DOCTORS in Britain are trying to contact 650 people who may have been exposed to a new resistant strain of tuberculosis.
The alert follows the discovery of four confirmed cases of a resistant strain at St Thomas's Hospital in central London. A helpline has been set up.
A leading respiratory specialist in Ireland, however, has said the risk of contracting resistant strains is minimal, that it accounts for 1 per cent of Irish cases and is treatable.
Dr Paul Kelly, of Peamount Hospital, Dublin, the country's main treatment centre for TB, said that where cases of resistant TB were found it was often due to mismanagement of the disease.
Where eases have been found in the Republic it has usually meant the infection was resistant to one, two or possibly three of the "front line" drugs, of which there are five, says Mr Kelly.
However, if the resistant strain was stronger, then the treatment would involve so called "second line" drugs, which would take longer, possibly a year or 18 months, rather than the usual six months.
Dr Kelly said the incidence of TB in Ireland was continuing to fall. There are now about 500 cases a year, compared to 12,000 or 13,000 in 1981.
In London doctors fear other patients may have caught the disease and taken it outside the hospital. The first patient infected, a woman, was in the hospital for a year. Doctors believe the second patient, who subsequently died, caught it from her.
Two more patients are known to be infected with multi drug resistant TB and doctors are still investigating how they acquired it.
The new forms of the disease cannot be treated with the normal drugs and often more toxic treatments might have to be used. However, Dr Kelly said that this often simply meant that it took longer to treat, but the resistant strains could be treated.
He said the incidence of resistant TB among those who are HIV positive is no different from the rest of the population.
The letters sent to the 650 former St Thomas's patients request that they be screened. If any are found to be positive, then efforts will be made to trace all those they have been in contact with.
Last night, Dr Kelly said there was about a 40 per cent chance of infection among those in close contact with anyone with the disease.
Last night, hospital managers at St Thomas's Hospital insisted that there was no danger of a serious epidemic.