Comparison between the classical and artificial xenodiagnosis in chronical Chagas' disease

O xenodiagnóstico (xeno) clássico e artificial feitos com Dipatalogaster maximus de primeiro estágio foi realizado simultaneamente em 57 pacientes com infecção chagásica crônica (22 do sexo masculino e 35 do sexo feminino, com idades entre 7 e 80 anos). Exceto dois pacientes com clínica de megaesôfago, os demais tinham dois exames sorológicos prévios positivos sendo feita nova sorológia no decorrer do estudo. Os pacientes eram provenientes do ambulatório do Hospital Universitário de Brasília (HUB) ou eram residentes no município de Mambaí, GO. Dos 57 pacientes, 24 (42%) apresentaram xenodiagnósticos positivos. Dos 114 xenodiagnósticos realizados, 36 (32%) foram positivos. A comparação das duas técnicas não mostrou diferença estatisticamente significante (p = 0,42), porém o xeno artificial apresenta vantagem porque o sangue é oferecido aos triatomíneos através de um aparelho enquanto, no xeno clássico, os triatomíneos sugam através da pele do paciente.Classical and artificial xenodiagnostic techniques made with Dipetalogaster maximus of first stage were performed simultaneously in 57 patients with chronic T. cruzi infection (22 male and 35 female patients, aged 7-80 years). With the exception of two patients with megaoesophagus, all had two previous positive serological reaction and a further test was done at the time of the examination. The patients came from the outpatient department of the university hospital or were resident in Mambaí, Goiás. Of the 57 patients, 24 (42%) had a positive xenodiagnoses. Of a total of 114 tests performed, 36(32%) were positive. Comparing the two xenodiagnostic techniques, no significant advantage was apparent statistically (p = 0,42), but the artificial technique has advantages because the blood is offered for triatomines through a device while in the classical technique, the triatomines suck through the patient's skin

The national survey of seroprevalence for evaluation of the control of Chagas disease in Brazil (2001-2008)

Um inquérito de soroprevalência de doença de Chagas foi realizado em amostra representativa da população com idade até cinco anos de toda a área rural brasileira, exceto o Estado do Rio de Janeiro. Foram estudadas 104.954 crianças, que tiveram amostras de sangue coletadas em papel de filtro e submetidas a testes de screening pelas técnicas de imunofluorescência indireta (IFI) e ELISA em um único laboratório. Todas as amostras com resultados positivos ou indeterminados, juntamente com 10% daquelas com resultados negativos, foram enviadas para um laboratório de referência e aí submetidas a novos testes por IFI e ELISA, além de western blot TESA (Trypomastigote Excreted Secreted Antigen). Para as crianças com resultado final positivo foi agendada uma re-visita para coleta de sangue venoso do próprio participante e das suas mães e familiares. Da avaliação do conjunto de testes resultaram 104 (0,1%) resultados positivos, dos quais apenas 32 (0,03%) foram confirmadas como infectadas. Destas, 20 (0,02%) com positividade materna concomitante (sugerindo transmissão congênita), 11 (0,01%) com positividade apenas na criança (indicativo de provável transmissão vetorial), e uma criança positiva cuja mãe havia falecido. Em 41 situações ocorreu confirmação apenas nas mães, sugerindo transferência passiva de anticorpos maternos; em 18 a positividade não se confirmou nem nas crianças nem nas suas mães; e em 13 não foi possível a localização de ambas. As 11 crianças que adquiriram a infecção por provável via vetorial distribuíram-se predominantemente na região nordeste (Piauí, Ceará, Rio Grande do Norte, Paraíba e Alagoas), acrescidas de um caso no Amazonas e um no Paraná. Dos 20 casos com provável transmissão congênita sobressaiu-se o Rio Grande do Sul, com 60% deles, representando este o primeiro relato de diferenças regionais na transmissão congênita da doença de Chagas no Brasil, possivelmente relacionada à existência de Trypanosoma cruzi grupo IId e IIe, atualmente classificados como TcV e TcVI. Os resultados deste inquérito apontam para a virtual inexistência de transmissão de doença de Chagas por via vetorial no Brasil em anos recentes, resultante da combinação dos programas regulares e sistemáticos de combate á moléstia e de mudanças de natureza socioeconômica observadas no país ao longo das últimas décadas. Por outro lado, reforçam a necessidade de manutenção de um programa de controle que garanta a consolidação deste grande avanço.A survey for seroprevalence of Chagas disease was held in a representative sample of Brazilian individuals up to 5 years of age in all the rural areas of Brazil, with the single exception of Rio de Janeiro State. Blood on filter paper was collected from 104,954 children and screened in a single laboratory with two serological tests: indirect immunofluorescence and enzyme linked immunoassay. All samples with positive or indetermined results, as well as 10% of all the negative samples were submitted to a quality control reference laboratory, which performed both tests a second time, as well as the western blot assay of TESA (Trypomastigote Excreted Secreted Antigen). All children with confirmed final positive result (n = 104, prevalence = 0.1%) had a follow-up visit and were submitted to a second blood collection, this time a whole blood sample. In addition, blood samples from the respective mothers and familiar members were collected. The infection was confirmed in only 32 (0.03%) of those children. From them, 20 (0.025%) had maternal positive results, suggesting congenital transmission; 11 (0.01%) had non-infected mothers, indicating a possible vectorial transmission; and in one whose mother had died the transmission mechanism could not be elucidated. In further 41 visited children the infection was confirmed only in their mothers, suggesting passive transference of maternal antibodies; in other 18, both child and mother were negative; and in 13 cases both were not localized. The 11 children that acquired the infection presumably through the vector were distributed mainly in the Northeast region of Brazil (States of Piauí, Ceará, Rio Grande do Norte, Paraíba and Alagoas), in addition to one case in Amazonas (North region) and another in Parana (South region). Remarkably, 60% of the 20 cases of probably congenital transmission were from a single State, Rio Grande do Sul, with the remaining cases distributed in other states. This is the first report demonstrating regional geographical differences in the vertical transmission of Chagas disease in Brazil, which probably reflects the predominant Trypanosoma cruzi group IId and IIe (now TcV and TcVI) found in this state. Overall, these results show that the regular and systematic control programs against the transmission of Chagas disease, together with socioeconomic changes observed in Brazil in the last decades, interrupted the vectorial transmission in Brazil, resumed in the few cases found in this national survey. Furthermore they reinforce the need for maintenance of control programs for the consolidation of this major advance in public health

