Geographic variations in test reactivity for the serological diagnosis of Trypanosoma cruzi infection

Chagas disease is a neglected disease caused by Trypanosoma cruzi parasites. Most of diagnosis is based on serological tests but the lack of a gold standard test complicates the measurement of test performance. To overcome this limitation, we used samples from a cohort of well-characterized T. cruzi infected women to evaluate the reactivity of two rapid diagnostic tests and one ELISA assay. Our cohort derived from a previous study on congenital transmission of T. cruzi , and consisted in 481 blood/plasma samples from Argentina (n=149), Honduras (n=228) and Mexico (n=104) with at least one positive T. cruzi PCR. Reactivity of the three tests ranged from 70.5% for the Wiener ELISA to 81.0% for the T-Detect and 90.4% for the Stat-Pak rapid tests. Test reactivity varied significantly among countries, and was highest in Argentina, and lowest in Mexico. When considering at least two reactive serological tests to confirm seropositivity, over 12% of T. cruzi infection cases from Argentina were missed by serological tests, over 21% in Honduras, and an alarming 72% in Mexico. Differences in test performance among countries were not due to differences in parasitemia, but differences in antibody levels against ELISA test antigens were observed. Geographic differences in T. cruzi parasite strains as well as genetic differences among human populations may both contribute to the discrepancies in serological testing. Improvements in serological diagnostics for T. cruzi infections are critically needed to ensure an optimum identification of cases.

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Etiological treatment of young women infected with Trypanosoma cruzi, and prevention of congenital transmission

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/s0037-86822009000500002 ◽

2009 ◽

Vol 42 (5) ◽

pp. 484-487 ◽

Cited By ~ 65

Author(s):

Sergio Sosa-Estani ◽

Estela Cura ◽

Elsa Velazquez ◽

Cristina Yampotis ◽

Elsa Leonor Segura

Keyword(s):

Trypanosoma Cruzi ◽

Young Women ◽

Serological Tests ◽

Congenital Transmission ◽

Cruzi Infection ◽

Efficacy Of Treatment

The objective was to detect Trypanosoma cruzi infection in 32 children in Salta, Argentina, born to 16 chronically infected young women who were treated with benznidazole. Tests were performed to assess the efficacy of treatment after 14 years. At the end of the follow up, 87.5% of the women were non-reactive to EIA tests, 62.5% to IHA and 43.8% to IFA. 62.5% of the women were non-reactive according to two or three serological tests. No infected children were detected among the newborns of mothers treated before their pregnancy.

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New evidence of spontaneous cure in human Chagas' disease

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/s0037-86822003000100014 ◽

2003 ◽

Vol 36 (1) ◽

pp. 103-107 ◽

Cited By ~ 22

Author(s):

Sonia S. Francolino ◽

Antonio Fernandez Antunes ◽

Rodolfo Talice ◽

Rachel Rosa ◽

Joel Selanikio ◽

...

Keyword(s):

Flow Cytometry ◽

Trypanosoma Cruzi ◽

Chagas Disease ◽

Acute Phase ◽

Clinical Data ◽

Specific Treatment ◽

Serological Tests ◽

Spontaneous Cure ◽

New Evidence ◽

Cruzi Infection

A new case of spontaneous cure of human Chagas' disease is described in Uruguay. An 87-year-old man who had a typical acute phase of Trypanosoma cruzi infection in 1947 and never received specific treatment against the disease, when examined in 1998 revealed several completely negative parasitological and serological tests, including traditional serology, PCR and flow cytometry. As a whole, such findings fulfill the current criteria to define the cure of Chagas' disease. Clinical data suggest the possibility of a benign evolution of Chagas' disease in this case, but the basic findings (slight cardiac and esophageal impairment) could also be due to the advanced age of the patient.

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Evaluation of Serological Tests To Identify Trypanosoma cruzi Infection in Humans and Determine Cross-Reactivity with Trypanosoma rangeli and Leishmania spp.

