Geographic patterns and environmental factors associated with human yellow fever presence in the Americas.

BACKGROUND: In the Americas, yellow fever virus transmission is a latent threat due to the proximity between urban and wild environments. Although yellow fever has nearly vanished from North and Central America, there are still 13 countries in the Americas considered endemic by the World Health Organization. Human cases usually occur as a result of the exposure to sylvatic yellow fever in tropical forested environments; but urban outbreaks reported during the last decade demonstrate that the risk in this environment still exists. The objective of this study was to identify spatial patterns and the relationship between key geographic and environmental factors with the distribution of yellow fever human cases in the Americas. METHODOLOGY/PRINCIPAL FINDINGS: An ecological study was carried out to analyze yellow fever human cases reported to the Pan American Health Organization from 2000 to 2014, aggregated by second administrative level subdivisions (counties). Presence of yellow fever by county was used as the outcome variable and eight geo-environmental factors were used as independent variables. Spatial analysis was performed to identify and examine natural settings per county. Subsequently, a multivariable logistic regression model was built. During the study period, 1,164 cases were reported in eight out of the 13 endemic countries. Nearly 83.8% of these cases were concentrated in three countries: Peru (37.4%), Brazil (28.1%) and Colombia (18.4%); and distributed in 57 states/provinces, specifically in 286 counties (3.4% of total counties). Yellow fever presence was significantly associated with altitude, rain, diversity of non-human primate hosts and temperature. A positive spatial autocorrelation revealed a clustered geographic pattern in 138/286 yellow fever positive counties (48.3%). CONCLUSIONS/SIGNIFICANCE: A clustered geographic pattern of yellow fever was identified mostly along the Andes eastern foothills. This risk map could support health policies in endemic countries. Geo-environmental factors associated with presence of yellow fever could help predict and adjust the limits of other risk areas of epidemiological concern.

The Use of Chemoprophylaxis after Floods to Reduce the Occurrence and Impact of Leptospirosis Outbreaks.

Record-breaking and devastating rainfall events have occurred in the past decade. Rain and floods are considered the main risk factors for leptospirosis and several outbreaks have been reported following extreme weather events. In such situations, one possible intervention to prevent leptospirosis cases in high-risk groups is the use of chemoprophylaxis. However, not enough evidence of its effect is available. The objectives of this study were to review the literature on the current practices of chemoprophylaxis for leptospirosis and to explore, using a mathematical model, how various chemoprophylaxis scenarios may affect the progression of a leptospirosis outbreak. Twenty-six peer-reviewed publications were selected (10 quantitative studies, two systematic reviews and 14 articles of other types). Oral doxycycline was the most used antibiotic for chemoprophylaxis of leptospirosis. Post-exposure prophylaxis was assessed in four studies following a natural disaster. Although evidence of the effectiveness of post-exposure prophylaxis is inconsistent, the direction of association supported a protective effect for morbidity and mortality. The theoretical model showed how the assumed benefit of chemoprophylaxis was influenced by the time and rate of administration. Future models should consider the heterogeneity of affected communities, improved estimates of the effect of chemoprophylaxis on leptospirosis infection and disease, as well as potential detrimental impacts. Additional research is critical to provide clear evidence-based recommendations for leptospirosis control during an outbreak. The results of this study suggest that chemoprophylaxis may provide some protection in reducing the number of leptospirosis cases after a high-risk exposure; however, the effective benefit may depend on a variety of factors such as the timing and coverage of prophylaxis. The information summarized can be used to support decision-making during a high-risk event.

Leptospirosis in Latin America: exploring the first set of regional data.

OBJECTIVES: To demonstrate the importance of country surveillance systems for leptospirosis and their use for preliminary epidemiological analysis, as well as to generate research questions for future, morecomprehensive studies on the disease. METHODS: In 2015, for the first time, the Pan American Health Organization (PAHO) included human cases of leptospirosis in its Regional Core Health Data Initiative, an open-access database that collects annual health indicators from the countries and territories of the Americas. This new information was used to analyze leptospirosis cases by country and sex and to calculate cumulative incidence rates. Maps were used to help present the results. To supplement that general review of leptospirosis in the Americas, more detailed descriptions of the epidemiological situation and the surveillance programs of four selected countries (Brazil, Colombia, Cuba, and Honduras) were provided. RESULTS: In this first year of PAHO requesting leptospirosis data, of the 49 countries and territories in the Americas, 38 of them (77.6%) reported information. Among those 38, 28 of them (73.7%) reported the presence of human cases; the majority of instances of zero cases were in Caribbean territories. From those 28, a total of 10 702 human cases were recorded. The largest numbers of cases in Latin America were in Brazil (40.2%), Peru (23.6%), Colombia (8.8%), and Ecuador (7.2%). The cumulative incidence rate for Latin America was estimated to be 2.0 per 100 000 population. On average, 65.1% of cases were males. CONCLUSIONS: This study demonstrates that many countries in Latin America are making efforts to establish strong surveillance systems and programs for leptospirosis. The study also shows the importance of having leptospirosis surveillance systems as well as how the information generated can be used for evidence-based decision-making on leptospirosis.

