The changing pattern of imported malaria in British visitors to Kenya 1987-1990

Following a sudden increase of imported malaria from Kenya in December 1989-January 1990, an investigation was set up to identify risk factors for travellers' malaria. A questionnaire asking for details of travel patterns and compliance with prophylaxis was sent to cases reported over the 6-month Kenyan winter period. Quarterly malaria attack rates between January 1987 and June 1991 were calculated and linked to meteorological conditions in Mombasa. The number of travellers to Kenya has doubled in the 4 years studied and the quarterly rates varied 4-fold over this period. There was no clear seasonal pattern of malaria in travellers, nor was there any clear relation of malaria to coastal rainfall. Compliance with chemoprophylaxis was poor, with only 16% of cases using currently advised regimens. While the annual malaria attack rate per 10,000 travellers decreased by 37% over the study period, the total numbers of malaria cases imported from Kenya rose by 61%, reflecting the increase in the numbers of travellers to the region. As the popularity of East Africa as a tourist destination continues to increase, Kenya will remain an important and significant source of malaria imported into the UK.