Intestinal myiasis.

ABSTRACT

Purpose: Intestinal myiasis is a condition when the fly larvae inhabit the gastrointestinal tract and are passed out in faeces. This type of infestation results when eggs or larvae of the fly, deposited on food are inadvertently taken by man. They survive the unfavourable conditions within the gastrointestinal tract and produce disturbances, which may vary from mild to severe. The condition is not uncommon and is often misdiagnosed as pinworm infestation. Correct diagnosis by the clinical microbiologist is important to avoid unnecessary treatment. Materials and Methods: We had 7 cases of intestinal myiasis. In 2 cases the larvae were reared to adult fly in modified meat and sand medium (developed by Udgaonkar). This medium is simple and can be easily prepared in the laboratory. Results: Of the 7 larvae, 5 were Sarcophaga haemorrhoidalis, 1 Megaselia species and 1 was identified as Muscina stabulans. Conclusions: S. haemorrhoidalis was the commonest maggot involved. A high index of suspicion is required for clinical diagnosis when the patient complains of passing wriggling worms in faeces for a long period without any response to antihelminthics. The reason for long duration of illness and recurrence of infestation is baffling. The nearest to cure was colonic wash. We feel prevention is of utmost importance, which is to avoid eating food articles with easy access to flies.