Keith Vickerman was a parasitologist and protozoologist who made major contributions to our understanding of the biology of African trypanosomes, the causative agents of human sleeping sickness and nagana in cattle. His first academic post was at University College London, where he quickly mastered the techniques of electron microscopy (EM) and produced some of the best electron micrographs of parasitic protozoa at that time. He was a great believer in observation and deduction, and what began as an exercise in EM led him to investigate two of the then outstanding problems of trypanosome biology: how the parasites manage the transition from the tsetse fly vector to its mammalian host, and how they evade the host's immune response. Morphological changes, he found, were correlated with changes in the single mitochondrion and ensuring biochemical changes during the transition from a glucose-rich environment in mammalian blood to the glucose-poor tsetse gut. It was while comparing bloodstream and tsetse forms that he observed that the trypanosomes possessed a thick surface coat in the blood, which he subsequently identified as the variable antigen that was repeatedly formed and reformed and that this was the basis of antigenic variation—findings that stimulated a vast amount of interest among immunologists, biochemists and geneticists. In his later career a new problem emerged, and he found that a disease devastating stocks of the commercially important Norway lobster,
Nephrops norvegicus
, thought to be caused by a virus was actually caused by a protozoan,
Hematodinium
. Keith will always be remembered as one of the founders of modern parasitology.
African trypanosomes evade immune clearance by O-glycosylation of the VSG surface coat
