A research team said a recent outbreak of melioidosis in Sham Shui Po could be caused by an airborne transmission in the area, and called on members of the public to be extra cautious during the monsoon season.

A team of experts from the Polytechnic University (PolyU) collected air samples from a Pak Tin Estate construction site five days after typhoon Mulan hit Hong Kong in August, and confirmed for the first time that the bacteria remained in the air after the storm.

"That concluded that airborne transmission is [one of] the possible causes that led to the urban outbreak in some districts," said Gilman Siu, an associate professor from the university who oversaw the project.

Siu also said their findings were somewhat in line with the outcome of a recent epidemiology investigation conducted by the Centre of Health Protection and the University of Hong Kong (HKU).

"Both of us identified that the soil in the Sham Shui Po district contains that bacteria," Siu said.

"But because those bacteria have different possible routes of transmission, ours suggest airborne transmission and Professor Yuen [Kwok-yung] from HKU suggests it could be waterborne."

The PolyU expert said there could be more severe outbreaks during the monsoon season, adding that high-risk individuals should keep their masks on after a typhoon or a major storm.

"Especially for those who have chronic diseases, such as diabetes… during the typhoon season, when you stay at home, I suggest that you close the windows for a while, [until] a couple of days after the typhoon," Siu said.

He also pointed out that unvegetated soil in the area could facilitate the growth of the bacteria, and officials should to do more to tackle the problem.

"I would suggest the authority to enhance or improve the vegetation so that the soil integrity can be improved near the [Sham Shui Po] district."