Trends of T. cruzi infection based on data from blood bank screening

Abstract

Between October 1988 and April 1989 a cross-sectional survey was carried out in six out of eight blood banks of Goiánia, Central Brazil. Subjects attending for first-time blood donation in the mornings of the study period (n = 1358) were interviewed and screened for T. cruzi infection as a part of a major study among blood donors. Tests to anti-T. cruzi antibodies were performed, simultaneously, by indirect hemagglutination test (IHA) and complement fixation test (CFT). A subject was considered seropositive when any one of the two tests showed a positive result. Information on age, sex, place of birth, migration and socio-economic level was recorded. Results from this survey were compared with seroprevalence rates obtained in previous studies in an attempt to analyse trend of T. cruzi infection in an endemic urban area. The overall seroprevalence of T. cruzi infection among first-time donors was found to be 3.5% (95% confidence interval 2.5%-4.5%). The seroprevalence rate increased with age up to 45 years and then decreased. Migrants from rural areas had higher seroprevalence rates than subjects from urban counties (1.8%-16.2% vs. 0%-3.6%). A four fold decrease in prevalence rates was observed when these rates were compared with those of fifteen years ago. Two possible hypotheses to explain this difference were suggested: 1. a cohort effect related with the decrease of transmission in rural areas and/or 2. a differential proportion of people of rural origin among blood donors between the two periods. The potential usefulness of blood banks as a source of epidemiological information to monitor trends of T. cruzi infection in an urban adult population was stressed.

Prevalência de infecção chagásica em doadores de sangue do Hemocentro Regional de Iguatu, CE

“…Silva et al 12 realizaram um estudo nos bancos de sangue do Estado do Ceará no período de 1996 a 1997, onde foram atendidos 34.943 doadores dos quais 377 (1,1%) apresentavam soropositividade para infecção chagásica. A prevalência de (1,9%) de doadores soropositivos, encontrada por nós, foi superior (1%) à encontrada por Souza et al 14 , em 1989/90, para doadores de sangue de 585 municípios brasileiros e inferior a prevalência encontrada (3,5%) por Zicker et al 19 , em 1988/89, para doadores de seis bancos de sangue de Goiânia, GO.…”

Transfusion‐transmitted American and African trypanosomiasis (Chagas disease and sleeping sickness): neglected or reality?

“…Despite vectorial transmission, Chagas disease is also transmitted by blood transfusions [38], congenitally, accidental laboratory contamination, organ transplants [41,42], by breastfeeding or incidental oral ingestion of infected food [43]. The prevalence in blood donors from the American continent (more than 20 different countries) varies from as low as 0·01% in the USA, to 60% in certain Bolivian cities [24,25,38,[44][45][46][47][48][49], with a progressive decrease in the prevalence of Trypanosoma cruzi among Latin American blood donors over the past 10 years [50]. Continuous surveys display a progressive decrease in the prevalence of Trypanosoma cruzi among Latin American blood donors.…”

Clínica e terapêutica da doença de Chagas: uma abordagem prática para o clínico geral

“…Esses mecanismos de redução progressiva podem ser divididos em 4 grupos: a) Programas sanitários de erradicação de vetores -Fazendo com que as gerações mais novas apresentem menor taxa de prevalência do que aquelas mais velhas (efeito coorte) (ZICKER et al, 1990). Esse fenômeno tem sido observado tanto em escolares quanto em jovens candidatos ao alistamento militar (MARZO¬ CHI, 1981) ou em doadores de sangue.…”