To quantify the host genetic component of meningococcal disease (MD) susceptibility, the sibling risk ratio (lambdaS) was calculated as the ratio of observed MD cases among 845 siblings of 443 UK Caucasian cases to that expected, calculated from age-calendar year specific rates for England and Wales. Twenty-seven siblings contracted MD compared with an expected 0.89, generating a lambdaS value of 30.
View Article and Find Full Text PDFInt J Epidemiol
December 1994
Background: Cluster sample surveys of health and nutrition in rural areas of developing countries frequently utilize the EPI (Expanded Programme on Immunization) method of selecting households where complete enumeration and systematic or simple random sampling (SRS) is considered impractical. The first household is selected by choosing a random direction from the centre of the community, counting the houses along that route, and picking one at random. Subsequent households are chosen by visiting that house which is nearest to the preceding one.
View Article and Find Full Text PDFBetween January 1987 and February 1988, 4590 homes of children under five years of age were visited in three areas of Kurunegala district, Sri Lanka and data were collected on water related practices. 60% of the population used protected wells, 30% used unprotected sources and 10% used handpumps on boreholes or piped supplies. 90% of households had a source less than 1 km away.
View Article and Find Full Text PDFObjectives: To identify which British residents travelling abroad are at greatest risk of malaria infection, and to determine the efficacy of malaria chemoprophylaxis for preventing P falciparum infections in tropical Africa.
Design: Prospective cohort study (case-base linkage) with routine national surveillance systems. Denominators (base population) were obtained from monitoring a random sample of returning British travellers with the international passenger survey.
A study of morbidity in Schistosoma mansoni infection was made in 593 Sudanese patients seen in a four-year period in Khartoum Civil Hospital. Clinical and laboratory findings were compared in three egg-count groups and in four clinical forms of the infection. Patients were divided into three levels of intensity of infection: light (up to 100 eggs/gram of stool), moderate (101--400 eggs/g) and heavy (more than 400 eggs/g).
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