World TB Day 2011
Today is World TB Day, raising awareness of a disease that causes millions of deaths each year, mainly in the developing world. Caused primarily by the bacterium Mycobacterium tuberculosis, it is estimated that one third of the world’s population is infected with the tubercle bacilli, but only a small fraction go on to develop the full disease.
Spread through the air through coughs, sneezes or spit, M. tuberculosis is a devious bacterium. It can stay dormant in a person for many years without being destroyed. Only around one in ten people go on to develop the full disease, with the remainder having a symptomless latent infection.
Tuberculosis typically affects the lungs, but can also cause disease in many other parts of the body such as the brain or the skeleton. TB is a disease of poverty but has no respect for class. Those with a weakened immune system are more susceptible, with TB a leading cause of death among people who are HIV-positive.
The majority of reported causes of TB are found in Africa and South-East Asia. While relatively uncommon in the UK, about 9,000 new cases are presented each year, mostly in cities, with around 40 per cent found in London.
Unfinished or incorrect treatment courses have led to the emergence of drug resistant forms of M. tuberculosis. Multidrug-resistant TB (MDR-TB) is described as one resistant to at least two of the most powerful anti-TB drugs, isoniazid and rifampicin. This form of the disease takes longer to treat and the drugs are more expensive. Extensively drug-resistant TB (XDR-TB) shows resistance to the majority of drugs. It is very difficult to treat.
Typically treatment for uncomplicated TB is a six-month course of antibiotics, but the emergence of drug resistance means that the development of novel treatments, as well as better diagnostic tools and monitoring strategies is essential. This week saw a potential new vaccine candidate described by scientists from Imperial College London.
Combating infectious diseases, including TB, is one the five major challenges laid out in our ten year Strategic Plan. In 2009 there were 9.4 million new cases of TB reported. In the same year 1.7 million people died of the disease, that’s about one person every 20 seconds.
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