The Centre for Health Protection (CHP) on Wednesday reported three more imported cases of chikungunya fever, bringing the total to four in Hong Kong this year.

One of the patients is a 79-year-old woman who lives in Southern District.

The CHP said she visited Foshan in Guangdong province last month, but cannot recall if she was bitten by mosquitoes there.

After returning to Hong Kong, she started experiencing a fever and joint pain on Monday and sought medical treatment at Queen Mary Hospital a day later.

A 12-year-old boy who was the city's first imported case of chikungunya fever this year had also visited Foshan, which has seen an outbreak in which thousands of cases were reported.

The other two new cases involved a 55-year-old man and his 10-year-old son, who recently travelled to Bangladesh.

They live in Kwai Tsing.

According to the CHP, the boy said he was bitten by mosquitoes in Bangladesh, but his father did not recall if he was bitten.

The three latest patients are in stable condition.

The CHP said it would continue to monitor the recent chikungunya fever cases closely.

It reminded the public to pay attention to environmental hygiene and take precautionary measures, whether locally or abroad. Avoiding mosquito bites and preventing mosquito breeding are effective ways to prevent chikungunya fever, it added.

The Food and Environmental Hygiene Department said it will step up mosquito prevention and control measures at the patients' homes and the locations they had visited after the onset of symptoms.