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Transmission of urinary schistosomiasis in Sukumaland, Tanzania. 1. Snail infection rates and incidence of infection in school children

Published online by Cambridge University Press:  05 June 2009

N. J. S. Lwambo
N. J. S. Lwambo
Affiliation:
National Institute for Medical Research, Mwanza Centre, P.O. Box 1462, Mwanza, Tanzania.
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Abstract

Seasonal density fluctuations of Bulinus nasutus populations with accompanying Schistosoma haematobium infection rates in relation to rainfall and habitat water volumes were studied at Ukiriguru, Mwanza, Tanzania. Alongside the snail investigations, 50 school children initially negative for urinary schistosomiasis were examined regularly to determine seasonal incidence rates for the infection. Of the 17 646 B. nasutus collected in 2 years, 156 (0.88%) were found shedding cercariae. Snail populations fluctuated seasonally as influenced by rainfall through its effects on habitat water volume. Monthly snail infection rates ranged from 0.09% to 3.19% and were highest in February and March, at the time of the short dry period. Monthly incidence of S. haematobium in school children ranged between 2.6% and 12.5%, being highest in April and May. There was a significant linear association between monthly snail infection rates and S. haematobium incidence rates in school children ( in 1983/84) suggesting that the maximum transmission period for urinary schistosomiasis in the area occurs during the short dry period, sometime in February/March so that most of the infections in the community would be detected in April/May.

Keywords

Schistosoma haematobiumBulinus nasutusTanzaniaepidemiologyincidenceinfection rates
Type
Research Papers
Information
Journal of Helminthology , Volume 62 , Issue 3 , September 1988 , pp. 213 - 217
Copyright
Copyright © Cambridge University Press 1988

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