Zoonotic sporotrichosis in humans and domestic cats: Profile of notifications and spatio-temporal distribution in Southeastern Brazil between 2017 and 2023.

The research addresses zoonotic sporotrichosis in Brazil, particularly caused by Sporothrix brasiliensis, highlighting its epidemiological severity. Transmission occurs through contact with sick animals, especially felines, and diagnosis in humans is challenging due to the low fungal load in the lesions. The study analyzed data from Information System for Notifiable Diseases (SINAN) and Zoonosis Surveillance Unit (UVZ) from January 2017 to March 2023, carried out in Contagem, Minas Gerais. Geospatial tools and statistical analysis revealed a significant increase in cases, peaking in 2021 for felines and 2022 for humans. The geospatial analysis highlighted areas of higher incidence, suggesting a correlation between human and feline populations. The research contributes to the understanding of sporotrichosis in Contagem, emphasizing the importance of integrated approaches for surveillance and control strategies, aiming to mitigate impacts on the local community.

Temporal trends of dengue cases and deaths from 2007 to 2020 in Belo Horizonte, Brazil.

Dengue, a disease with multifactorial determinants, is linked to population susceptibility to circulating viruses and the extent of vector infestation. This study aimed to analyze the temporal trends of dengue cases and deaths in Belo Horizonte, Minas Gerais, Brazil, from 2007 to 2020. Data from the Notifiable Diseases Information System (Sinan) were utilized for the investigation. To assess the disease's progression over the study period and predict its future incidence, time series analyses were conducted using a generalized additive model (GAM) and a seasonal autoregressive integrated moving average (SARIMA) model. Over the study period, a total of 463,566 dengue cases and 125 deaths were reported. Notably, there was an increase in severe cases and deaths, marking hyperendemics characterized by simultaneous virus circulation (79.17% in 2016-50% in 2019). The generalized additive model revealed a non-linear pattern with epidemic peaks in 2010, 2013, 2016, and 2019, indicating an explosive pattern of dengue incidence. The SARIMA (3,1,1) (0,0,0)12 model was validated for each year (2015 to 2019). Comparing the actual and predicted numbers of dengue cases, the model demonstrated its effectiveness for predicting cases in the municipality. The rising number of dengue cases emphasizes the importance of vector surveillance and control. Enhanced models and predictions by local health services will aid in anticipating necessary control measures to combat future epidemics.

Determining the relationship between dengue and vulnerability in a Brazilian city: a spatial modeling analysis.

Dengue is a viral infection transmitted by the Aedes aegypti mosquito. This study aimed to assess the distribution of cases and deaths from dengue and severe dengue, and its relationship with social vulnerability in Belo Horizonte, State of Minas Gerais, Brazil, from 2010 to 2018. The incidence and lethality rates of dengue and their relationship with sex, age, education, skin color, and social vulnerability were studied using chi-square tests, Ordinary Least Squares (OLS), and Geographically Weighted Regression (GWR) analyses. The number of cases of dengue in Belo Horizonte during the study period was 324,044 dengue cases, with 1,334 cases of severe dengue and 88 deaths. During the past few decades, the incidence rate of both dengue and severe cases varied, with an average incidence rate of respectively 1515.5 and 6.2/100,000 inhabitants. The increase in dengue cases was directly related to areas with higher social vulnerability areas and more working-age people. Also, the disease is more severe in people self-declared as black, elderly, and male. The findings of this study might provide relevant information for health services in the organization of control and prevention policies for this problem, emphasizing the most vulnerable urban areas and categories.

Emergence of zoonotic sporotrichosis due to Sporothrix brasiliensis in Minas Gerais, Brazil: A molecular approach to the current animal disease.

Sporotrichosis is a neglected fungal zoonosis with significant impacts on human and animal health. Accurate diagnosis, treatment, and understanding of the transmission dynamics of Sporothrix species are essential for mitigating the spread of sporotrichosis. This study aimed to identify the Sporothrix species involved in the ongoing outbreaks of animal sporotrichosis in the metropolitan region of Belo Horizonte, Minas Gerais, Brazil, and analyse the phylogenetic relationships between pathogenic species to investigate the outbreak origin. Additionally, to better understand the evolution of the disease, we conducted a retrospective survey of positive feline and canine cases from November 2017 to July 2021 with proven cultures for Sporothrix. A significant increase in animal cases over the last 4 years was observed, with cats being the most affected host. Sporothrix brasiliensis was the predominant agent in 100% of the clinical isolates (n = 180) molecularly identified. Phylogenetic and haplotype analysis points towards the cases isolated from Minas Gerais sharing the haplotype originating from a long-lasting outbreak of cat-transmitted sporotrichosis in Rio de Janeiro, however, with a secondary contribution from genotypes circulating in other outbreaks in Brazil. Thus, we present clear evidence of the circulation of different S. brasiliensis genotypes associated with animal sporotrichosis in the metropolitan region of Belo Horizonte. Genetic monitoring can contribute to understanding the causal agent for zoonotic sporotrichosis in epidemiological processes and help to implement disease prevention and control measures.

