Absence of both circadian rhythm and Trypanosoma cruzi periodicity with xenodiagnosis in chronic chagasic individuals

Castro, Cleudson; Prata, Áluízio

doi:10.1590/s0037-86822000000500003

Cited by 17 publications

(14 citation statements)

References 6 publications

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“…The data presented here show the superiority of the immunological tests over parasitological ones, particularly the high sensitivity of the rCRP ELISA. The differences of PCR sensitivity could be explained by the intermittent presence and quantity of circulating parasites at the time of blood collection as shown previously (10,11). Moreover, different populations of T. cruzi with high genetic variability are found in different regions of endemicity and may be related to biological variability as virulence or susceptibility to the immune response, influencing parasitemia levels in humans (5).…”

Section: Discussionmentioning

confidence: 60%

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Use of theTrypanosoma cruziRecombinant Complement Regulatory Protein To Evaluate Therapeutic Efficacy following Treatment of Chronic Chagasic Patients

Meira

Galvão²,

Gontijo

et al. 2004

J Clin Microbiol

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One of the greatest concerns in Chagas' disease is the absence of reliable methods for the evaluation of chemotherapy efficacy in treated patients. The tests available to evaluate cure after the specific treatment are the complement-mediated lysis (CoML) and flow cytometry tests, but they are not feasible for routine clinical use. In this study, we evaluated an enzyme-linked immunosorbent assay (ELISA) based on the recombinant Trypanosoma cruzi complement regulatory protein (rCRP) as a method to determine parasite clearance in comparison to the CoML and other methods such as conventional serology, hemoculture, and PCR in serum samples of 31 patients collected before and after the treatment, monitored for an average of 27.7 months after chemotherapy. The results showed that the percentage of patient samples that were positive by rCRP ELISA was reduced from 100 to 70.3, 62.5, 71.4, and 33.4% in the first, second, third, and fourth years after treatment, respectively, while the samples positive by CoML were reduced to 85.2, 81.2, 71.4, and 33.4% during the same period, demonstrating the same significant tendency in the reduction of positive samples. On the other hand, the conventional serology (CS) tests did not present this reduction. The percentage of samples positive by PCR was initially 77.4% and decreased to 55.5, 68.7, 47.7, and 50.0% at the fourth year after treatment, confirming the drastic clearance of circulating parasites after treatment. Our results strongly suggest that the rCRP ELISA was capable of detecting the early therapeutic efficacy in treated patients and confirmed its superiority over the CS tests and parasitologic methods.

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Section: Discussionmentioning

confidence: 60%

“…Treatment of all acute-phase patients is therefore indicated; however, its efficacy in chronic-phase patients remains controversial (11). Nevertheless, treatment of patients in the early chronic phase, before the development of overt clinical symptoms, has been advocated.…”

mentioning

confidence: 99%

Use of theTrypanosoma cruziRecombinant Complement Regulatory Protein To Evaluate Therapeutic Efficacy following Treatment of Chronic Chagasic Patients

Meira

Galvão²,

Gontijo

et al. 2004

J Clin Microbiol

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“…The sensitivity of these methods seems to reflect the different genetic constitution of circulating T. cruzi strains, which vary according to geographic origin (19). The presence of the parasite in the blood at a given time depends on the parasite's life cycle as well as on the immunological equilibrium between the parasite and the host (14). The analysis of these results leads us to conclude that this recombinant antigen is a strong candidate for use in diagnosis of Chagas' disease.…”

Section: Discussionmentioning

confidence: 96%

Trypanosoma cruziRecombinant Complement Regulatory Protein: a Novel Antigen for Use in an Enzyme-Linked Immunosorbent Assay for Diagnosis of Chagas' Disease

