Vinícius Silva Belo

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.

Spatial analysis for identification of priority areas for surveillance and control in a visceral leishmaniasis endemic area in Brazil.

Spatial analysis of epidemiological data may be used to assist in the implementation of surveillance and control measures against visceral leishmaniasis (VL) in endemic areas. This ecological study aimed to identify priority areas for surveillance and control of VL in São Luís, the capital of the state of Maranhão in northeast Brazil, a highly endemic area for the disease. We evaluated the spatial structure of the incidence rates of human VL and of the mean number of human and canine cases occurring between 2005 and 2007 in 355 neighborhoods (aggregated into 203 geographical analytical units) within the municipality. The presence of spatial autocorrelation was explored using global and local Morans I statistics. A local indicator of spatial autocorrelation was used to generate maps for the identification of VL clusters. The global Morans I index revealed a weak, but statistically significant spatial autocorrelation for human VL incidence rates (I=0.138). A total of 43 geographical analytical units, encompassing 121 neighborhoods, were identified as priority areas for implementing surveillance and control actions. For the purpose of defining an action plan for the delivery of these measures, those 16 geographical analytical units (encompassing 54 neighborhoods) identified as clusters with high incidence rates of human VL should receive the highest priority. An additional nine geographical analytical units (comprising 28 neighborhoods) showed non-significant clustering of high rates of human, and might be considered as the next priority for VL management. Finally, a further 18 geographical analytical units (covering 39 neighborhoods) had records of coexisting human and canine VL cases during the study period, and these should receive priority attention when resources become available. Spatial data analysis is a valuable tool for defining priority areas for VL surveillance in high transmission areas contributing to a more effective management of financial and technical resources, increasing the sustainability and efficiency of control efforts.

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.

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.

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.

Fatores associados à ocorrência de parasitoses intestinais em uma população de crianças e adolescentes

OBJETIVOS: Analizar la prevalencia de infecciones por parasitas intestinales en ninos y adolescentes matriculados en escuelas de ensenanza primaria en el municipio de Sao Joao del-Rei, Minas Gerais (Brasil), y los factores asociados a la infeccion. METODOS: Estudio epidemiologico seccional, realizado entre marzo/2008 y julio/2009. Se realizaron examenes coproscopicos por sedimentacion espontanea y Kato-Katz en 1.172 escolares. Se ajustaron modelos de regresion logistica multiple para el estudio de los factores asociados a las infecciones en general y, separadamente, por helmintos y protozoos. RESULTADOS: La prevalencia de infecciones fue de 29%, habiendo una variacion de 7 a 83%, respectivamente, entre las escuelas de menor y mayor ocurrencia. La presencia de instalacion sanitaria en el domicilio fue asociada a una ocurrencia menor de helmintos; el aumento en la edad de los escolares se asocio a una mayor ocurrencia de protozoos y de parasitas en general; mientras que la presencia de filtro de agua y la ubicacion del domicilio en area urbana se mostraron asociadas a una ocurrencia menor de los tres desenlaces analizados. En todas las regiones, se registro el consumo de medicacion preventiva contra helmintos. CONCLUSIONES: Desigualdades en las condiciones de vida convirtieron las prevalencias diferenciadas entre las regiones del estudio. El estudio subraya la necesidad de promover el uso de filtros de agua en las residencias de areas epidemicas y de evaluar el consumo preventivo de medicamentos anti-helminticos en la dinamica de las infecciones y en la salud de los individuos. Medidas de control que tengan en cuenta los factores descritos deben ser prioritarias en nivel de Salud Publica.

Factors associated with intestinal parasitosis in a population of children and adolescents

OBJETIVOS: Analizar la prevalencia de infecciones por parasitas intestinales en ninos y adolescentes matriculados en escuelas de ensenanza primaria en el municipio de Sao Joao del-Rei, Minas Gerais (Brasil), y los factores asociados a la infeccion. METODOS: Estudio epidemiologico seccional, realizado entre marzo/2008 y julio/2009. Se realizaron examenes coproscopicos por sedimentacion espontanea y Kato-Katz en 1.172 escolares. Se ajustaron modelos de regresion logistica multiple para el estudio de los factores asociados a las infecciones en general y, separadamente, por helmintos y protozoos. RESULTADOS: La prevalencia de infecciones fue de 29%, habiendo una variacion de 7 a 83%, respectivamente, entre las escuelas de menor y mayor ocurrencia. La presencia de instalacion sanitaria en el domicilio fue asociada a una ocurrencia menor de helmintos; el aumento en la edad de los escolares se asocio a una mayor ocurrencia de protozoos y de parasitas en general; mientras que la presencia de filtro de agua y la ubicacion del domicilio en area urbana se mostraron asociadas a una ocurrencia menor de los tres desenlaces analizados. En todas las regiones, se registro el consumo de medicacion preventiva contra helmintos. CONCLUSIONES: Desigualdades en las condiciones de vida convirtieron las prevalencias diferenciadas entre las regiones del estudio. El estudio subraya la necesidad de promover el uso de filtros de agua en las residencias de areas epidemicas y de evaluar el consumo preventivo de medicamentos anti-helminticos en la dinamica de las infecciones y en la salud de los individuos. Medidas de control que tengan en cuenta los factores descritos deben ser prioritarias en nivel de Salud Publica.

Um novo olhar sobre a elaboração de materiais didáticos para educação em saúde

This article aims to cast a critical eye on the preparation process used for a set of teaching materials in health education, which was produced from 2007 at the Federal University of Sao Joao del Rei for use in a program aimed at combating intestinal parasites. The materials were analyzed in order to address the strengths and weaknesses that were found. As a result, such materials were reworked for use as educational media that respect identities and contribute to building knowledge on health. It is expected that the proposals that were made for material redesign and correction, along with the positive characteristics that were analyzed, may contribute to the production of new materials and contribute to improving the supply of products that mediate the process of building knowledge in health.