Tuberculosis

In animals communicable diseases range from mild to fatal. Tuberculosis is a bacterial diseases caused by Mycobacterium tuberculosis and Mycobacterium bovis.It affects humans, cows, pigs, badgers and deer. The bacteria damages lung tissue and suppresses the immune system so the body is less able to fight off the disease.It affects around 8.6 million people worldwide and is an opportunistic infection for people with HIV/AIDS. In 2012 1.3 million people died from the disease.TB is curable by antibiotics and can be prevented by vaccination or improved living standards.Once the bacteria are inhaled they invade lung tissue and replicate slowly. The primary infection may cause no obvious symptoms.A mass of tissue called a tubercle forms at a localised site of infection. The tubercle contains bacteria and macrophages. The primary infection is often controlled, the lung tissue heals and the person recovers.Some bacteria may survive deep in the tubercle growing slowly for years.If the person is malnourished or their immune system is weakened, these bacteria then cause active TB.