Use of a Latent Class Analysis in the Diagnosis of Chronic Chagas Disease in the Washington Metropolitan Area.

BACKGROUND: The diversity of individuals at risk for Trypanosoma cruzi infection in the United States poses challenges for diagnosis. We evaluated the diagnostic accuracy of Food and Drug Administration (FDA)-cleared tests in the Washington Metropolitan area (WMA). METHODS: In total, 1514 individuals were evaluated (1078 from Mexico, Central and northern South America [TcI-predominant areas], and 436 from southern South America [TcII/V/VI-predominant areas]). Optical density (OD) values from the Hemagen EIA and Chagatest v.3 Wiener, and categorical results of the IgG-TESA-blot (Western blot with trypomastigote excretory-secretory antigen), and the Chagas detect plus (CDP), as well as information of area of origin were used to determine T. cruzi serostatus using latent class analysis. RESULTS: We detected 2 latent class (LC) of seropositives with low (LC1) and high (LC2) antibody levels. A significantly lower number of seropositives were detected by the Wiener, IgG-TESA-blot, and CDP in LC1 (60.6%, P < .001, 93.1%, P = .014, and 84.9%, P = .002, respectively) as compared to LC2 (100%, 100%, and 98.2%, respectively). LC1 was the main type of seropositives in TcI-predominant areas, representing 65.0% of all seropositives as opposed to 22.8% in TcII/V/VI-predominant areas. The highest sensitivity was observed for the Hemagen (100%, 95% confidence interval [CI]: 96.2-100.0), but this test has a low specificity (90.4%, 95% CI: 88.7-91.9). The best balance between positive (90.9%, 95% CI: 83.5-95.1), and negative (99.9%, 95% CI: 99.4-99.9) predictive values was obtained with the Wiener. CONCLUSIONS: Deficiencies in current FDA-cleared assays were observed. Low antibody levels are the main type of seropositives in individuals from TcI-predominant areas, the most frequent immigrant group in the United States.

Chagas disease knocks on our door: a cross-sectional study among Latin American immigrants in Milan, Italy.

OBJECTIVES: We aimed to assess the prevalence and risk factors for Chagas disease (CD) in Latin American immigrants and to evaluate the accuracy of diagnostic tests. Moreover, we offered to all positive subjects a complete free-of-charge clinical/instrumental evaluation as well as benznidazole treatment in order to stage the disease and verify drug tolerability. METHODS: A cross-sectional survey of CD among Latin Americans living in Milan and its metropolitan area was conducted between July 2013 and July 2014. Blood samples were tested for serologic evidence of CD together with a questionnaire covering demographic and clinical-epidemiological information. RESULTS: Forty-eight (9.6%) of the 501 tested subjects were conclusively diagnosed as having CD. The highest prevalence of CD was among those from Bolivia (43/169, 25.4%) and El Salvador (4/68, 5.9%). Older age (adjusted odds ratio (aOR)] 1.05, p =0.004), a Bolivian origin (aOR 8.80; p =0.003), being born in the department of Santa Cruz (aOR 3.72, p =0.047), having lived in mud houses (aOR 2.68; p =0.019), and having an affected relative (aOR 12.77, p =0.001) were independently associated with CD. The ARCHITECT Chagas test showed the highest sensitivity (100%) and specificity (99.8%). Twenty-nine of the subjects with CD (60.4%) underwent disease staging, 10 of whom (35.7%) showed cardiac and/or digestive involvement. Benznidazole treatment was associated with high frequency of adverse reactions (19/27, 70.4%) and permanent discontinuation (8/27, 29.6%). CONCLUSIONS: CD is highly prevalent among Bolivians and Salvadorans living in Milan. Regions with a large Latin American immigrant population should implement programmes of active detection and treatment.

Equity in health: tuberculosis in the Bolivian immigrant community of São Paulo, Brazil.

OBJECTIVES: To analyse the profile of tuberculosis (TB) among Bolivian immigrants, investigate the impact that this population has on the trends of TB and assess equity in access to TB treatment, in the city of São Paulo, Brazil. METHODS: Descriptive study of the epidemiological profile of TB in four city districts with large Bolivian populations, comparing cases among Brazilians and Bolivians, during the 1998-2008 period was carried out. We used logistic regression to adjust the treatment outcome for potential confounders. RESULTS: We identified 2056 new TB cases: 65.7% in Brazilians, 32.1% in Bolivians and 2.2% among other nationalities. Although TB incidence remained stable (high) over the study period, the annual proportion of cases among Bolivians increased from 15.0% to 53.0%. In comparison with the Brazilians, the Bolivians were younger (median age, 24 vs. 40 years; P < 0.0001) and presented a lower unemployment rate (3.1%vs. 11.6%; P < 0.0001), a lower rate of HIV co-infection (1.5%vs. 28.5%; P< 0.001), a higher proportion of individuals receiving supervised treatment (81.5%vs. 62.0%; P < 0.0001) and a higher proportion of cures (71.6%vs. 63.2%; P< 0.0001). After having been adjusted for potential confounder, cure after treatment was not associated with nationality. CONCLUSIONS: Bolivian immigrants influenced the incidence but not the trends of TB among Brazilians in the study area. We found no significant differences between Bolivians and Brazilians regarding healthcare access or treatment outcome. Guaranteed universal health care access for all, including undocumented individuals, contributes to health equity. Specific intervention strategies are warranted for immigrants with tuberculosis.