Temporal relationship between human and canine visceral leishmaniasis in an urban area in southeastern Brazil: An application of the ARIMAX model.

Visceral leishmaniasis (VL) is a neglected disease of public and animal health importance. With the urbanization of the disease, there is evidence of a temporal correlation between the occurrence of human (HVL) and canine (CVL) visceral leishmaniasis, usually with cases in dogs preceding those in humans. In this context, the objective of this study was to develop a time series model suitable for canine-human transmission of Leishmania infantum. Monthly cases of HVL and CVL from 2006 to 2018 in Belo Horizonte, Minas Gerais, Brazil, were evaluated, and monthly health indicators were calculated for HVL and CVL, i.e., incidence coefficient (HVL_IC) and proportion of seropositive dogs (PSD), respectively. The temporal relationship was evaluated using an autoregressive integrated moving average with exogenous variable (ARIMAX) model for two different periods (January 2006-August 2013 and September 2013-December 2018). During the 13 years studied, 1115 new cases of HVL and 103,358 dogs seropositive for CVL were recorded. HVL_IC and PSD exhibited decreasing trends throughout the first study period (January 2006-August 2013). According to the ARIMAX model adjusted for this period, there was a temporal relationship between HVL_IC and PSD, with HVL_IC being influenced by HVL_IC for the last two and five months and by PSD for the third previous month. For the second study period (September 2013-December 2018), it was not possible to fit an ARIMAX model. This study highlights the improvements made by VL surveillance since 2006 in Belo Horizonte and contributes to a better understanding of the epidemiology of the disease by public health policy-makers, doctors and veterinarians involved in the prevention and control of zoonoses.

Disentangling associations between vegetation greenness and dengue in a Latin American city: Findings and challenges.

Being a Re-Emerging Infectious Disease, dengue causes 390 million cases globally and is prevalent in many urban areas in South America. Understanding the fine-scale relationships between dengue incidence and environmental and socioeconomic factors can guide improved disease prevention strategies. This ecological study examines the association between dengue incidence and satellite-based vegetation greenness in 3826 census tracts nested in 474 neighborhoods in Belo Horizonte, Brazil, during the 2010 dengue epidemic. To reduce potential bias in the estimated dengue-greenness association, we adjusted for socioeconomic vulnerability, population density, building height and density, land cover composition, elevation, weather patterns, and neighborhood random effects. We found that vegetation greenness was negatively associated with dengue incidence in a univariate model, and this association attenuated after controlling for additional covariates. The dengue-greenness association was modified by socioeconomic vulnerability: while a positive association was observed in the least vulnerable census tracts, the association was negative in the most vulnerable areas. Using greenness as a proxy for vegetation quality, our results show the potential of vegetation management in reducing dengue incidence, particularly in socioeconomically vulnerable areas. We also discuss the role of water infrastructure, sanitation services, and tree cover in lowering dengue risk.

Characterization of animal sporotrichosis in a highly urbanized area.

An epidemiological characterization of animal sporotrichosis was carried out between 2017 and 2018, in a highly urbanized area in Brazil, including outcomes and the spatial distribution of the cases according to the health vulnerability index (HVI) of the study territory. One hundred and sixty-five cats and four dogs suspected of sporotrichosis were identified by a surveillance and control program previously implemented in the study area. One hundred and five of these animals (62.1 %) were considered positive for Sporothrix spp., of which 103 were cats and two were dogs. Cases predominated among male cats (53.4 %), although gender did not present a statistically significant association (p > 0.05) with sporotrichosis cases. Considering the positive cats, 55.4 % were not neutered and free access to the street was reported as a habit for 86.4 % of them. Roaming free in the streets increased the chance of infection by 2.54 times. We observed a high frequency of euthanasia or death (48.8 %) among 86 infected cats available to be included in the follow-up stage of the study, even when they were treated (46.5 %) and a low cure rate (31 %). The disease spread, unrelated to the HVI in the territory. Data produced suggested that avoiding access to the street seems to have greater importance to sporotrichosis control in cats than neutering and reinforces the importance of health education, especially in relation to responsible feline ownership. The free offer of diagnosis and treatment also should be taken into consideration as important measures to control the disease.

