Exposure, infection and immune responses to Schistosoma haematobium in young children
Behavioural, parasitological and immunological data were obtained from 48 children up to 6 years old, resident in a Schistosoma haematobium endemic area in Zimbabwe. The children averaged more than 1 contact with infective water bodies every 3 days and all showed immunological evidence of exposure (an anti-cercarial and/or anti-egg antibody response). IgM was the dominant isotype and appeared in the youngest children, followed by IgA, IgE and IgG3. However, only 38 children showed evidence of infection (an anti-egg response or eggs in urine) and only 14 were excreting eggs. The best estimates from these data are that less than 1 in 100 contacts result in infection and less than 1 in 1000 result in egg output. This suggests that there may be substantial attrition of invading cercaria even in naïve individuals.(Received May 8 1999)
(Revised July 1 1999)
(Accepted July 15 1999)
Key Words: antibody; cercaria; epidemiology; schistosomiasis; water contact; Zimbabwe.
c1 Corresponding author: Centre for Veterinary Tropical Medicine, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, Scotland. Tel/Fax: +0131 6506264. E-mail: email@example.com