The Centre for Health Protection has confirmed myiasis cases involving two elderly women, bringing the year's total to 13.

The first case involved an 85-year-old Sham Shui Po woman. She went to Caritas Medical Centre with a nose bleed on November 23 and was found to have maggots in her nostril. She was transferred to Yan Chai Hospital and is in stable condition.

The second case involved a 94-yer-old woman. Maggots were found in her mouth on November 26 and she was admitted to Ruttonjee Hospital in stable condition.

Human myiasis is caused by parasitic maggots of flies which infest superficial wounds and body orifices, such as the mouth, ears and nose, of debilitated people.

Elderly home staff are urged to be particularly vigilant. People should:

* treat wounds immediately, cleaning and dressing them properly, as fluids and blood are known to attract some fly species that produce maggots;

* use window screens to keep out flies; and,

* observe good personal and environmental hygiene.