Serological diagnostics of imported malaria in Czechoslovakia

Two serologic techniques for malaria detection were compared in this study; the indirect fluorescent antibody (IFA) test used in 214 persons (38 Czechoslovak citizens returning from visits to tropical countries and 176 foreign visitors arriving to Czechoslovakia from areas endemic for malaria) and the indirect hemagglutination (IHA) test employed in 125 persons (29 Czechoslovak citizens and 96 foreigners). Comparisons revealed poor correlation between the IFA test and IHA test data. Of the two tests the IFA test appeared to be distinctly more reliable, more sensitive and more specific, the IHA test turned out to yield both false positive and false negative results. The antigen from Plasmodium gallinaceum gave lower IFA titres than P. falciparum antigen, but reacted with antibodies to all species of human plasmodia, and gave reliable test results. Positive serologic responses were appreciably more frequent in foreigners (46.0%) than Czechoslovak citizens (23.7%). The maximum percent positivity for malarial antibody was among individuals from tropical countries of Africa (74.6%), seropositivity in people from malaria endemic areas in Asia and Latin America was far less frequent (28.4% and 44.4%, respectively).