Resumen

NESTOR, Añez et al. Epidemiological study on visceral leishmaniasis in the semiarid region of western Venezuela with special reference to inapparent infections . Bol Mal Salud Amb [online]. 2012, vol.52, n.2, pp.245-256. ISSN 1690-4648.

An epidemiological study on visceral leishmaniasis (VL) in the semiarid region of western Venezuela, where some acute cases have been previously reported, is recorded. A total of 1036 symptomless people's sera samples from 25 villages, and 67 dogs from 8 different localities, were tested by using 3 different serologic methods (DAT, IFAT, ELISA) and the polymerase chain reaction assay (PCR). Serological tests revealed 16.9% and 76.1% seropositive to Leishmania infantum in asymptomatic humans and dogs, respectively. In addition, a PCR assay detected the presence of L. infantumspecific DNA in 17.7% of the symptomless sampled individuals and in 29.9% of the tested dogs. The combined analyses of serologic and molecular findings demonstrate the presence of subclinical or inapparent VL infections in local people from this part of western Venezuela. The observed prevalence of VL in asymptomatic people is by itself a matter of concern from the epidemiological point of view. The present results also serve to call the attention to the presence of infected dogs as a risk factor in the maintenance of L. infantum as a source for infection to humans in the studied semiarid region. A total of 12 sand fly species were identified from 6000 specimens collected in 12 sampled villages, with a predominance of Lu. evansi (66.6%) over Lu. longipalpis (14.9%). In both sand fly species natural infection by L. infantum was detected using a PCR assay. It is concluded that the association among VL infected people, L. infantum-infected dogs and the presence of Lu. evansi, together with the observed poor sanitary and/or nutritional conditions, are risk factors to explain the high endemicity by VL at the semiarid region of western Venezuela.

Palabras clave : Visceral leishmaniasis; epidemiology; semiarid region; Venezuela.

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