. Generally, males showed higher microfilarial rates than their female counterparts. All microfilariae were identified as Wuchereria bancrofti. A prevalence rate of 0.4% was recorded for leg elephantiasis. None of the cases were seen in individuals below 20 years of age. Only two cases of elephantiasis of the breasts were seen and no cases of elephantiasis of the arms were encountered. Rates for scrotal elephantiasis and hydrocoeles in males were 8.7% and 11.5% respectively, and enlargement of the inguinal and/or femoral lymph glands was common and the onset of this manifestation is early.