Seroprevalence of American trypanosomiasis in adults in an area of the western Brazilian Amazon region

Foi realizado no período de janeiro a março de 2001 um inquérito soroepidemiológico para tripanossomíase americana (doença de Chagas) em populações humanas, urbana e rural, de áreas da bacia do alto Purus, Amazônia Ocidental Brasileira, através de testagem em série utilizando três técnicas sorológicas. A amostra foi constituída de 1. 055 indivíduos, 844 da área urbana e 211 da área rural. Foi identificada a infecção autóctone em nove indivíduos, cinco da área urbana e quatro da área rural, com idades variando entre 16 e 72 anos. As prevalências estimadas de infecção chagásica foram: 0,6% (IC95% 0,2-1,4) e 1,9% (IC95% 0,6-4,5) para as áreas urbana e rural respectivamente. Observou-se aparente tendência à aglomeração: sete eram naturais do rio Purus, três residiam na mesma localidade, dois habitavam o mesmo domicílio.From January to March 2001 a seroepidemiological survey for American trypanosomiasis (Chagas disease) was carried out among urban and rural human populations in areas of the Upper Purus basin, in the western Brazilian Amazon region, using serial testing with three different serological techniques. The sample was composed of 1,055 individuals: 844 from urban and 211 from rural areas. Autochthonous infection was identified in nine individuals aged 16 to 72 years: five from urban and four from rural areas. The estimated prevalences of Chagas infection for the urban and rural areas were 0. 6% (95% CI: 0. 2-1. 4) and 1. 9% (95% CI: 0. 6-4. 5) respectively. An apparent clustering trend was noted: seven were born along the Purus river: three lived at the same locality and two of them in the same dwelling

Parasite persistence in treated chagasic patients revealed by xenodiagnosis and polymerase chain reaction

Polymerase chain reaction (PCR) was compared with xenodiagnosis performed 20 years after trypanocidal chemotherapy to investigate parasite clearance. Eighty-five seropositive individuals for Chagas disease presenting a positive xenodiagnosis were treated with specific drugs; 37 in the acute phase and 48 in the chronic phase. Fifteen chronic assymptomatic patients received a placebo. Treatment in the acute phase led to PCR negative results in 73% of the cases, while xenodiagnosis was negative in 86%. In the chronic phase, PCR was negative in 65% of the patients and 83% led to xenodiagnosis negative results. Regarding the untreated group (placebo), 73% gave negative results by xenodiagnosis, of which 36% were positive by PCR. Individuals that were considered seronegative (n=10), presented unequivocally negative results in the PCR demonstrating the elimination of parasite DNA. Seventeen individuals had their antibodies titers decreased to such a level that the final results were considered as doubtful and 16 of them presented negative PCR. The molecular method represents a clear advantage over conventional techniques to demonstrate persistent infections in Chagas disease patients that underwent chemotherapy

Development of peptide-based lineage-specific serology for chronic Chagas disease: geographical and clinical distribution of epitope recognition.

