LEISHMANIA-INFANTUM IS CLONAL IN AIDS PATIENTS TOO - EPIDEMIOLOGIC IMPLICATIONS

Objective: To test, in AIDS patients, a previously proposed hypothesis of clonal population structure in Leishmania infantum, the agent of v isceral leishmaniasis. Design: Forty-three stocks of L. infantum isola ted from AIDS patients in Spain were analysed by multilocus enzyme ele ctrophoresis. Methods: The results were analysed in terms of populatio n genetics according to previously described statistical methods. Depa rtures from panmixia were examined by linkage disequilibrium analysis. Results: As previously shown in HIV-negative patients, classical mani festations of clonality were shown, namely strong linkage disequilibri um, over-representation of genotypes and overall lack of genotype dive rsity. The same dominant clonal genotype (MON1) was recorded in both H IV-positive and HIV-negative patients. Frequency of this dominant geno type was not statistically different in HIV-positive and HIV-negative patients. Conclusions: The parasite population under survey appears to be clonal; parasite genotypes can therefore be equated to natural clo nes, stable in space and time, which can be used as multilocus epidemi ological markers. Nevertheless, additional studies are required to bet ter estimate the long-term stability of these clonal genotypes and the possible interference of gene exchange at an evolutionary scale.