ABSTRACT
Since 2002, the Egyptian Ministry of Health and Population in collaboration with the WHO implemented a lymphatic filariasis elimination campaign in Egypt. Yet, surveillance and follow-up measures detected asymptomatic microfilaraemic cases among the at risk population. The present work aimed to evaluate and compare tile diagnostic value of filarial immunoassays currently used in clinical as well as research institutions in Egypt regarding their sensitivity, specificity and reliability. Accordingly, Dirofilaria immitis adult crude antigen was evaluated as a capture molecule for anti-human filarial antibodies in serum of patients with occult as well as overt infections. A comparative study was done on a total of 82 subjects. Serum samples from all subjects were tested for the presence of anti-fliarial antibodies, utilizing reagents currently used for the diagnosis of lymphatic filariasis in Egypt. Tile commercially available Dirofilaria immitis adult crude antigen was used to detect serum IgG by indirect ELISA, lgG4 ELISA, Dot-ELISA and dipstick ELISA techniques. Among 18 microfilaraemic cases, indirect ELISA, IgG4 ELISA, Dot-ELISA and dipstick ELISA techniques were positive in 61.1%, 100%. 77.8% and 77, respectively. Corresponding figures among 20 symptomatic amicrofilaraemic cases were 95%, 0%. 85% and 80% with 75%, 95.5%, 88.6% and 88.6% specificity, respectively. Although IgG4 ELISA was more sensitive and specific in detection of microfilaraemic asymptomatic group than other ELISA techniques, Dot ELISA was found to be relatively more sensitive than other techniques among all groups of patients examined. The use of Dirofilaria immitis adult worm crude antigen in ELISA tests revealed an acceptable degree of sensitivity and specificity, in addition to its commercial availability. It is a reliable reagent with high immunodiagnostic potential