International meeting: new diagnostic tests are urgently needed to treat patients with Chagas disease

Abstract

Trypanosoma cruzi infection is often not detected early on or actively diagnosed, partly because most infected individuals are either asymptomatic or oligosymptomatic. Moreover, in most places, neither blood banks nor healthcare units offer diagnostic confirmation or treatment access. By the time patients present clinical manifestations of advanced chronic Chagas disease, specific treatment with current drugs usually has limited effectiveness. Better-quality serological assays are urgently needed, especially rapid diagnostic tests for diagnosis patients in both acute and chronic phases, as well as for confirming that a parasitological cure has been achieved. Some new antigen combinations look promising and it is important to assess which ones are potentially the best, together with their requirements in terms of investigation and development. In August 2007, a group of specialized researchers and healthcare professionals met to discuss the state of Chagas infection diagnosis and to build a consensus for a plan of action to develop efficient, affordable, accessible and easy-to-use diagnostic tests for Chagas disease. This technical report presents the conclusions from that meeting.

Serum biomarkers predictive of cure in Chagas disease patients after nifurtimox treatment

“…There is no consensus regarding optimal treatment duration which varies from 30 days to 90 days depending on the tolerance to the drugs. There is also no reliable test of cure that can be used to monitor the effectiveness of treatment in chronic CD patients [13]. …”

Comparative Evaluation of 11 Commercialized Rapid Diagnostic Tests for Detecting Trypanosoma cruzi Antibodies in Serum Banks in Areas of Endemicity and Nonendemicity

“…These tests also must be highly sensitive, specific, and easy to use (22). The need for highly sensitive and specific RDTs was reiterated in 2010 when the 63rd World Health Assembly outlined, through its resolution WHA63.20, the need "to promote and encourage operational research on control of Chagas disease in order to establish systems of early detection" and "to integrate, at the primary health care level, diagnosis and treatment of Chagas disease in patients in both acute and chronic phases of the disease," in countries that are endemic and nonendemic for the disease (23).…”

Genome-Wide Screening and Identification of New Trypanosoma cruzi Antigens with Potential Application for Chronic Chagas Disease Diagnosis

“…(ii) high immunogenicity regardless the clinical form of Chagas disease and (iii) stability and adaptability to quality-control tests to guarantee reproducibility [13], [49], [50]. We believe that the antigens identified in this study meet all these criteria.…”

“…The lack of highly accurate methods to diagnose Chagas disease hampers the correct identification and treatment of infected individuals and restricts the evaluation of effectiveness of any initiative aiming at blocking transmission or vaccination in endemic countries [13], [15]. Additionally, reports of blood transfusion transmission in the USA, Spain and Canada, countries that receive a high contingency of Latin-American immigrants also highlights the importance of an accurate diagnostic test to identify Chagas disease infection in samples from blood banks of non-endemic countries [5]–[8], [44], [45].…”

“…Because parasitemia is low during chronic Chagas disease, diagnosed is mainly carried out using serologic assays, such as indirect ELISA, indirect hemagglutination and indirect immunofluorescence [13]–[15]. The use of whole or fractionated parasite protein extracts as antigens has been replaced by recombinant proteins or peptides, which have higher specificity due to lower cross-reactivity with other infections, such as leishmaniasis [16]–[18] and T. rangeli [15], [19].…”