ABSTRACT
The authors S Wendel & J E Levi present a critical review on our previously published proposal for the introduction of dengue NS1 antigen EIA screening in the blood bank routine, aiming at preventing transmission of the dengue virus through blood transfusions. Theyfocus on the fact that just a few cases were reported in non-peerreviewedpapers; they put under question the adequacy of the NS1 antigen EIA test and evoke its unfavorable cost-benefit. Also, they claim the testing system has yet to be validated in Brazil. Weunderstand that several factors comprise a solid set of elements supporting the need for immediate preventive measures, as proposed including: 1) the recognized parenteral infectivity of dengue virus; 2) the case of transfusion transmitted denguereported in Transfusion this year; 3) under-diagnosis and undernotification;4) the environmental issues and disease evolution; 5) ethical questions; 6) the presence of NS1 for all virus strains; and7) the high cost of molecular assays.
Subject(s)
Humans , Blood Transfusion , Dengue , Disease Transmission, InfectiousABSTRACT
Dengue is an endemic/epidemic arboviral disease with a variable symptomatic benign course, but potentially fatal. Once in an inhabited area, the disease will exist forever, with the best achievement being to keep vectors suppressed and the disease under control. Tiger mosquitoes (aedes aegypti, aedes albopictus) are active breeders and urban hunters, becoming resistant to pesticides. Global warming and population growth are propelling the disease worldwide at tropical and subtropical regions, victimizing new populations. Dengue virus is very infective, and has been transmitted by needlestick, intrapartum, through blood transfusion and mucosal contact with blood. One patient got dengue while undergoing bone marrow transplantation. We address the growing dengue epidemics in Brazil, with more than half a million official cases in 2007, to estimate the risks of transfusion transmitted dengue. Calculations however were surpassed by reality: the major Blood Center in Brazil (FHSP-USP) has found dengue virus in one out of each thousand blood units. In 2007, industry sold 2,6 million disposable blood bags in Brazil. Plotting data from FHSP-USP to the whole country, 2600 blood units would have been infective. Through blood components, around 5000 patients must have received dengue virus intravenously. Beatty et al. estimated to be 1:1300 the risk for dengue transmission through blood transfusion in Puerto Rico, close to what has been demonstrated in Sao Paulo. Throughout Brazil, the average risk may be lower, but the epidemics grows towards a worst scenario. Whatever the risk is, it imposes that all blood units in Brazil (and wherever dengue is endemic) must be EIA tested for dengue NS1 antigen. This marker appears early after infection, and the EIA testing platform is available at all blood banks. Also, donors must report febrile states up to two weeks after donation. Morbidity from dengue virus injected in hospitalized patients is unknown, but...