Eduardo Sérgio da Silva

A systematic review and meta-analysis of the factors associated with Leishmania infantum infection in dogs in Brazil

The risk factors associated with canine visceral leishmaniosis (CVL) in Brazil are unclear and controversial. The objectives of this systematic review and meta-analysis were to identify the best evidence available in this field and to determine the gaps in existing knowledge. Literature searches were carried out using four databases, the reference lists within articles, and references provided by experts in the field. Theoretical discussions or separate and independent meta-analyses of p-values or of effect sizes were used to pool information about each variable. Thirty-six articles were selected for detailed review, including 31 cross-sectional, two ecological and three cohort studies. The variables showing significant association with CVL were short hair, purebred, peri-domestic restricted (as compared with domestic-restricted dogs), and presence of green areas adjacent to home. The occurrence of CVL was also associated with the presence of domestic fowl in the home environment, with free dogs (as compared with restrained dogs), with male gender and with dogs >1 or 2 years of age, although these associations were not statistically significant. Due to the small number of publications, consistent results could not be obtained concerning the role of other factors. Most studies did not describe the criteria of eligibility and the process of selection of participants in sufficient detail and employed only one diagnostic test as proof of infection. Few studies controlled for confounding variables. No statistical evidence of publication bias was detected, but a great deal of information contained in the primary articles was lost because the results were not adequately described. The results of this review contribute to a better understanding of CVL and should assist in optimizing the development and implementation of control policies. Continuous actions, prioritizing dogs at higher risk and areas with higher abundance of green vegetation, together with policies to promote responsible dog ownership are mandatory. Problems concerning study design and data analysis described in the present study need to be taken into consideration in future studies. These must follow clear procedures to select participants and utilize standardized, valid and reliable diagnostic methods. The development of multivariate models and the use of the STROBE statement for description of the results should also be encouraged. Further research should investigate the patterns identified and prioritize CVL-related factors that have not been fully recognized or elucidated. Finally, ecological and cohort studies of CVL and investigations in other countries of Latin America are urgently required.

Risk factors for adverse prognosis and death in American visceral leishmaniasis: a meta-analysis.

Background In the current context of high fatality rates associated with American visceral leishmaniasis (VL), the appropriate use of prognostic factors to identify patients at higher risk of unfavorable outcomes represents a potential tool for clinical practice. This systematic review brings together information reported in studies conducted in Latin America, on the potential predictors of adverse prognosis (continued evolution of the initial clinical conditions of the patient despite the implementation of treatment, independent of the occurrence of death) and death from VL. The limitations of the existing knowledge, the advances achieved and the approaches to be used in future research are presented. Methods/Principal Findings The full texts of 14 studies conforming to the inclusion criteria were analyzed and their methodological quality examined by means of a tool developed in the light of current research tools. Information regarding prognostic variables was synthesized using meta-analysis. Variables were grouped according to the strength of evidence considering summary measures, patterns and heterogeneity of effect-sizes, and the results of multivariate analyses. The strongest predictors identified in this review were jaundice, thrombocytopenia, hemorrhage, HIV coinfection, diarrhea, age <5 and age >40–50 years, severe neutropenia, dyspnoea and bacterial infections. Edema and low hemoglobin concentration were also associated with unfavorable outcomes. The main limitation identified was the absence of validation procedures for the few prognostic models developed so far. Conclusions/Significance Integration of the results from different investigations conducted over the last 10 years enabled the identification of consistent prognostic variables that could be useful in recognizing and handling VL patients at higher risk of unfavorable outcomes. The development of externally validated prognostic models must be prioritized in future investigations.

Study of sand flies (Diptera: Psychodidade) in visceral and cutaneous leishmaniasis areas in central western of Minas Gerais state - Brazil

