Recent advances in the laboratory diagnosis of filariasis

The specific laboratory diagnosis of filariasis depends either on the demonstration of circulating microfilaria in the peripheral blood or various stages of the parasite in tissue sections. Various morphological characteristics of the parasite will normally assist in its identification to the genus and specific level. Concentration techniques, especially those using the polycarbonate membrane filtration of a ml or more of heparinised blood, can detect the parasite in those with very low microfilaria counts. Serological techniques using the indirect fluorescent assay with microfilaria and adult worm antigens can assist in confirming a clinical suspicion of filaria infection when the parasite is not demonstrable. The development and use of specific monoclonal antibodies for the detection of circulating antigens in the enzyme-linked immunosorbent assay will probably increase the specificity of the assay. Presently available specific DNA probes for filariasis are probably not as useful for patient diagnosis as they are for epidemiological purposes.