Abstract
Malaria of the vivax type is transmitted in n. Holland by Anopheles maculipennis. The disease is endemic, showing spring and fall seasonal peaks, and seems to assume epidemic proportions at intervals of around 20 years (1880, 1902, 1922, 1946). Density of anopheline population, human immunity factors, shifts in population, and malnutrition are all involved in the epidemics but do not give a complete picture.