Spatiotemporal dynamics and risk estimates of COVID-19 epidemic in Minas Gerais State: analysis of an expanding process.

COVID-19 is an infectious disease caused by the recently discovered coronavirus SARS-Cov-2. The disease became pandemic affecting many countries globally, including Brazil. Considering the expansion process and particularities during the initial stages of the epidemic, we aimed to analyze the spatial and spatiotemporal patterns of COVID-19 occurrence and to identify priority risk areas in Minas Gerais State, Southeast Brazil. An ecological study was performed considering all data from human cases of COVID-19 confirmed from the epidemiological week (EW) 11 (March 08, 2020) to EW 26 (June 27, 2020). Crude and smoothed incidence rates were used to analyze the distribution of disease patterns based on global and local indicators of spatial association and space-time risk assessment. Positive spatial autocorrelation and spatial dependence were found. Our results suggest that the metropolitan region of the State capital Belo Horizonte (MRBH) and Vale do Rio Doce mesoregions, as major epidemic foci in the beginning of the expansion process, have had important influence on the dispersion of SARS-CoV-2 in Minas Gerais State. Triangulo Mineiro/Alto Paranaiba region presented the highest risk of infection. In addition, six statistically significant spatiotemporal clusters were identified in the State, three at high risk and three at low risk. Our findings contribute to a greater understanding of the space-time disease dynamic and discuss strategies for identification of priority areas for COVID-19 surveillance and control.

Twenty-Two years of dengue fever (1996-2017): an epidemiological study in a Brazilian city.

This ecological study analyzed the temporal pattern of clinically diagnosed and laboratory confirmed dengue cases in Belo Horizonte, Minas Gerais, Brazil from 1996 to 2017. The study was divided into two analytical parts, the first of which evaluated the association between dengue incidence and host and climatic factors. The second part encompassed data from 2002 to 2017 and examined dengue incidence in relation to virus serotype and an intra-urban socioeconomic index. Over 22 years there were 469,171 cases and four epidemic peaks. There was an increase in the number, severity, and lethality of cases over the last 10 years of the study period. Biological and environmental factors appear to modulate the behavior of dengue in a large urban center.

Spatial analysis of dengue incidence and Aedes aegypti ovitrap surveillance in Belo Horizonte, Brazil.

OBJECTIVES: Understanding the intra-urban spatial dynamics of Aedes aegypti and dengue transmission is important to effectively guide vector control. Ovitraps are a sensitive, cost-effective vector surveillance tool, yet few longitudinal studies have evaluated ovitrap indices and dengue occurrence. We aimed to assess the spatial patterns of dengue incidence and Ae. aegypti ovitrap positivity index (OPI) over time and to examine the spatial relationship between these two variables. METHODS: This study used 12 years (2007-2018) of dengue case records and biweekly Ae. aegypti ovitrap data in Belo Horizonte, Brazil. We aggregated data by year and health centre catchment area (n = 152) and used both univariate and bivariate global Moran's I statistic and LISA to evaluate spatial clustering. RESULTS: Annual dengue incidence ranged from 18 to 6262/100 000 residents and displayed spatial autocorrelation in 10/12 years, with shifting areas of high incidence. Annual OPI ranged from 35.7 to 47.6% and was clustered in all study years, but unlike dengue had consistent spatial patterns over time. Bivariate analysis found both positive (6/12 years) and negative (1/12 years) spatial associations between the two variables. CONCLUSIONS: Low detected presence of Ae. aegypti was not a limiting factor in dengue transmission. However, stable spatial distribution of OPI suggests that certain areas may have persistent breeding sites. Future research should identify factors related to persistent Ae. aegypti hotspots to better guide vector management. Vector control efforts should be paired with additional data on population immunity, circulating serotypes and urban factors to better predict and control outbreaks.

