Leprosy Transmission in Amazonian Countries: Current Status and Future Trends

Roxane Schaub,Carolina Talhari,Josafá Barreto,Karin Sewpersad,Lucibel Crespo,Heather Morris-Wilson,Richard W Truman,Purna Dwivedi,Pierre Couppié,Nora Cardona-Castro,John Jairo Dávila,Alberto Paniz-Mondolfi,Pedro Legua,Pushpendra Singh,Benoit De Thoisy,Maria Paredes Larrea,Rodolphe E Gozlan,Charlotte Avanzi,Ramanuj Lahiri

doi:10.1007/s40475-020-00206-1

Abstract

Purpose of ReviewLeprosy is one of the first pathologies described in the history of mankind. However, the ecology, transmission, and pathogenicity of the incriminated bacilli remain poorly understood. Despite effective treatment freely distributed worldwide since 1995, around 200,000 new cases continue to be detected yearly, mostly in the tropics. This review aims to discuss the unique characteristics of leprosy in Amazonian countries, which exhibit a very heterogeneous prevalence among human and animal reservoirs.Recent FindingsGroundbreaking discoveries made in the last 15 years have challenged the dogmas about leprosy reservoirs, transmission, and treatment. The discovery of a new leprosy causative agent in 2008 and the scientific proof of zoonosis transmission of leprosy by nine-banded armadillos in the southern USA in 2011 challenged the prospects of leprosy eradication. In the Amazonian biome, nine-banded and other armadillo species are present but the lack of large-scale studies does not yet allow accurate assessment of the zoonotic risk. Brazil is the second country in the world reporting the highest number of new leprosy cases annually. The disease is also present, albeit with different rates, in all neighboring countries. Throughout the Amazonian biome, leprosy is mainly found in hyperendemic foci, conducive to the emergence and transmission of drug-resistant strains.SummaryThe deepening of current knowledge on leprosy reservoirs, transmission, and therapeutic issues, with the One Health approach and the help of molecular biology, will allow a better understanding and management of the public health issues and challenges related to leprosy in Amazonia.

Highlights

Leprosy, called Hansen’s disease, is a chronic mycobacterial infection of the peripheral nerves and skin that generally manifests as loss of sensation and skin patches
This is the first time that all studies carried out in this region have been brought together and put into perspective, highlighting the unique characteristics concerning the epidemiology of leprosy in the Amazonian biome and surrounding regions
Pockets of high human leprosy endemicity within global areas of medium endemicity and the presence of armadillos, the most important non-human reservoir of M. leprae known to date, characterize leprosy epidemiology in this region

Summary

Introduction

Called Hansen’s disease, is a chronic mycobacterial infection of the peripheral nerves and skin that generally manifests as loss of sensation and skin patches. The disease presents over a broad clinical and histopathological spectrum [1] and is caused by the closely related pathogens Mycobacterium leprae and M. lepromatosis [2] These obligate intracellular bacteria are clinically indistinguishable and uncultivable in vitro, but molecular diagnostic tests were recently developed using species-specific primers for polymerase chain reaction-based detection [3, 4]. We aim to discuss the unique characteristics of leprosy epidemiology in the Amazonian countries that combine high and low prevalence areas, as well as the potential role of the sole animal reservoir known to date in this region. This is the first review focusing on global leprosy epidemiology in the Amazonian biome and its surroundings

A Contrasted Continental Pattern

20 Euphractus sexcinctus

Paniz-Mondolfi, personal data

Findings

Conclusions