ACP Broadsheet no 148. July 1996. Laboratory diagnosis of malaria.

Introduction Persons with a history of travel in parts of the world where malaria is endemic who develop fever within weeks of return, may be suffering from malignant tertian malaria (Plasmodium falciparum). P falciparum infections rarely persist for more than one year untreated, but may be fatal within days. In 1994 and 1995 there were 11 and four, respectively, imported malaria fatalities in the UK. The other three species of malaria infecting humans may, after the initial feverish symptoms have died down, recur after several months to four years in the case ofP vivax and P ovale, which have dormant liver forms, and for up to 40 or more years in the case of P malariae, which can persist in the blood of untreated persons.' Although a history of overseas travel is usually a factor when malaria presents, it should be remembered that malarial infections may be acquired by blood transfusion, sharing syringes, organ transplants, and accidental laboratory inoculation. A significant number of reports exist of malaria transmission having taken place in the vicinity of airports in non-endemic countries, owing to the accidental importation of infected vector female Anopheles mosquitoes. Currently, the accepted diagnostic technique for malaria is the examination of stained blood films under the oil immersion lens of the microscope. Serology plays a part in epidemiology and in various special investigations.2