tailieunhanh - Hanbook of pediatric transfusion medicine - part 5

Các vấn đề lây truyền của HBV và HCV tương tự như HIV. WHO khuyến cáo sàng lọc HBV trên tất cả các máu, sàng lọc như vậy không phải là phổ thực hiện. Đến năm 2002, các nước đang phát triển ở subSaharan châu Phi báo cáo rằng chỉ có 55% máu hiến là sàng lọc HBV | 154 Kenneth A. Clark higher rates of HIV testing in most Central and South American countries. The probability of transmitting HIV infection by blood transfusion is generally much lower than the risk for transmitting hepatitis or trypanosomiasis Schmunis et al. 1998 . Hepatitis The issues of transmission of HBV and HCV are similar to HIV. The WHO recommends HBV screening on all donated blood yet such screening is not universally performed. As of 2002 developing countries in subSaharan Africa report that only 55 of donated blood is screened for HBV despite relatively high prevalence rates Tapko 2003 . The prevalence of chronic carriage of HBV in blood donors in subSaharan Africa ranges from 2 to 22 . Yet the WHO estimates that no more than 50 of the blood donations in subSaharan Africa are screened for HBsAg. The low screening rate is due to both the lack of funds and to the low perceived utility Allain et al. 2003 . HCV screening is performed on only 40 of donated blood units in Africa Tapko 2003 . The main barrier to implementation of hepatitis testing is the cost of test kits which is currently prohibitive for many resource-restricted countries. The WHO estimates that unsafe blood transfusions contribute to at least 10 of the global burden of HCV Rapiti et al. 2003 . The risk of HBV transmission by blood transfusion in developing countries is not currently well known but in areas of high prevalence and lack of universal screening it is most likely significant. In Central and South America the risk of acquiring HBV infection from blood transfusions is 1 to 17 per 10 000 transfused units and for HCV is 4 to 75 per 10 000 transfused units Schmunis et al. 1998 . In Southeast Asia it has been estimated that there are 85 million carriers of HBV and 25 million carriers of HCV making for an enormous potential for transfusion transmission Kumari 2003 . Other Malaria Malaria screening of donated blood is recommended by WHO when considered appropriate. Such screening .