Major environmental and socioeconomic determinants of cutaneous leishmaniasis in Brazil - a systematic literature review

Tegumentary leishmaniasis in Brazil: priority municipalities and spatiotemporal relative risks from 2001 to 2020

Understanding the distribution of tegumentary leishmaniasis (TL) in different periods enables the adequate conduction of actions at the public health level. The present study analyzes the spatiotemporal evolution of TL incidence rates in the municipalities of Brazil and identifies priority areas from 2001 to 2020. Notifications of new cases were analyzed employing space-time scan statistics and Local Indicators of Spatial Association. As TL incidence rates presented a downward trend in most Brazilian municipalities, spatiotemporal clusters of high relative risks (RR) were more frequent in the first decade of the series. There was a concentration of those clusters in the North and Northeast regions, mainly in the Legal Amazon area. More recent high-RR areas were identified in municipalities of different regions. The number of priority municipalities showed a stable trend in Brazil. There was a great concentration of such municipalities in the states of Acre, Mato Grosso, Rondônia, Pará, and Amapá, as well as large areas in Roraima, Amazonas, Maranhão, and Tocantins, and smaller areas in the states of Goiás, Ceará, Bahia, Minas Gerais, São Paulo, and Paraná. The present study contributes to the understanding of the historical evolution of TL in Brazil and subsidizes actions to combat the disease.

Temporal patterns, spatial risks, and characteristics of tegumentary leishmaniasis in Brazil in the first twenty years of the 21st Century

BACKGROUND

Tegumentary leishmaniasis (TL) is a significant public health issue in Brazil. The present ecological study describes the clinical and epidemiological characteristics of TL cases reported in the country, and analyzes the spatial and temporal patterns of the incidences and risks of occurrence across the five geopolitical regions and 27 federative units.

METHODOLOGY/PRINCIPAL FINDINGS

Data regarding new cases of TL notified between 2001 and 2020 were obtained from the Information System for Notifiable Diseases of the Brazilian Ministry of Health. Joinpoint and spatial and temporal generalized additive models were used to establish trends in the evolution of TL during the target period. The incidence rate for the entire period was 226.41 cases/100,000 inhabitants. All regions of Brazil showed trends of decreasing incidence rates, albeit with fluctuations at specific times, with the exception of the Southeast where rates have increased since 2014, most particularly in Minas Gerais state. The disease was concentrated predominantly in the North region, with Acre state leading the incidence rank in the whole country, followed by Mato Grosso (Midwest), Maranhão and Bahia (Northeast) states. The spatial distribution of the risk of TL occurrence in relation to the annual averages was relatively stable throughout the period. The cutaneous form of TL was predominant and cases most frequently occurred in rural areas and among men of working age. The ages of individuals contracting TL tended to increase during the time series. Finally, the proportion of confirmations by laboratory tests was lower in the Northeast.

CONCLUSION/SIGNIFICANCE

TL shows a declining trend in Brazil, but its widespread occurrence and the presence of areas with increasing incidence rates demonstrate the persistent relevance of this disease and the need for constant monitoring. Our findings reinforce the importance of temporal and spatial tools in epidemiologic surveillance routines and are valuable for targeting preventive and control actions.

Promising natural products for the treatment of cutaneous leishmaniasis: A review of in vitro and in vivo studies

Although there are available treatments for cutaneous leishmaniasis (CL), the drugs used are far from ideal, toxic, and costly, in addition to the challenge faced by the development of resistance. Plants have been used as a source of natural compounds with antileishmanial action. However, few have reached the market and become phytomedicines with registration in regulatory agencies. Difficulties related to the extraction, purification, chemical identification, efficacy, safety, and production in sufficient quantity for clinical studies, hinder the emergence of new effective phytomedicines against leishmaniasis. Despite the difficulties reported, the major research centers in the world see that natural products are a trend concerning the treatment of leishmaniasis. The present work consists of a literature review of articles with in vivo studies, covering the period from January 2011 to December 2022, providing an overview of promising natural products for CL treatment. The papers show encouraging antileishmanial action of natural compounds with reduced parasite load and lesion size in animal models, suggesting new strategies for the treatment of the disease. The results reported in this review show advances in using natural products as safe and effective formulations, which can stimulate clinical studies to establish clinical therapy. In conclusion, the information in this review article serves as a preliminary basis for establishing a therapeutic protocol for future clinical trials that can validate the safety and efficacy of natural compounds, providing the development of affordable and safe phytomedicines for the treatment of CL.