Clinical and Vaccine Immunology ◽

10.1128/cvi.00127-07 ◽

2007 ◽

Vol 14 (8) ◽

pp. 1045-1049 ◽

Cited By ~ 99

Author(s):

Zuleima C. Caballero ◽

Octavio E. Sousa ◽

Waldelania P. Marques ◽

Amadeo Saez-Alquezar ◽

Eufrosina S. Umezawa

Keyword(s):

Trypanosoma Cruzi ◽

Synthetic Peptides ◽

Cross Reactivity ◽

Reference Test ◽

Trypanosoma Rangeli ◽

Serological Tests ◽

Western Blot Assay ◽

Leishmania Spp ◽

Cruzi Infection ◽

Secreted Antigens

ABSTRACT Five commercially available enzyme-linked immunosorbent assays (ELISAs), one in-house ELISA, and two hemagglutination assays were evaluated to determine their diagnostic accuracy for Chagas' disease in two studies. In study 1, ELISA kits showed 100% sensitivity, but specificities ranged from 82.84% to 100% when leishmaniasis cases were included and from 95.57% to 100% when leishmaniasis cases were excluded. Kits using recombinant antigens or synthetic peptides are more specific than those using crude extracts from Trypanosoma cruzi epimastigote forms. Kits evaluated in Panama, in study 2, showed 75% to 100% sensitivity and 97.12% to 100% specificity. These data were obtained by using a Western blot assay with T. cruzi trypomastigote excreted-secreted antigens as a reference test to confirm T. cruzi infection.

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Course of Chronic Trypanosoma cruzi Infection after Treatment Based on Parasitological and Serological Tests: A Systematic Review of Follow-Up Studies

PLoS ONE ◽

10.1371/journal.pone.0139363 ◽

2015 ◽

Vol 10 (10) ◽

pp. e0139363 ◽

Cited By ~ 24

Author(s):

Yanina Sguassero ◽

Cristina B. Cuesta ◽

Karen N. Roberts ◽

Elizabeth Hicks ◽

Daniel Comandé ◽

...

Keyword(s):

Systematic Review ◽

Trypanosoma Cruzi ◽

Serological Tests ◽

Follow Up Studies ◽

Cruzi Infection

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Genetic diversity of Trypanosoma cruzi parasites infecting dogs in southern Louisiana sheds light on parasite transmission cycles and serological diagnostic performance

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0008932 ◽

2020 ◽

Vol 14 (12) ◽

pp. e0008932

Author(s):

Eric Dumonteil ◽

Ardem Elmayan ◽

Alicia Majeau ◽

Weihong Tu ◽

Brandy Duhon ◽

...

Keyword(s):

Genetic Diversity ◽

Trypanosoma Cruzi ◽

Test Performance ◽

Serological Test ◽

Parasite Transmission ◽

Parasite Diversity ◽

Serological Tests ◽

Transmission Cycle ◽

Southern Us ◽

Transmission Cycles

Background Chagas disease is a neglected zoonosis of growing concern in the southern US, caused by the parasite Trypanosoma cruzi. We genotyped parasites in a large cohort of PCR positive dogs to shed light on parasite transmission cycles and assess potential relationships between parasite diversity and serological test performance. Methodology/principal findings We used a metabarcoding approach based on deep sequencing of T. cruzi mini-exon marker to assess parasite diversity. Phylogenetic analysis of 178 sequences from 40 dogs confirmed the presence of T. cruzi discrete typing unit (DTU) TcI and TcIV, as well as TcII, TcV and TcVI for the first time in US dogs. Infections with multiple DTUs occurred in 38% of the dogs. These data indicate a greater genetic diversity of T. cruzi than previously detected in the US. Comparison of T. cruzi sequence diversity indicated that highly similar T. cruzi strains from these DTUs circulate in hosts and vectors in Louisiana, indicating that they are involved in a shared T. cruzi parasite transmission cycle. However, TcIV and TcV were sampled more frequently in vectors, while TcII and TcVI were sampled more frequently in dogs. Conclusions/significance These observations point to ecological host-fitting being a dominant mechanism involved in the diversification of T. cruzi-host associations. Dogs with negative, discordant or confirmed positive T. cruzi serology harbored TcI parasites with different mini-exon sequences, which strongly supports the hypothesis that parasite genetic diversity is a key factor affecting serological test performance. Thus, the identification of conserved parasite antigens should be a high priority for the improvement of current serological tests.

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Evaluation of the immune response to CRA and FRA recombinant antigens of Trypanosoma cruzi in C57BL/6 mice

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/s0037-86822003000400001 ◽

2003 ◽

Vol 36 (4) ◽

pp. 435-440 ◽

Cited By ~ 7

Author(s):

Valéria Rêgo Alves Pereira ◽

Virginia Maria Barros de Lorena ◽

Mineo Nakazawa ◽

Ana Paula Galvão da Silva ◽

Ulisses Montarroyos ◽

...

