Performance of diagnostic tests for pulmonary tuberculosis in indigenous populations in Brazil: the contribution of Rapid Molecular Testing.

OBJECTIVE: To evaluate the accuracy of rapid molecular testing as a diagnostic tool and estimate the incidence of smear-positive pulmonary tuberculosis among the indigenous population. METHODS: This is an epidemiological study based on secondary data. We calculated the incidence of smear-positive pulmonary tuberculosis between January 1st, 2011 and December 31, 2016, and the performance of bacilloscopy and rapid molecular testing in diagnosing pulmonary tuberculosis compared to sputum culture (standard test). RESULTS: We included 4,048 cases of indigenous people with respiratory symptoms who provided sputum samples for analysis. Among them, 3.7%, 6.7%, and 3.7% had positive results for bacilloscopy, sputum culture, and rapid molecular testing, respectively. The mean incidence of pulmonary tuberculosis was 269.3/100 thousand inhabitants. Rapid molecular testing had 93.1% sensitivity and 98.2% specificity, compared to sputum culture. Bacilloscopy showed 55.1% sensitivity and 99.6% specificity. CONCLUSIONS: Rapid molecular testing can be useful in remote areas with limited resources and a high incidence of tuberculosis, such as indigenous villages in rural regions of Brazil. In addition, the main advantages of rapid molecular testing are its easy handling, fast results, and the possibility of detecting rifampicin resistance. Together, these attributes enable the early start of treatment, contributing to reduce the transmission in communities recognized as vulnerable to infection and disease.

Performance of diagnostic tests for pulmonary tuberculosis in indigenous populations in Brazil: the contribution of Rapid Molecular Testing / Desempenho de testes para o diagnóstico de tuberculose pulmonar em populações indígenas no Brasil: a contribuição do Teste Rápido Molecular

ABSTRACT Objective: To evaluate the accuracy of rapid molecular testing as a diagnostic tool and estimate the incidence of smear-positive pulmonary tuberculosis among the indigenous population. Methods: This is an epidemiological study based on secondary data. We calculated the incidence of smear-positive pulmonary tuberculosis between January 1st, 2011 and December 31, 2016, and the performance of bacilloscopy and rapid molecular testing in diagnosing pulmonary tuberculosis compared to sputum culture (standard test). Results: We included 4,048 cases of indigenous people with respiratory symptoms who provided sputum samples for analysis. Among them, 3.7%, 6.7%, and 3.7% had positive results for bacilloscopy, sputum culture, and rapid molecular testing, respectively. The mean incidence of pulmonary tuberculosis was 269.3/100 thousand inhabitants. Rapid molecular testing had 93.1% sensitivity and 98.2% specificity, compared to sputum culture. Bacilloscopy showed 55.1% sensitivity and 99.6% specificity. Conclusions: Rapid molecular testing can be useful in remote areas with limited resources and a high incidence of tuberculosis, such as indigenous villages in rural regions of Brazil. In addition, the main advantages of rapid molecular testing are its easy handling, fast results, and the possibility of detecting rifampicin resistance. Together, these attributes enable the early start of treatment, contributing to reduce the transmission in communities recognized as vulnerable to infection and disease.

RESUMO Objetivo: Avaliar a acurácia do teste rápido molecular como ferramenta diagnóstica e estimar a incidência de casos pulmonares positivos entre a população indígena. Métodos: Estudo epidemiológico baseado em dados secundários. Foi calculada a incidência de casos de tuberculose pulmonar positiva entre 1° de janeiro de 2011 e 31 de dezembro de 2016, e o desempenho da baciloscopia e do teste rápido molecular no diagnóstico de tuberculose pulmonar, em comparação à cultura de escarro (teste padrão). Resultados: Foram incluídos 4.048 casos de indígenas considerados sintomáticos respiratórios, que forneceram amostras de escarro para análise. Destes, 3,7%, 6,7% e 3,7% apresentaram resultados positivos para baciloscopia, cultura e teste rápido molecular, respectivamente. A incidência média de tuberculose pulmonar foi de 269,3/100 mil habitantes. A sensibilidade do teste rápido molecular, em relação à cultura, foi 93,1% e a especificidade foi 98,2%. A baciloscopia apresentou sensibilidade 55,1% e especificidade 99,6%. Conclusões: O teste rápido molecular pode ser útil em áreas remotas, com recursos limitados e incidência de tuberculose elevada, como as aldeias indígenas nas áreas rurais do país. Ademais, o teste rápido molecular apresenta como principais vantagens o fácil manuseio, os resultados rápidos e a possibilidade de identificar a resistência à rifampicina. Em conjunto, esses atributos facilitam o início do tratamento precoce, contribuindo para reduzir a transmissão em comunidades reconhecidamente vulneráveis à infecção e à doença.

[Leprosy in indigenous populations of Amazonas State, Brazil: an epidemiological study in the counties of Autazes, Eirunepé and São Gabriel da Cachoeira (2000 to 2005)]. / Hanseníase em populações indígenas do Amazonas, Brasil: um estudo epidemiológico nos municípios de Autazes, Eirunepé e São Gabriel da Cachoeira (2000 a 2005).

