Isoenzymatic analysis of 712 strains of Leishmania infantum in the south of France and relationship of enzymatic polymorphism to clinical and epidemiological features

Abstract

In the south of France, leishmaniasis due to Leishmania infantum occurs in the following five foci of endemicity (from west to east): Pyrénées-Orientales, Cévennes, Provence, Côte d'Azur, and Corsica. Between 1981 and 2002, 712 Leishmania strains obtained from humans, dogs, cats, and sand flies were studied by isoenzyme analysis. In total, seven zymodemes were identified: MON-1, MON-11, MON-24, MON-29, MON-33, MON-34, and MON-108. The Pyrénées-Orientales focus is characterized by a predominance of human cutaneous leishmaniasis and a high enzymatic polymorphism (five zymodemes). In the other foci, where human visceral leishmaniasis is predominant, only two zymodemes are present. L. infantum MON-1 is the parasite most frequently found, in patients both with and without concomitant human immunodeficiency virus infection. MON-1 is the only zymodeme present in dogs, which act as the reservoir host in all of the foci. In Cévennes, where the complete life cycle of zymodeme MON-1 has been identified, Phlebotomus perniciosus and Phlebotomus ariasi are vectors. The enzymatic polymorphism is compared to that of neighboring countries (Spain and Italy). In Pyrénées-Orientales, small variant zymodemes with electromorphs of heterozygote-like and homozygotic patterns can be explained by different genetic hypotheses.

FIG. 1.

Geographical locations of the leishmaniasis foci of southern France. 1, Pyrénées-Orientales; 2, Cévennes; 3, Provence; 4, Côte d'Azur; 5, Corsica. The Mediterranean climate extension is in white. For Corsica, the localities of origin of the strains are shown as dots, due to the small sample size.