Risk factors for Leishmania chagasi infection in an urban area of Minas Gerais State

Abstract

In order to understand the determinants of human infection by Leishmania chagasi in an urban area, a cross-sectional population based study was conducted using molecular and serologic methods to identify infection. Participants were interviewed using a pre-coded questionnaire. Two criteria were tested to identify risk factors: Model 1-including all participants positive in hybridization by Leishmania donovani complex probe; Model 2-including all participants positive for hybridization and at least one serologic test. In Model 1, the variables associated with infection were: ownership of birds, time spent outside house between 6:00-10:00 PM and garbage not collected. In Model 2, the variables associated with infection were: family with knowledge of the vector, garbage not collected, garbage not removed or buried, ownership of birds and eroded areas in the neighborhood. The risk factors identified were associated with household conditions, presence of animals and the likelihood of contact with phlebotomine sandflies. Key-words: Visceral leishmaniasis. Kala-Azar. Leishmania chagasi. Asymptomatic infection. Risk factors. RESUMOCom o objetivo de identificar os determinantes da infecção humana por Leishmania chagasi em uma área urbana, foi realizado um estudo seccional de base populacional utilizando-se métodos moleculares e sorológicos para identificar a infecção. Os participantes foram entrevistados utilizando-se questionário pré-codificado. Dois critérios foram testados para identificar os fatores de risco: Modelo 1-incluindo todos os participantes positivos na hibridização com sonda para o complexo Leishmania donovani; Modelo 2-incluindo todos os participantes positivos na hibridização e em pelo menos um teste sorológico. No Modelo 1, as variáveis associadas à infecção foram: criar pássaros, encontrar-se fora de casa entre 18:00-22:00h e não ter o lixo coletado. No Modelo 2, as variáveis associadas à infecção foram: família conhecer o vetor, não ter o lixo coletado, lixo não removido ou queimado, criar pássaros, proximidade de áreas erodidas. Os fatores de risco identificados foram associados às condições das moradias, presença de animais e probabilidade de contato com flebotomíneos. Palavras-chaves: Leishmaniose visceral. Calazar. Leishmania chagasi. Infecção assintomática. Fatores de risco.

Canine visceral leishmaniasis: seroprevalence and risk factors in Cuiabá, Mato Grosso, Brazil

“…The lack of garbage collection represented a risk factor (OR 4.53) for the occurrence of dog infection in the Barreiro Branco neighborhood when compared to Coxipó do Ouro, where such service is provided. As observed by Moreno et al (2005), the lack of public garbage collection tends to predispose the occurrence of infection by contributing to the proliferation of the L. longipalpis. Although CVL autochthony is known in Cuiabá (ALMEIDA et al, 2010, the maintenance of high levels of seropositive dogs in areas with occurrences of the disease reinforces the importance of epidemiological surveillance, as well as the knowledge of the risk factors associated to the canine infection, as a way to clarify the gaps that may be involved in the maintenance of the transmission cycle.…”

“…The chronic disease is the most severe clinical form of leishmaniasis and a serious problem for Brazilian public health, mainly due to the high prevalence and increased number of cases in humans and dogs in urban and suburban areas of large cities (ARIAS et al, 1996;MORENO et al, 2005;MARZOCHI et al, 2009). CVL urbanization has been associated to migration processes linked to the deterioration of social and economic conditions of the population (ANTONIALLI et al, 2007;HARHAY et al, 2011).…”

Sand flies (Diptera: Psychodidae) in a cerrado area of the Maranhão state, Brazil

“…Chicken rearing is a very common activity among the inhabitants of Maranhão (Dias et al 2003) and the presence of animals in the peridomicile, along with other environmental elements, is thought to be a risk factor for visceral leishmaniasis transmission (Moreno et al 2005). The forest area in which a light trap was set up for capturing sand fl ies presents environmental aspects of gallery forest.…”

Phlebotomine sand flies (Diptera: Psychodidae) in the municipality of Várzea Grande: an area of transmission of visceral leishmaniasis in the state of Mato Grosso, Brazil

“…The risk factors for L. (L.) infantum chagasi infection and the occurrence of human VL cases in urban areas, identified by Moreno et al (2005), are associated with the environment surrounding residences, mainly with the presence of organic matter, domestic animals in peridomiciliary areas and the contact between susceptible hosts and phlebotomine vectors. Dogs are regarded as infective for phlebotomine vectors even when they are asymptomatic.…”