Diagnosis of Loiasis Observation of an adult worm subconjunctivally crossing the eye Identification of an adult worm removed from the eye or skin Identification and quantification of microfilariae in blood by microscopy or quantitative polymerase chain reaction (PCR) Loiasis should be suspected in immigrants or travelers who have a history of exposure in an endemic area and who present with eye worms, Calabar swellings, or unexplained peripheral eosinophilia.