The World Health Organization (WHO) recommends mass treatment of all schoolchildren with the drug praziquantel in areas where the prevalence of urinary schistosomiasis (bilharzia) is greater than 50 percent. But is there any way that children can get treatment in areas where the prevalence is lower than this? For example, in the absence of expensive laboratory tests can children diagnose the illness themselves?

Researchers from the Partnership for Child Development tested a questionnaire that records symptoms of the disease reported by schoolchildren. They found that the majority of children could correctly identify whether or not they had schistosomiasis. This approach could provide a cheap and effective strategy for targeting treatment in Tanzania.

The symptoms of urinary schistosomiasis include lower abdominal pain, bloody urine and pain when urinating. Infections tend to be heaviest among school-age children and this can have harmful consequences for their nutrition, growth and school performance. A highly effective single-dose treatment is available (praziquantel) which is safe and easy to administer. Treating schoolchildren for worm infections is a highly cost-effective public health intervention in the developing world. However, laboratory-based microscopy for eggs in urine samples is expensive and time-consuming.

Public health nurses adminstered a questionnaire to a total of 2356 children in 15 schools in the Tanga region of Tanzania. The questionnaire asked whether children currently had 'kichocho', the Kiswahili name for schistosomiasis, or were passing blood in their urine. They also tested urine samples from the same children for blood and examined them microscopically for worm eggs in order to gauge the accuracy and reliability of the questionnaire results.

The research found that:

• Around three-quarters of children gave a correct positive or negative self-diagnosis and this was independent of the prevalence of infection in the school.
• The rates of false positive and false negative self-diagnosis were three and 22 percent respectively.
• Blood was detected in the urine of over a third of false positive cases suggesting that, although no eggs were seen, infection may have been present.
• Children who gave a false negative answer tended to be lightly infected.
• It was more effective to ask children about infection with kichocho than about blood in their urine.
• Adolescent girls were more likely to give a false negative diagnosis than boys or younger girls.

The implications of this study for schistosomiasis diagnosis and treatment include:

• Children in Tanzania can quite easily detect and identify the symptoms of moderate or heavy schistosomiasis infection.
• The efficiency of self-diagnosis is independent of the prevalence of infection, although this must be verified in other sites and populations.
• Treatment of individual children who report infection may be a good strategy in areas where mass medication is not needed.

Source(s):
‘Self-diagnosis as a possible basis for treating urinary schistosomiasis: a study of schoolchildren in a rural area of the United Republic of Tanzania’ by the Partnership for Child Development, Bulletin of the World Health Organisation 77 (1999) Full document.

Funded by: The Wellcome Trust; UK Medical Research Council

id21 Research Highlight: 18 January 2002

Further Information:
Celia Maier
Partnership for Child Development,
Department of Infectious Disease Epidemiology
Imperial College School of Medicine
St. Mary's Campus
Norfolk Place
London, W2 1PG,
UK

Tel: +44 (0)20 7594 3292/1
Fax: +44 (0)20 7402 2150
Contact the contributor: c.maier@imperial.ac.uk

Partnership for Child Development, Imperial College

Other related links:
The WHO has information on schistosomiasis.

Other resources are available from the TDR website.

Child Health Dialogue is Healthlink Worldwide's newsletter on child health and disease prevention.

UNICEF's State of the World's Children report is now on-line.

Refer to AED for information on child nutrition programmes.