OBJECTIFS: La compréhension de la dynamique spatiale intra-urbaine d'Aedes aegypti et de la transmission de la dengue est importante pour guider efficacement la lutte antivectorielle. Les ovitraps sont un outil de surveillance des vecteurs sensible et rentable, mais peu d'études longitudinales ont évalué les indices d'ovitrap et l'occurrence de la dengue. Nous visions à évaluer les modèles spatiaux de l'incidence de la dengue et de l'indice de positivité d'ovitrap (OPI) d'Ae. aegypti au fil du temps, et à examiner la relation spatiale entre ces deux variables. MÉTHODES: Cette étude a utilisé des dossiers de cas de dengue et des données bihebdomadaires d'ovitrap Ae. aegypti sur 12 ans (2007-2018) à Belo Horizonte, au Brésil. Nous avons agrégé les données par année et par zone d'étude du centre de santé (n = 152) et avons utilisé à la fois la statistique I globale de Moran univariée et bivariée et LISA pour évaluer le regroupement spatial. RÉSULTATS: L'incidence annuelle de la dengue variait de 18 à 6.262/100.000 habitants et affichait une autocorrélation spatiale en 10/12 ans, avec des zones de déplacement de forte incidence. L'OPI annuel variait de 35,7 à 47,6% et était groupé dans toutes les années d'étude, mais contrairement à la dengue, il avait des modèles spatiaux consistents au fil du temps. Une analyse bivariée a trouvé des associations spatiales positives (6/12 ans) et négatives (1/12 ans) entre les deux variables. CONCLUSIONS: La détection d'une faible présence d'Ae. aegypti n'était pas un facteur limitant de la transmission de la dengue. Cependant, la distribution spatiale stable de l'OPI suggère que certaines zones peuvent avoir des sites de reproduction persistants. Les recherches futures devraient identifier les facteurs liés à des hotspots persistants d'Ae. aegypti pour mieux guider la gestion des vecteurs. Les efforts de lutte antivectorielle devraient être associés à des données supplémentaires sur l'immunité de la population, les sérotypes circulants et les facteurs urbains pour mieux prévoir et contrôler les flambées.

Spatial association between sporotrichosis in cats and in human during a Brazilian epidemics.

Sporotrichosis is a subcutaneous granulomatous disease caused by the fungus Sporothrix spp. In Brazil, S. brasiliensis is reported in regions of outbreaks and epidemics in the zoonotic form of the disease where cats play an important role in the transmission of the disease to humans. Therefore, it is important to assess how the presence of infected cats impacts the risk for sporotrichosis in humans. The objective of this study was to analyze the spatial association of sporotrichosis in cats and in humans from Belo Horizonte, a Brazilian city where an epidemics of sporotrichosis occurs since the first human case register in 2015, through an inhomogeneous Poisson process model. Feline and human cases of sporotrichosis recorded between January 2016 and June 2019 were georeferenced by address and spatial point patterns were generated. Feline case intensity and human demographic density were calculated using a kernel smoothed estimate. The distance to the nearest feline case was also compute. Model parameters were estimated by Maximum Likelihood Estimate. The model validation was performed by the evaluation of partial residual, leverage and influence measure. There were 343 cases of cats and 135 human cases of sporotrichosis. The average incidence of human sporotrichosis in the period was 1.343 per 100 thousand inhabitants, which is relatively low in relation to the population, but higher than that observed in other regions in zoonotic outbreak of the disease. The southern region of the municipality has a higher intensity of feline cases. According to the fitted model, the risk for human sporotrichosis is greater when at distances very close to a feline case, with a virtually stable effect for distances greater than 1 km. Regarding the intensity of feline cases there is a gradual increase in risk as the intensity of cases increases. From the leverage analysis it was observed that the model was particularly sensitive to the occurrence of human cases in the south and east regions, places with extreme values ​​of covariates. Poisson point process model seems to be a reasonable approach in spatial epidemiology when multiple sources of infection are involved, and there is a low incidence of the disease as long as it is reasonable to assume independence between cases. Interventions for disease prevention and control in humans are suggested to encompass disease control in cats and the search for feline cases, focused on diagnosis and control, close to reported human cases.

Spatiotemporal patterns and integrated approach to prioritize areas for surveillance and control of visceral leishmaniasis in a large metropolitan area in Brazil.

