Leptospirosis in Mexico: Epidemiology and Potential Distribution of Human Cases

Abstract

BackgroundLeptospirosis is widespread in Mexico, yet the potential distribution and risk of the disease remain unknown.Methodology/Principal FindingsWe analysed morbidity and mortality according to age and gender based on three sources of data reported by the Ministry of Health and the National Institute of Geography and Statics of Mexico, for the decade 2000–2010. A total of 1,547 cases were reported in 27 states, the majority of which were registered during the rainy season, and the most affected age group was 25–44 years old. Although leptospirosis has been reported as an occupational disease of males, analysis of morbidity in Mexico showed no male preference. A total number of 198 deaths were registered in 21 states, mainly in urban settings. Mortality was higher in males (61.1%) as compared to females (38.9%), and the case fatality ratio was also increased in males. The overall case fatality ratio in Mexico was elevated (12.8%), as compared to other countries. We additionally determined the potential disease distribution by examining the spatial epidemiology combined with spatial modeling using ecological niche modeling techniques. We identified regions where leptospirosis could be present and created a potential distribution map using bioclimatic variables derived from temperature and precipitation. Our data show that the distribution of the cases was more related to temperature (75%) than to precipitation variables. Ecological niche modeling showed predictive areas that were widely distributed in central and southern Mexico, excluding areas characterized by extreme climates.Conclusions/SignificanceIn conclusion, an epidemiological surveillance of leptospirosis is recommended in Mexico, since 55.7% of the country has environmental conditions fulfilling the criteria that favor the presence of the disease.

Spatial distribution and spread potential of sixteenLeptospiraserovars in a subtropical region of Brazil

“…On the other hand, at serovar level, we did not observe a clear geographic pattern, which was also reflected in their environmental preferences, evidencing the diversity of environmental conditions where Leptospira exposure can occur. Recent efforts have been made to understand the environmental tolerances of Leptospira at serovar level (Fouts et al, ; Guernier et al, ; Jaeger, Loureiro, & Lilenbaum, ; Zarantonelli et al, ), as well as to identify potential risk areas for future leptospirosis outbreaks (Sánchez‐Montes et al, ; Zhao et al, ). However, there have been no studies able to forecast regions where high‐transmission risk exists and where disease surveillance and control strategies (e.g.…”

“…A comprehensive understanding of the geographic distribution and environmental factors that facilitate Leptospira infections will help to inform intervention and prevention strategies for humans and animals (Grooms, ; Lilenbaum & Martins, ; Sánchez‐Montes, Espinosa‐Martínez, Ríos‐Muñoz, Berzunza‐Cruz, & Becker, ; Zhao et al, ). Such assessments have been widely applied in epidemiology through ecological niche modelling (ENM) in disease ecology.…”

Sociodemographic and clinical characteristics of patients infected with Leptospira spp. treated at four hospitals in Medellín, Colombia, 2008-2013

“…Este estudio incluyó 119 pacientes hospitalizados con diagnóstico de leptospirosis, en quienes se encontró una mayor frecuencia de complicaciones, especialmente falla hepática y síndrome de Weil, y una mortalidad general similar a la reportada en Colombia, pero inferior a la informada en algunas series de casos en otros países (22)(23)(24)(25)(26)(27)(28)(29). Se encontró, además, que cerca del 10 % de los pacientes no recibió tratamiento antibiótico a pesar de encontrarse hospitalizado.…”

“…Aunque la frecuencia de complicaciones fue superior a la descrita en la mayoría de las series, la mortalidad no excedió la informada en otros estudios colombianos y en el Sistema Nacional de Vigilancia en Salud Pública (1,5 a 5 %) (6,15,18,22,24,31), y fue inferior a la reportada en las series de casos en otros países (7 a 22 %) (23)(24)(25)(26)(27)(28)(29)32,33). Esta disociación entre una mayor frecuencia de complicaciones y una menor mortalidad es difícil de explicar, especialmente si se tiene en cuenta el gran número de pacientes que presentó síndrome de Weil, complicación asociada con una mayor mortalidad (32)(33)(34).…”

Spatial distribution and spread potential of sixteen Leptospira serovars in a subtropical region of Brazil

“…A comprehensive understanding of the geographic distribution and environmental factors that facilitate Leptospira infections will help to inform intervention and prevention strategies for humans and animals (Grooms, 2006; Lilenbaum and Martins, 2014; Sánchez-Montes et al, 2015; Zhao et al, 2016). Such assessments have been widely applied in epidemiology through ecological niche modeling (ENM) in disease ecology.…”