Tropical medicine: recent advances in malaria and other protozoal diseases.

Two recent developments in the field of trypanosomiasis and malaria are presented: 1) A novel mode of gene expression has been discovered in trypanosomes which enables the parasite to change its surface antigenicity with each new wave of parasitaemia, thus making an effective host response impossible. 2) The possibility to cultivate Plasmodium falciparum in vitro allows studies on the interaction of parasites and red cells, on drug resistance and on surface antigens.- Research in tropical diseases has given important contributions to biology and medicine in general. Basic research on the other hand is necessary to fight successfully tropical disease which are still common and often fatal.