"It's not all about the disease": do treatment and socioeconomic status affect perceived impact and satisfaction of patients treated for cutaneous leishmaniasis?

BACKGROUND

This cross-sectional study compared the general impact of cutaneous leishmaniasis (CL) and patient satisfaction with treatment and health services as perceived by those undergoing different therapeutic regimens in an endemic region in South-Eastern Brazil. We also investigated the factors associated with both outcomes (general impact and satisfaction).

METHODS

We included 84 patients with CL treated between 2018 and 2019 with intravenous meglumine antimoniate, liposomal amphotericin B, or intralesional meglumine antimoniate therapy. Data were collected through interviews that assessed sociodemographic characteristics, comorbidity status, access and use of health services for CL diagnosis and treatment, and the items of the Cutaneous Leishmaniasis Impact Questionnaire (CLIQ). The CLIQ is a psychometric questionnaire previously validated to assess the general impact of CL on patient satisfaction with treatment and health services. Multivariate logistic regression analysis was used to identify the factors associated with high CL impact and low patient satisfaction.

RESULTS

The general impact of CL and patient satisfaction with treatment and health services were not significantly associated with the therapeutic regimen. High CL impact was associated with low family income (odds ratio [OR]:3.3; 95% confidence interval [CI]:1.0-10.3), occurrence of complications/adverse effects during treatment (OR:7.7; 95%CI:2.4-25.6), and additional costs during diagnosis and/or treatment (OR:12.1; 95% CI:2.8-52.4). Low satisfaction was associated with high disease impact (OR: 9.5; 95% CI:2.7-33.9), occurrence of complications/adverse effects (OR:4.2; 95% CI:1.3-13.0), and high family income (OR:7.1; 95%CI:1.7-28.2).

CONCLUSIONS

Our data support public health policies aimed at reducing the impact of CL and its treatment as well as the use of therapy with fewer adverse effects.

Influence of anthropic changes and environmental characteristics on the occurrence of Tegumentary Leishmaniasis in Montes Claros, Minas Gerais, Brazil, between 2012 and 2019

This is an ecological study that investigated the influence of environmental, socioeconomic characteristics and changes in land use and cover on the occurrence of Tegumentary Leishmaniasis (TL) in the city of Montes Claros. The relationships between the number of cases of TL, which occurred between 2012 and 2019, in each census sector and the standardized covariates (Number of properties, altitude, Brazilian Deprivation Index, Normalized Difference Vegetation Index (NDVI), proportion of sector (PS) deforested, PS that underwent other anthropic alterations and unaltered PS) were evaluated with ecological Bayesian Models. Four multivariate models were constructed, with similar quality of adjustments, but Model 1 was the most parsimonious. Model 1 revealed that for each one-unit increase of standard deviation (SD) in the log of the number of properties, at the altitude and root of the deforested PS, corresponds to an increase of 44%, 34% and 24.5% in the number of cases of TL, respectively. The variable NDVI, included in models 3 and 4, was positively associated with the increase in the number of TL cases, being that for each one-unit increase in the NDVI was verified an increase of 21.3% and 20.2% respectively in the models. This study showed that the spatial distribution of TL cases in the city of Montes Claros occurs in a heterogeneous way and our findings support the hypothesis that socio-environmental characteristics and deforestation influence the occurrence of this disease in the studied area. Thus, these factors must be considered for the development of disease control strategies.

[Synthesis of evidence and recommendations: guideline for the treatment of leishmaniasis in the Region of the AmericasSíntese de evidências e recomendações: diretrizes para o tratamento das leishmanioses na Região das Américas]

Introduction

Leishmaniasis continues to be a neglected infectious disease of great importance, mainly affecting the poorest people with the least access to health services. In the Americas, it is a public health problem due to its magnitude, wide geographical distribution, and levels of morbidity and mortality.

Objective

Summarize the recommendations included in Guideline for the Treatment of Leishmaniasis in the Region of the Americas, published by the Pan American Health Organization/World Health Organization, in order to provide adequate management of patients diagnosed with leishmaniasis, reduce clinical complications and deaths caused by drug toxicity, reduce the lethality of visceral leishmaniasis, and address key aspects of implementation of the guidelines.

Methods

The guideline and its recommendations were summarized and a systematic search was carried out in PubMed, Lilacs, Health Systems Evidence, Epistemonikos, and gray literature for other studies conducted in the Region of the Americas, in order to identify barriers, facilitators, and implementation strategies.

