Seroepidemiology of human hydatidosis: use of dried blood samples on filter paper

Programmes for the control of hydatidosis caused by Echinococcus granulosus in Argentina use an enzyme immunoassay (EIA) as a screening test for population surveys aimed at detecting asymptomatic patients. Persons thus selected are referred to health centres for the arc 5 double diffusion test and imaging techniques. One of the most costly procedures of these surveys is the collection of blood samples under field conditions; the possibility of collecting dry blood samples on filter paper was therefore investigated. In a survey of 497 rural inhabitants of an endemic area, the same number of hydatidosis cases (22) were identified by EIA using (i) serum samples and (ii) capillary blood samples obtained by finger prick and collected on filter paper. The latter system was both simpler and cheaper.