[Temporal analysis of the relationship between leptospirosis and the occurrence of flooding due to rainfall in the city of Rio de Janeiro, Brazil, 2007-2012]

Spatiotemporal assessment of pathogenic Leptospira in subtropical coastal watersheds

The World Health Organization classifies leptospirosis as a significant public health concern, predominantly affecting impoverished and unsanitary regions. By using the Pensacola Bay System as a case study, this study examines the underappreciated susceptibility of developed subtropical coastal ecosystems such as the Pensacola Bay System to neglected zoonotic pathogens such as Leptospira. We analyzed 132 water samples collected over 12 months from 44 distinct locations with high levels of Escherichia coli (>410 most probable number/100 mL). Fecal indicator bacteria (FIB) concentrations were assessed using IDEXX Colilert-18 and Enterolert-18, and an analysis of water physiochemical characteristics and rainfall intensity was conducted. The LipL32 gene was used as a quantitative polymerase chain reaction (qPCR) indicator to identify the distribution of Leptospira interrogans. The results revealed 12 instances of the presence of L. interrogans at sites with high FIB over various land cover and aquatic ecosystem types. Independent of specific rainfall events, a seasonal relationship between precipitation and elevated rates of fecal bacteria and leptospirosis was found. These findings highlight qPCR's utility in identifying pathogens in aquatic environments and the widespread conditions where it can be found in natural and developed areas.

Occurrence of serological reactions for Leptospira spp. in donkeys and mules from Minas Gerais, Brazil

Research concerning leptospirosis in donkeys and mules has been neglected around the world. Therefore, the aim of this study was to investigate the epidemiological situation of the prevalence of anti-Leptospira spp. antibodies in donkeys and mules from the state of Minas Gerais, Brazil. Blood serum samples were collected from 180 animals (109 donkeys and 71 mules) in two rural properties from the state of Minas Gerais, Brazil, and then submitted to a microscopic agglutination test (MAT). Urea and creatinine values were also quantified. Epidemiological variables such as age, breeding system, contact with other animal species, source of water and food, vaccination against leptospirosis, presence of reproductive alterations, and rodent control were also investigated. From 180 samples collected, 39 (21.67%) showed positive results in the MAT, at a dilution ≥ 1:100. Some animals were reactive for more than one serovar. The serovar Tarassovi was the most frequent (14.07%), followed by Hardjo (11.85%) and Wolffi (11.11%). There was a statistically significant difference between animals from 0 to 3 years of age reactive in the MAT in comparison to the other age groups. Most of the animals had urea and creatinine concentrations within the acceptable reference limit; however, there was a significant increase in creatinine levels in some of the test animals. The studied properties showed differences in some epidemiological aspects such as vaccination of the animals, presence of reproductive problems in the herd, and rodent control. Such aspects pointed as risk factors that may influence the frequency of positive serological results in property 1. The present study demonstrated that the prevalence of leptospirosis in donkeys and mules is high and several serovars are being maintained by these animals, representing a potential public health risk.

Spatiotemporal clustering, social inequities and the risk of leptospirosis in an endemic area of Brazil: a retrospective spatial modelling

BACKGROUND

Leptospirosis is an endemic disease in Brazil of social and economic relevance related to behavioural and socioenvironmental factors. This study aimed to analyse the spatiotemporal distribution of the incidence of leptospirosis and its association with social determinants in health in a state of northeastern Brazil.

METHODS

An ecological study of temporal series with techniques of spatial analysis using secondary data of the cases of leptospirosis notified in the Information System of Notifiable Diseases of the state of Sergipe (2008-2017) was conducted. The analysis of temporal trends was performed using Poisson regression. Spatial analyses were performed using the Moran index, the local empirical Bayesian model, scan statistics and spatial regression.

RESULTS

The incidence rate decreased from 3.66 to 1.44 cases per 100 000 inhabitants in 2008 and 2017, respectively. Leptospirosis was associated with social inequities, mostly affecting males aged 20-49 y living in urban areas. The space-time scan indicated the formation of a risk cluster in municipalities in the metropolitan region of the state.

CONCLUSIONS

The data indicated the persistence of leptospirosis transmission, maintaining a pattern of high endemicity in some municipalities associated with social inequities. The study showed the temporal and spatial dynamics of the disease to better target specific actions for prevention and control.

Human leptospirosis in the municipality of São Paulo, SP, Brazil: distribution and trend according to sociodemographic factors, 2007-2016

OBJECTIVES

This study aimed to describe the incidence and proportional lethality of human leptospirosis in the municipality of São Paulo, between 2007 and 2016, according to sociodemographic factors and characteristics of the disease, and to assess the temporal trends of incidence, according to age group and region of residence.

METHODS

Proportional distributions of leptospirosis cases of residents in the municipality were built and regression models with a Binomial Negative response were adjusted.

