RESUMO
Bolivia has the highest incidence of Chagas disease (CD) worldwide. Caused by the parasite Trypanasoma cruzi, CD is generally a chronic condition. Diagnosis is logistically and financially challenging, requiring at least two different laboratory-based serological tests. Many CD cases are missed; in Bolivia it is estimated just 6% of individuals chronically infected with T. cruzi get diagnosed. Achieving control on the way to elimination of CD requires a radical simplification of the current CD testing pathways, to overcome the barriers to accessing CD treatment. We aimed to generate unbiased performance data of lateral flow assays (LFAs) for T. cruzi infection in Bolivia, to evaluate their usefulness for improving T. cruzi diagnosis rates in a precise and efficient manner. This retrospective, laboratory-based, diagnostic evaluation study sought to estimate the sensitivity/specificity of 10 commercially available LFAs for T. cruzi, using the current CD diagnostic algorithm employed in Bolivia as the reference test method. All tests were blinded at the study site and performed by three operators. In total, 470 serum samples were tested, including 221 and 249 characterized as CD-positive/-negative, respectively. The LFAs were scored according to their relative importance using a decision-tree-based algorithm, with the mean decrease in Gini index as the scoring metric. The estimates of sensitivities ranged from 62.2-97.7% (95% confidence interval (CI) lower bound 55.0-94.7%); for specificities the range was 78.6-100% (95% CI lower bound 72.0-97.5%); 5/10 and 6/10 tests had sensitivity >90% and specificity >95%, respectively. Four LFAs showed high values of both sensitivity (93-95%) and specificity (97-99%). The agreement between 6 LFAs and the reference tests was almost perfect (Kappa 0.83-0.94). Most LFAs evaluated thus showed performances comparable with current laboratory-based diagnostic methods.
Assuntos
Doença de Chagas , Trypanosoma cruzi , Humanos , Bolívia , Estudos Retrospectivos , Doença de Chagas/parasitologia , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Chagas disease (CD), caused by the parasite Trypanosoma cruzi, is the most important endemic anthropozoonosis in Argentina. Since 2010, the World Health Organization has highlighted the urgent need to validate diagnostic systems that allow rapid detection of T. cruzi, infection in primary healthcare centers. Serological rapid diagnostic tests (RDTs) for T. cruzi, infection could be used to improve case management, as RDTs do not require specialized laboratories or highly trained staff to use them. We aimed to generate unbiased performance data of RDTs in Argentina, to evaluate their usefulness for improving T. cruzi, diagnosis rates. METHODS AND PRINCIPAL FINDINGS: This is a retrospective, laboratory-based, diagnostic evaluation study to estimate the clinical sensitivity/specificity of four commercially available RDTs for T. cruzi, using the Chagas disease diagnostic algorithm currently used in Argentina as the reference standard. In total, 400 serum samples were tested, 200 from individuals with chronic T. cruzi infection and 200 from individuals not infected with T. cruzi. All results were registered as the agreement of at least two operators who were blinded to the reference standard results. The sensitivity estimates ranged from 92.5-100% (95% confidence interval (CI) lower bound 87.9-98.2%); for specificity, the range was 76-96% (95% CI lower bound 69.5-92.3%). Most RDTs evaluated showed performances comparable with the reference standard method, showing almost perfect concordance (Kappa 0.76-0.92). CONCLUSIONS: Our study demonstrates that, under controlled laboratory conditions, commercially available RDTs for CD have a performance comparable to the Argentinian diagnostic algorithm, which is based on laboratory-based serological tests. For the next stage of our work, the RDTs will be evaluated in real-world settings.
Assuntos
Doença de Chagas , Trypanosoma cruzi , Humanos , Argentina/epidemiologia , Estudos Retrospectivos , População Urbana , Testes de Diagnóstico Rápido , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Anticorpos , Sensibilidade e Especificidade , Anticorpos AntiprotozoáriosRESUMO
BACKGROUND: Chagas disease is a public health challenge in Colombia, where only an estimated 1.2% of people at risk have accessed diagnosis, while less than 0.5% of affected people have obtained treatment. The development of simplified diagnostic algorithms would enable progress in access to diagnosis; however, the current diagnostic algorithm relies on at least two laboratory-based tests that require qualified personnel, processing equipment, and infrastructure, which are still generally lacking at the primary care level. Rapid diagnostic tests (RDTs) for Chagas disease could simplify diagnosis, but their performance in the epidemiological context of Colombia is not well known. METHODOLOGY: A retrospective analytical observational study of RDTs was performed to estimate the operational characteristics of 11 commercially available RDTs designed for in vitro detection of anti-T. cruzi IgG antibodies. The study was performed under controlled laboratory conditions using human serum samples. PRINCIPAL FINDINGS: Eleven RDTs were assessed, ten using 585 serum samples and one using 551 serum samples. Employing the current national diagnostic algorithm as a reference standard for serological diagnosis of chronic infection, the sensitivity of the assessed RDTs ranged from 75.5% to 99.0% (95% CI 70.5-100), while specificity ranged from 70.9% to 100% (95% CI 65.3-100). Most tests (7/11, 63.6%) had sensitivity above 90%, and almost all (10/11, 90.9%) had specificity above 90%. Five RDTs had both sensitivity and specificity above 90%. CONCLUSIONS/SIGNIFICANCE: The evaluation of these 11 commercially available RDTs under controlled laboratory conditions is a first step in the assessment of the diagnostic performance of RDTs in Colombia. As a next step, field studies will be conducted on available RDTs with sensitivity and specificity greater than 90% in this study, to evaluate performance in real world conditions, with the final goal to allow simplified diagnostic algorithms.
