Considerable antigenic heterogeneity of
Plasmodium falciparumhas been demonstrated in natural parasite populations. However, very little is known about the relative virulence, transmission efficiency and prevalence over space and time of parasites expressing different serotypes of variant antigens. The recent application of recombinant DNA techniques to express a wide range of P. falciparumantigens in Escherichia colihas led to a better understanding of the molecular basis of antigenic diversity of a number of parasite proteins including the precursor to the major merozoite surface antigen (PMMSA) and the heat-stable S-antigens. Highly specific reagents such as DNA probes, monoclonal antibodies and polyclonal antisera to either cloned antigens or synthetic peptides have become available for serotypic analysis of natural parasite populations. With these reagents important epidemiological questions can now be asked concerning the population biology of different serotypes of P. falciparum.The use of the polymorphic S-antigen system as a serotypic marker to analyse the transmission dynamics of P. falciparumin Madang, Papua New Guinea (PNG) is discussed. Results of serotyping studies with the Santigen system highlight the complexities of malaria transmission, which require consideration in the design of malaria vaccine trials.