SINGAPORE - There is no evidence that the contagious bacterial disease which killed a Bangladeshi construction worker last Friday (Aug 4) has spread further, said the Ministry of Health (MOH) in a statement released on Thursday (Aug 10).

All of his 48 close contacts, including those who stayed at the same dormitory in Yishun Avenue 7 and worked at Teban Gardens, have been cleared of diphtheria after screening conducted by the ministry on Tuesday.

"The two close contacts who had developed sore throat since Aug 3 and were warded in Khoo Teck Puat Hospital have been discharged. The remaining 46 contacts remain well. All 48 contacts have been given preventive medication and a booster diphtheria vaccine," said MOH.

The death of the 21-year-old worker was the first local case of the disease in 25 years.

The disease causes an inflammation of the mucous membranes, and can result in fatal heart and nerve damage. Treatment involves administering diphtheria antitoxin, as well as antibiotics.

The worker had developed a fever and neck swelling on July 30, and was later isolated and hospitalised at Khoo Teck Puat Hospital, but died five days later.

MOH said that cases of diphtheria are rare in Singapore and that the threat of spread is low because of compulsory vaccination against diphtheria as part of the National Childhood Immunisation Programme.

It added that vaccination against diphtheria is effective in reducing infection and the severity of diphtheria. According to the 2010 National Health Survey, a high proportion (92 per cent) of adult Singapore residents (citizens and permanent residents) aged 18 to 79 have some immunity to diphtheria.

The Straits Times understands that the source of the infection is being investigated.