The Macau Health Bureau has issued a public warning after Vibrio cholerae bacteria was detected at Hac Sa beach on the island of Coloane. Although no cholera cases have been confirmed, the government has said it will closely monitor the situation, and warned public and visitors not to swim at Hac Sa, Oriental Daily reported.

The officials said testing will be stepped up from weekly to daily to monitor the water quality and keep a close eye on the situation.

Chan Chun-ming, chairperson of Macau Green Student Union said water quality in Macau has been bad because the government does not monitor pollution carefully enough, and allows inadequately treated sewage to be released into the sea.

Macau Ecological Society also slammed the government for its limited measures to tackle the city’s water pollution problems, which it says has led to the water quality at Macau beaches worsening.

Cholera is an acute, diarrheal illness caused by infection of the intestine by the bacterium Vibrio cholerae and is spread by ingestion of contaminated food or water.

Symptoms include abrupt onset of watery diarrhea, occasional vomiting and abdominal cramps.