In order to investigate the possible role of dog fleas in the transmission of trypanosomatids, ectoparasites were removed from 59
dogs testing positive for canine zoonotic visceral leishmaniasis according to the indirect fluorescent antibody test (IFAT). Of the
fleas collected, 4/207 (1.9%) showed the presence of promastigotes in smears stained by Giemsa, whilst 43/144 (29.9%) exhibited
positive polymerase chain reaction (PCR) amplification assays for Leishmania DNA. Fleas (409) from 9 Leishmania chagasi-
infected dogs, each hosting more than 20 fleas per animal, were macerated and administered by peritoneal injection or orally to 36
hamsters. After 6 months, the 30 surviving hamsters were sacrificed and liver and spleen fragments were removed for PCA assay
and to produce imprint smears, whilst blood samples were subjected to IFATassay. Sixteen hamsters tested positive for Leishmania
infection, 14 on the basis of PCR amplification and four by IFATassay (two animals testing positive in both assays). Of the infected
hamsters, 11/16 (68.7%) had been infected peritoneally and 5/16 (31.2%) orally. The imprint smears for all animals were, however,
negative. Since both PCR and IFAT could present cross-reactivity for Leishmania and Leptomonas, the possibility of oral
transmission of L. chagasi by fleas cannot be proven unambiguously even though the hamsters developed infection.
# 2007 Elsevier B.V. All rights reserved.