RESUMO
The role of Proechimys semispinosus as reservoir of Leishmania (Viannia) panamensis on the Colombian Pacific coast was experimentally evaluated. The susceptibility to L. chagasi also was assessed to determine the utility of this rodent as a model for studying reservoir characteristics in the laboratory. Wild-caught animals were screened for natural trypanosomatid infections, and negative individuals were inoculated intradermally (ID) in the snout or feet with 10(7) promastigotes of L. panamensis. L. chagasi was inoculated intracardially (10(7) promastigotes) or ID in the ear (10(8) promastigotes). PCR-hybridization showed that 15% of 33 spiny rats were naturally infected with L. Viannia sp. Animals experimentally infected with L. panamensis developed non-ulcerated lesions that disappeared by the 7th week post-infection (p.i.) and became more resistant upon reinfection. Infectivity to sand flies was low ((1/2)0-(1/4)8 infected/fed flies) and transient, and both culture and PCR-hybridization showed that L. panamensis was cleared by the 13th week p.i. Animals inoculated with L. chagasi became subclinically infected and were non-infective to sand flies. Transient infectivity to vectors of spiny rats infected with L. panamensis, combined with population characteristics, e.g., abundance, exploitation of degraded habitats and high reproductive rates, could make them epidemiologically suitable reservoirs.
Assuntos
Reservatórios de Doenças , Leishmania/isolamento & purificação , Roedores/parasitologia , Animais , Colômbia , Feminino , Leishmania/imunologia , Leishmania guyanensis/isolamento & purificação , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/transmissão , Masculino , Reação em Cadeia da Polimerase , Roedores/imunologia , Baço/parasitologiaRESUMO
The role of Proechimys semispinosus as reservoir of Leishmania (Viannia) panamensis on the Colombian Pacific coast was experimentally evaluated. The susceptibility to L. chagasi also was assessed to determine the utility of this rodent as a model for studying reservoir characteristics in the laboratory. Wild-caught animals were screened for natural trypanosomatid infections, and negative individuals were inoculated intradermally (ID) in the snout or feet with 10(7) promastigotes of L. panamensis. L. chagasi was inoculated intracardially (10(7) promastigotes) or ID in the ear (10(8) promastigotes). PCR-hybridization showed that 15 percent of 33 spiny rats were naturally infected with L. Viannia sp. Animals experimentally infected with L. panamensis developed non-ulcerated lesions that disappeared by the 7th week post-infection (p.i.) and became more resistant upon reinfection. Infectivity to sand flies was low (1/20-1/48 infected/fed flies) and transient, and both culture and PCR-hybridization showed that L. panamensis was cleared by the 13th week p.i. Animals inoculated with L. chagasi became subclinically infected and were non-infective to sand flies. Transient infectivity to vectors of spiny rats infected with L. panamensis, combined with population characteristics, e.g., abundance, exploitation of degraded habitats and high reproductive rates, could make them epidemiologically suitable reservoirs
Assuntos
Animais , Masculino , Feminino , Reservatórios de Doenças , Leishmania , Roedores , Colômbia , Leishmania , Leishmania guyanensis , Leishmaniose Cutânea , Reação em Cadeia da Polimerase , Roedores , BaçoRESUMO
Polytene chromosomes (n = 108) and morphology (n = 22) of Simulium metallicum Bellardi were described from larvae collected in different localities in Cundinamarca, Colombia, and compared with the standard polytene chromosome banding patterns of S. metallicum A. Polytene chromosomes of S. metallicum from Cundinamarca were characterized by a fixed inversion on the IIL chromosome arm (IIL-22), by 2 sex-linked inversions (IIL-24 and IIL-25), 6 floating inversions, and a heteroband in the IIIS chromosome arm. This taxon was considered to be a cytotype distinct from the 11 members of the S. metallicum complex from Central and South America, and we propose here the name S. metallicum L, following the convention for naming cytotypes in this species complex. There were slight larval morphological differences between S. metallicum from Cundinamarca and S. metallicum A and S. horacioi Okazawa & Onishi (or S. metallicum H).