Canine serological survey and dog culling and its relationship with human visceral leishmaniasis in an endemic urban area

Abstract

Background: Visceral leishmaniasis is an important but neglected disease that is spreading and is highly lethal when left untreated. This study sought to measure the Leishmania infantum seroprevalence in dogs, the coverage of its control activities (identification of the canine reservoir by serological survey, dog culling and insecticide spraying) and to evaluate its relationship with the occurrence of the disease in humans in the municipalities of Araçatuba and Birigui, state of São Paulo, Brazil. Methods: Information from 2006 to 2015 was georeferenced for each municipality and modeling was performed for the two municipalities together. To do this, latent Gaussian Bayesian models with the incorporation of a spatiotemporal structure and Poisson distribution were used. The Besag-York-Mollie models were applied for random spatial effects, as also were autoregressive models of order 1 for random temporal effects. The modeling was performed using the INLA (Integrated Nested Laplace Approximations) deterministic approach, considering both the numbers of cases as well as the coverage paired year by year and lagged at one and two years. Results: Control activity coverage was observed to be generally low. The behavior of the temporal tendency in the human disease presented distinct patterns in the two municipalities, however, in both the tendency was to decline. The canine serological survey presented as a protective factor only in the two-year lag model. Conclusions: The canine serological coverage, even at low intensity, carried out jointly with the culling of the positive dogs, suggested a decreasing effect on the occurrence of the disease in humans, whose effects would be seen two years after it was carried out.

Canine Leishmaniasis in an Endemic Area for Human Leishmaniasis in Nicaragua

“…In this study, canines from a community endemic to human atypical cutaneous leishmaniasis were examined using PCR, which showed a high prevalence of infected dogs (28.89%) as compared to other studies carried out in other endemic areas, such as Venezuela, where only 5.3% of positive dogs were detected [ 21 ]; however, it was lower than that observed in the north of Brazil, one of the countries most affected by this parasitosis, in which they found a prevalence in dogs (54.7%) applying conventional PCR in blood [ 22 ]. This study demonstrates that the transmission of leishmaniasis to humans is high in this area, which reinforces the important role that dogs play in the endemic cycle of leishmaniasis, whose main strategies include timely diagnosis and treatment of human cases, environmental management, chemical control of the vector with residual insecticide sprays, and canine serological surveillance [ 23 ]. Tools to prevent L. infantum infection in dogs include the use of topical insecticides, insecticide-impregnated collars, and vaccinations [ 24 ].…”

Precision Medicine in Control of Visceral Leishmaniasis Caused by L. donovani

“…However, some proteins are upregulated such as Gp63 and PSA, that may alter the parasite and promote accumulation in the skin ( Salotra et al., 2006 ). Parasite strains from Sudan examined by PCR single strand conformation polymorphism did not show correlation with clinical manifestations ( Bermudi et al., 2020 ). VL and PKDL strains clustered in the same branches of the tree examined by multi-locus microsatellite typing (MLMT) or multi-locus sequence typing (MLST) ( Alkhaldy et al., 2020 ; Bolia et al., 2020 ).…”

Canine visceral leishmaniasis: risk factors and spatial analysis in an endemic area of Northeastern Brazil

“…From an epidemiological point of view, these animals are very important, since they may act as sources of infection while remaining unperceived because of their clinical status. Therefore, it is necessary to carry out serological surveys for early detection of these cases and for preventive measures to be adopted ( Rondon et al, 2008 ; Bermudi et al, 2020 ). The univariate analysis revealed that age (> 10 years) was considered to be the sole risk factor ( OR = 0.029).…”

“…However, it is important to note that most infected animals remain asymptomatic, while serving as important reservoirs ( Akhtardanesh et al, 2021 ; Peris et al, 2021 ). Because of the presence of asymptomatic animals in endemic regions, serological surveys are pivotal for understanding the distribution of potential reservoirs in these areas ( Rondon et al, 2008 ; Bermudi et al, 2020 ).…”