Learn about tuberculosis

• What is TB?
• How does it spread?
• How is it treated?
• Deadly new forms of TB (MDR-TB and XDR-TB)
• TB in Australia
• Quick facts about TB
   

What is TB?

Tuberculosis or TB is a contagious and airborne infectious disease that is caused by mycobacteria, specifically Mycobacterium Tuberculosis. A TB infection attacks the lungs but can also have an impact on other areas of the body.

TB exists in two forms – latent and active. About nine in 10 people who have TB will have a latent infection that lays dormant and doesn't cause any symptoms. However, of the 2 billion people carrying the TB bacteria, one in 10 will develop active TB - the type that is contagious and can cause serious illness and death.

Most new cases of TB occur in young adults in low or medium resource countries and as a result, has a major impact on socioeconomic costs in these countries. It is also regarded as one of the three ‘diseases of poverty’ alongside malaria and HIV, and  is now the number one cause of death among people infected with HIV.

The earliest traces of TB in humans dates back to 7000BC. Disease symptoms were also found in the spines of Egyptian mummies from 3000-2400BC.

How does it spread?

TB is spread when a person with an active, pulmonary infection sneezes, coughs, spits or simply speaks. Like the common cold, infectious droplets are sprayed into the air and can be inhaled by people nearby.

M. Tuberculosis is a tough microorganism, withstanding some disinfectants and surviving in a dry state for weeks. Even the smallest of droplets can transmit the disease and few bacteria are required for infection.

Considering these factors, TB spreads very easily and is capable of infecting many people due to today’s highly mobile population.

How is it treated?

After diagnosis via microbe identification in clinical sample, chest X-ray and/or a tuberculin (Mantoux) skin test, treatment is possible for TB. It involves a prolonged course of special antibiotics. Due to the TB bacterium’s cellular structure and chemical composition, people are treated with a course of four standard drugs and they can be on these strict medication courses for up to 24 months. DOTS or directly observed treatment, short-course is the WHO-recommended control strategy for TB. Although, many strains have become resistant and new, more complex, methods of control are needed.

A preventative vaccine called Bacille Calmette-Guerin (BCG) is available, but as this was developed almost 90 years ago, it is no longer as effective and does not control the spread of the disease. The development of more effective vaccines and new anti-TB drugs will be of major benefit to human health.

Deadly new forms of TB (MDR-TB and XDR-TB)

The TB bacteria can usually be treated with a course of four standard antibiotics, known as ‘first line’ drugs, taken over six months or more. If these antibiotics are not given or taken correctly or if the person with TB does not take them until the TB bacteria is completely eradicated, then Multi-Drug Resistant TB (MDR-TB) can occur.

MDR-TB occurs when the antibiotics have not had a chance to completely kill off all of the TB bacteria. One antibiotic is not likely to kill all TB bacteria as a small percentage may have a genetic mutation that makes them resistant to a particular drug or the drugs may not have been taken long enough to work properly. These surviving cells then multiply and grow to the same level as before except now all the TB bacteria is drug resistant.

MDR-TB takes longer to treat and can only be cured by ‘second-line’ drugs. When these second-line drugs are not given or taken correctly, then a very deadly form of TB called Extensively Drug-Resistant TB (XDR-TB) can occur. XDR-TB is resistant to basically all the available anti-TB drugs so treatment options are limited and the hope of survival is slim.

TB in Australia

We have been fortunate in Australia to not worry about the threat of tuberculosis since the 1960s but we are no longer making advances in reducing TB rates in Australia. However, it is far from being eliminated in Australia. You may be surprised to hear that we still experience more than 1,000 cases of TB each year and MDR-TB cases are four times higher today than just a few years ago.

Additionally, our regional neighbours in South-East Asia have one of the world’s fast-growing rates of TB.

TB is a curable disease and we can make a difference to the future’s outlook.

Can We Stop TB in Our Lifetime? Together we can.

Quick facts about TB

• TB is a contagious, airborne infectious disease caused by the bacteria Mycobacterium tuberculosis.
• One in three people in the world are infected with the TB bacteria. Of these 10% will get sick and every 20 seconds someone will die of TB.
• Although weakened immune systems and genetic risks all contribute -- scientists don't fully understand why 10% of people get sick with TB.
• TB is treated with a course of four antibiotics. These 'first line' drugs must be taken for 6-9 months.
• If these drugs are not taken as prescribed, multidrugresistant TB (MDR-TB) can develop.
• This requires 'second line' drugs that are expensive, less effective and have more side-effects.
• Extensively drug-resistant TB (XDR-TB) can develop when people can't access or stop treatment with second-line drugs and this is virtually untreatable.
• South-East Asia has one of the world's fastest growing rates of TB and in Papua New Guinea the rate has increased by 42% in the last decade and is growing.
• TB is among the three main causes of death in women aged 15-44 years globally.
• Exposure to TB becomes greater with increased travel and work in countries with a high occurrence of TB.

Please join Centenary Institute and contribute to our research to overcome TB.  Visit www.tb.org.au or click the button on the left to donate.