The Centre for Health Protection said on Wednesday that local hospitals have reported 15 cases of melioidosis between August and October this year, with the center now continuing with epidemiological investigations of the cases.

Initial investigation has shown that the patients were either suffering from chronic illnesses or had a weakened immune system, the center said.

According to the center’s spokesperson, melioidosis is a disease caused by the bacterium Burkholderia pseudomallei, with the bacterium widespread in soils and muddy water, particularly common in moist clay soils.

“Humans can become infected through contact with contaminated soil and surface waters; inhalation of contaminated dust/water droplets; and ingestion of contaminated water. Person-to-person transmission is rare but may occur through contact with an infected person's blood or body fluids,” said the spokesperson.

According to information from the Hospital Authority, a total of 29 melioidosis cases have been recorded this year, involving 21 males and eight females aged from 42 to 93. Nineteen patients have been discharged, four patients are still hospitalised, and six patients passed away, which five of them with underlying diseases.

A spokesman for the CHP said that no vaccine is currently available for melioidosis. The CHP reminded members of the public, especially high risk groups such as persons with underlying diseases, to avoid contact with soil or muddy water after storms and heavy rain to prevent melioidosis infection.

Melioidosis is a bacterial disease, also known as Whitmore’s disease, which causes nonspecific symptoms such as fever, joint pain, and headaches, but can also cause pneumonia, abscess formation, and blood infections.

The disease can be treated with antibiotics; however, long-term treatment may be necessary for some chronic infection cases. The mortality rate of the illness ranges from around 40-75 percent.