Blood banking in a malaria-endemic area: evaluating the problem posed by malarial parasitaemias.
The emergence and wide dissemination of drug-resistant malarial parasites underscore the need to prevent post-transfusion malaria. In Nigeria, as in most of sub-Saharan Africa, however, blood donors are not routinely screened for malarial infection. Recently, 391 consecutive potential blood donors in a malaria-endemic area of south-western Nigeria were each checked for malarial parasitaemia using three methods: microscopy (all samples), OptiMAL (315 samples) and/or the Clinotech Malaria Cassette (142 samples). OptiMAL detects parasite-specific lactate dehydrogenase whereas the Clinotech test detects the surface proteins of merozoites and sporozoites. Microscopy revealed parasitaemias in 79 (20.2%) of the potential donors, the levels of parasitaemia varying from 34 to 6289 asexual parasites/microl (mean=445/microl). The prevalence of malarial parasitaemia, as detected by microscopy, was significantly higher during the rainy season than in the dry season (27.3% v. 5.5%; P<0.0001). There was no significant association between patent parasitaemia and fever (i.e. an axillary temperature > or =37.5 degrees C), blood group, gender or anaemia. The corresponding prevalences of malarial parasitaemia detected using the rapid diagnostic tests were 3.8% (12/315) for OptiMAL and 57.8% (82/142) for the Clinotech. With the results of the microscopy used as the 'gold standard', OptiMAL gave a sensitivity of only 16.0% but a specificity of 98.5%. The corresponding values for the Clinotech tests were 69.2% and 50.0%, respectively. It would clearly be beneficial to include screening for malaria parasitaemia in the routine investigation of potential blood donors in Nigeria, especially during the rainy season, when the risk of transfusion-transmitted malaria appears relatively high.
Falade
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Department of Pharmacology and Therapeutics, University of Ibadan, Ibadan, Nigeria. fallady@skannet.com
Nash
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Akingbola
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Michael
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Olojede
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Ademowo
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D000293:Adolescent; D000328:Adult; D000818:Animals; D001782:Blood Donors; D005260:Female; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D016778:Malaria, Falciparum / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D052940:Merozoites / Q000737:chemistry; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D018512:Parasitemia / Q000175:diagnosis / Q000453:epidemiology*; D010963:Plasmodium falciparum; D015995:Prevalence; D015800:Protozoan Proteins / Q000032:analysis; D012680:Sensitivity and Specificity; D034101:Sporozoites / Q000737:chemistry; D055815:Young Adult
D015800:Protozoan Proteins; D007770:L-Lactate Dehydrogenase