Leptospirosis in Latin America: exploring the first set of regional data / La leptospirosis en América Latina: exploración del primer conjunto de datos regionales / Leptospirose na América Latina: avaliação do primeiro conjunto de dados regionais

ABSTRACT Objectives To demonstrate the importance of country surveillance systems for leptospirosis and their use for preliminary epidemiological analysis, as well as to generate research questions for future, more comprehensive studies on the disease. Methods In 2015, for the first time, the Pan American Health Organization (PAHO) included human cases of leptospirosis in its Regional Core Health Data Initiative, an open-access database that collects annual health indicators from the countries and territories of the Americas. This new information was used to analyze leptospirosis cases by country and sex and to calculate cumulative incidence rates. Maps were used to help present the results. To supplement that general review of leptospirosis in the Americas, more detailed descriptions of the epidemiological situation and the surveillance programs of four selected countries (Brazil, Colombia, Cuba, and Honduras) were provided. Results In this first year of PAHO requesting leptospirosis data, of the 49 countries and territories in the Americas, 38 of them (77.6%) reported information. Among those 38, 28 of them (73.7%) reported the presence of human cases; the majority of instances of zero cases were in Caribbean territories. From those 28, a total of 10 702 human cases were recorded. The largest numbers of cases in Latin America were in Brazil (40.2%), Peru (23.6%), Colombia (8.8%), and Ecuador (7.2%). The cumulative incidence rate for Latin America was estimated to be 2.0 per 100 000 population. On average, 65.1% of cases were males. Conclusions This study demonstrates that many countries in Latin America are making efforts to establish strong surveillance systems and programs for leptospirosis. The study also shows the importance of having leptospirosis surveillance systems as well as how the information generated can be used for evidence-based decision-making on leptospirosis.

RESUMEN Objetivos Demostrar la importancia de los sistemas nacionales de vigilancia de la leptospirosis y su uso para realizar el análisis epidemiológico preliminar, así como para generar preguntas de investigación que se utilicen en futuros estudios más integrales sobre la enfermedad. Métodos En el año 2015, la Organización Panamericana de la Salud (OPS) incluyó por primera vez casos humanos de leptospirosis en su Iniciativa Regional de Datos Básicos de Salud, base de datos de acceso abierto que recoge indicadores de salud anuales de los países y territorios de la Región de las Américas. Esta nueva información fue utilizada para analizar los casos de leptospirosis por país y sexo, así como para calcular las tasas de incidencia acumulada, y los resultados se presentaron en mapas. Para complementar ese examen general de la leptospirosis en esta Región, se aportó una descripción más detallada de la situación epidemiológica y los programas de vigilancia de cuatro países (Brasil, Colombia, Cuba y Honduras). Resultados En este primer año en que la OPS solicitó datos sobre la leptospirosis, de los 49 países y territorios en la Región de las Américas, aportaron información 38 (77,6 %). De esos 38, 28 (73,7 %) notificaron casos humanos; la mayor parte de las instancias sin ningún caso humano se registraron en territorios del Caribe. En esos 28 países y territorios, se registraron 10 702 casos humanos. En América Latina, los países que registraron los números más altos de casos fueron Brasil (40,2 %), Perú (23,6 %), Colombia (8,8 %) y Ecuador (7,2 %). Se calculó que la tasa de incidencia acumulada de América Latina es de 2,0 por 100 000 habitantes. En promedio, 65,1 % de los casos correspondieron a hombres. Conclusiones Este estudio demuestra que muchos países de América Latina están tomando medidas para instaurar sistemas y programas sólidos de vigilancia de la leptospirosis. Asimismo, revela la importancia de los sistemas de vigilancia de la leptospirosis, así como el modo en que la información generada puede servir para tomar decisiones basadas en la evidencia acerca de esta enfermedad.

RESUMO Objetivos Demonstrar a importância dos sistemas nacionais de vigilância para a leptospirose e seu uso na análise epidemiológica preliminar, além de gerar perguntas de pesquisa para futuros estudos mais aprofundados sobre a doença. Métodos Em 2015, a Organização Pan-Americana da Saúde (OPAS) incluiu, pela primeira vez, casos humanos de leptospirose em sua Iniciativa Regional de Dados Básicos de Saúde, uma base de dados de acesso aberto que coleta indicadores de saúde anuais nos países e territórios das Américas. Utilizamos estas novas informações para analisar os casos de leptospirose por país e por sexo e calcular as taxas de incidência acumuladas. A apresentação dos dados é facilitada pelo uso de mapas. Para complementar esta revisão geral da leptospirose nas Américas, apresentamos descrições mais detalhadas da situação epidemiológica e dos programas de vigilância de quatro países selecionados (Brasil, Colômbia, Cuba e Honduras). Resultados Neste primeiro ano em que a OPAS solicitou dados sobre a leptospirose, 38 dos 49 países e territórios das Américas (77,6%) apresentaram informações. Destes 38, 28 (73,7%) notificaram a presença de casos humanos; em sua maioria, os que não apresentaram nenhum caso foram territórios do Caribe. Dentre os 28, foi registrado um total de 10.702 casos humanos. O maior número de casos na América Latina foi observado no Brasil (40,2%), Peru (23,6%), Colômbia (8,8%) e Equador (7,2%). A taxa de incidência acumulada para a América Latina foi estimada em 2,0 por 100.000 habitantes. Em média, 65,1% dos casos foram em homens. Conclusões Este estudo demonstra que muitos países da América Latina estão fazendo esforços para estabelecer fortes sistemas de vigilância e programas contra a leptospirose. O estudo também revela a importância da existência de sistemas de vigilância para a leptospirose e demonstra que as informações geradas podem ser usadas para a tomada de decisões baseadas em evidências científicas para a leptospirose.