Blooming alarm

warning that deadly new strains of tuberculosis, virtually untreatable using the drugs currently available, appear to be spreading across the globe, raising the spectre of a resurgence in a disease which for many generations has laid in the background, seemingly beaten, but which may now make a major comeback as a lethal new pathogen. The new strains are known as extreme drug-resistant TB or XDR-TB. They have been identified and have killed people in several countries, including the US and Eastern Europe, and they have recently been found in Africa, where they could swiftly put an end to all hope of containing the Aids pandemic through treatment. Paul Nunn, head of the WHO's TB resistance team, said the situation was very serious. There are nine million cases of TB in the world and the WHO estimates that two per cent of them — or 180,000 — could be XDR-TB. " This is raising the spectre of something that we have worried might happen for a decade — the possibility of virtually untreatable TB, " he said. Even in the US, which has the best medicines available, a third of those diagnosed with XDR-TB have died. In March, the Centers for Disease Control registered 64 cases in the US; 21 of those ended in death. Significant numbers of cases have been confirmed in Latvia and Russia, but in many parts of the world XDR-TB could be present but unrecognised. One of the reasons the WHO is concerned is that tuberculosis spreads easily in confined spaces, such as aircraft. Multi-drug resistant TB strains — those that are resistant to the two basic, first-line drugs used to treat the disease — have spread everywhere, including to the UK. Multi-drug resistant TB is increasingly common and difficult and expensive to treat. The patient must be given four out of the six existing second-line drugs. But the XDR-TB strains now appearing seem resistant to at least three out of those six second-line drugs and there are no third-line drugs. The spectre of a new outbreak of untreatable TB has been raised because of the identification of a cluster of cases in KwaZulu-Natal, South Africa. Researchers studied 544 TB patients and found 221 had strains against which the two common drugs had no effect. They further found that 53 of the patients had XDR-TB, and 52 of them died within an average of 25 days. All …