PATTERN OF MALARIA IMPORTED BY FOREIGN RESIDENTS UNDER ACTIVE SURVEY

An active of imported malaria was carried out on 1 432 foreign residen ts entering Czechoslovakia between 1986-1989. The survey group consist ed of adult aged 18-35 years who arrived from malaria endemic regions. Of 660 people surveyed who were from regions of Africa south of the S ahara, 10 % were positive for Plasmodium falciparum. Whereas, those ar riving from South East Asia had a relatively low prevalence of malaria (2.6 %), predominantly P. vivax. Of the 10 % of cases testing positiv e for P. falciparum, 85 % had less than 10,000 asexual stages/mul of b lood and 75 % were asymptomatic carriers. By contrast, 93.8 % of P. vi vax/ovale infections were diagnosed because of the onset of symptoms. Both the frequency of seropositivity and the geometrical mean reciproc al titre (IgG), using P. falciparum antigen, were higher in those peop le arriving from Africa (79 % and 1 307) compared with those arriving from S.E. Asia (44.4 % and 628). Malaria was confirmed, by blood smear examination, in only 23.8 % of the seropositive cohort. There was a p ositive correlation between the percentage of P. falciparum-positive b lood smears and the level of antibody titre. There was no correlation between serum reactivity and level of parasitaemia.