Impact of the dog population and household environment for the maintenance of natural foci of Leishmania infantum transmission to human and animal hosts in endemic areas for visceral leishmaniasis in Sao Paulo state, Brazil

Abstract

When it comes to visceral leishmaniasis (VL) in Brazil, one of the main targets of public health policies of surveillance is the control of domestic canine reservoirs of Leishmania infantum. This paper aims to evaluate the effect of the dog population and household environment for the maintenance of natural foci in the transmission to human and animal hosts in an endemic city for VL, Bauru, in Brazil. We collected 6,578 blood samples of dogs living in 3,916 households from Nov.2019 to Mar.2020 and applied geospatial models to predict the disease risk based on the canine population. We used Kernel density estimation, cluster analysis, geostatistics, and Generalized Additive Models (GAM). To validate our models, we used cross-validation and created a receiver operating characteristic (ROC) curve. We found an overall canine VL (CVL) seroprevalence of 5.6% for the sampled dogs, while for the households, the positivity rate was 8.7%. Odds ratios (OR) for CVL increased progressively according to the number of canines for >2 dogs (OR 2.70); households that already had CVL in the past increased the chances for CVL currently (OR 2.73); and the cases of CVL increase the chances for human VL cases (OR 1.16). Our models were statistically significant and demonstrated a spatial association between canine and human disease cases, mainly in VL foci that remain endemic. Although the Kernel density ratio map had the best performance (AUC = 82), all the models showed high risk in the city’s northwest area. Canine population dynamics must be considered in public policies, and geospatial methods may help target priority areas and planning VL surveillance in low and middle-income countries.

Comparative Study of a Novel Lateral Flow Rapid Test with Conventional Serological Test Systems for the Diagnosis of Canine Leishmaniosis in Croatia and Brazil

“…Although surveys that assess the VL/CanL situation in Brazil are scarce, the expansion of cities into forest areas, the high number of domestic dogs and the adaptability of sandflies are likely to be responsible for the spread of leishmaniasis in northeastern municipalities of Brazil [ 12 , 13 , 14 ]. Thus, dogs have become the main target for disease control [ 15 ]. In Europe, the import of L. infantum into previously non-endemic countries has been known for a long time, but lately, it has become a problem and seems to be a consequence of the increased travelling with dogs into endemic areas and the import of infected puppies and stray dogs from endemic areas [ 16 , 17 , 18 , 19 ].…”

Comparative Study of a Novel Lateral Flow Rapid Test with Conventional Serological Test-Systems for the Diagnosis of Canine Leishmaniosis in Croatia and Brazil

“…Although surveys that assess the VL/CanL situation in Brazil are scarce, the expansion of cities into forest areas, the high number of domestic dogs and the adaptability of sandflies are likely to be responsible for the spread of leishmaniasis in northeastern municipalities of Brazil [12][13][14]. Thus, dogs have become the main target for disease control [15]. In Europe, the import of L. infantum into previously nonendemic countries has been known for a long time, but lately, it has become a problem and seems to be a consequence of the increased travelling with dogs into endemic areas and the import of infected puppies and stray dogs from endemic areas [16][17][18][19].…”

Aspectos epidemiológicos da evolução da Leishmaniose Visceral Canina em Santarém, Pará, Brasil

“…Essa enfermidade é endêmica em vários países, inclusive no Brasil, havendo cerca de 90% dos casos ocorridos nos países da América Latina (Matsumoto et al, 2021). Durante a última década, com destaque para o ano de 2013 em diante, tem ocorrido surto da doença em alguns estados brasileiros como no Rio de Janeiro (RJ), Belo Horizonte (MG), Araçatuba (SP), Santarém (PA), Corumbá (MS), Teresina (PI), Natal (RN), São Luis (MA), Fortaleza (CE), Três Lagoas (MS), Palmas (TO) (Casagrande et al, 2013, Cavalcante et al, 2014, Moura et al, 2015.…”