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 results 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.
Woolhouse
M E
ME
Centre for Veterinary Tropical Medicine, University of Edinburgh, Scotland. mark.woolhouse@ed.ac.uk
Mutapi
F
F
Ndhlovu
P D
PD
Chandiwana
S K
SK
Hagan
P
P
D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use; D000909:Antibodies, Helminth / Q000097:blood*; D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth / Q000097:blood; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000469:parasitology; D006801:Humans; D007136:Immunoglobulins / Q000097:blood; D007223:Infant; D016013:Likelihood Functions; D008954:Models, Biological; D010270:Parasite Egg Count; D011223:Praziquantel / Q000627:therapeutic use; D015995:Prevalence; D012548:Schistosoma haematobium / Q000276:immunology*; D012553:Schistosomiasis haematobia / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000652:urine; D014867:Water / Q000469:parasitology*; D015030:Zimbabwe / Q000453:epidemiology
D000871:Anthelmintics; D000909:Antibodies, Helminth; D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth; D007136:Immunoglobulins; D014867:Water; D011223:Praziquantel