Controle da transmissão transfusional da doença de Chagas na Iniciativa do Cone Sul

Abstract

The Southern Cone Initiative against Chagas' disease, was launched in 1991. The aim was to interrupt the transmission of Chagas disease by elimination of domestic populations of the major vector, Triatoma infestans, and by improved screening of blood donors. As a result of these activities, a marked reduction in the risk of transfusional transmission can now be seen throughout the programme area. In addition to specific legislation concerning the quality of transfused blood, a series of national and regional reference laboratories have been set up with the help of PAHO in order to improve the quality of pre-transfusional serodiagnosis. Results indicate a progressive reduction in the overall infection prevalence of blood donors, and show that the age-prevalence curve has shifted towards older age-groups. In this paper we analyse the changes in infection prevalence in the Southern Cone countries, drawing attention to the situation in Bolivia which has the highest indices of infection and lowest levels of coverage by the control programme. In this situation chemoprophylaxis of blood prior to transfusion may be recommended in accordance with PAHO criteria. In the medium term however, interruption of human Chagas disease transmission may be expected over most of the Southern Cone region, as long as the control activities are continued and consolidated through effective epidemiological surveillance.

Vigilância epidemiológica em doença de Chagas

“…O que se observa hoje no Brasil em termos da luta contra a doença de Chagas é, ao mesmo tempo, estimulante (nível de controle obtido) e preocupante (consolidação do trabalho por uma VE eficiente e sustentável). As boas notícias correm por conta da minimização da transmissão vetorial, atestada por inúmeros inquéritos soroepidemiológicos, assim como pelo avanço do controle transfusional, que hoje cobre mais de 90% das transfusões realizadas no Brasil (Dias & Schofield, 1998). A VE para doença de Chagas que agora se impõe tem de ser ampliada e consolidada, nas perspectivas de sua construção histórica e, principalmente, no contexto do Sistema Único de Saúde.…”

The evolution of Chagas disease (American Trypanosomiasis) control after 90 years since Carlos Chagas discovery

“…The practical consequences of these facts in vector control correspond to the extreme difficulty these insects have in selecting insecticide resistance. In summary, T. infestans has at least four biological characteristics functioning as key factors favouring its control: (a) limited range of habitats, with all stages confined to houses and some peridomestic animal enclosures; (b) slow rate of population development, and consequent low rate of genetic rearrangement; (c) extreme specialisation with a low rate of genetic variability and consequently limited genetic repertoire for further adaptation (including insecticide resistance), and, (d) complete susceptibility to modern pyrethroid insecticides (Schofield & Dias 1998). Organisation of control campaigns against Triatominae is generally based on the administrative structures previously set up for campaigns against other insect pests -particularly mosquito vectors of yellow fever and malaria.…”

Seroprevalence of Chagas disease in schoolchildren from two municipalities of Jequitinhonha Valley, Minas Gerais, Brazil; six years following the onset of epidemiological surveillance

“…Although CARNEIRO et al 9 demonstrated that children seropositive for Chagas disease from other municipalities under epidemiological surveillance showed higher probability of having mother and relatives also seropositive, additional studies are necessary to elucidate the real mechanisms involved in the transmission, since congenital infection seems to be rare in Berilo and José Gonçalves de Minas 22 as well as in Minas Gerais State 15 and Brazil 25 .…”