Assuntos
Doença de Chagas , Testes de Diagnóstico Rápido , Humanos , Colômbia/epidemiologia , Estudos Retrospectivos , Doença de Chagas/diagnóstico , AnticorposRESUMO
BACKGROUND: Mother-to-child transmission of Chagas disease (CD) has become a relevant problem in both endemic and non-endemic areas. METHODS: Description of the CUIDA Chagas Project - Communities United for Innovation, Development and Attention for Chagas disease'. RESULTS: Through innovative and strategic research, this project will provide improved diagnostic and treatment options as well as replicable implementation models that are adaptable to different contexts. CONCLUSIONS: By integrating test, treat and care actions for CD into primary health care practices, the burden of CD on people and health systems may be significantly reduced.
Assuntos
Doença de Chagas , Transmissão Vertical de Doenças Infecciosas , Bolívia/epidemiologia , Brasil/epidemiologia , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Doença de Chagas/prevenção & controle , Colômbia , Feminino , Humanos , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Paraguai/epidemiologiaRESUMO
ABSTRACT Background: Mother-to-child transmission of Chagas disease (CD) has become a relevant problem in both endemic and non-endemic areas. Methods: Description of the CUIDA Chagas Project - Communities United for Innovation, Development and Attention for Chagas disease'. Results: Through innovative and strategic research, this project will provide improved diagnostic and treatment options as well as replicable implementation models that are adaptable to different contexts. Conclusions: By integrating test, treat and care actions for CD into primary health care practices, the burden of CD on people and health systems may be significantly reduced.
RESUMO
Microbial explorations of hot springs have led to remarkable discoveries and improved our understanding of life under extreme conditions. The Andean Mountains harbor diverse habitats, including an extensive chain of geothermal heated water sources. In this study, we describe and compare the planktonic microbial communities present in five high-mountain hot springs with distinct geochemical characteristics, at varying altitudes and geographical locations in the Colombian Andes. The diversity and structure of the microbial communities were assessed by pyrosequencing the V5 - V6 region of the 16S rRNA gene. The planktonic communities varied in terms of diversity indexes and were dominated by the bacterial phyla Proteobacteria, Aquificae, Chloroflexi, Cyanobacteria, Firmicutes, Nitrospirae, and Thermotogae, with site-specific bacterial taxa also observed in some cases. Statistical analyses showed that these microbial communities were distinct from one another and that they clustered in a manner consistent with physicochemical parameters of the environment sampled. Multivariate analysis suggested that pH and sulfate were among the main variables influencing population structure and diversity. The results show that despite their geographical proximity and some shared geochemical characteristics, there were few shared operational taxonomic units (OTUs) and that community structure was influenced mainly by environmental factors that have resulted in different microbial populations.
Assuntos
Fontes Termais/microbiologia , Microbiologia da Água , Altitude , Chloroflexi/genética , Análise por Conglomerados , Colômbia , Cianobactérias/genética , Ecossistema , Euryarchaeota/genética , Genes Arqueais , Genes Bacterianos , Bactérias Gram-Negativas/genética , Fontes Termais/química , Concentração de Íons de Hidrogênio , Tipagem Molecular , Fitoplâncton/genética , Proteobactérias/genética , RNA Ribossômico 16S/genética , Sulfatos/químicaRESUMO
La identificación de genes para proteorodopsinas en aguas termales amplía el rango de ecosistemas en los cuales se encuentran estos genes, los que codifican para bombas de protones y pueden estar implicados en la productividad de estas comunidades microbianas acuáticas. (AU)
Assuntos
Águas Termais , Ecossistema Andino , Microbiologia da Água , Microrganismos AquáticosRESUMO
La identificación de genes para proteorodopsinas en aguas termales amplía el rango de ecosistemas en los cuales se encuentran estos genes, los que codifican para bombas de protones y pueden estar implicados en la productividad de estas comunidades microbianas acuáticas.
Assuntos
Águas Termais , Ecossistema Andino , Microbiologia da Água , Microrganismos AquáticosRESUMO
Proteorhodopsin (PR) sequences were PCR amplified from three Andean acidic hot spring samples. These sequences were similar to freshwater and marine PRs and they contained residues indicative of proton-pumping activity and of proteins that absorb green light; these findings suggest that PRs might contribute to cellular metabolism in these habitats.
Assuntos
Bactérias/genética , Bactérias/metabolismo , Fontes Termais/microbiologia , Consórcios Microbianos/genética , Rodopsina/genética , Altitude , Sequência de Aminoácidos , Água Doce/microbiologia , Luz , Filogenia , Rodopsina/análise , Rodopsinas Microbianas , Alinhamento de SequênciaRESUMO
The microbial community of a Colombian high mountain hot spring, El Coquito, was analyzed using three different culture-independent assessments of 16S ribosomal RNA genes: clone libraries, pyrosequencing of the V5-V6 hypervariable region, and microarray. This acidic spring had a diverse community composed mainly of Bacteria that shared characteristics with those from other hot springs and extreme acidic environments. The microbial community was dominated by Proteobacteria, Firmicutes, and Planctomycetes and contained chemotrophic bacteria potentially involved in cycling of ferrous and sulfur-containing minerals and phototrophic organisms, most of which were eukaryotic micro-algae. Despite the presence of a large proportion of novel, unclassified sequences, the taxonomic profiles obtained with each strategy showed similarities at higher taxonomic levels. However, some groups, such as Spirochaetes and Aquificae, were identified using only one methodology, and more taxa were detected with the gene array, which also shared more groups with the pyrosequencing data. Overall, the combined use of different approaches provided a broader view of the microbial community in this acidic hot spring.