Canine visceral leishmaniasis in Colombia: relationship between clinical and parasitologic status and infectivity for sand flies.

Abstract

Abstract. We studied the reservoir competency of canines with distinct clinical presentations of Leishmania chagasi infection. The parasitologic status of asymptomatic and symptomatic dogs was determined by standard culture methods Infectivity was assessed by multiple xenodiagnoses with Lutzomyia longipalpis, over a period of 2-11 months. Asymptomatic dogs were non-infective (0 of 5) while 2 of 7 oligosymptomatic dogs infected L. longipalpis, transmitting the parasites at low rates (range 0.9-5.2% of engorged flies). Polysymptomatic dogs transmitted L. chagasi more frequently (4 of 8 dogs) and reached higher infection rates (range 5.0-22.5% of engorged flies). The skin of the ear tended to be more infective to sand flies than that of the abdomen. Polymerase chain reaction hybridization (PCR-H) was a sensitive method for detection of L. chagasi, yielding the highest positive rate in serum (16 of 17 dogs) with no distinction between clinical groups. No association between skin positivity by PCR-H and infectivity to sand flies was found. The infectivity of dogs from clinically comparable groups from Colombian and Mediterranean foci differed. This may be a reflection of varied nutritional conditions or vector competency of distinct sand fly species.

Leishmania (Viannia) braziliensis infection in two Colombian dogs: a note on infectivity for sand flies and response to treatment

“…Nevertheless, the observations made on these two dogs contrasted with xenodiagnoses performed on dogs infected with L. infantum in which parasites are readily transmitted to sand flies, including non-natural vector species (20)(21)(22). In our case, the low reservoir competence was emphasized by the negative results obtained with Lutzomyia trapidoi, L. gomezi, and L. youngi, which are proven vectors of cutaneous leishmaniasis (13,15), and have shown to acquire Leishmania at high rates (37-44%) after feeding on laboratory animals experimentally infected with L. Viannia (23; CIDEIM unpublished).…”

“…and establish the reservoir role in Colombian foci of American cutaneous leishmaniasis. Studies in Brazil have shown that the majority of lesions were localized on the ears (63.6% of all lesions detected), and this may have epidemiological implications because in other Leishmania species (L. infantum) we determined that transmission to sand flies was more efficient at this site than in other body areas (21,25).…”

Leishmaniose visceral canina em Maricá, Estado do Rio de Janeiro: relato do primeiro caso autóctone

“…Em áreas urbanas, cães domésticos são considerados os principais reservatórios de Leishmania chagasi e embora a doença possa manifestar-se de maneira bastante variável, o parasitismo da pele constitui uma das características mais importantes, fazendo desse animal um elo no ciclo epidemiológico 13 . A retirada de cães sororreatores das áreas endêmicas, ainda é um assunto polêmico.…”

Presence of Leishmania amastigotes in peritoneal fluid of a dog with leishmaniasis from Alagoas, Northeast Brazil

“…Previous studies concerning the infectivity of dogs naturally parasitized by L. infantum to sandflies showed divergent results 9,16,18 . In general, asymptomatic dogs are either non-infective 18 or modest sources of infection 15 , while symptomatic dogs are often infective 18 .…”

“…In general, asymptomatic dogs are either non-infective 18 or modest sources of infection 15 , while symptomatic dogs are often infective 18 . Indeed, every infected dog must be seen as a potential risk to phlebotomine sandfly infection.…”