SINGAPORE, Dec 29 — Singapore has recorded its first known case of bovine tuberculosis (TB) in a human, involving a former dairy farmer whose infection was traced to drinking unpasteurised cow’s milk decades earlier.

The case was identified in 2021 and involved a 73-year-old Indian man who had worked as a dairy farmer for 28 years and regularly consumed raw milk during that time. 

He has since completed treatment with standard TB medication, and none of his close contacts tested positive for the disease, Singapore’s Communicable Diseases Agency confirmed.

In response to queries from The Straits Times, the agency said the man remains the only known human case of bovine TB in Singapore. It did not disclose how many close contacts were tested.

Associate Professor Lim Poh Lian, group director for the agency’s communicable diseases programmes, said the man was reported to the National TB Programme in 2021 with symptoms, chest X-rays and medical tests consistent with pulmonary TB. Whole genome sequencing later confirmed infection by Mycobacterium bovis.

“Uncommon cases, such as this, demonstrate our capabilities to detect and confirm rare TB species and to manage them appropriately,” she said.

TB is caused by the Mycobacterium tuberculosis complex, a group of related bacteria that can infect humans and animals. 

While most human cases are caused by Mycobacterium tuberculosis, M. bovis is commonly found in cattle and can be transmitted through unpasteurised milk and dairy products. 

Lim said such transmission is now rare in Singapore, where milk products are generally required to be pasteurised.

Details of the case were published in a letter to the Singapore Medical Journal by researchers from Tan Tock Seng Hospital, the National Public Health Laboratory and Singapore General Hospital. 

The report said the man had no known exposure to other TB patients, but further checks revealed his past occupation as a dairy farmer until 1990, during which he drank at least one glass of raw milk daily.

He presented with poor appetite and weight loss, symptoms consistent with TB, which can also include prolonged coughing, fever and night sweats.

TB remains endemic in Singapore. Ministry of Health data show 1,156 new cases of active TB among residents in 2024, slightly fewer than the 1,201 reported in 2023. 

Globally, there were more than 10.8 million active TB cases in 2023, with about 1.25 million deaths.