Susceptibility of Spiny Rats (Proechimys semispinosus) to

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 107 promastigotes of L. panamensis. L. chagasi was inoculated intracardially (107 promastigotes) or ID in the ear (108 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/ 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. Key words: spiny rats- Leishmania- reservoir- experimental infection Spiny rats (Proechimys spp.) are parasitized by a va-riety of Leishmania species, including L. aristidesi and recognized pathogenic species such as L. guyanensis, L. amazonensis, and L. mexicana s.l. Although these ro-dents have been incriminated as natural hosts for patho-genic species in several endemic foci in South America