Visceral leishmaniasis (VL) is a neglected disease with worldwide distribution. Brazil is the country with the largest number of cases in the Americas, and the state of Minas Gerais presents a high VL-related burden and a high case fatality rate. We aimed to analyse the spatial and spatiotemporal patterns of VL occurrence and to identify priority risk areas for surveillance and control in the metropolitan region of Belo Horizonte-MG, the third largest metropolitan area in Brazil. An ecological study was conducted considering all cases of VL in humans confirmed from 2006 to 2017. The crude and smoothed incidence rates were used to analyse the distribution patterns of the disease (dispersed, random, or clustered) based on global and local indicators of spatial association and space-time risk assessment. Positive spatial autocorrelation and spatial dependence were found between incidence rates. It was possible to observe a high concentration of VL cases in the metropolitan core area, with the identification of two high-risk clusters in strictly urban areas, showing an urban association with the disease. Ten municipalities were categorised as high risk for VL occurrence. Our results provide evidence for making decisions in surveillance programs, suggesting the prioritisation of the municipalities with more risk of transmission.

Visceral leishmaniasis control actions: epidemiological indicators for its effectiveness evaluation in a Brazilian urban area.

This research applies indicators concerning control of the visceral leishmaniasis canine reservoir in the city of Belo Horizonte, Minas Gerais State, Brazil. Data were obtained from the Zoonoses Control Information System (SCZOO) and the Brazilian Information System on Diseases of Notification (SINAN) database. First we analyzed (i) existing associations between canine epidemiological indicators, where the dependent variable was the canine seroprevalence A (2007 to 2013), and the independent variables were, as follows: canine seroprevalence B (2006 to 2012); percentage of positive dogs by ELISA test reagents that were not euthanized; the relationship between the human and canine population; canine population testing coverage by census surveys; and the years of study (2006 to 2013); (ii) then, we examined the association between human visceral leishmaniasis (HVL) cases between 2007 to 2013 and the mentioned variables related to dogs and years. Statistical analysis was done by a generalized linear model (GLM). One unit increases in canine seroprevalence B and canine seroprevalence A were associated to 13% and 12% increases in HVL rates, respectively. The increase in one human/dog ratio unit was associated with a 13% decrease in HVL rates. Canine seroprevalence, human/dog ratio and non-euthanasia of ELISA-reactive dogs in the environment were adequate indicators for analyzing the canine enzootic transmission and the occurrence of HVL cases.

Associated factors and spatial patterns of the epidemic sporotrichosis in a high density human populated area: A cross-sectional study from 2016 to 2018.

An epidemiological characterization of human and feline sporotrichosis was carried out between 2016 and 2018, in a high density-populated area in Brazil. Professionals were trained to identify suspect cats and notify vets to interview the owners and collect swabs of the wounds from these animals. Mycological cultures were performed, and colonies identified as Sporothrix spp. Subsequently, data regarding the outcome from suspect animals were collected. Confirmed cases of human sporotrichosis (56) were also counted and analyzed for spatial distribution. 118 positive animals were observed. The prevalence of feline sporotrichosis was 8.36 ‰ (CI 95 %, 5.38-9.55 ‰). The odds for being positive in animals that lived only partially at home were 3.02 times greater than for those cats without access to the street (OR 3.02, CI 95 % 1,96-10,43). There was no statistically significant association between environmental variables and positive diagnosis, corroborating the hypothesis that direct transmission by infected cats plays a greater role in the occurrence and continuous outbreaks of sporotrichosis in Brazil. Among the positive animals, 61.90 % (CI 95 % 58.95-64.96) died, and they had an odds to die in the next six months 6.30 times greater than negative animals (p < 0.05, OR 6.30, CI 95 % 2,79-14,42). The case fatality rate was 55.08 % in cats (CI 95 % 49.20-51.15). The cause-specific death rate was 4.6 ‰ in cats (CI 95 % 3.4-6 ‰). Only 7.62 % (CI 95 % 7.12-8.16) positive cats were treated and cured. Among dead positive animals, 29.23 % were inappropriately discarded. In the study period 56 human cases were recorded in the Barreiro region. Regions with highest prevalence of feline sporotrichosis, had greater frequencies of both human and feline cases. This is the first report on the epidemic of sporotrichosis in Minas Gerais, Brazil. The free offer for treatment and veterinary care for these animals should be taken into consideration, as well as the collection and incineration of the dead ones, as measures of public health, followed by the guidance and care for the human patient.

Prognostic factors associated with death from visceral leishmaniasis: a case-control study in Brazil.