RESULTS

2,201 cases of leptospirosis were registered, most of them being males (82%), aged between 20 to 59 years (64.6%), white (39%) or brown (32.8%), residing in the South (27.8%), East (23.8%) and North (18.5%) regions. The overall lethality was 15.1%. The risk was higher in the 20 to 59 age group. There was a downward trend in incidence in all age groups and regions, estimated at 5.6% per year.

CONCLUSIONS

Despite the downward trend in incidence, leptospirosis is a serious disease with high lethality, affecting mainly male individuals in the age groups considered economically active and living in the peripheral regions of the municipality.

[Floods and leptospirosis in Brazilian municipalities from 2003 to 2013: use of data mining techniques]

Leptospirosis is related to problems with environmental sanitation, and the incidence tends to increase during flood periods. Considering issues related to climate change, floods can be expected to increase. Floods do not affect populations homogeneously, and communities with worse socioeconomic conditions tend to be impacted more heavily. In order to determine whether the number of floods increases the incidence of leptospirosis and its relationship to contextual variables, the study used socioeconomic, environmental, and disease occurrence data at the municipal (county) level. Municipalities suffering problems with sewage disposal showed a higher risk of leptospirosis incidence. Total flooding since the municipality's declaration of flood emergency was an important risk marker for leptospirosis incidence. Regression tree modeling proved useful for estimating leptospirosis incidence in Brazil.

Análise espacial da leptospirose no Brasil

RESUMO A leptospirose é um problema de saúde pública mundial. No Brasil, ela é uma doença de notificação compulsória e está relacionada a áreas com precárias condições sanitárias. Foi realizado um estudo ecológico retrospectivo para observar a distribuição espacial e temporal de casos confirmados da leptospirose em escala nacional no período entre 2007 e 2017. A espacialização da leptospirose utilizou técnicas de geoprocessamento por análise de padrões pontuais e por mapas de densidade Kernel. Os resultados revelaram que, no período, foram registrados 42.310 casos confirmados de leptospirose no País, com média anual de 3.846 casos e prevalência de 1,9 a cada 100 mil habitantes. As localidades com mais casos prevalentes foram as regiões Sul e Norte. O Sudeste apresentou taxa de prevalência inferior à taxa nacional em virtude da alta densidade demográfica. O método Kernel se mostrou útil na análise global da situação epidemiológica da leptospirose nas regiões do Brasil.

Vigilância em saúde e desastres de origem natural: uma revisão da literatura

RESUMO As projeções climáticas para o final do século XXI sugerem a intensificação de eventos extremos que podem causar danos diretos e indiretos à saúde pública e impactar, em diferentes proporções, as populações vulneráveis. Nesse âmbito, destaca-se a vigilância em saúde por suas relevantes ações em todas as etapas de gestão de risco dos desastres. O objetivo deste artigo foi realizar uma revisão da literatura científica sobre a vigilância em saúde e desastres de origem natural, com intuito de descrever as principais abordagens desses temas. Observou-se que as publicações têm como assunto central os efeitos dos desastres sobre a saúde; as ações do setor saúde em desastres, o sistema/fluxo de informação em saúde e as condições de vulnerabilidade aos desastres. Os dois primeiros tópicos são mais prevalentes na literatura e permitem o compartilhamento das lições aprendidas ao longo dos anos. Embora em menor número, os dois últimos temas apresentam discussões relevantes para a temática da gestão de risco de desastres e têm muito a contribuir para o avanço da cultura de risco no País, para uma melhor compreensão da realidade e para a resiliência tanto populacional quanto institucional. Nesse sentido, ressalta-se a importância de mais estudos sobre essas temáticas.

Relationship between cases of hepatitis A and flood areas, municipality of Encantado, Rio Grande do Sul, Brazil

The relationship between hydrometeorological disasters and the health of affected populations is still hardly discussed in Rio Grande do Sul (RS), Brazil. Hepatitis A is a disease that involves health and urban environment issue and is an avoidable disease. This study aims to analyze the relationship between flood areas and waterborne diseases, in this case, Hepatitis A. A database of confirmed cases of Hepatitis A and flood events in the municipality of Encantado-RS, Brazil between 2012 and 2014 was structured. These data were analyzed spatially from the kernel estimator of the occurrence points of Hepatitis A cases and correlated to the urban perimeter. It was verified that 44 cases were registered in the three months following the occurrence of flood, an increase of almost 300% in the records of Hepatitis A. The results identified that all the confirmed cases are in the urban area located in the floodplain. This reaffirms the importance of encouraging the formulation and implementation of policies to prevent outbreaks of waterborne diseases post hydrometeorological disaster.

Leptospirosis in Campinas, São Paulo, Brazil: 2007-2014

OBJECTIVE

to analyze the distribution of leptospirosis according to sociodemographic, epidemiologic, and clinical characteristics, assistance time, rainfall and spatial distribution in Campinas/SP in the period from 2007 to 2014.

