[Ecology of leishmaniasis in southern France. 9. Sampling methods in the study and analysis of canine enzootic leishmaniasis].

An account is given of the fundamental methods used on an investigation of the canine enzootic of leshmaniasis in the Cévennes. The objective was to determine the relationship between the prevalence of infection on dogs and the density of the sandfly vector. The basis of the work was a phyto-ecological map of the two parameters. The results are of epidemiological interest as a logical approach which enable comparisons to be made between ecologically homogeneous sectors or strata. In each stratum the methods were carried out in two steps: the rural parishes were designated as statistical units, and were then examined for clusters composed of the dogs of each parish. Strata of small size were more exhaustively examined than the largest. The clustering techniques clearly revealed a heterogeneity in the distribution of canine leishmaniasis and villages in which non infections were found, were next to others where dogs were infected. The development of the enzootic was seen to be by an increase in the number of microfoci, rather than by a spread of the existing foxi. Finally the methods revealed a gradient in the morbidity of dogs from the cost to the highest points of the mountainrange. This gradient was strongly linked to the distribution and density of the vector, Phlebotomus ariasi.