Microscopic examination of microfilariae is a practical diagnostic procedure to find<unk> <unk> . It is important to time the blood collection with the known periodicity of the microfilariae (between 10:00 a.m. and 2:00 p.m.). The blood sample can be a thick smear, stained with Giemsa or haematoxylin and eosin (see staining). For increased sensitivity, concentration techniques can be used. These include centrifugation of the blood sample lyzed in 2% formalin (Knott's technique), or filtration through a nucleopore membrane. Antigen detection using an immunoassay for circulating filarial antigens constitutes a useful diagnostic approach, because microfilaremia can be low and variable. Though the Institute for Tropical Medicine reports that no serologic diagnostics are available, tests that are highly specific to<unk> <unk>  have been developed in recent years. This is despite the fact that many recently developed methods of antibody detection are of limited value because substantial antigenic cross-reactivity exists between filaria and other parasitic worms (helminths), and that a positive serologic test does not necessarily distinguish among infections. The new tests have not reached the point-of-care level yet, but show promise for highlighting high-risk areas and individuals with co-endemic loiasis and onchocerciasis. Specifically, Thomas Nutman and colleagues at the National Institutes of Health have described the a luciferase immunoprecipitation assay (LIPS) and the related QLIPS (quick version). Whereas a previously described LISXP-1 ELISA test had a poor sensitivity (55%), the QLIPS test is practical, as it requires only a 15 minutes incubation, while delivering high sensitivity (97%) and specificity (100%). No report on the distribution status of LIPS or QLIPS testing is available, but these tests would help to limit complications derived from mass ivermectin treatment for onchocerciasis or dangerous strong doses of diethylcarbamazine for loiasis alone (as pertains to individual with high<unk> <unk>  microfilarial<unk> ds). Calabar swellings are the primary tool for visual diagnosis. Identification of adult worms is possible from tissue samples collected during subcutaneous biopsies. Adult worms migrating across the eye are another potential diagnostic, but the short timeframe for the worm's passage through the conjunctiva makes this observation less common. In the past, healthcare providers used a provocative injection of Dirofilaria immitis as a skin-test antigen for<unk>  diagnosis. If the patient was infected, the extract would cause an artificial allergic reaction and associated Calabar swelling similar to that caused, in theory, by metabolic products of the worm or dead worms. Blood tests to reveal microfilaremia are useful in many, but not all cases, as one-third of loiasis patients are amicrofilaremic. By contrast, eosinophilia is almost guaranteed in cases of loiasis, and blood testing for eosinophil fraction may be useful.
Loa loa filariasis
Onchocerciasis
Isosporiasis
Thelaziasis
Cyclosporiasis
Necatoriasis
Toxocariasis
Paragonimiasis