Meira¹,

Galvão²,

Gontijo

et al. 2002

J Clin Microbiol

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Currently, diagnosis of Chagas' disease is based on serological methods, but due to the high occurrence of inconclusive results, more reliable methods are needed. The use of recombinant antigens for serodiagnosis of Chagas' disease is recommended in order to increase the sensitivity and specificity of the serological tests. The Trypanosoma cruzi complement regulatory protein (CRP) is a surface glycoprotein present on the trypomastigote forms of the parasite, and the recombinant CRP (rCRP) was cloned in a mammalian expression system and purified by affinity chromatography. The purified recombinant protein was used as an antigen in an enzyme-linked immunosorbent assay (rCRP ELISA) in order to verify its sensitivity and specificity compared with other established methods. In this evaluation, a panel of 184 serum samples distributed among chronic chagasic patients (n ‫؍‬ 65), blood bank donors (n ‫؍‬ 100), and patients infected with Leishmania spp. (n ‫؍‬ 19) was used. The sensitivity and specificity of the rCRP ELISA were 100% when compared to conventional serology and complement-mediated lysis tests from these groups. When hemoculture and PCR tests were evaluated for diagnosis of chronic chagasic patients, using the rCRP ELISA as a reference test, the positivities were found to be 64.62 and 81.54%, respectively, showing a higher degree of sensitivity of the test. The data demonstrate that rCRP ELISA was able to discriminate between chronic chagasic patients and nonchagasic individuals, such as blood donors and patients with leishmaniasis. Thus, the rCRP is an excellent antigen for use in Chagas' disease diagnosis, due to the absence of false-negative or false-positive results.

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“…Patients living in Virgem da Lapa, Minas Gerais showed high levels of parasitemia based on positive xenodiagnosis when compared with individuals from other areas 51 . The presence of T. cruzi in the peripheral circulation at any given time of blood collection depends on the parasite's life cycle, the immune balance between parasite and host 52 , and the time between the blood collection and sample processing 4,21 . In this study, the volume of blood collected did not influence the positivity of PCR, consistent with a previous study of patients from the Triângulo Mineiro 50 .…”

Section: Discussionmentioning

confidence: 99%

Combined parasitological and molecular-based diagnostic tools improve the detection of Trypanosoma cruzi in single peripheral blood samples from patients with Chagas disease

Volpato

Sousa

D’Ávila

et al. 2017

Rev. Soc. Bras. Med. Trop.

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Introduction:In order to detect Trypanosoma cruzi and determine the genetic profiles of the parasite during the chronic phase of Chagas disease (ChD), parasitological and molecular diagnostic methods were used to assess the blood of 91 patients without specific prior treatment. Methods: Blood samples were collected from 68 patients with cardiac ChD and 23 patients with an indeterminate form of ChD, followed by evaluation using blood culture and polymerase chain reaction. T. cruzi isolates were genotyped using three different genetic markers. Results: Blood culture was positive in 54.9% of all patients, among which 60.3% had the cardiac form of ChD, and 39.1% the indeterminate form of ChD. There were no significant differences in blood culture positivity among patients with cardiac and indeterminate forms. Additionally, patient age and clinical forms did not influence blood culture results. Polymerase chain reaction (PCR) was positive in 98.9% of patients, although comparisons between blood culture and PCR results showed that the two techniques did not agree. Forty-two T. cruzi stocks were isolated, and TcII was detected in 95.2% of isolates. Additionally, one isolate corresponded to TcIII or TcIV, and another corresponded to TcV or TcVI. Conclusions: Blood culture and PCR were both effective for identifying T. cruzi using a single blood sample, and their association did not improve parasite detection. However, we were not able to establish an association between the clinical form of ChD and the genetic profile of the parasite.

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Absence of both circadian rhythm and Trypanosoma cruzi periodicity with xenodiagnosis in chronic chagasic individuals

Cited by 17 publications

References 6 publications

Use of theTrypanosoma cruziRecombinant Complement Regulatory Protein To Evaluate Therapeutic Efficacy following Treatment of Chronic Chagasic Patients

Use of theTrypanosoma cruziRecombinant Complement Regulatory Protein To Evaluate Therapeutic Efficacy following Treatment of Chronic Chagasic Patients

Trypanosoma cruziRecombinant Complement Regulatory Protein: a Novel Antigen for Use in an Enzyme-Linked Immunosorbent Assay for Diagnosis of Chagas' Disease

Combined parasitological and molecular-based diagnostic tools improve the detection of Trypanosoma cruzi in single peripheral blood samples from patients with Chagas disease

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