Pathophysiology: Extensively drug-resistant tuberculosis (XDR-TB) is a form of tuberculosis caused by bacteria that are resistant to some of the most effective anti-TB drugs. XDR-TB strains have arisen after the mismanagement of individuals with multidrug-resistant TB. One in three people in the world is infected with TB bacteria. Only when the bacteria become active do people become ill with TB. Bacteria become active as a result of anything that can reduce the person’s immunity.
Statistics: As per the World Health Report the there are about 348,000 deaths from tuberculosis in Africa in the year 2002 (The World Health Report, WHO, 2004). An incurable form of the disease may develop from infections caused by these organisms. WHO estimates more than 50 million people worldwide may be infected with MDR strains of TB.
Treatment: The principles of treatment for MDR-TB and for XDR-TB are the same. Treatment requires extensive chemotherapy for up to two years. Second-line drugs are more toxic than the standard anti-TB regimen and can cause a range of serious side-effects including hepatitis, depression, hallucinations and deafness. Patients are often hospitalized for long periods, in isolation. In addition, second-line drugs are extremely expensive compared with the cost of drugs for standard TB treatment.
Major Research: A number of groups including the Stop TB Partnership, the South African Tuberculosis Vaccine Initiative, and the Aeras Global TB Vaccine Foundation, are involved with research. Among these, the Aeras Global TB Vaccine Foundation received a gift of more than $280 million (US) from the Bill and Melinda Gates Foundation to develop and license an improved vaccine against tuberculosis for use in high burden countries.
Pathophysiology: The bacteria that cause TB can develop resistance to the antimicrobial drugs used to cure the disease. Multidrug-resistant TB (MDR-TB) is TB that does not respond to at least isoniazid and rifampicin, the two most powerful anti-TB drugs. it is becoming increasingly difficult to treat MDR-TB. Treatment options are limited and expensive, recommended medicines are not always available, and patients experience many adverse effects from the drugs. In some cases even more severe drug-resistant TB may develop.
TB is the world's leading cause of death from a single infectious organism, killing 2 million people each year. The TB crisis has intensified because multidrug-resistant (MDR) microbes have emerged. 5,532 deaths in Brazil 2000 (Regional Core Health Data Initiative, Pan American Health Organisation, 2003).
Treatment: Treatment of tuberculosis starts with prevention. In countries where tuberculosis is common, vaccination with the BCG vaccine is often recommended. The BCG vaccine is not commonly used in the U.S. Preventing the spread of tuberculosis and other contagious diseases also includes covering the mouth and nose with an elbow or a tissue when sneezing or coughing. Treatment of tuberculosis also includes ensuring good nutrition and extra rest.
Major Research: The study of host-pathogen interactions with the aim to identify host and bacterial factors playing a role in infection, development of the disease or protection. Biomarkers resulting from these studies might provide information on the immune status of infected or vaccinated individuals and allow identifying persons that are either protected against the TB disease or at risk to develop the disease after infection.