The transmission of Leishmania involves several species of sand flies that are closely associated with various parasites and reservoirs, with differing transmission cycles in Brazil. A study on the phlebotomine species composition has been conducted in the municipality of Divinópolis, Minas Gerais, Brazil, an endemic area for cutaneous leishmaniasis (CL), which has intense occurrence of visceral leishmaniasis (VL) cases. In order to study the sand flies populations and their seasonality, CDC light traps (HP model) were distributed in 15 houses which presented at least one case of CL or VL and in five urban parks (green areas). Collections were carried out three nights monthly from September 2010 to August 2011. A total of 1064 phlebotomine specimens were collected belonging to two genera and seventeen species: Brumptomyia brumpti, Lutzomyia bacula, Lutzomyia cortelezzii, Lutzomyia lenti, Lutzomyia sallesi, Lutzomyia longipalpis, Lutzomyia migonei, Lutzomyia intermedia, Lutzomyia neivai, Lutzomyia whitmani, Lutzomyia christenseni, Lutzomyia monticola, Lutzomyia pessoai, Lutzomyia aragaoi, Lutzomyia brasiliensis, Lutzomyia lutziana, and Lutzomyia sordellii. L. longipalpis, the main vector of Leishmania infantum in Brazil, was the most frequent species, accounting for 76.9% of the total, followed by L. lenti with 8.3%, this species is not a proven vector. Green and urban areas had different sand flies species composition, whereas the high abundance of L. longipalpis in urban areas and the presence of various vector species in both green and urban areas were also observed. Our data point out to the requirement of control measures against phlebotomine sand flies in the municipality of Divinópolis and adoption of strategies aiming entomological surveillance.

Canine visceral leishmaniasis in an urban setting of Southeastern Brazil: an ecological study involving spatial analysis

BackgroundThe physical characteristics of the environment influence the composition, distribution and behavior of the vectors and mammalian hosts involved in the transmission of visceral leishmaniasis (VL), thereby affecting the epidemiology of the disease. In Brazil, urbanization of human VL is a recent phenomenon and represents an issue of particular concern to local health authorities. The present study aimed to establish the degree of spatial dependency between canine and human VL in the municipality of Divinópolis, Minas Gerais, Brazil, and to identify priority risk areas in which stricter control measures should be implemented.MethodsThe selected canine population comprised 3,652 dogs distributed within 11 strata and 1,247 urban blocks. Serum samples were collected between March 2013 and February 2014. Serodiagnosis of dogs was performed using the enzyme-linked immunosorbent assay and the indirect fluorescent-antibody test. The blocks sampled for canine VL and the addresses of the 16 confirmed cases of human VL notified in Divinópolis during the period 2007-2013 were georeferenced. Spatial analysis of the data was performed using Kernel density estimation, Ripley’s bivariate K-function and directional distribution methods.ResultsThe overall prevalence of seropositive animals was 4.63% (range 3.95 - 5.31) (n =169) and varied in different strata between 0.9 (range 0.0 - 1.91) and 8.73% (range 5.65 - 11.81). A positive spatial dependency was detected between human and canine VL in which the occurrence of human cases of the disease tended to concentrate in locations that were close to areas with a higher incidence of canine VL. The priority risk area could be clearly distinguished from Kernel density estimation and standard deviational ellipse plots in which the human VL ellipse was totally enclosed within the canine VL ellipse.ConclusionsThe results presented herein will enable the Municipal Health Office of Divinópolis to devise a more effective management plan for human VL in which specific strategies would be applied to areas presenting different levels of risk. This spatial evaluation of leishmaniasis model could be applied in other urban areas of Brazil.

Inquérito canino em foco recente de leishmaniose tegumentar no Município de Sabará, região metropolitana de Belo Horizonte

In 1992, a dog naturally infected with Leishmania was found in a periurban area of Sabara, State of Minas Gerais, where human cutaneous leishmaniasis had been previously described. The parasite was classified as Leishmania, subgenus Viannia, which L. braziliensis, the main species of parasite present in the southeast Brazil, also belongs. In order to assess the importance of the dog in the transmission cycle of the disease, a canine survey was undertaken. Six hundred thirty-one dogs were examined and the prevalence of seropositive dogs for crude Leishmania amazonensis antigen was 3.2%. The presence of infected people and seropositive dogs either near or in the same house was observed. This fact suggests some transmission in the domiciliar environment, with the dogs being a risk factor for human infection in that periurban area. In the other hand, the low percentage of seropositive dogs points towards a secondary importance of these animals in the transmission of Leishmaniasis in that recentfocus of the disease.

Formação em ciências da saúde: diálogos em saúde coletiva e a educação para a cidadania

In the last decades there have been discussions concerning the educational process of health professionals in Brazil. The discussed subjects are based on the verification of precarious aspects concerning a kind of formation that should be focused on attending the demands of the population, on the principles of SUS and an extended understanding of healthcare. We intended to think about alternatives in relation to the graduation in health sciences and in analyzing the way education in health is registered in the context of higher education.