Nuevas formas de muestreo para minorías y poblaciones ocultas: muestras por encuestado conducido en una población de inmigrantes sudamericanos / New forms of sampling for minority and hidden populations: respondent samples conducted in a south american immigrant population

El Respondent-Driven Sampling (RDS) es un método de muestreo para poblaciones ocultas o de difícil acceso. Se trata de un procedimiento que permite realizar estimaciones de la representatividad de la muestra en aquellos grupos en que desconocemos el marco muestral. En este estudio, se presenta tanto la descripción teórica de dicha forma de muestreo como el reporte de su aplicación práctica en el caso de minorías étnicas (inmigrantes bolivianos, peruanos y colombianos) en el norte de Chile. El estudio comenzó con ocho semillas y se reclutó una muestra total de 109 personas provenientes de Colombia, Perú y Bolivia. La información resultante del procedimiento RDS informa de un patrón similar de reclutamiento entre hombres y mujeres, reflejando que los tamaños de las redes de ambos grupos no difieren significativamente.

The Respondent-Driven Sampling (RDS) is a method of sampling for hidden or hard-to-reach populations. This is a procedure for estimating the representativeness of the sample in those groups that is unknow the sampling frame. This study presents both the theoretical description of this form of sampling as the report of its practical application in the case of ethnic minorities (immigrants Bolivians, Peruvians and Colombians) in northern Chile. The study started with 8 seeds and recruited a total sample of 109 people from Colombia, Peru and Bolivia. The information resulting from the procedure RDS reports a similar pattern of recruitment for men and women, reflecting the sizes of the networks of both groups did not differ significantly.

Equidade em saúde: o caso da tuberculose na comunidade de bolivianos no município de São Paulo / Equity in health: the case of tuberculosis in the bolivian community in São Paulo municipality

Descrever o comportamento da tuberculose (TB) na comunidade boliviana residente em quatro distritos do município de São Paulo (MSP), Belém, Bom Retiro, Brás e Pari, no período de 1998 a 2008, analisar seu possível impacto na tendência dessa doença e investigar possíveis disparidades em relação ao acesso aos serviços e na qualidade do atendimento entre bolivianos e brasileiros. Metodologia: Estudo descritivo de casos notificados de TB entre migrantes bolivianos. Os dados foram obtidos junto à vigilância da TB do MSP. As variáveis de interesse foram: características sócio-demográficas, aspectos diagnósticos, clínicos e terapêuticos, comportamentais, co-morbidades e indicadores de acesso aos serviços e de qualidade do atendimento. A análise foi efetuada comparando a as variáveis de interesse entre pacientes de nacionalidade boliviana e brasileira residentes nos mesmos distritos. Para a comparação de proporções aplicamos o teste do qui-quadrado ou teste exato de Fisher e para médias o teste de Kruskal-Wallis. Resultados: Foram notificados 2434 casos de TB nos distritos estudados, dos quais 67,5 por cento, 30,4 por cento e 2,1 por cento eram, respectivamente de nacionalidade brasileira, boliviana e outras; a participação boliviana foi crescente no período, elevando-se de 15 por cento para 53 por cento dos casos; observando­ se uma queda de 43,5 por cento no número absoluto de casos entre os brasileiros e um incremento de 250 por cento entre bolivianos. A incidência na área de estudo em 2008 era 3,5 vezes maior do que a verificada, em média, no MSP. Comparados aos brasileiros os bolivianos eram mais jovens (média: 26 versus 39 anos; p<=0,0001) e a prevalência de desemprego entre eles era mais baixa (2,4 por cento versus 10,4 por cento; p<0,0001). Para o período de 2006 a 2008, os bolivianos apresentam taxas mais elevada de cura (70,9 por cento versus 62,1 por cento; p<0,001) e de tratamento supervisionado (81,9 por cento versus 62,2 por cento; p<0,001)...

Describing the tuberculosis in the bolivian community resident in the districts of Belém, Bom Retiro, Bras and Pari, located in the municipality of São Paulo (MSP), in the period 1998 to 2008, analyze its possible difference in relation to access services and quality of health care among bolivians and brazilians. Methods: Descriptive study of notified cases of TB among bolivian immigrants. The data are obtained from the TB surveillance of the MSP. The variables of interest were socio-demographic characteristics, diagnostic aspects, clinical and therapeutical, behavioral, comorbidities and indicators of access to services and quality of care. The analysis was performed comparing the variables between bolivians and brazilians patients residing in the same districts. For comparison of proportion was applied the chi-square test or Fisher exact test and for means the Kruskal-Wallis test. Results: Were reported 2434 TB cases in districts studied, whom 67,5%, 30,4% e 2,1% were respectively brazilians, bolivians and others nationalities; the bolivian participation increased in the period, rise from 15% to 53% of all cases, observing a drop of 43,5% in the absolute numbers of cases among the brazilians and a increase of 250% among bolivians. The incidence in study area in 2008 was 3,5 times greater than that seen on average in MSP. Compared to brazilians, bolivians were younger (mean: 26 versus 39 years, p=0.0001 and the prevalence of unemployment was lowest (2,4% versus 10,4%, p<0,0001. In 2006 to 2008, bolivians have higher rates of cure (70,9 versus 62,1%, p<0,001) and supervised treatment (81,9% versus 62,2%), and lower rates of TB in past (6,9% versus 16,9%, p<0,0001)...