In 2005, Amazonas State, Brazil, showed hyperendemic leprosy detection coefficients and prevalence with medium endemicity. Although this State has the largest indigenous population in Brazil, there are no data on the leprosy profile in these groups. This study aimed to describe and analyze the epidemiological characteristics of leprosy case reporting in the municipalities (counties) of Autazes, Eirunepé, and São Gabriel da Cachoeira, comparing indigenous and non-indigenous findings according to target variables. A total of 386 cases reported to SINAN from 2000 to 2005 were analyzed. Mean detection rates were 3.55, 14.94, and 2.13/10,000 (among non-indigenous) and 10.95, 1.93, and 0.78/10,000 (among indigenous peoples) in Autazes, Eirunepé, and São Gabriel da Cachoeira, respectively. Paucibacillary cases predominated among both indigenous and non-indigenous populations; however, dimorphous cases represented one-third of notifications. Despite coverage limitations and underreporting, the findings suggest that leprosy is a major public health problem for indigenous populations in Amazonas State. Classification according to race/ethnicity has been a useful tool for solving health inequalities.

Hanseníase em populações indígenas do Amazonas, Brasil: um estudo epidemiológico nos municípios de Autazes, Eirunepé e São Gabriel da Cachoeira (2000 a 2005) / Leprosy in indigenous populations of Amazonas State, Brazil: an epidemiological study in the counties of Autazes, Eirunepé and São Gabriel da Cachoeira (2000 to 2005)

In 2005, Amazonas State, Brazil, showed hyperendemic leprosy detection coefficients and prevalence with medium endemicity. Although this State has the largest indigenous populationin Brazil, there are no data on the leprosy profile in these groups. This study aimed to describe and analyze the epidemiological characteristics of leprosy case reporting in the municipalities (counties) of Autazes, Eirunepé, and São Gabriel da Cachoeira, comparing indigenous and nonindigenousfindings according to target variables.A total of 386 cases reported to SINAN from 2000 to 2005 were analyzed. Mean detection rates were 3.55, 14.94, and 2.13/10,000 (among nonindigenous) and 10.95, 1.93, and 0.78/10,000 (among indigenous peoples) in Autazes, Eirunepé, and São Gabriel da Cachoeira, respectively. Paucibacillary cases predominated among both indigenous and non-indigenous populations; however, dimorphous cases represented one-thirdof notifications. Despite coverage limitations and underreporting, the findings suggest that leprosy is a major public health problem for indigenouspopulations in Amazonas State. Classification according to race/ethnicity has been a useful tool for solving health inequalities.

O Estado do Amazonas, Brasil, apresentou, em 2005, coeficientes hiperendêmicos de detecção de hanseníase e prevalência de média endemicidade. O estado detém a maior população indígena no país, mas inexistem informações sobre o perfil da hanseníase nesses grupos. O estudo objetivou a descrição e análise das características epidemiológicas das notificações de hanseníase nos municípios de Autazes, Eirunepé e São Gabriel da Cachoeira, comparando achados entre indígenas e não indígenas, segundo variáveis de interesse. Foram analisados os casos notificados no SINAN, no período de 2000 a 2005. Do total de 386 casos notificados, verificaram- se coeficientes médios de detecção de 3,55, 14,94 e 2,13/10 mil (entre os não indígenas) e de 10,95, 1,93 e 0,78/10 mil (para os indígenas), para Autazes,Eirunepé e São Gabriel da Cachoeira, respectivamente. Houve predomínio de casos paucibacilares em indígenas e em não indígenas, no entanto, a forma dimorfa representou 1/3 das notificações. Apesar das limitaçõesde cobertura e do sub-registro, os achados sugerem que a hanseníase representa importante problema de saúde pública para os indígenas no Amazonas. A classificação segundo “raça/etnicidade” se constituiu em ferramenta útil para elucidar desigualdades em saúde.

[Role of HLA-DR and HLA-DQ alleles in multibacillary leprosy and paucibacillary leprosy in the province of Chaco (Argentina)]. / Papel de las moléculas HLA-DR y HLA-DQ en la lepra multibacilar y paucibacilar en la provincia del Chaco; Argentina.

OBJECTIVES: Segregation analyses in several populations have suggested a relationship between specific human leukocyte antigen (HLA) class II alleles and the development of different types of leprosy. The aim of this study was to determine the frequency of HLA class II DR and DQ alleles among leprosy patients in Chaco province, northeast Argentina, in an effort to determine whether these alleles might be involved in the development of the multibacillary (MB) and paucibacillary (PB) forms of leprosy. PATIENTS AND METHODS: Samples from 89 leprosy patients (MB = 70, PB = 19) and 112 healthy control subjects were analyzed. The HLA-DRB1 and HLA-DQB1 alleles were determined by PCR amplification and reverse hybridization with sequence-specific oligonucleotide probes, and analyzed with the INNO-LiPA typing system and LiPA software. DQB1*0201/0202/0203 in patients with MB leprosy and DRB1*04 in patients with PB leprosy were detected at significantly lower frequencies as compared with the normal controls. RESULTS: These data indicate that DQB1* 0201/0202/0203 may be a protective factor in MB leprosy and DRB1*04 in PB leprosy. DISCUSSION: We attribute the differences between our findings and those of other authors to the fact that the Caucasian inhabitants of Chaco include a considerable mixture of South American natives (Guaraníes and Tobas).