Bovine TB can spread from human to human, scientists fear after a cluster of six cases, one fatal, in England.
All the people who are infected were visited the same Birmingham bar or nightclub but only one person was in contact with infected unpasteurised milk or cattle.
Experts told the Lancet that bovine TB was an under-appreciated cause of disease and death in humans.
The first case was reported in 2004 and four cases were reported in 2005 and one more case in 2006. They have launched HPA investigation as soon as they were reported the first case in 2004.
The results of DNA fingerprinting tests showed all six cases were identically linked, most probably by person-to-person spread. In 19th and 20th centuries these Mycobacterium bovis infection in humans were common and more than 2,500 human deaths were recorded each year in Britain.
Pasteurisation laws and eradication programmes in cattle helped reduce the toll. Estimates suggest only 1% of TB cases in the western world are caused by bovine TB - the rest are down to the conventional human TB bug Mycobacterium tuberculosis.
It was said that the infection may be occurred in different ways. Grace Smith and colleagues from the HPA say "four of the patients had weakened immune systems through either HIV infection, diabetes or misuse of alcohol or steroids, which may have made them more susceptible to the infection"
She also added lack of ventilation, more smoke in bars and clubs would lead to spread of airborne bugs
A Defra spokesman said: "Human to human spread of M bovis is extremely unusual.
This gives us a tip that we should be careful in such areas which has more chances of spreading.