BACKGROUND: Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, remains a serious public health issue in Latin America. Genetically diverse, the species is sub-divided into six lineages, known as TcI-TcVI, which have disparate geographical and ecological distributions. TcII, TcV, and TcVI are associated with severe human disease in the Southern Cone countries, whereas TcI is associated with cardiomyopathy north of the Amazon. T. cruzi persists as a chronic infection, with cardiac and/or gastrointestinal symptoms developing years or decades after initial infection. Identifying an individual's history of T. cruzi lineage infection directly by genotyping of the parasite is complicated by the low parasitaemia and sequestration in the host tissues. METHODOLOGY/PRINCIPAL FINDINGS: We have applied here serology against lineage-specific epitopes of the T. cruzi surface antigen TSSA, as an indirect approach to allow identification of infecting lineage. Chagasic sera from chronic patients from a range of endemic countries were tested by ELISA against synthetic peptides representing lineage-specific TSSA epitopes bound to avidin-coated ELISA plates via a biotin labelled polyethylene glycol-glycine spacer to increase rotation and ensure each amino acid side chain could freely interact with their antibodies. 79/113 (70%) of samples from Brazil, Bolivia, and Argentina recognised the TSSA epitope common to lineages TcII/TcV/TcVI. Comparison with clinical information showed that a higher proportion of Brazilian TSSApep-II/V/VI responders had ECG abnormalities than non-responders (38% vs 17%; p<0.0001). Among northern chagasic sera 4/20 (20%) from Ecuador reacted with this peptide; 1/12 Venezuelan and 1/34 Colombian samples reacted with TSSApep-IV. In addition, a proposed TcI-specific epitope, described elsewhere, was demonstrated here to be highly conserved across lineages and therefore not applicable to lineage-specific serology. CONCLUSIONS/SIGNIFICANCE: These results demonstrate the considerable potential for synthetic peptide serology to investigate the infection history of individuals, geographical and clinical associations of T. cruzi lineages

Correlation of Bcl-2 expression with prognosis and survival in patients with head and neck cancer: a systematic review and meta-analysis

Head and neck cancer (HNC) is a growing disease, affecting more than 700.000 cases per year and ranking as the sixth most prevalent type of cancer worldwide. The impossibility of properly entering into apoptosis directly influences uncontrolled growth and consequently tumor development and progression. Bcl-2 emerged as a key regulator in the balance between cell apoptosis and proliferation in apoptosis machinery. This systematic review and meta-analysis aimed to review all published studies investigating changes in Bcl-2 protein expression assessed by immunohistochemistry (IHC) and related to prognostic and survival values of patients with HNC. After applying the inclusion and exclusion factors, we reached the number of 20 articles included in the meta-analysis. The random-effect pooled HR (CI95%) value of OS related to Bcl-2 IHC expression in tissues from HNC patients was 1.80 (CI95% 1.21–2.67) (p 0.0001) and DFS was 1.90 (CI95% 1.26–2.86 (p 0.0001). The OS value for the specific oral cavity tumors was 1.89 (1.34–2.67), while in the larynx it was 1.77 (0.62–5.06), and the DFS in the pharynx was 2.02 (1.46–2.79). The univariate and multivariate analyses of OS were respectively 1.43 (1.11–1.86) and 1.88 (1.12–3.16), while in DFS it was 1.70 (0.95–3.03) and 2.08 (1.55–2.80). The OS considering a low cut-off for Bcl-2 positivity was 1.19 (0.60–2.37) and DFS was 1.48 (0.91–2.41), while studies with a high cut-off demonstrated OS of 2.28 (1.47–3.52) and DFS of 2.77 (1.74–4.40). Our meta-analysis demonstrates that Bcl-2 protein overexpression can result in worse LNM, OS, and DFS in patients with HNC, however, it is not a reliable conclusion, due to the wide divergences between the original studies and the fact that many studies have a very high range of confidence and also a high risk of bias

Target product profile for a test for the early assessment of treatment efficacy in Chagas disease patients: An expert consensus.

Six to 7 million people are estimated to be infected by Trypanosoma cruzi, the parasite causing Chagas disease. Thirty to 40% of them, i.e., 1.8 to 2.4 million people, will suffer cardiac disorders and/or digestive clinical manifestations if they are not treated early during the course of the infection [1, 2]. However, only a small fraction of patients are properly diagnosed and treated [3]. Current clinical guidelines recommend treating T. cruzi–infected people if they are asymptomatic or present early symptoms of the disease (Table 1) [4, 5]. Benznidazole (BNZ) and nifurtimox (NFX) are the first-line antiparasitic treatments currently available, both with long administration regimens (60 days) that can produce adverse side effects [6–8]. Despite the fact they are not 100% effective in patients with chronic disease [9–12], they are the only drugs currently registered, and the benefits of their administration have been confirmed in several clinical studies. Currently, clinical trials with new compounds, using alternative regimens that aim to maintain efficacy whilst reducing toxicity, are ongoing and could lead to new therapeutic opportunities and/or policy change

Drug discovery for Chagas disease should consider Trypanosoma cruzi strain diversity.

This opinion piece presents an approach to standardisation of an important aspect of Chagas disease drug discovery and development: selecting Trypanosoma cruzi strains for in vitro screening. We discuss the rationale for strain selection representing T. cruzi diversity and provide recommendations on the preferred parasite stage for drug discovery, T. cruzi discrete typing units to include in the panel of strains and the number of strains/clones for primary screens and lead compounds. We also consider experimental approaches for in vitro drug assays. The Figure illustrates the current Chagas disease drug-discovery and development landscape

Congenital Chagas Disease: Recommendations for Diagnosis, Treatment and Control of Newborns, Siblings and Pregnant Women

SCOPUS: ar.jinfo:eu-repo/semantics/publishe