Seropositivity for anti-Trypanosoma cruzi antibodies among blood donors of the "Hospital Universitário Regional do Norte do Paraná", Londrina, Brazil

Abstract

The most frequent form of acquisition of Chagas' disease in endemic areas was the transmission through the feces of contaminated triatominae. However, special attention should be paid in urban areas to transmission by blood transfusion, justifying the compulsory screening of blood donors. Early investigations at blood banks in the town of Londrina, Brazil, demonstrated that the seroprevalence of anti-Trypanosoma cruzi antibodies among blood donors was approximately 7.0% in the fifties9,34. Further studies demonstrated pratically the same seroprevalence until the eighties4,32,41. In an attempt to obtain data about the real dimension of the seropositivity for anti-Trypasonoma cruzi antibodies in the region, the authors carried out a large-scale study on 45,774 serum samples from blood donors of the Hemocentro of Hospital Universitário Regional do Norte do Paraná (HURNP), Universidade Estadual de Londrina. The immunological tests were done at the Division of Clinical Immunology of HURNP from May 1990 to December 1994. The serum samples were studied by the indirect hemagglutination assay (IHA, using kits commercially obtained from EBRAM) and by indirect immunofluorescence (IFI, using kits from LIO SERUM) with anti-human IgG conjugate (LABORCLIN). The results demonstrated that 643 serum samples were positive in both assay corresponding to a seroprevalence of 1.4%, i.e., a significant decrease in anti-Trypanosoma cruzi antibodies in the region in comparison with the previously mentioned rates. Data correlating sex and age of seropositive blood donors are presented, as well as the possible factors that may have contributed to the results observed.

Patterns of nucleolar activity during spermatogenesis of two triatomines,Panstrongylus megistusandP. herteri

“…It is estimated that about 20 million people are infected by Trypanosoma cruzi in endemic areas (KIRCH-HOFF 1993;BIAS 1993;CARDOSO et al 1995;GRIJALVA et al 1995;LUQUETTI 1995;GUHL and SCHOFIELD 1996;ALTCLAS et al 1996;CAR-VALHO et al 1996;REICHE et al 1996), and that approximately 50,000 deaths occur each year as result of chronic infection by T. cruzi (ALTCLAS et al 1996;GALEL and KIRCHHOFF 1996). Mexico, Central America and Latin America where it contributes (GuHL and SCHOFIELD 1996).…”

Evaluation of the western blot in the confirmatory serologic diagnosis of Chagas' disease.

“…[7][8][9][10][11][12] The rates of inconclusive serologic results for diagnosis of Chagas' disease obtained in routine procedures among the blood donors (2.46%) and patients (1.85%) seen at the Hospital Universitário Regional Norte do Paraná (HURNP) prompted us to evaluate the Western blot method to detect specific antibodies against T. cruzi antigenic polypeptides as an alternative method to confirm the laboratory diagnosis of Chagas' disease. 13,14 …”

Advances in Serological Diagnosis of Chagas' Disease by Using Recombinant Proteins

“…In this line, unspecific reactivity has been described for infections caused by T. cruzi phylogenetically related microorganisms, such as T. rangeli and Leishmania sp. (Soto et al, 1996;Araujo, 1986;Saez-Alquezar et al, 2000) Moreover, other falsepositive results due to cross-reactions have been described when testing samples from patients with autoimmune diseases, (Reiche et al, 1996) or from individuals suffering from other acute infections or pregnant women who display an important, polyclonal unspecific response. (Konishi, 1993) The clinical practice often finds an important number of inconsistent results regarding reproducibility and confidence when diagnosing chagasic infection.…”