A 21-year-old Bangladeshi construction worker died of diphtheria on Friday, in what is the first local case of the contagious bacterial disease in 25 years.
A total of 48 others who worked directly with or lived close to the worker have been identified for further checks, with two "close contacts" now in isolation wards at Khoo Teck Puat Hospital (KTPH), the Ministry of Health (MOH) said yesterday.
As he had not travelled out of Singapore recently, he was likely to have been infected here, it added.
"Investigations are ongoing to determine the source of the infection," the ministry said, in response to queries from The Sunday Times.
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The worker, who lived in a dormitory in Yishun Avenue 7 and worked at Teban Gardens, developed a fever and neck swelling on July 30. He sought medical help at KTPH, where he was immediately isolated and hospitalised, but died five days later. A respiratory sample taken from the patient tested positive for the bacterium causing diphtheria.
MOH said it was alerted to the case last Thursday. It stressed that the risk of diphtheria spreading here is low, as Singaporeans have had compulsory vaccination against it as part of the National Childhood Immunisation Programme since 1962. Vaccination coverage for diphtheria among two-year-olds here is at 96 to 98 per cent, said MOH.
Those born before 1962 are also likely to have had mild or childhood infections, and would have developed immunity to the disease, said infectious diseases specialist Leong Hoe Nam, in response to queries.
Illness fatal in 5-10% of cases
Diphtheria, a serious illness affecting the mucous membranes of the nose and throat, is fatal in 5 to 10 per cent of cases, with a higher fatality rate in young children, said the Ministry of Health (MOH).
The best way to prevent the bacterial disease is by vaccination, MOH added. Diphtheria vaccination is compulsory by law for children.
The Corynebacterium diphtheria is spread from person to person through close contact, such as through air droplets from coughing or sneezing.
Symptoms include fever, chills, a sore throat, swelling of the neck and nasal discharge.
Diphtheria can cause an infection of the airway, which may lead to breathing difficulties and death.
Infectious diseases specialist Leong Hoe Nam said mild infections that are untreated by antibiotics could lead to serious illness.
Seow Bei Yi
MOH said evidence of previous vaccination upon arrival to Singapore is not required for foreigners, as diphtheria is included in the childhood vaccination schedule of most countries.
The contagious disease causes an inflammation of the mucous membranes, and could result in fatal heart and nerve damage as well.
Treatment involves administering diphtheria antitoxin, as well as antibiotics.
The last local case of diphtheria was reported in 1992, and the last imported case here was in 1996.
All 48 contacts - 46 foreigners and two Singaporeans - were given preventive medication and a booster diphtheria vaccine, said MOH. Their respiratory samples have been taken for testing as well.
There are two workers' dormitories in Yishun Avenue 7. It is unknown which one the victim lived in, but several other workers interviewed last night expressed worry.
Bangladeshi construction worker Alam Jahangir, 26, who has lived at Simpang Lodge 2 dormitory for four years, said: "There are so many people here - it might be easy (for the disease) to spread."
Thai construction worker Nantha Khoei, 47, who has lived in Simpang Lodge 2 for six years, said he was scared as he had not heard of the disease. "Our employer has told us about Sars and Zika before, and how to report if we have headaches, body pains and fever, but we don't know what to do for this disease."
Dr Leong, who has a practice at Mount Elizabeth Novena Hospital, said the worker who died may have been infected by an asymptomatic carrier of the bacteria, where the germ could be carried at the back of one's throat, or by a person suffering from a mild infection.
"The question is: Is there a circulation of bacteria inside the foreign workers' dormitories, which we are not aware of?" he asked of the recent case. He added that the authorities might have to consider looking into having such vaccinations for foreign workers as well.