BACKGROUND: The aim of this study was to identify the prognostic factors associated with death from visceral leishmaniasis (VL) considering the clinical evolution of patients through a case-control study. METHODS: We randomly selected 180 cases (death caused by VL) and 180 controls (cured) from Belo Horizonte's hospitals in Brazil, according to data found in the patients' medical records. Five models of multivariate logistic regression were performed following the chronological order of the variables between the onset of the symptoms and evolution of the VL cases. RESULTS: Considering the multivariate models and the stages of clinical evolution of VL, the prognostic factors associated with death are: age >60 y, minor hemorrhagic phenomena, increased abdominal volume, jaundice, dyspnea, malnutrition, TB, billirubin >2 mg/dL, Aspartate Aminotransferase (AST) or Alanine Aminotransferase (ALT) >100 U/L, leukocytes >7000/mm3, hemoglobin <7 g/dL, platelets <50 000/mm3 and infection without defined focus and bleeding. CONCLUSIONS: Knowledge regarding the prognostic factors associated with death from VL in different stages of the disease in large Brazilian urban centers such as Belo Horizonte may help optimize patient management strategies and contribute to reduce the high fatality rates in these cities.

Visceral leishmaniasis control actions: epidemiological indicators for its effectiveness evaluation in a Brazilian urban area / Ações de controle da leishmaniose visceral: indicadores epidemiológicos da avaliação de efetividade em uma área urbana brasileira / Acciones de control de la leishmaniosis visceral: indicadores epidemiológicos de la evaluación de efectividad en un área urbana brasileña

Abstract: This research applies indicators concerning control of the visceral leishmaniasis canine reservoir in the city of Belo Horizonte, Minas Gerais State, Brazil. Data were obtained from the Zoonoses Control Information System (SCZOO) and the Brazilian Information System on Diseases of Notification (SINAN) database. First we analyzed (i) existing associations between canine epidemiological indicators, where the dependent variable was the canine seroprevalence A (2007 to 2013), and the independent variables were, as follows: canine seroprevalence B (2006 to 2012); percentage of positive dogs by ELISA test reagents that were not euthanized; the relationship between the human and canine population; canine population testing coverage by census surveys; and the years of study (2006 to 2013); (ii) then, we examined the association between human visceral leishmaniasis (HVL) cases between 2007 to 2013 and the mentioned variables related to dogs and years. Statistical analysis was done by a generalized linear model (GLM). One unit increases in canine seroprevalence B and canine seroprevalence A were associated to 13% and 12% increases in HVL rates, respectively. The increase in one human/dog ratio unit was associated with a 13% decrease in HVL rates. Canine seroprevalence, human/dog ratio and non-euthanasia of ELISA-reactive dogs in the environment were adequate indicators for analyzing the canine enzootic transmission and the occurrence of HVL cases.

Resumo: O estudo aplica indicadores referentes ao controle do reservatório canino da leishmaniose visceral na cidade de Belo Horizonte, Minas Gerais, Brasil. Os dados foram obtidos do Sistema de Controle de Zoonoses (SCZOO) e do Sistema de Informação de Agravos de Notificação (SINAN). Começamos com a análise das associações existentes entre indicadores epidemiológicos caninos, onde a variável dependente foi a soroprevalência canina-A (de 2007 a 2013) e a variável independente foi a soroprevalência canina-B (de 2006 a 2012); o percentual de cães positivos de acordo com o teste ELISA e que não foram sacrificados; a relação entre as populações humana e canina; a cobertura da testagem da população canina de acordo com inquéritos censitários e os anos de estudo (de 2006 a 2013). Em seguida, examinamos a associação entre casos de leishmaniose visceral humana (LVH) entre 2007 e 2013 e as variáveis citadas relacionadas aos cães e aos anos. A análise estatística usou um modelo linear generalizado (MLG). Os aumentos de uma unidade na soroprevalência canina-B e soroprevalência canina-A estiveram associados a aumentos de 13% e 12% nas taxas de LVH, respectivamente. Um aumento de uma unidade na razão humano/cão esteve associado a uma diminuição de 13% nas taxas de LVH. A soroprevalência canina, a relação humano/cão e a não-eutanásia de cães ELISA-reativos foram indicadores adequados para analisar a transmissão enzoótica canina e a ocorrência de casos de LVH.

