Molecular typing reveals the co-existence of two transmission cycles of American cutaneous leishmaniasis in the Andean Region of Venezuela with Lutzomyia migonei as the vector

BACKGROUND The transmission routes for American cutaneous leishmaniasis (ACL) are in flux, so studies examining its transmission in humans, mammalian hosts, and sand fly vectors are urgently needed. OBJECTIVES The aim of this work was understand the epidemiological cycles of Leishmania spp., which causes ACL in the Andean Region of Venezuela, by identifying the Leishmania and the sand fly species involved in human and dog infections. METHODS Thirty-one biopsies from patients in Mérida and Táchira states with suspected ACL were studied by both parasitological tests (cultures and hamster inoculation) and a molecular test [Internal transcribed spacer 1 (ITS1) nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)]. We also conducted a survey to detect Leishmania infection in dogs (Immunifluorescence antibody test and ITS1 nested PCR-RFLP) and sand flies (ITS1 nested PCR-RFLP) from El Carrizal, a highly endemic focus of ACL in Venezuela. FINDINGS Three different Leishmania species were identified in the clinical samples from humans (Leishmania braziliensis, L. guyanensis, and L. mexicana) and dogs (L. guyanensis and L. mexicana). The predominant sand fly species found were those from the Verrucarum group (infected with L. mexicana) and Lutzomyia migonei (infected with L. guyanensis and L. mexicana). MAIN CONCLUSIONS We show that Lu. migonei may be the putative vector in two ACL epidemiological cycles, involving L. guyanensis and L. mexicana. We also report for the first time the presence of L. guyanensis in domestic animals.

Isolation and molecular identification of Leishmania chagasi from a bat (Carollia perspicillata) in northeastern Venezuela

This report describes the isolation of a Leishmania chagasi strain from a bat (Carollia perspicillata), and its identification using biological methods and molecular characterization. The parasites were isolated in an artificial culture medium from a blood sample extracted from a bat heart. The isolate was then inoculated into the footpads of Balb/c mice, which subsequently developed a typical nodular leishmanial lesion; the parasites were confirmed as Leishmania by smear and histopathology. Molecular characterization of the parasites was performed by polymerase chain reaction with species-specific primers, kDNA restriction pattern following Hae III endonuclease digestion and dot blot hybridization using a kDNA probe. This report demonstrates that bats can be hosts for L. chagasi species and suggests the need for studies to determine whether they may be involved in foci of visceral leishmaniasis.

Trypanosoma (Herpetosoma) lewisi in Rattus spp from La Matica, Lara State, Venezuela and the possible relationship with zoonotic diseases

During a study carried out searching reservoir vertebrates for Leishmania spp in the area of La Matica, Lara State, Venezuela from March 1997 to October 1998, 40 specimens of Rattus spp were captured. Blood was extracted from all of them by means of cardiac puncture. Fresh blood and blood smears stained with Giemsa were examined. Of the 40 specimens studied, 22 (55 por ciento) resulted positive for the presence of Trypanosoma lewisi in blood. 63.15 por ciento of the infected animals were males (12/19), and 47.62 por ciento (10/21) females. By age, adult animals were infected in 62.96 por ciento of the cases (17/27) while young specimens were infected in 38.46 por ciento (5/13). The differences were not statistically significant. Regarding the period of capture almost all the individuals were captured during the raining season; a positive correlation between the average of the monthly rain and the number of individual captured was observed. Finally, we suggest the possible increase of the susceptibility of Rattus spp infected with T. lewisi to the infection by other species of the family Trypanosomatidae of public health importance