Factors associated with obesity and overweight in school-aged children

Evaluar los factores asociados con el exceso de peso (sobrepeso/obesidad) en los ninos matriculados en una escuela primaria de la red publica de Divinopolis, Minas Gerais, Brasil. Estudio transversal con 1.187 escolares de 6 a14 anos de edad de la red municipal de ensenanza de Divinopolis, Minas Gerais. La prevalencia de la obesidad y el sobrepeso se calculo a partir de los parametros de la Organizacion Mundial de la Salud, mediante el Programa WHO Anthro-Plus. Se utilizo la regresion logistica para identificar las variables asociadas con el exceso de peso, considerando un nivel de significacion del 5%. Se observo una prevalencia de 24,4% de sobrepeso. Los ingresos familiares y la educacion materna fueron determinantes con sobrepeso en la poblacion estudiada (p<0,05). El exceso de peso fue configurado como el principal problema de salud en escolares. Medidas de orden intersectorial deben ser implementadas por el gobierno con el fin de prevenir y reducir la prevalencia del sobrepeso y la obesidad en la escuela.Resumen pt: Avaliar os fatores associados ao excesso de peso (sobrepeso/obeso) em escolares matriculados no ensino fundamental da rede publica de ensino de Divinopol...

Population Estimation Methods for Free-Ranging Dogs: A Systematic Review.

The understanding of the structure of free-roaming dog populations is of extreme importance for the planning and monitoring of populational control strategies and animal welfare. The methods used to estimate the abundance of this group of dogs are more complex than the ones used with domiciled owned dogs. In this systematic review, we analyze the techniques and the results obtained in studies that seek to estimate the size of free-ranging dog populations. Twenty-six studies were reviewed regarding the quality of execution and their capacity to generate valid estimates. Seven of the eight publications that take a simple count of the animal population did not consider the different probabilities of animal detection; only one study used methods based on distances; twelve relied on capture-recapture models for closed populations without considering heterogeneities in capture probabilities; six studies applied their own methods with different potential and limitations. Potential sources of bias in the studies were related to the inadequate description or implementation of animal capturing or viewing procedures and to inadequacies in the identification and registration of dogs. Thus, there was a predominance of estimates with low validity. Abundance and density estimates carried high variability, and all studies identified a greater number of male dogs. We point to enhancements necessary for the implementation of future studies and to potential updates and revisions to the recommendations of the World Health Organization with respect to the estimation of free-ranging dog populations.

Fatores associados à obesidade e sobrepeso em escolares

Evaluar los factores asociados con el exceso de peso (sobrepeso/obesidad) en los ninos matriculados en una escuela primaria de la red publica de Divinopolis, Minas Gerais, Brasil. Estudio transversal con 1.187 escolares de 6 a14 anos de edad de la red municipal de ensenanza de Divinopolis, Minas Gerais. La prevalencia de la obesidad y el sobrepeso se calculo a partir de los parametros de la Organizacion Mundial de la Salud, mediante el Programa WHO Anthro-Plus. Se utilizo la regresion logistica para identificar las variables asociadas con el exceso de peso, considerando un nivel de significacion del 5%. Se observo una prevalencia de 24,4% de sobrepeso. Los ingresos familiares y la educacion materna fueron determinantes con sobrepeso en la poblacion estudiada (p<0,05). El exceso de peso fue configurado como el principal problema de salud en escolares. Medidas de orden intersectorial deben ser implementadas por el gobierno con el fin de prevenir y reducir la prevalencia del sobrepeso y la obesidad en la escuela.Resumen pt: Avaliar os fatores associados ao excesso de peso (sobrepeso/obeso) em escolares matriculados no ensino fundamental da rede publica de ensino de Divinopol...

Leishmania infection in a population of dogs: an epidemiological investigation relating to visceral leishmaniasis control.

Identification of factors associated with Leishmania infection in dogs is essential for targeting visceral leishmaniasis control actions. Thus, the present study analyzed some of these factors in a population of dogs in a Brazilian municipality, along with the limitations of control strategies implemented there. The association between the exposure variables and occurrences of infection was analyzed through logistic regression models. The disease control interventions were treated qualitatively. Out of the 755 animals examined, 13.6% (103/755) were seropositive. Of these, 23.3% (24/103) were asymptomatic and 76.7% (79/103) presented at least one clinical sign possibly associated with visceral leishmaniasis. With weak associations, purebred, shorthaired, over 5 years of age, male and large dogs were more prone to infection. The latter two variables formed the final regression model and the association with dog size was statistically significant. The control strategies developed presented limitations and a great number of seronegative dogs was culled. The data presented contribute towards better understanding of the dynamics of infection in canine visceral leishmaniasis and indicate that actions aimed towards adequate implementation of Visceral Leishmaniasis control program in Brazilian endemic areas should be prioritized.