ObjectiveTo estimate the total dog and cat population with owners in order to enable better planning of the control actions against diseases involving these animals. MethodsThe study was carried out in the non-metropolitan regions of the State of São Paulo, Brazil, from May to December 2002. Forty-one municipalities and 100 census tracts were surveyed. These were selected by probabilistic stratified cluster sampling in two stages. The strata were formed by grouping the municipalities according to their populations and living conditions. The Pasteur São Paulo Technique was used to obtain data on the canine population. This technique was developed to estimate and classify dogs according to their degree of dependence and restriction. Results Almost 53% of the 20,958 households visited owned a dog, and the average was 1.6 dogs per household. A total of 4,624 cats were found, concentrated in 12.6% of the households. The results indicate a dog/inhabitant ratio of 1:4.0 and a cat/inhabitant ratio of 1:16.4. ConclusionsThe animal/inhabitant ratios were much higher than expected. Incorporation of these ratios into evaluations of the vaccination campaign against rabies has revealed more realistic coverage patterns, thus leading to renewed discussion of the vaccination targets for municipalities. An association was observed between the size of the municipality or its inhabitant's living conditions and the level of restrictions on dogs.

This paper describes a technique developed by the Pasteur Institute in São Paulo, Brazil, for counting and classifying a canine population according to levels of dependency and confinement. First, a household survey was performed to identify dogs with owners and their degree of restriction. Different-colored collars were given to totally and partially restricted dogs. Dogs cared for by individuals who did not consider themselves the owners received collars of a third color. After the survey, surveyors counted and recorded dogs on the streets according to the color of their collars. Absence of collars identified dogs without owners. Surveyors were positioned at predetermined sites, an average of 50 meters apart. Counting time lasted 30 seconds and was repeated every 10 to 15 minutes for one hour, with starting and finishing times signaled by blasts on a whistle. The technique was used in the city of Serra Azul, São Paulo, Brazil, by 13- to 17-year-olds after a one-day training program. A total of 498 dogs were recorded in two census tracts, 5% of which were classified as without owners and unrestricted.

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