Rapid diagnosis of malaria by fluorescence microscopy with light microscope and interference filter.

Fluorochrome staining to detect malaria parasites in bloodfilms is more sensitive, is easier to do, and is less time-consuming than Giemsa staining. However, standard epi-illuminated, mercury vapour, fluorescence microscopes are expensive, especially for tropical countries where malaria is endemic. Fluorescence microscopy with a standard light microscope and a new interference filter specially designed for the fluorochrome stain, acridine orange, was used to detect malaria parasites in thick and thin bloodfilms. In this system two fluorescence colours, green (nuclei) and red (cytoplasm), were emitted from stained parasites. Thick and thin bloodfilms from patients with malaria were examined with this system. Bloodfilms had been fixed and stored for 1-5 years. Rapid scanning of both thick and thin bloodfilms was possible at a magnification of x200 with standard lenses, indicating that this may be a useful economic system for rapid diagnosis of malarias.