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

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 spatio-temporal 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 visceral leishmaniasis in Araçatuba, state of São Paulo, Brazil, and its relationship with characteristics of dogs and their owners: a cross-sectional and spatial analysis using a geostatistical approach.

BACKGROUND: The incidence of visceral leishmaniasis (VL), one of the most important neglected diseases worldwide, is increasing in Brazil. The objectives of this study were to determine the canine VL (CanL) seroprevalence in an urban area of Araçatuba municipality and to evaluate its relationship with the characteristics of dogs and their owners. RESULTS: The CanL seroprevalence in the study area was 0.081 (95% credible interval [CI]: 0.068-0.096). The following covariates/categories were positively associated with the occurrence of a seropositive dog: more than 10 dogs that had lived in the house (odds ratio [OR] = 2.36; 95% CI: 1.03-5.43) (baseline: 0-10 dogs); house with dogs that previously died of VL (OR = 4.85; 95% CI: 2.65-8.86) or died of causes other than old age (OR = 2.26; 95% CI: 1.12-4.46) (baseline: natural or no deaths); dogs that spent the day in a sheltered backyard (OR = 2.14; 95% CI: 1.05-4.40); dogs that spent the day in an unsheltered backyard or the street (OR = 2.67; 95% CI: 1.28-5.57) (baseline: inside home). Spatial dependence among observations occurred within about 45.7 m. CONCLUSIONS: The number of dogs that had lived in the house, previous deaths by VL or other cause, and the place the dog stayed during the day were associated with the occurrence of a VL seropositive dog. The short-distance spatial dependence could be related to the vector characteristics, producing a local neighbourhood VL transmission pattern. The geostatistical approach in a Bayesian context using integrated nested Laplace approximation (INLA) allowed to identify the covariates associated with VL, including its spatially dependent transmission pattern.

Influence of serum progesterone levels on the inflammatory response of female dogs with visceral leishmaniosis.

The aim of this study was to evaluate the histopathological changes to the mammary gland that occur in female dogs with visceral leishmaniosis and to correlate the findings with the parasite load, inflammatory cell profile in mammary tissue and serum progesterone levels. For this, 20 adult female dogs that were naturally infected with Leishmania infantum, not spayed, not pregnant and free from mammary tumors were used. They were divided into two groups: G1 (n = 9) with high serum progesterone levels and G2 (n = 11) with low serum progesterone levels. The parasite load and the immunophenotype of leukocytes infiltrated into the mammary tissue (CD3, CD4, CD8 and MCA874) were evaluated using the immunohistochemical technique. In the mammary gland, chronic inflammatory infiltrate was mainly found in G1, sometimes associated with granulomatous inflammation, higher parasite load and higher density of cells immunolabeled for CD3, CD4, CD8 and MCA874. A significant positive correlation (p < 0.05) was observed between the parasite load and the immunolabeled leukocytes. The influence of the serum progesterone level in the mammary gland of infected female dogs can contribute to the maintenance of an immunosuppressive cell profile and favor the persistence of the parasite in this site.

Human visceral leishmaniasis and relationship with vector and canine control measures.

OBJECTIVE: Estimate the coverage of control measures of visceral leishmaniasis and relate them with the occurrence of human visceral leishmaniasis in endemic urban area. METHODS: Cases of human and canine visceral leishmaniasis were considered as study population and evaluated by a serological survey conducted in Araçatuba, state São Paulo, from 2007 to 2015. The cases of human visceral leishmaniasis were geocoded by the address of the patients and the canine disease by the address of the dogs' owners. The coverage of serological survey, euthanasia, and insecticide spraying was calculated, as well as the canine seroprevalence and the incidence rates of human visceral leishmaniasis. The relationship between human visceral leishmaniasis and control measures was evaluated, as well as the seroprevalence by comparing maps and by linear regression. The relationship between the canine and the human disease was also evaluated by the Ripley's K function. RESULTS: The incidence rates of human visceral leishmaniasis showed a period of decline (2007 to 2009) and a period of stability (2010 to 2015), a behavior similar to that of canine seroprevalence. In general, the coverage of control measures was low, and the non-association with the incidence of human visceral leishmaniasis can be a result of the period analyzed and of the small number of analyzed units (sectors of the Superintendence for the Control of Endemic Diseases). The distribution of human cases showed spatial dependence with the distribution of seropositive dogs from 2007 to 2009. CONCLUSIONS: This study reaffirmed the relationship between the occurrence of the disease in humans and dogs, it verified a decrease in the rates of visceral leishmaniasis in Araçatuba over time, even at low coverage of control activities. However, further studies are needed to determine if factors beyond monitoring and control measures are involved in the reduction of incidences.

