Incidence and transmission patterns of tuberculosis among indigenous populations in Brazil.

Eunice Atsuko Cunha,Lucilaine Ferrazoli,Lee W Riley,Paulo Cesar Basta,Izaias Pereira da Costa,Rosalia Maia,Michael Robert Honer

doi:10.1590/0074-0276130082

Abstract

Approximately 10% of the Brazilian indigenous population lives in the state of Mato Grosso do Sul (MS), where a large number of new cases of tuberculosis (TB) are reported. This study was conducted to assess TB occurrence, transmission and the utility of TB diagnosis based on the Ogawa-Kudoh (O-K) culture method in this remote population. The incidence of TB was estimated by a retrospective review of the surveillance data maintained by the Notifiable Diseases Surveillance System for the study region. The TB transmission pattern among indigenous people was assessed by genotyping Mycobacterium tuberculosis isolates using the IS 6110 restriction fragment length polymorphism (RFLP) technique. Of the 3,093 cases identified from 1999-2001, 610 (~20%) were indigenous patients (average incidence: 377/100,000/year). The use of the O-K culture method increased the number of diagnosed cases by 34.1%. Of the genotyped isolates from 52 indigenous patients, 33 (63.5%) belonged to cluster RFLP patterns, indicating recently transmitted TB. These results demonstrate high, on-going TB transmission rates among the indigenous people of MS and indicate that new efforts are needed to disrupt these current transmissions.

Highlights

In Brazil, the incidence and mortality from tuberculosis (TB) decreased by 20% and 30% from 19902010, respectively
One particular challenge is the control of TB among remote populations, such as the indigenous populations of Brazil
M. tuberculosis isolates were genotyped according to a standardised IS6110 restriction fragment length polymorphism (RFLP) method described by van Embden et al (1993)

Summary

Introduction

In Brazil, the incidence and mortality from tuberculosis (TB) decreased by 20% and 30% from 19902010, respectively. The purpose of this study was to describe TB incidence and transmission patterns among indigenous people in MS during the period ranging from 1999-2001 and to assess the improvement in TB case detection based on the O-K culture method. Cases in which Mycobacterium tuberculosis was isolated from culture were included in the analysis of transmission patterns.

Objectives

Results

Conclusion