Tuberculosis The evolution of a bacterium

2 World Health Organization (WH.O. declared TB a global health emergency in cases per 100, statistics: 9.4 million incident cases, 14 million prevalent cases, 8.9 million new cases, and 1.7 million deaths, mostly in developing countries (0.4 million in HIV- positive)

3 TB prevalence 2009

TB around the world Endemic in Latin America, Eastern Europe, Russia, Asia and Africa High burden countries – 22 of them including Afghanistan, Bangladesh, Brazil, Cambodia, China, Congo, Ethiopia, India, Indonesia, Kenya, Mozambique, Myanmar, Nigeria, Pakistan, Philippines, Russian Federation, South Africa, Tanzania, Thailand, Uganda, Viet Nam, Zimbabwe 4

5 caused by Mycobacterium tuberculosis usually attacks the lungs, destroying lung tissue can also infect the nervous system, skin, bone, joints…

6 Spread through the air, when people who have the disease cough, sneeze, or spit –inhalation of a single bacterium can cause an infection most infections in human beings will be asymptomatic and latent about one in ten latent infections will eventually progress to active disease, which, if left untreated, kills more than half of its victims

Latent TB infection 90 % of people infected with TB develop latent infection (inactive) 3-5% develop active TB in first year 5-15% develop it later 7

8 The Difference between Latent TB Infection and TB Disease A Person with Latent TB InfectionA Person with TB Disease Has no symptoms Has symptoms that may include: - a bad cough that lasts 3 weeks or longer - pain in the chest - coughing up blood or sputum - weakness or fatigue - weight loss - no appetite - chills - fever - sweating at night Does not feel sick Usually feels sick Cannot spread TB bacteria to others May spread TB bacteria to others Usually has a skin test or blood test result indicating TB infection Has a normal chest x-ray and a negative sputum smear May have an abnormal chest x-ray, or positive sputum smear or culture Needs treatment for latent TB infection to prevent active TB disease Needs treatment to treat active TB disease

9 Symptoms symptoms include chest pain, coughing up blood, and a productive, prolonged cough for more than three weeks systemic symptoms include fever, chills, night sweats, appetite loss, weight loss, pallor, and often a tendency to fatigue very easily –as the disease progresses lung tissue is replaced by scar tissue non-pulmonary TB causes all kinds of symptoms

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11 Risk Factors chronic conditions: diabetes, cancer, renal failure, other immunosuppression low body weight, very young or very old HIV patients Working with TB patients Exposure to people in prisons, or travel to countries where TB is endemic

12 Diagnosis usually a tuberculin skin test followed by an X-ray to see if the infection is active

13 Life Cycle

14 Following inhalation the bacterium can reside in lung tissue for decades without becoming active During a time of immunological stress the bacterium can begin to multiply, forming granulomas and destroying lung tissue, as well as spreading through the rest of the body –Granulomas contain the slowly diving bacteria as long as immune cells are healthy –Detectable by X-ray

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16 TB in Canada (2009) 1,599 new active and re-treatment tuberculosis (TB) cases (a rate of 4.9 per 100,000 population) (BC, ON and QC, 18 % are years old; % are Aboriginal; rate of nearly 30 per 100,000) foreign-born individuals accounted for 63% of all reported TB cases in Canada –Canadian-born non-Aboriginal and Canadian-born Aboriginal cases made up 11% and 20%, – TB rate in the Canadian-born Aboriginal group continues to be the highest of the three groups, approximately five times the overall Canadian rate. pulmonary TB represents 68% of all reported cases

17 Treatment people with latent infections will develop TB when it overwhelms their immune system (10%) ISOLATION! (forced in North America) antibiotics, usually a combination, 6-12 months

Multi-drug resistant TB Of the 1,200 to 1,450 new cases reported per year, up to 20 percent have been found to be drug-resistant 18

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20 Public Health requirement to report education of patients isolation

21 Current Problems with TB Drug resistance: due to improper treatment there are drug-resistant strains of TB Increase in TB cases in Canada’s Aboriginal peoples

22 Prevention BCG vaccine is somewhat effective in children (used in South Africa) people with latent infections are treated to prevent active TB Patient education instructional video