A new form of tuberculosis, resistant to most current drug therapies and described by the World Health Organisation as "virtually incurable" in developing countries, has been detected in Irish patients.
The new TB strains were the focus of an unprecedented joint report issued in Washington and Geneva yesterday by the WHO and the US Centres for Disease Control and Prevention (CDC).
The two agencies confirmed that tuberculosis "hot zones" were emerging around the world where people were "nearly helpless to protect themselves" from drug-resistant TB strains.
The deputy director of the WHO Global TB Programme, Mr Richard Bumgarner, also confirmed that TB strains for which there were no effective drugs had been identified. Strain W was isolated in a New York patient who had caused associated infections in patients in Paris and Milan.
"This report provides the first scientific evidence for what we most feared but could not previously prove: the world again faces the spectre of incurable tuberculosis," said Dr Michael Iseman of the University of Colorado and National Jewish Medical and Research Centre in the US. "Today in the developing world, multi-drug-resistant (MDR) TB is usually a death sentence."
Up to 10 cases of MDR-TB are detected here each year, according to the leading Irish specialist on TB, Dr Luke Clancy of Peamount Hospital, Dublin. He confirmed that the number of drug-resistant TB cases here was small but increasing and could pose a threat to Ireland if not properly addressed. "Ireland has between five and 10 cases (of MDR-TB) a year. We know that will increase. It's inevitable," he said yesterday.
Developed countries have a better chance of controlling the spread of MDR-TB, according to Dr Arata Kochi, director of the WHO Global TB programme. There were more resources for drug therapy and long-term treatment of patients, which was not the situation in developing countries.
Inconsistent or partial treatment of TB was the root cause of MDR-TB, Mr Bumgarner explained. Patients were either misdiagnosed and not treated for the MDR-TB strains, or they discontinued or took medication improperly.
Asked what Ireland should do to contain any spread of MDR strains, he suggested authorities had to "ensure that Ireland's TB treatment programmes are good" so new resistant strains were not being produced. One untreated, undetected patient typically infected 10 to 20 more a year, he said.
The WHO/CDC report, Anti-Tuberculosis Drug Resistance in the World, identified a number of countries, "hot zones" where between two and 22 per cent of all TB cases were MDR-TB strains. The work was based on testing carried out in 35 countries involving 50,000 TB cases.
The incidence of MDR-TB cases in Europe, and indications they will increase, has convinced WHO of the urgent need for a programme to monitor such strains of tuberculosis in each country, according to one of the report's authors, Dr Mario Raviglione of WHO Global TB Programme in Geneva. This should be in place within two years.