A PLAG1 mutation contributed to stature recovery in modern cattle.

The recent evolution of cattle is marked by fluctuations in body size. Height in the Bos taurus lineage was reduced by a factor of ~1.5 from the Neolithic to the Middle Ages, and increased again only during the Early Modern Ages. Using haplotype analysis, we found evidence that the bovine PLAG1 mutation (Q) with major effects on body size, weight and reproduction is a >1,000 years old derived allele that increased rapidly in frequency in Northwestern European B. taurus between the 16th and 18th centuries. Towards the 19th and 20th centuries, Q was introgressed into non-European B. taurus and Bos indicus breeds. These data implicate a major role of Q in recent changes in body size in modern cattle, and represent one of the first examples of a genomic sweep in livestock that was driven by selection on a complex trait.

Human visceral leishmaniasis and relationship with vector and canine control measures / Leishmaniose visceral em humanos e relação com medidas de controle vetorial e canino

ABSTRACT OBJECTIVE Estimate the coverage of control measures of visceral leishmaniasis and relate them with the occurrence of human visceral leishmaniasis in endemic urban area. METHODS Cases of human and canine visceral leishmaniasis were considered as study population and evaluated by a serological survey conducted in Araçatuba, state São Paulo, from 2007 to 2015. The cases of human visceral leishmaniasis were geocoded by the address of the patients and the canine disease by the address of the dogs' owners. The coverage of serological survey, euthanasia, and insecticide spraying was calculated, as well as the canine seroprevalence and the incidence rates of human visceral leishmaniasis. The relationship between human visceral leishmaniasis and control measures was evaluated, as well as the seroprevalence by comparing maps and by linear regression. The relationship between the canine and the human disease was also evaluated by the Ripley's K function. RESULTS The incidence rates of human visceral leishmaniasis showed a period of decline (2007 to 2009) and a period of stability (2010 to 2015), a behavior similar to that of canine seroprevalence. In general, the coverage of control measures was low, and the non-association with the incidence of human visceral leishmaniasis can be a result of the period analyzed and of the small number of analyzed units (sectors of the Superintendence for the Control of Endemic Diseases). The distribution of human cases showed spatial dependence with the distribution of seropositive dogs from 2007 to 2009. CONCLUSIONS This study reaffirmed the relationship between the occurrence of the disease in humans and dogs, it verified a decrease in the rates of visceral leishmaniasis in Araçatuba over time, even at low coverage of control activities. However, further studies are needed to determine if factors beyond monitoring and control measures are involved in the reduction of incidences.

RESUMO OBJETIVO Estimar a cobertura das atividades de controle da leishmaniose visceral e relacioná-las com a ocorrência de leishmaniose visceral em humanos em área urbana endêmica. MÉTODOS Foram considerados como população de estudo os casos de leishmaniose visceral em humanos e em cães avaliados por inquérito sorológico censitário realizado em Araçatuba, SP, de 2007 a 2015. Os casos de leishmaniose visceral em humanos foram geocodificados pelo endereço de residência dos pacientes e, os cães, pelo endereço de residências dos respectivos tutores. Foram calculadas as coberturas do inquérito sorológico, da eutanásia e de borrifação de inseticida, as soroprevalências caninas e as taxas de incidência de leishmaniose visceral em humanos. A relação entre a leishmaniose visceral em humanos e as medidas de controle, bem como a soroprevalência foram avaliadas por comparação de mapas e por meio de regressão linear. A relação entre a doença canina e a humana também foi avaliada por meio da função K de Ripley . RESULTADOS As taxas de incidência de leishmaniose visceral em humanos apresentaram um período de declínio (2007 a 2009) e um período de estabilidade (2010 a 2015), comportamento semelhante ao das soroprevalências caninas. Em geral, a cobertura das medidas de controle foi baixa e a não associação com a incidência de leishmaniose visceral em humanos pode ser consequência do período analisado e do número pequeno de unidades analisadas (setores da Superintendência de Controle de Endemias). A distribuição dos casos humanos apresentou dependência espacial com a distribuição dos cães soropositivos de 2007 a 2009. CONCLUSÕES Este trabalho reafirmou a relação entre a ocorrência da doença no homem e no cão, verificou a diminuição das taxas de leishmaniose visceral em humanos e em cães em Araçatuba ao longo do tempo, mesmo em baixa cobertura das atividades de controle. Entretanto, novos estudos são necessários para averiguar se fatores além das atividades de vigilância e controle estariam envolvidos na diminuição das incidências.