Preventing zoonotic canine leishmaniasis in northeastern Brazil: pet attachment and adoption of community Leishmania prevention

Abstract

Visceral leishmaniasis (VL), caused by Leishmania infantum chagasi (L.i. chagasi syn. infantum) in northeastern Brazil, was responsible for 51,000 new VL cases from 1980 to 2003. Household presence of L. infantum-infected dogs is a major risk factor for human infection. Despite culling of dogs based on seropositivity, canine L. infantum seroprevalence remains near 20%, suggesting that dog culling is ineffective for preventing VL spread. We administered a cross-sectional survey to 224 households within 300 m of the homes of VL human patients diagnosed within the last year. The goal was to develop a model for voluntary preventative use based on characteristics and motivations of dog owners. We identified that owner knowledge deficiencies regarding canine transmission of L. infantum associated with increased risk of dog infection (odds ratio [OR] = 3.681, confidence interval [CI] = 1.223, 11.08). Higher owner education was associated with decreased levels of dog seropositivity (OR = 0.40, CI = 0.20, 0.81). Pet attachment (P = 0.036) and perception of risk/disease knowledge (P = 0.040) were significantly associated with willingness to voluntarily purchase canine VL prevention. These results highlight the importance of owner attachment to their pet in implementing reservoir-targeted zoonotic VL prevention.

Figure 1.

Knowledge and risk perception related to the transmission of L. i. chagasi in periurban Brazil. Participants were asked to rate the risk of seven actions or occurrences as complete lack of knowledge (1; e.g., “I don't know”), no risk (2), some risk (3), or high risk (4). The y axis represents the percentage of respondent responses.

Figure 2.

Misperceptions about L. infantum transmission are associated with increased risk for cVL. (A) Percentage responding to “how do people get hVL?” (open-ended question). Responses were categorically sorted into groups (x axis) and are presented as the percentage of total responses. An answer of correct transmission was one indicating that sandfly feeding on infected canines and then on humans was a primary means of hVL (B). Categorical responses from A were compared with SLA ELISA seropositivity by contingency tables and Fisher exact tests for relative risk.

Figure 3.

The precaution adoption model created for canine-focused zoonotic VL control.