The Centre for Health Protection urges people to observe good personal and food hygiene after 18 locally-acquired, and one imported, cases of bacillary dysentery, or shigellosis, so far this month.

The 10 women and nine men, aged two to 58, came down with fever, diarrhoea, vomiting and abdominal pain August 26 to September 12. All have recovered.

Five of the local cases involved people eating at a Tsuen Wan fast food restaurant.

There were six cases in the same month last year and 17 cases in both 2005 and 2006.

Bacillary dysentery is an intestinal infection caused by a group of Shigella bacteria which can be found in the human gut. It is characterised by the sudden onset of fever, diarrhoea with abdominal cramps and nausea or vomiting.

It is transmitted directly by faecal material of a carrier or indirectly through contaminated food and water. Infection can spread among household members or in institutions. The incubation period usually lasts one to three days, but can be up to seven days. Click here for more details.