European strategies against the parasite transfusion risk

Abstract

Protozoal infections are endemic in mainly tropical low income countries, affecting millions of people. Malaria, American trypanosomiasis (Trypanosoma cruzi/Chagas disease) and protozoal tickborne diseases (e.g. Babesia) can be efficiently transmitted by transfusion of cellular blood components. In non-endemic areas like Europe malaria, Chagas disease and Babesia are imported diseases resulting of travelling to endemic areas and migration of autochthons from these endemic areas. A recent International Forum showed that in Europe, as well as the USA, prevention of transfusion-associated protozoal infections depend mainly on selection of donors using questionnaires. Most countries divide donors at risk for malaria in two groups: individuals who have lived in the first 5 years of their life in malaria endemic areas and those who are borne and residing in non-endemic areas and visited the endemic area(s). The first category of donors is rejected for 3 years after their last visit to the endemic area, and in one country such donors are permanently rejected. In some countries such donors are accepted after 4 months-3 years, provided a test for malaria is non-reactive. Persons from non-endemic areas, who visited the malaria endemic area, are rejected for 4-12 months. Some countries reject these donors for 3 years or permanently when they resided for more than 6 months in the endemic area. The rejection rate of donors for malaria risk in the various countries was 0.003-0.43% of all donations. Over the last decade only a few cases of TT-malaria were reported in the various countries. In several countries donors are questioned for risk of T. cruzi infection. In some countries donors are excluded when they (or their mothers) were born in South or Central America, if they received a blood transfusion in these areas and if they lived in rural areas in these endemic countries for more than 4 weeks. In none of the countries donors are asked if they had Babesia or Leishmania. At present implemented measures to prevent TT-malaria in the European countries are probably highly effective. More research is needed to establish the theoretical risk of TT-T. cruzi and TT-Leishmania infection in Europe, before preventive measures may be considered.