METHOD

This is an ecological study using information from the confirmed cases. A descriptive analysis was carried out according to the selected variables. The relationship between the cases and rainfall was verified through the Spearman's correlation coefficient. The cases/deaths were georeferenced per areas classified according to socioenvironmental deprivation indexes in Campinas.

RESULTS

From the 264 cases, 76.1% occurred in men, 58,4% in the 20 to 49 years old age range. Approximately 55% were hospitalized, with a prevalence of clinical-laboratorial diagnoses of 89.4%, and the lethality was 10.6%. The urban area concentrated 74.2% of the cases, and 48,9% occurred in the household environment. The main risk factor was evidence of the presence of rodents at the site. There was strong correlation between the incidence of cases and rainfall (p < 0.05) in 2010 to 2012. A higher concentration of the cases was observed in the Center-Southwest region. Spatial distribution of cases/deaths showed clusters in regions classified at lower socioeconomic levels.

CONCLUSIONS

The patterns of occurrence of leptospirosis in Campinas showed similarity with other Brazilian municipalities. The identification of areas with higher incidence of cases/deaths contributes to the adoption of strategies for intervention and prioritization of resources aiming at the reduction of the risk of infection and at early treatment for those affected.

Temporal analysis of the relationship between leptospirosis, rainfall levels and seasonality, Santa Catarina, Brazil, 2005-2015

The objective of the study is to analyze the temporal trend of leptospirosis incidence, according to rainfall levels in Santa Catarina, according to seasonality, from 2005 to 2015. This is an ecological study of time series, with date of leptospirosis, rainfall levels and population. The incidence rates of leptospirosis, relative excess of incidence, Pearson's correlation coefficient (r) and an angular coefficient (β) were analyzed from the linear regression adjustment, with a 5% significance level. Distribution of leptospirosis cases, rainfall levels and cases reason/rainfall levels, stratified by month of occurrence were presented. There were 5,274 cases of leptospirosis, with the monthly average being 439 cases, ranging from 211 in September to 770 in January. The mean rate of leptospirosis was 7.03 per 100,000 habitants. The average rainfall level was 158.68 mm, with the lowest levels occurring in August, average of 124.9 mm, and the highest in January average of 213.20 mm. The positive correlation between leptospirosis rates and rainfall levels, during the period from January to December (r = 0.68, p = 0.023), indicates a positive temporal association between the amount of rainfall and the cases of the disease. The disease occurred all year round and presented a distinct seasonality from October to March.

Human leptospirosis as a doubly neglected disease in Brazil

The aim of this article is to analyze discrepancies and informational gaps which produce a doubly neglected version of human leptospirosis in the Brazilian public health policy. To achieve this goal, we compared data on morbidity, mortality, hospital and social costs, population profiles, vector habits, social health determinants and diagnostic practices related to leptospirosis with another disease of higher recognition in Brazil: dengue fever. Our analysis shows that the arbitrariness of criteria for assigning health priorities, the invisibility of the population profile of human leptospirosis in official data and its mimetic character in clinic corroborate the production of a version of human leptospirosis that is invisible and, because of that, doubly neglected by the Brazilian public health policy. We conclude that these discrepancies and informational gaps are related to the fact that human leptospirosis affects a population which the State has no interest in keeping alive.

Analysis of the spatial distribution of scientific publications regarding vector-borne diseases related to climate variability in South America

Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. Rainfall, temperature, and other climate variables affect in many ways both the vectors and the pathogens they transmit. Likewise, climate can be determinant in outbreaks incidence. A growing number of studies have provided evidence indicating the effects of climate variability on vector-borne diseases. However, oftentimes, the different diseases and regions are not uniformly represented, scarcity or lack of publications in some countries is common. The objectives of this work were to analyze the distribution and abundance of publications on vector-borne diseases associated with climate variability in South America, identify those works that conducted a geographic analysis and detect the countries where outbreaks occurred and the climate variables with which they were associated. A systematic review of the literature published on vector-borne diseases linked to climate variability in South America was conducted, identifying, evaluating and summarizing scientific papers. The distribution of the study areas and disease type in the publications were represented on maps. Dengue and leishmaniasis were the most studied and widely represented diseases in South America. The country with the largest number of published papers and presence of all disease types was Brazil. Outbreaks of disease were related to different climate variables. Most diseases from the publications under study occurred in equatorial and tropical climates. The disease represented by the largest number of different types of climates was dengue. The technique used in this work allowed us to determine the status of knowledge of the main diseases associated with climate variability in South America. This methodology could be improved in the future by incorporating other bibliographic sources as well as other diseases related to climate variability.

