Natural infections of Leishmania peruviana in animals in the Peruvian Andes

Abstract

Evidence that domestic dogs may act as reservoir hosts for cutaneous leishmaniasis in the Peruvian Andes is provided by the isolation, for the first time, from naturally infected dogs of parasites identified (by isoenzymes) as Leishmania peruviana. Leishmania parasites were isolated from nasal aspirates or biopsies from 5 (1·8%) of 279 asymptomatic dogs sampled in endemic villages of the Peruvian Andes. In addition, Leishmania (Viannia) infections were identified in 15 (5·4%) of 276 nasal samples by the polymerase chain reaction (PCR) using subgenus-specific primers. Further circumstantial evidence for a reservoir role for dogs comes from the finding of a relatively high dog blood index among the sandfly vectors collected inside houses (29% for Lutzomyia peruensis and 17% for Lu. verrucarum). Possible wild mammal reservoir hosts for Andean cutaneous leishmaniasis were also detected in endemic villages. At least 8 species were identified among the 1266 small mammals trapped. Leishmania parasites were isolated from blood or skin biopsies taken from 2 (2·6%) of 78 Didelphis albiventris and 6 (1·2%) of 511 Phyllotis andinum. Three isolates were identified by isoenzymes as L. peruviana, and the other 5 were identified by PCR as Leishmania (Viannia) species. Leishmania (Viannia) infections were also identified by PCR directly on skin biopsies taken from 2 (2·8%) of 72 D. albiventris, 1 (0·2%) of 499 P. andinum, and 4 (2·6%) of 153 Akodon sp.