Resumen: El estudio aplica indicadores referentes al control del reservorio canino de la leishmaniosis visceral en la ciudad de Belo Horizonte, Minas Gerais, Brasil. Los datos fueron obtenidos del Sistema de Control de Zoonosis (SCZOO) y del Sistema Brasileño de Información de Enfermedades de Notificación (SINAN). Comenzamos con el análisis de las asociaciones existentes entre indicadores epidemiológicos caninos, donde la variable dependiente fue la seroprevalencia canina-A (de 2007 a 2013) y la variable independiente fue la seroprevalencia canina-B (de 2006 a 2012); el porcentaje de perros positivos, de acuerdo con el test ELISA, y que no fueron sacrificados; la relación entre las poblaciones humana y canina; la cobertura del test de la población canina, de acuerdo con encuestas censales y los años de estudio (de 2006 a 2013). En seguida, examinamos la asociación entre casos de leishmaniosis visceral humana (LVH) entre 2007 y 2013 y las variables citadas, relacionadas con los perros y los años. El análisis estadístico usó un modelo lineal generalizado (MLG). Los aumentos de una unidad en la seroprevalencia canina-B y seroprevalencia canina-A estuvieron asociados a aumentos de 13% y 12% en las tasas de LVH, respectivamente. Un aumento de una unidad en la razón humano/perro estuvo asociado a una disminución de un 13% en las tasas de LVH. La seroprevalencia canina, la relación humano/perro y la no-eutanasia de perros ELISA-reactivos fueron indicadores adecuados para analizar la transmisión enzoótica canina y la ocurrencia de casos de LVH.

Effectiveness of the mass use of deltamethrin-impregnated dog collars for preventing transmission of canine leishmaniasis by Lutzomyia spp.: A cluster randomized controlled trial.

Visceral leishmaniasis (VL) is a zoonosis that greatly impacts public health, especially in developing countries. The effectiveness of deltamethrin-impregnated dog collars for preventing transmission of canine leishmaniasis (CanL) by the sand fly Lutzomyia spp. in countries with high incidence of the disease, such as Brazil, remains unknown. A cluster randomized controlled trial was carried out to evaluate the effectiveness of these collars in preventing infection of dogs with Leishmania infantum. Two areas were selected in a municipality endemic for VL in Brazil: an experimental area (EA) and a control area (CA). In both areas, blood samples were collected from dogs for detection of CanL. Seronegative dogs from the EA received collars impregnated with deltamethrin 4%. After six months, the dogs were retested for CanL and the incidence of the disease, the relative risk, and the effectiveness of collaring determined. In the baseline survey, 1020 dogs from the EA and 589 from the CA were examined. The prevalence calculated for EA was 4.41% (CI95% 3.27-5.91), and 7.13% (CI95% 5.25-9.59) for CA. In the second evaluation, 454 dogs from the EA and 292 from the CA were examined. The person-time incidence calculated for EA was 3.51% (CI95% 1.30-7.48), and for CA was 11.81% (CI95% 7.03-18.23). The difference between the calculated incidences was statistically significant (p = 0.009). The relative risk was 0.2972 (CI95% 0.1204-0.7339; p = 0.009), and the efficacy of the proposed measure was estimated in 70.27%. This report evaluated the effectiveness of the mass use of deltamethrin-impregnated dog collars in areas of transmission of VL by Lutzomyia spp. Collaring was able to protect dogs and may represent an effective strategy that could be implemented to control infection in both dogs and humans in Brazil and perhaps other countries where Lutzomyia spp. is the main vector of the disease.

Space-time analysis of the incidence of human visceral leishmaniasis (VL) and prevalence of canine VL in a municipality of southeastern Brazil: Identification of priority areas for surveillance and control.

Human and canine visceral leishmaniasis (HVL and CVL, respectively) represent serious public health issues in Brazil. The surveillance and control measures currently employed have had limited effect in impeding the territorial expansion of the disease and in reducing the number of cases. We have investigated the space-time distribution of HVL incidence rates and CVL prevalence in the coverage areas of the 148 primary healthcare units in Belo Horizonte (MG, Brazil) during a 6-year period in order to identify those that should be prioritized for disease control actions. Data were smoothed using the empirical Bayes method and analyzed by space-time scanning and application of univariate global Moran's I index and local indicators of spatial association (LISA) statistics to identify spatial autocorrelations. Point data of CVL were analyzed using the Kernel method. Bivariate global Moran's I and LISA techniques were employed to identify spatial correlations between HVL and CVL. Based on our results, we were able to formulate two proposals for establishing the prioritization of coverage areas, namely: (i) classification of maximum priority areas as identified by bivariate LISA for HVL and CVL, and (ii) combination of maximum priority areas with high priority areas as identified by univariate LISA for HVL. According to our proposals, 27 coverage areas in Belo Horizonte were categorized as maximum priority and a further 13 were classified as high priority. Our proposals, which are based on practical, feasible and inexpensive statistical tools, will contribute to a better understanding of VL distribution in urban settings and improving the efficiency of governmental control programs.