Análise sociodemográfica e ambiental para ocorrência de anticorpos antiLeptospira em cães de Teresina, Piauí, Brasil

Resumo A leptospirose é uma zoonose mundial cuja transmissão está interligada por múltiplos fatores na interface homem-animal-ecossistema. Objetivou-se com este estudo avaliar os fatores de risco para a ocorrência de anticorpos antiLeptospira em cães na capital Teresina (PI), e determinar sua distribuição espacial. Amostras sanguíneas de 558 cães foram submetidas à prova de Soroaglutinação Microscópica (SAM). Aplicou-se questionários semiestruturados para os proprietários dos cães e obteve-se a localização geográfica da residência para a sua projeção em mapas geográficos. A soroprevalência foi de 13,8%, no qual o sorogrupo mais frequente foi o Icterohaemorrhagiae com 49,2%. Foram considerados fatores de risco os cães com acesso à rua, o não recolhimento da vasilha de alimento e a baixa renda dos proprietários. Foi observado maior número de cães soropositivos no período chuvoso com 87,1%, sendo um possível fator de risco para a ocorrência de casos. A distribuição dos cães soropositivos na cidade se apresentou de forma dispersa, com predominância dos casos em área antropizada. Esses fatores de risco favorecem a ocorrência de anticorpos antiLeptospiraem cães, os quais podem ser fontes de manutenção do agente na cidade e reforça a necessidade de vigilância epidemiológica e ambiental na prevenção da leptospirose.

Estudo espacial de riscos à leptospirose no município do Rio de Janeiro (RJ)

RESUMO A leptospirose é relevante para saúde pública pela sua gravidade e modo de disseminação, cuja ocorrência é maior em local com vulnerabilidade socioambiental. No município do Rio de Janeiro, os casos estariam relacionados com sua estrutura social e espacial. Analisou-se a espacialidade da leptospirose nesse município, de 2000 a 2010, por meio de mapas e observações de campo. Resultados sugeriram que os bairros de Barra de Guaratiba, Pedra de Guaratiba e Grumari foram de alto risco - locais com estruturas sanitárias precárias e constantes alagamentos. Ações da Vigilância em Saúde são de grande importância na identificação e intervenção em locais de situações risco à saúde.

Leptospirosis: risk factors and management challenges in developing countries

Leptospirosis is a widespread bacterial zoonosis with highest burden in low-income populations living in tropical and subtropical regions, both in urban and in rural environments. Rodents are known as the main reservoir animals, but other mammals may also significantly contribute to human infections in some settings. Clinical presentation of leptospirosis is nonspecific and variable, and most of the early signs and symptoms point to the so-called “acute fever of unknown origin”, a major diagnostic challenge in tropical and subtropical areas. However, leptospirosis can rapidly evolve to life-threatening complications, especially if left untreated. There is a need for good awareness of leptospirosis and rapid antibiotic treatment based on clinical and epidemiological suspicion. Severe leptospirosis cases include renal and/or respiratory failure and shock, necessitating intensive care, also seldom available or with limited capacity. Confirmation of leptospirosis relies on biological diagnosis, which unfortunately uses tricky methods seldom available. This biological confirmation, however, is essential for surveillance and public health purpose. A good knowledge of leptospirosis epidemiology (eg, the reservoir animals involved, the Leptospira strains circulating, the seasonal and geographical patterns, and specific populations at risk) can be achieved through adequate surveillance and diagnosis. This can pave the way to prevention and intervention strategies and in turn alleviate the toll leptospirosis takes on affected populations. Over the past few years, leptospirosis has been increasingly recognized, as the need for multidisciplinary approaches in a One-Health perspective has been acknowledged, raising hope to successfully tackle the challenges of this zoonosis.

An Unprecedented High Incidence of Leptospirosis in Futuna, South Pacific, 2004 - 2014, Evidenced by Retrospective Analysis of Surveillance Data

Futuna is a small Polynesian island in the South Pacific with a population of 3,612 in 2013. The first human leptospirosis case was confirmed in 1997. Active surveillance started in 2004. Cases were confirmed by PCR or real time PCR, or by serology using MAT or a combination of IgM-ELISA and MAT. A retrospective analysis of surveillance data shows that the disease was endemic with a mean annual incidence of 844 cases per 100,000 over an 11-year period from 2004 to 2014. An epidemic peak as high as 1,945 cases per 100,000 occurred in 2008. Serogroup Australis was predominant until 2007, Icterohaemorrhagiae was dominant afterwards. Cluster analysis revealed different hot spots over time. Lifestyle habits, such as walking barefoot in irrigated taro fields or pig pens probably contributed to contamination from the swine and rodent reservoirs to humans. Severe forms were rare, and the case fatality rate was 0.5%. The medical community and general population were aware of leptospirosis and rapid treatment with amoxycillin was the main treatment, probably contributing to this low fatality rate.