Orbital ophthalmomyiasis caused by Chrysomya bezziana in Thailand

Orbital ophthalmomyiasis occurs infrequently in Thailand. Herein, we report a case in Chiang Mai, Thailand, of orbital ophthalmomyiasis due to larvae of the blow fly Chrysomya bezziana (Diptera: Calliphoridae). A 94-year-old woman was admitted to Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, with a swollen and ulcerated right upper eyelid. The lesion in the eyelid had multiple holes around the ulcer site; bleeding was accompanied by pus and necrotic tissue - the site was filled with dipteran larvae. Eleven larvae were removed from the patient, of which five were killed for microscopic examination and six were reared in the laboratory under ambient temperature and natural relative humidity until they metamorphose into adult. Five third instars and one adult were morphologically identified as C. bezziana. The predisposing factors were probably chronic immobility, inability of the patient to perform daily activities, and presumably neglected and/or poor personal hygiene. To our knowledge, this case represents the first reported case of orbital ophthalmomyiasis caused by C. bezziana in Thailand.