Effectiveness of the Brazilian Visceral Leishmaniasis Surveillance and Control Programme in reducing the prevalence and incidence of Leishmania infantum infection.

BACKGROUND: Control strategies adopted by the Brazilian Visceral Leishmaniasis Surveillance and Control Programme (VLSCP) include identifying and culling seropositive infected dogs, early diagnosis and treatment of human cases, chemical control of the vector and population awareness. This study evaluated the effectiveness of the VLSCP on the prevalence and incidence rates of Leishmania infantum in children residing in areas under different VLSCP intervention times. METHODS: A quasi-experimental epidemiological study with a panel (two cross-sectional) and a concurrent cohort was performed in three areas of Belo Horizonte, southeast Brazil. The first cross-sectional study (I) was carried out with 1875 children, 478 of which were enrolled in the cohort study. In the second cross-sectional study (II), 413 additional children were included, totalizing 891 children. Laboratory diagnosis was performed by ELISA-rK39. Analyses included multilevel logistic and Poisson regression models. RESULTS: The incidence rates of L. infantum infection were: 14.4% in the area where VLSCP intervention was initiated in 2006 (AI2006); 21.1% in the area where intervention was initiated in 2008 (AI2008); and 11.6% in the area where intervention was initiated in 2010 (AI2010 - control area). A follow-up period of 24 months showed that the persons-time incidence rates in AI2006, AI2008, and AI2010 were: 6.2/100, 10/100, and 5.6/100 persons/24 months, respectively. The final prevalence rates of infection (cross-sectional II - in 2012), compared to the initial rates (cross-sectional I - in 2010), increased 83.7% in AI2006, 74.1% in AI2008, and decreased 5% in AI2010. Analysis of the effectiveness revealed that children residing in AI2008 are more likely to be infected (OR = 1.84; 95% CI: 1.06-3.23) and present a higher risk of infection (IRR = 1.76; 95% CI: 1.05-2.95) compared to those in AI2010. No statistically significant differences were observed in asymptomatic infection (OR and IRR) in AI2006 compared to AI2010. CONCLUSIONS: The VLSCP was not effective at controlling L. infantum infection in areas where interventions had respectively been carried out for six and four years. However, it is unclear what the consequences in terms of human infection and diseases would be in the absence of the VLSCP. Efforts to improve the effectiveness of control measures remain a necessary priority.

Spatial and temporal relationships between human and canine visceral leishmaniases in Belo Horizonte, Minas Gerais, 2006-2013.

BACKGROUND: Visceral leishmaniasis is a serious public health problem in Brazil, and control of this disease constitutes a major challenge. The purpose of this study was to assess the existing spatial and temporal relationships between cases of canine visceral leishmaniasis (CanL) and human visceral leishmaniasis (HVL) recorded in Belo Horizonte, State of Minas Gerais, from 2006 to 2013. METHODS: Data provided by the Belo Horizonte Health Services regarding the disease control routine were analyzed in order to perform a retrospective observational and ecological study. Information regarding the incidence rate of HVL and canine seroprevalence was examined in relation to control actions performed atthe 148 coverage areas of healthcare centers for the period between 2006 and 2013. A time series analysis was performed using the Gretl 1.9.12 software followed by the assessment of the existing increasing or declining trend and seasonality in the occurrence of CanL and HVL. Autoregressive integrated moving average (ARIMA) models were adjusted, intervention analysis was performed, vector autoregressive models were developed, and Granger causality was used for testing temporal relationships between variables. The hot spot analysis tool was used for cluster identification through Getis-OrdGi statistics. The ArcGis for desktop 10.2.1 software was used for spatial analysis. RESULTS: We identified 866 HVL cases in Belo Horizonte between 2006 and 2013. The mean proportion of canine seroprevalence (PCP) was 7.31% and the mean proportion of monitored hosts (PMH) was 6.73%.HVL and PCP showed a decreasing trend, while PMH increased over time (P<0.05). Vector Autoregressive (VAR) and Granger analysis showed a temporal relation between CanL and HVL cases. Maps illustrating the spatial distribution of cases and obituaries of HVL and CanL cases also showed an apparent association between the occurrence of leishmaniasis in humans, and data about canine cases recorded in the previous years. CONCLUSIONS: Cases of HVL were preceded by PMH and PCP cases. Similar results were observed for intraspecific cases (i.e. between PCP and other canine cases and between HVL and other HVL cases), which indicated the existence of favorable environmental conditions for the transmission and spread of L. infantum in Belo Horizonte.