One man died and six others were taken ill in a rare outbreak of bovine tuberculosis in Birmingham.

The source of the illness is thought to have been a man who drank untreated, unpasteurised milk. But health experts said the risk was "tiny" and most of the victims were already suffering from other diseases.

Three of the victims are thought to have picked up the infection at a nightclub. New DNA investigation techniques showed that all six cases were linked by person-to-person spread or by being infected by a common source. The Health Protection Agency said measures were taken to halt the spread of the infection and that there was no continuing public health risk.

Professor Peter Hawkey, from the Regional Centre for Mycobacteriology at Birmingham Heartlands Hospital, which made the discovery, said the six were connected by a "complex social web". All were young people - they had an average age of 32 - and were known to go to nightclubs. Two were found to be a couple. Professor Hawkey said most cases of TB were found in people in their sixties and seventies and that people using clubs in the Birmingham area should not be concerned. "The risk is tiny," he said. "But the health message is that anyone who experiences persistent weight loss with night sweats, tiredness and a cough should seek medical attention as it is just possible they might have TB."

The last case was reported in February and the outbreak is thought to be over.