Results

Recommendations are presented, addressing the pharmacological treatment of patients diagnosed with cutaneous, mucosal, and visceral leishmaniasis in the Americas, as well as case management and secondary prophylaxis in patients coinfected with visceral leishmaniasis and HIV, and patients with other diseases that cause immunosuppression.

Conclusions

The recommendations aim to provide the government entities and health professionals that care for leishmaniasis patients in the Americas with knowledge on management of the disease. Barriers are discussed (related to human resources, knowledge of guidelines, inputs, costs, access, and patient access), as well as facilitators and strategies to support implementation.

Socioecological vulnerability and the risk of zoonotic disease emergence in Brazil

In developing countries, outbreaks of zoonotic diseases (ZDs) result from intertwined ecological, socioeconomic, and demographic processes that shape conditions for (i) increased contact between vulnerable human population and wildlife in areas undergoing environmental degradation and (ii) the rapid geographic spread of infections across socially vulnerable regions. In Brazil, recent increases in environmental and social vulnerabilities, amplified by economic and political crises, are potential triggers for outbreaks. We discuss Brazilian features that favor outbreaks and show a novel quantitative method for zoonotic risk assessment. Using data on nine ZDs from 2001 to 2019, we found that the most significant causal variables were vegetation cover and city remoteness. Furthermore, 8 of 27 states presented low-level risk of ZD outbreaks. Given the ZD-bushmeat connection, we identified central hunted mammals that should be surveilled to prevent spillover events. The current challenge is to coordinate intersectoral collaboration for effective One Health management in megadiverse countries with high social vulnerability and growing environmental degradation like Brazil.

Interaction between environmental and socioeconomic determinants for cutaneous leishmaniasis risk in Latin America

OBJECTIVE

Determine and characterize potential risk areas for the occurrence of cutaneous leishmaniasis (CL) in Latin America (LA).

METHOD

Ecological observational study with observation units defined by municipalities with CL transmission between 2014-2018. Environmental and socioeconomic variables available for at least 85% of the municipalities were used, combined in a single database, utilizing the R software. The principal component analysis methodology was combined with a hierarchical cluster analysis to group clusters of municipalities based on their similarity. The V-test was estimated to define the positive or negative association of the variables with the clusters and separation by natural breaks was used to determine which ones contributed the most to each cluster. Information on cases was also incorporated in the analyses to attribute CL risk for each cluster.

RESULTS

This study included 4,951 municipalities with CL transmission (36.5% of the total in LA) and seven clusters were defined by their association with 18 environmental and socioeconomic variables. The historical risk of CL is positively associated with the Amazonian, Andean and Savannah clusters in a decreasingly manner; and negatively associated with the Forest evergreen, Forest/crop and Forest/populated clusters. The Agricultural cluster did not reveal any association with the CL cases.

CONCLUSIONS

The study made it possible to identify and characterize the CL risk by clusters of municipalities and to recognize the epidemiological distribution pattern of transmission, which provides managers with better information for intersectoral interventions to control CL.

A follow-up study (2007-2018) on American Tegumentary Leishmaniasis in the municipality of Caratinga, Minas Gerais State, Brazil: Spatial analyses and sand fly collection

Background

The municipality of Caratinga is an important endemic area for American Tegumentary Leishmaniasis (ATL) and no epidemiological studies were performed during the past two decades. Here, we analyzed the epidemiological situation and the geographical distribution of ATL cases in the municipality of Caratinga from 2007 to 2018 using geographic information systems (GIS). Also, we evaluated the impact of several demographic parameters in ATL distribution and the sand flies incriminated in its transmission.

Methods

All demographic information (gender, age, educational level, clinical form, diagnostic criteria and case evolution) used in this study was retrieved from the public health archives and confirmed in the State Health Services databases. All cases were analyzed using GIS software based on ATL distribution. Also, non-systematic sand fly collections and molecular detection of Leishmania were performed in the hotspots.

Results and conclusions

During the period, ATL cases continued and increased especially in the past years (2016–2018). Hotspots included urban Caratinga areas and the districts of Patrocínio de Caratinga and Sapucaia. The species Nyssomyia whitmani, Nyssomyia intermedia, Migonemyia migonei and Evandromyia cortelezzii complex were captured. However, ITS1-PCR did not detect Leishmania DNA in those insects. Based on our analyses, urbanization of ATL in Caratinga has occurred in the past years. Due to the increase in the number of cases and vectors presence, it is recommended that health authorities focus on control measures in the most affected areas (Patrocínio of Caratinga and Sapucaia districts and urban Caratinga).

