Capture-recapture to estimate the number of street children in a city in Brazil.

BACKGROUND Street children are an increasing problem in Latin America. It is however difficult to estimate the number of children in the street as this is a highly mobile population. AIMS To estimate the number of street children in Aracaju, northeast Brazil, and describe the characteristics of this population. METHODS Three independent lists of street children were constructed from a non-governmental organisation and cross-sectional surveys. The number of street children was estimated using the capture-recapture method. The characteristics of the children were recorded during the surveys. RESULTS The estimated number of street children was 1456. The estimated number of street children before these surveys was 526, although non-official estimates suggested that there was a much larger population. Most street children are male, maintain contact with their families, and are attending school. Children contribute to the family budget a weekly average of R21.2 dollars (4.25 pounds sterling, 6.0 euros, US7.5 dollars) for boys and R17.7 dollars(3.55 pounds sterling, 5.0 euros, US6.3 dollars) for girls. CONCLUSION Street children of Aracaju have similar characteristics to street children from other cities in Brazil. The capture-recapture method could be a useful method to estimate the size of this highly mobile population. The major advantage of the method is its reproducibility, which makes it more acceptable than estimates from interested parties.