ONCHOCERCA-VOLVULUS - COMPARISON OF FIELD COLLECTION METHODS FOR THE PRESERVATION OF PARASITE AND VECTOR SAMPLES FOR PCR ANALYSIS

In recent years, methods for the identification of the filarial worm O nchocerca volvulus and its vector, blackflies of the Simulium damnosum complex (S. damnosum sensu late (s.l.)), based on the amplification o f parasite and vector DNA sequences with the polymerase chain reaction (PCR), have been developed. Routine application of these methods requ ires techniques for sample collection and preservation that are compat ible with the limitations of field collection, yet preserve DNA in a f orm suitable for PCR. Two different methods for sample preservation we re evaluated by the field collection teams and the DNA probe laborator y of the Onchocerciasis Control Programme in West Africa. The most suc cessful involved the preservation of material from O. volvulus and its associated vectors in a dried state on microscope slides. Of over 120 0 parasite samples preserved in this manner, more than 93% retained DN A yielding positive results in PCR analysis (1208/1291). Vector materi al (malpighian tubules and ovaries) preserved in the same manner on th e same microscope slides also yielded DNA that was suitable for PCR.