SINGAPORE - Outgoing Transport Minister Khaw Boon Wan's dengue diagnosis has been confirmed, his office said on Thursday (July 23) afternoon.

Mr Khaw had posted in the morning that he was admitted to an isolation ward for observation. He also received a swab test.

Speculating on his condition then, he said: "Unlikely to be Covid but dengue is possible as my area is a hot zone. Did the swab test just now and hopefully it's a false alarm, I had dengue before and it was not pleasant."

"Meanwhile I will just let the body rest and think about retirement!" said Mr Khaw, who announced before the recent general election that he would be retiring from politics.

His Covid test was negative for the virus. The Straits Times understands he was first stricken with the mosquito-borne viral disease in the 1980s.

Mr Khaw, 67, lives in the Yio Chu Kang area, which has parts listed in the National Environment Agency as red zones. Red zones are high-risk dengue areas with 10 or more cases.

He is currently warded in Singapore General Hospital.

He said in his post that he had only recently finalised negotiations for the Johor Baru-Singapore Rapid Transit System (RTS) and was looking forward to the ceremony.

He said that he had also been preparing his office for the next transport minister.

"Everything was going well; I have finalised the RTS negotiations and was looking forward to the ceremony! Then my temperature shot up."

In uploading a selfie of himself with nasal tube attached, Mr Khaw described the photograph as "hilarious".

"I started my career in the Health Ministry. After 42 years, I would not expect to exit the stage in bed as a patient!" he wrote.

While a civil servant in the Health Ministry in the late 1970s and early 1980s, Mr Khaw helped formulate Medisave, which is used by many Singaporeans to pay for hospitalisation.

As Senior Minister of State for Health during the severe acute respiratory syndrome (Sars) outbreak in 2003, Mr Khaw was on the front line checking on arrangements and encouraging hospital staff.

In 2004, he was appointed Health Minister and learning from the painful lessons of Sars, he instituted new processes and extensive preparations to ready Singapore for the next novel disease outbreak.

These have "served us well when Covid-19 came upon us", Prime Minister Lee Hsien Loong wrote in his thank-you letter to Mr Khaw on June 26 following the announcement of Mr Khaw's retirement.

Singapore's dengue outbreak has continued to surge with the number of dengue infections topping 1,000 cases for the sixth consecutive week. There were 1,733 infections diagnosed last week, 65 more than the previous week.

Until this year, the highest weekly infection number was 891 in 2014. As of 3pm on Wednesday, there have been 954 infections diagnosed this week since Sunday.

There are now 424 active dengue clusters concentrated mostly in the eastern part of the country. Nineteen people have died so far this year, compared to the 20 dengue deaths recorded in 2019.

In May, Senior Parliamentary Secretary Low Yen Ling said she had dengue.

Newly elected MP for Bukit Panjang Liang Eng Hwa was also struck by the virus last September.