Occult Infection by Trypanosoma cruzi in Human Blood Donors of the Morelos State, Mexico
Copyright (c) 2019 Herrera-Arellano
This work is licensed under a Creative Commons Attribution 4.0 International License.
Background: Chagas Disease (CD) is endemic in Mexico and Latin America, giving rise to serious cardiovascular and digestive-system complications that limit the quality of life of those chronic disease. It is caused by the intracellular parasite Trypanosoma cruzi, which is transmitted by insects of different species of the genus Triatoma. Aside from the vectorial route, the transfusional route is the second via of T. cruzi infection. With PCR techniques, subjects have been identified who are infected with T. cruzi with negative serology.
Objective: Detection of DNA of T. cruzi by conventional PCR in T. cruzi seronegative human blood donors.
Materials and Methods: A medical questionnaire and somatometry were performed in 500 HBD ranging in age from 18 to 65 years, with prior signed informed consent. We evaluated glucose, lipids, and anti-T. cruzi serum antibodies. From the refrigerated Buffy Coat, we purified DNA by means of the phenol-chloroform method, evaluating yield, purity, integrity, and amplifiability. Prior to evaluation, we utilized the TcS35 and TcS36 primers and the DNA of each HBD. The amplicons were separated by electrophoresis in 2% agarose gel in Tris borate-EDTA buffer, stained with ethidium bromide and visualized under ultra violet light in a photodocumenter.
Results: We identified 45 cases that were initially positive with PCR, considered indeterminate cases, and 10 repeatedly positive cases, generating 2% of confirmed cases of CD in the studied population. Additionally, among the donors, we identified Chronic-Degenerative Diseases, including six repeatedly positive subjects with metabolic syndrome. The blood of the donors studied, including the 10 repeatedly positive cases that we identified in our study, was available at the hospital, according to norm then in force.
Conclusions: It is recommended to implement PCR tests for all blood-donor candidates to identify T. cruzi carriers and to avoid cases of post-transfusional CD.