A One Health Approach to Investigating Leptospira Serogroups and Their Spatial Distributions among Humans and Animals in Rio Grande do Sul, Brazil, 2013⁻2015.

Noemi Polo,Rogerio Rodrigues,Maria Schneider,Gustavo Machado,Patricia Nájera Hamrick,Marilina Bercini,Loeci Timm,Claudia Munoz-Zanzi,Martha Pereira

doi:10.3390/tropicalmed4010042

Abstract

Leptospirosis is an endemic zoonotic disease in Brazil and is widespread throughout rural populations in the state of Rio Grande do Sul. This study aimed to identify presumptive infecting Leptospira serogroups in human and animal cases and describe their occurrences within the ecoregions of the state by animal species. Data for human and animal leptospirosis cases were gathered from the government’s passive surveillance systems and presumptive infecting serogroups were identified based on a two-fold titer difference in serogroups in the microscopic agglutination test (MAT) panel. A total of 22 different serogroups were reported across both human and animal cases. Serogroup Icterohaemorrhagiae was the most common among humans, while serogroup Sejroe predominated among animal cases, particularly bovines. Each ecoregion had a large distribution of cases, with 51% of the human cases in the Parana–Paraiba ecoregion, and 81% of the animal cases in the Savannah ecoregion. Identifying and mapping the serogroups circulating using the One Health approach is the first step for further understanding the distribution of the disease in the state. This study has the potential to aid in guiding public health and agricultural practices, furthering the need for a human vaccine in high-risk populations to complement control and prevention efforts.

Highlights

Leptospirosis, a zoonotic bacterial disease, is one of the most important neglected tropical bacterial diseases in Latin America and the Caribbean and is among the leading zoonotic causes of morbidity worldwide [1]
* Species chi-squared of 87.942 p < 0.001 and for serogroup chi-squared of 446.88 p < 0.001. This spatial description of serogroups circulating in humans and animals within ecoregions allowed for further understanding of the complex epidemiology of leptospirosis in the state of Rio Grande do Sul
The findings from this study indicate a large variety of Leptospira presumptive infecting serogroups circulating within the state ecosystems among humans and in animal species

Summary

Introduction

Leptospirosis, a zoonotic bacterial disease, is one of the most important neglected tropical bacterial diseases in Latin America and the Caribbean and is among the leading zoonotic causes of morbidity worldwide [1] This zoonotic disease has a higher incidence in sub-tropical and impoverished populations in developing countries. It primarily affects vulnerable populations, with an estimated annual global incidence of 1.03 million people and 58,900 deaths [2,3]. Even so, this number is assumed to be an underestimate, as leptospirosis is commonly misdiagnosed with other febrile illnesses such as dengue, malaria, and chikungunya, and is likely underreported [2]; especially within rural populations where access to health facilities is limited and awareness of the disease is low. According to Schneider et al 2015 [6], the risk for contracting leptospirosis is eight times higher in rural populations within the state compared to the urban populations due to various environmental factors and agriculture practices

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