Topic 10 - Tuberculosis

Contact tracing

finding everyone who came in contact with an infected individual

Causative agent

Bacterium

Mycobacterium tuberculosis

Incidence

found in 1 in 3 people worldwide

8 million ppl present with the disease per year

1 million+ of these ppl will die

Waxy coating

makes the bacterium is very strong

can live outside the body well for long period of time due to this

keeps it alive inside the macrophages despite the corrosive enzymes

Ilness

as few as 5 bacteria in the lung can cause illness

us and Europe → 80-85% of cases are pulmonary, but can also move spine, kidney, lymph, bloodstream

90% of exposures result in granuloma, but no illness

Diagnosis

Chest X-ray

Skin test

Granuloma

an organized cluster of immune cells formed in the lungs or other tissue to contain the bacteria

Spread

TB bacteria are spread only from a person with active TB disease

inhaling droplets

Active TB disease

1. bacteria must enter the body

2. The immune system cannot stop the TB bacteria from growing and spreading after the initial infection

Infection

bacteria remain in dormant state

no increase in number, don’t make a person sick

most people will test positive for skin test, or their chest X-ray will show signs of latent TB

Disease

bacteria are multiplying and attacking the lung(s), or other parts of the body such as the lymph nodes, bones, kidney, brain, spine, and even the skin

will show symptoms of active disease

Latent TB

those who do not get sick are said to have non-contagious

the bacteria are inactive/dormant in the body

Who might test positive

previously exposed to the Mtb bacterium

previously exposed to a bacterium similar to Mtb

those vaccinated to TB outside the US

How do we know if it is active

signs/symptoms

exposure history

sputum samples

Treatment

Antibiotics

not for all tho: mer-tb and xdr-tb

Antibiotics, non resistant strains

Isoniazid

Rifampin

Pyrazinamide

Ethambutol

XDR-TB

Extensively drug-resistant TB

MDR-TB

Multi-drug resistant TB

Origin

moved from cattle to humans

very old disease, animal versions found in prehistoric specimens

spread from Europe/asia to Africa and North America

Robert Koch

identified the bacillus that causes tb

identified tuberculin → used for testing

Newer drugs

SQ-109

Nitroimidazoles

Macrolides

Oxazolidinones

Pyrroles

Diarylquinoline

Albert Calmette

helped discover the BCG vaccine against TB

More effective in children than adults, still used in countries where TB is common

Camille Guerin

Immunity to TB was associated with living bacilli in the bloodstream

helped discover BCG

Sanitoriums

German origin

provided rest and good nutrition

mountains for clean air

very posh

Hermann Biggs

Father of public health

Develop 5-step systematic approach for disease containment (1889)

5 steps for disease containment

1. mandatory reporting

2. free testing through NYDPH

3. established nursing follow-up for all, isolation if necessary

4. awareness through public education

5. financial support from gov

TB in the US

once a leading cause of death

effort to eradicate once antibiotics were available (1945)

cases decreased until 1985, increased again from 85-92

emergence of drug-resistant strains

now approximately 15k cases per year

TB and HIV/AIDS

39 million ppl are currently living with HIV infection

one third of ppl with HIV are co-infected with TB

TB is though to be the cause of death in half of all person with AIDS

TB in art

romanticization of an illness

portrayed with pale skin, red lips, shine eyes, melancholy demeanor

among famous writers, poets, and composers