Keyword(s):

Trypanosoma Cruzi ◽

Immune Responses ◽

Control Group ◽

Mechanisms Of Resistance ◽

Recombinant Antigens ◽

Cellular Immune Responses ◽

Cellular Immune ◽

Antibody Levels ◽

Cruzi Infection

Humoral and cellular immune responses were evaluated in 44 C57BL/6 mice immunized with the Trypanosoma cruzi recombinant antigens CRA and FRA. Both antigens induced cutaneous immediate-type hypersensitivity response. The levels of IgG1, IgG2a, IgG2b and IgG3 were high in CRA immunized mice. IgG3 was the predominant isotype. Although no difference in antibody levels was observed in FRA-immunized mice when compared to control mice, both antigens were able to induce lymphoproliferation in immunized mice. Significant differences were observed between incorporation of [³H]- thymidine by spleen cell stimulated in vitro with CRA or FRA and the control group. These results suggest that CRA and FRA could be involved in mechanisms of resistance to Trypanosoma cruzi infection.

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Chagas disease in prehistory

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652011005000013 ◽

2011 ◽

Vol 83 (3) ◽

pp. 1041-1044 ◽

Cited By ~ 11

Author(s):

Luiz F. Ferreira ◽

Ana M. Jansen ◽

Adauto Araújo

Keyword(s):

Trypanosoma Cruzi ◽

Chagas Disease ◽

Human Populations ◽

Molecular Tools ◽

American Continent ◽

Way Of Life ◽

Andean Region ◽

Human Presence ◽

Cruzi Infection ◽

Classical Hypothesis

The classical hypothesis proposes that Chagas disease has been originated in the Andean region among prehistoric people when they started domesticating animals, changing to sedentary habits, and adopting agriculture. These changes in their way of life happened nearly 6,000 years ago. However, paleoparasitological data based on molecular tools showed that Trypanosoma cruzi infection and Chagas disease were commonly found both in South and North American prehistoric populations long before that time, suggesting that Chagas disease may be as old as the human presence in the American continent. The study of the origin and dispersion of Trypanosoma cruzi infection among prehistoric human populations may help in the comprehension of the clinical and epidemiological questions on Chagas disease that still remain unanswered.

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The Differences in the Level of Anti-SARS-CoV-2 Antibodies after mRNA Vaccine between Convalescent and Non-Previously Infected People Disappear after the Second Dose—Study in Healthcare Workers Group in Poland

Vaccines ◽

10.3390/vaccines9121402 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1402

Author(s):

Joanna Kwiecińska-Piróg ◽

Jana Przekwas ◽

Zuzanna Kraszewska ◽

Alicja Sękowska ◽

Sylwia Brodzka ◽

...

Keyword(s):

Healthcare Workers ◽

Elisa Test ◽

University Hospital ◽

System Response ◽

Igg Antibody ◽

Serological Tests ◽

Infected People ◽

Dose Study ◽

Immune System Response ◽

Antibody Levels

(1) Background: In many infections, antibodies play a crucial role in controlling infection. In COVID-19, the dynamics of the immune system response to SARS-CoV-2 is not fully understood. (2) Methods: The study was conducted on 120 healthcare workers from Dr. Antoni Jurasz University Hospital No. 1 in Bydgoszcz, between June and December 2020. In all participants, IgA and IgG antibody serum concentrations were measured using the semi-quantitative Anti-SARS-CoV-2 ELISA test (Euroimmun). After vaccination, in January and February 2021, antibody levels were examined using the quantitative IgG Anti-SARS-CoV-2 Quantivac ELISA test (Euroimmun). (3) Results: During the whole study period, the SARS-CoV-2 infection was confirmed in 29 (24.2%) participants. In all infected participants, IgA and IgG antibodies were detectable after infection by semi-quantitative serological tests. Levels of antibodies were higher one month after the first dose in the convalescents than in the non-previously infected participants. In this second group, the level of antibodies increased significantly after the second dose of vaccines compared to the first dose. (4) Conclusions: The level of antibodies after the first dose of vaccine in the convalescents’ group is higher than in the SARS-CoV-2 non-infected group, but the differences disappear after the second vaccination.

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