Epidemiologic aspects of American visceral leishmaniasis in an endemic focus in Eastern Venezuela.

Abstract

Abstract. An endemic focus of American visceral leishmaniasis (AVL) in eastern Venezuela has been evaluated in terms of patients (n ϭ 48), immunologic reactivity to Leishmania in household contacts (n ϭ 187) and neighborhood controls (n ϭ 170), detection of Leishmania (L. donovani complex) in dogs and wild animals by the polymerase chain reaction (PCR) and characteristics of the sandfly population. The male:female ratio of patients was 1.18:1; 89.6% were Յ12 years old. Serologic reactivity was significantly higher in household contacts than in controls (P ϭ 0.0008), as was the size of leishmanin reactions in contacts Յ10 years of age (P ϭ 0.0141). Leishmania donovani complex-specific PCRs were positive in dogs, an opossum (Didelphis marsupialis), and a black rat (Rattus rattus). Lutzomyia longipalpis and Lu. evansi, both implicated in the transmission of AVL, were identified among the 386 sand flies examined. These observations provide the bases for an active control program as well as further studies of reservoirs and vector-host relationships in this area.American visceral leishmaniasis (AVL) is caused by protozoa of the Leishmania donovani complex and is endemic throughout much of Central and South America. The causative agent in the Americas is considered to be L. chagasi sensu lato. Investigations in Brazil have shown that infection by L. chagasi is characterized by a spectrum of responses, including asymptomatic subclinical infections; relatively prolonged mild infection that may progress to classical AVL or heal spontaneously and severe classical visceral leishmaniasis.

Visceral leishmaniasis in Brazil: revisiting paradigms of epidemiology and control

“…The opossum Didelphis albiventris was found naturally infected by L. infantum in Brazil 44,45 , as well as D. marsupialis in Colombia 13,47 and Venezuela 52 . In Barra de Guaratiba, Rio de Janeiro State, the distance of the house from the forest border, its altitude and the presence of D. marsupialis in the backyard were found to be predictor factors for L. infantum infection in dogs 11 .…”

“…There are some records of natural infection in both domestic and wild rodents. In Italy, the common domestic rat Rattus rattus is strongly suspected as a secondary reservoir of L. infantum 48 and there is a record of L. chagasi infection in this same rodent in Venezuela 52 . Records of natural infection were also verified in the spiny rat Proechimys canicollis in Colombia 13 .…”

Serologic evidence of Leishmania infection in free-ranging wild and domestic canids around a Brazilian National Park

“…The domestic dog is an important reservoir and is responsible for the endemic and epidemic nature of the disease (Silva et al 2001, Courtenay et al 2002. Other mammals are natural reservoirs, such as marsupials, rodents (Zulueta et al 1999), the crab-eating fox C. thous (Lainson et al 1969, Courtenay et al 1996, Silva et al 2000. Crab-eating foxes are commonly infected but rarely infectious or symptomatic, although there are reports of individuals with clinical signs of the disease, which showed spontaneous recovery after showing symptoms (Courtenay et al 2002).…”

<i>Leishmania</i> in Marsupials—An Overview of Infection Records in the Americas and Australia

“…In the second study in Venezuela, Zulueta et al [34] studied aspects of the epidemiology of visceral leishmaniasis in an endemic focus in eastern Venezuela.…”