GLOBAL: Conference throws spotlight on growing TB threat

Monday, November 12, 2007

The 38th World Conference on Lung Health started in Cape Town on 9 November, bringing together more than 3,000 scientists in the ongoing battle against tuberculosis (TB) and other respiratory diseases.

The 4-day event, usually held in Paris, pulls together international donors, scientists, governments, civil society and the private sector. This year there is a special focus on the growing problem of drug-resistant forms of TB and the increasing numbers of people who are co-infected with HIV and TB.

Some experts have blamed the growing problem of drug-resistant TB on the failure of TB control programmes to properly motivate and supervise patients to complete their 6-month course of first-line TB medication.

The rise of drug-resistant TB has highlighted deficiencies in diagnosing, treating, and preventing the disease. The main method of diagnosis is over a century old, the only vaccine against TB is partially effective and dates back more than eight decades, and the cocktails of antibiotics used in the six-month treatment of the disease are 40 years old.

Experts have also argued that without new diagnostics and treatment - preferably with faster-acting drugs - governments are not going to meet the Millennium Development Goals for TB, or the targets set out in 2006 by the Stop TB Department of the World Health Organisation (WHO), which provides technical advice and guidelines for the global TB response.

On the eve of the conference Dr Mario Raviglione, of the Stop TB Department, said funding for the WHO's Global Plan to Stop TB 2006-2015 was about half a billion dollars short of its US$900 million target budget for 2007. More funding was needed for research and development, and to improve operational implementation of existing and new anti-TB strategies.

Raviglione said there were preliminary hints that the worldwide TB epidemic might have peaked, possibly as a result of fewer new infections in countries in the former Soviet Union and Africa.

However, with about 880 million new active infections each year, over 1.6 million deaths, and a third of the world's population infected with latent TB - which can develop into active TB, especially when the immune system is compromised - the battle against the disease had to be ratcheted up.

Experts now agree that the HIV and TB epidemics are so closely entwined that they need to be treated as one. HIV and TB have a synergistic relationship: HIV attacks the immune cells that protect against TB, while TB-infected cells are more susceptible to HIV. The two diseases also tend to cause the highest burden of disease among the same socio-economic groups.

Research into TB is gathering pace after decades of neglect, with six candidate vaccines developed by the Aeras Global TB Vaccine Foundation, a non-profit organisation, approaching the stage of human clinical trials. Aeras director Dr Jerald Sadoff said two candidate vaccines were already being tested in South Africa, as part of his organisation's drive to develop safe, effective and affordable TB vaccines.

Dr Maria Freire, of the Global TB Alliance for TB Drug Development (TB Alliance), said her organisation had 9 drugs in the development pipeline. Of these, 1 is about to enter large-scale stage III clinical trials to test efficacy, as the final requirement before applying for registration of the drug.

On the diagnostic front, Dr Giorgio Roscigno, CEO of the non-profit Foundation for Innovative New Diagnostics, announced that several new tools were heading towards the market, including 1 being tested by South Africa's Medical Research Council that could detect TB - and even drug-resistant TB - within a day.

The Tuberculosis Strategic Plan for South Africa 2007-2011, which sets targets for reducing both drug-susceptible and drug-resistant TB, was released by the government on the eve of the conference's opening.

South Africa, China, Russia and India account for two-thirds of cases of extensively drug-resistant TB (XDR-TB), which are resistant to multiple first-line and second-line treatments and are, in effect, often incurable.

A South African government presentation revealed that 481 XDR-TB cases had been diagnosed by the end of October 2007, of whom 216 had died. Thami Mseleku, Director-General of the Department of Health, said the government was looking at changing legislation to make it easier to confine defaulting TB patients as a last resort.

On a worldwide scale, about 4 percent of TB infections are thought to be multidrug-resistant, while XDR-TB has been diagnosed in 41 countries.

The conference will continue until Monday.

Source: PlusNews