First molecular-based detection study of Leishmania infantum in the Tapirapé indigenous population in the Brazilian Amazon.

D.S.C Freitas,A.H.H Minervino,J.O.J Costa,R.E Silva,J.T.R Lima,A Marcili,D.V Markus,H.S Soares,S.M Gennari

doi:10.1590/1414-431x2021e11654

Abstract

Species of the genus Leishmania parasitize mammals and have life cycles that alternate between vertebrate and invertebrate hosts. Most species develop in a hematophagous arthropod and infect a specific vertebrate host that may belong to diverse orders and families. Visceral leishmaniasis is a chronic zoonosis with a wide geographic distribution, affecting 350 million people globally, mostly in areas with a high risk of infection. In Brazil, this disease not only has a high incidence but is also expanding to new areas, both in urban centers and rural areas, including territories with tribal communities, due to increasing human intervention. The objective of this study was to perform cathepsin L-like gene-based molecular diagnosis of Leishmania infantum in the indigenous Tapirapé ethnic group in the state of Mato Grosso. From the 372 individuals assessed, only 0.8% (3/372) tested positive for L. infantum, all from the same village (Urubu Branco). Despite the small number of infected individuals, this study demonstrates the first human cases of Leishmania infantum infection in this population, suggesting the need for regular monitoring of visceral leishmaniasis in the area and leading to a broad discussion on the planning and implementation of public health measures for the indigenous population, while respecting their distinctive territories and culture.

Highlights

Visceral leishmaniasis is classified as a zoonosis and is a neglected tropical disease with an estimated incidence of 50,000 to 90,000 new cases per year according to the World Health Organization (WHO)
Leishmaniasis is caused by Leishmania infantum [3,4], and the transmission cycle involves a sand fly vector belonging to the Lutzomyia genus of Phlebotominae subfamily [5] and a variety of vertebrate hosts
This study reports for the first time infections by Leishmania infantum in the Tapirapé indigenous population assessed by molecular tests, confirming the circulation of L. infantum in this population

Summary

Introduction

Visceral leishmaniasis is classified as a zoonosis and is a neglected tropical disease with an estimated incidence of 50,000 to 90,000 new cases per year according to the World Health Organization (WHO). The domestic dog is the main reservoir, and wild mammals such as marsupials, bats, horses, and felines are hosts of secondary epidemiological importance [6,7,8,9,10,11]. In this multifactorial epidemiological context, the disease is prevalent throughout Brazil, affecting many states and different biomes [12]. The northeast region of Brazil has the highest concentration of cases, but attention must be paid to frequently expanding areas with new cases, which bring transmission circuits closer to urban areas [13,14]

Objectives

Methods

Conclusion