Toxoplasma seroprevalence in healthy voluntary blood donors from urban Karnataka

Background & objectives: Although many infections can be transmitted through blood transfusion, it is not possible to carry out screening tests for all. Among the protozoal diseases transmitted by blood transfusion in India the most important is malaria, followed by toxoplasmosis. Screening for malaria is mandatory in India. We evaluated the seroprevalence of Toxoplasma gondii in healthy adult population of blood donors in Karnataka, south India. Methods: A total of 1000 serum samples collected in two batches (500 each) in the years 2004 and 2005 from healthy voluntary blood donors were tested for T gondii antibodies by ELISA method, in addition to the other five mandatory tests. Results: Overall 20.3 per cent were positive for T gondii IgG antibody, of which, 63 per cent had high and 7 per cent low avidity, 3.6 per cent IgM positive. IgG titre ranged from 18-362 IU/ml. Interpretation & conclusion: Our study showed a high prevalence of T gondii antibodies in healthy voluntary blood population. It may be appropriate to include screening for T gondii also in the pretransfusion blood testing schedule.