Bovine TB 'spreads in humans'*

Bovine TB can spread from animals to humans and from human to human,
scientists fear after a cluster of six cases, one fatal, in England.

All had visited the same Birmingham bar or nightclub, yet only one of
the young patients had been in contact with infected unpasteurised milk
or cattle.

The Health Protection Agency said although rare, the cases emphasised
the need for rigorous checks and controls.

Experts told The Lancet that bovine TB was an under-appreciated cause of
disease and death in humans.

'Human-to-human spread'

The HPA investigation was launched after one case was reported in 2004,
four in 2005 and one at the beginning of 2006.

DNA fingerprinting showed all six cases were identically linked, most
probably by person-to-person spread.

Mycobacterium bovis infection in humans used to be relatively common in
the late 19th and early 20th centuries.

During this time, over 50,000 new cases and 2,500 human TB 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.

Human to human spread of M bovis is extremely unusual
A Defra spokesman

Grace Smith and colleagues from the HPA say there are several factors
that could explain how the cluster of infections linked to Birmingham
occurred.

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.

Also, the environment of clubs and bars is good for spreading airborne
bugs - prolonged and repeated contact in a confined space with poor
ventilation, noise resulting in shouting and smoke that makes people cough.

The authors warned in The Lancet: "Similar outbreaks of M tuberculosis,
and, to a lesser extent, M bovis, are possible unless public health
control measures are instituted and maintained."

A Defra spokesman said: "Human to human spread of M bovis is extremely
unusual.

"A low occupational risk of M bovis infection remains for farmers,
veterinarians, abattoir workers and other people who may come into
contact with infected animals or their carcases, or for those who
regularly consume unpasteurised cows milk."

Charles O Thoen, of the College of Veterinary Medicine at Iowa State
University in the US, said M bovis infections in humans was most likely
to be a problem in places where HIV infection is widespread, such as
sub-Saharan Africa.