[Prevention of transfusion transmitted malaria in endemic area]

Malaria is a real public health problem in Africa; more than 300 million new cases and approximately two million deaths arise every year. In spite of the blood transfusion is a potential way of Plasmodium transmission, there is no consensus for measures to prevent post-transfusion malaria in endemic area. This work aimed at comparing some tools and to discuss various strategies to be implemented.

The study concerned 3001 blood donors recruited in seven blood transfusion centers in Senegal during two periods: dry season (June-July, 2003) and rainy season (October-November, 2003). We evaluated the efficiency of the selection questionnaire for the blood donors to exclude those who are potentially asymptomatic carriers of the Plasmodium. Every donation was screened for pLDH antigen and antibodies against Plasmodium by Elisa technique (DiaMed, Cressier sur Morat, Suisse), morphological tests was also performed, as well as the screening of HIV, HBs Ag, HCV Ab and syphilis.

Median age of blood donors was of 27.7 years. Anti-Plasmodium antibodies prevalence was 65.3% and pLDH antigen was of 0.53%, all positivity was confirmed by microscopy. The prevalence of the other infectious markers was 11.7% for HBs Ag; 0.83% for syphilis; 0.49% for HCV Ab and 0.46% for HIV Ab. The risk factors associated with an asymptomatic carrier of Plasmodium were: the rainy season, irregular character of the blood donations, high frequency of malaria attacks in the past, and absence of treatment during the last episode.

Plasmodium represents the third risk of blood transmitted infectious agents after hepatitis B virus, syphilis, and before HCV and HIV in Senegal. The medical questionnaire is not useful enough for asymptomatic carriers deferral, and we propose to introduce Plasmodium screening. The screening for Plasmodium pLDH by Elisa technique seems to be the best tool in endemic area and the strategy of systematic screening is the most suited in terms of blood transfusion safety.