Leishmaniasis is an important health problem in Latin American countries and worldwide. In some places, notification is limited and underreported hindering correct assessment of existing data. In Brazil, ATL is mainly caused by Leishmania (Viannia) braziliensis. It is transmitted by sand fly vectors Nyssomyia whitmani and Nyssomyia intermedia. ATL comprises different clinical manifestations including cutaneous leishmaniasis, muco-cutaneous leishmaniasis and atypical leishmaniasis. The objective is to present the spatial distribution of cases of ATL notified by the Public Health System of Caratinga between the period of 2007 and 2018. This city is one of the most important endemic areas in the State of Minas Gerais and compose the panel of knowledge on epidemiological aspects of cutaneous leishmaniasis caused by L. braziliensis. This information will be important for developing strategies for ATL control in the affected areas. There is strong evidence that supports ATL urbanization in the city of Caratinga and increase of cases in two rural districts (Sapucaia and Patrocínio de Caratinga).

[Interaction among environmental and socioeconomic determinants of risk for cutaneous leishmaniasis in Latin AmericaInteração entre os determinantes ambientais e socioeconômicos para o risco de leishmaniose cutânea na América Latina]

OBJECTIVE

Determine and characterize areas at potential risk for the occurrence of cutaneous leishmaniasis (CL) in Latin America.

METHOD

Ecological observational study with observation units defined by municipalities with CL transmission during 2014-2018. Environmental and socioeconomic variables available for at least 85% of municipalities were combined in a single database, using R software. Principal component analysis was combined with hierarchical cluster analysis for the formation of clusters of municipalities according to their similarity. The V-test was used to define positive or negative association of variables with clusters and separation by natural divisions to determine which contributed more to each cluster. Cases were included to attribute CL risk for each cluster.

RESULTS

The study included 4 951 municipalities with CL transmission (36.5% of municipalities in Latin America); seven clusters were defined by their association with 18 environmental and socioeconomic variables. Historical risk of CL is associated positively and in descending order with the Amazonian, Andean, and Savanna clusters; and negatively with the Forest/perennial, Forest/cultivated, and Forest/populated clusters. The Agricultural cluster showed no association with CL cases.

CONCLUSIONS

The study made it possible to identify and characterize CL risk by clusters of municipalities and to understand the characteristic epidemiological distribution patterns of transmission, providing program managers with better information for intersectoral interventions to control CL.

American Tegumentary Leishmaniasis in an endemic municipality in the North of Minas Gerais State: spatial analysis and socio-environmental factors

American Tegumentary Leishmaniasis (ATL) is endemic in the municipality of Montes Claros, Minas Gerais State. The use of geotechnology such as spatial statistics and remote sensing has contributed to a better understanding of the eco-epidemiology of diseases, and consequently a better definition of control strategies. This study aimed to analyze the spatial distribution of probable sites of cases of ATL infection (2007-2011) in the municipality of Montes Claros and to identify related socio-environmental factors. Data on ATL cases notification were obtained from the Municipal Health Department of Montes Claros. The annual incidence of ATL in the municipality was calculated and the probable sites of infection were georeferenced. Crude Rate and the Local Empirical Bayesian Rate were calculated with census sectors considered as the unit of analysis. The Normalized Difference Vegetation Index (NDVI) was calculated from LANDSAT 5 TM images. The spatial association between the crude rate of ATL and the NDVI of the census tracts was evaluated using the Local Bivariate of Moran I. The socio-environmental aspects of household structures were assessed based on a structured questionnaire. The incidence of ATL in the evaluated period ranged from 6.2 to 16.6 cases/100,000 inhabitants. The highest rates of ATL occurrence were found in the census sectors located in the rural area and in the peripheral census sectors in the city. Through the Empirical Bayes Smoothed Rate map, it was found that in the peripheral areas of the city, the rates of ATL occurrence were lower than in the rural area and their values decreased as they approach the city center. Local Bivariate of Moran I showed a positive correlation between NDVI and crude ATL rates, with significant high-high clusters observed in the rural area and in the census sectors in the Western peripheral area of the city that have experienced an urban expansion concomitant to the period investigated. In most homes of people affected by the disease, there were domestic animals and organic matter in the peridomicile. In addition, a high percentage of individuals affected by ATL reported the presence of rodents circulating near their homes. In conclusion, it is possible that the disorderly expansion process in the city of Montes Claros favored the establishment of the ATL periurban and urban transmission cycle. These regions deserve special attention from health surveillance to combat this zoonosis.