HLTB21H3 Lecture Notes - Selman Waksman, Pseudoephedrine, Pus
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Tuberculosis –The White Plague/People’s Plague
-TB since Antiquity. Egyptian mummies (2400BC). aka „Phthisis‟(pulmonary tb, „to waste‟) or „consumption‟ – Homer 800BC.
460BC :Hippocrates-“due to evil air, not contagious”. 384-322BC: Aristotle – due to bad/heavy breath. (130-200AD: Galen‟s Theory of Contagion of
-documented in Egypt (5000 ya), India(3300ya), & China (2300 ya – typical skeletal abnormalities („Pott‟s deformities‟)
-in animals only(prehistoric times 8000-4000 BC) til lifestyle changed.
- Epidemics likely from changes in host pop. + environment, not really change in agent
-“Kings Evil” or “Royal Touching” - claims of royal supernatural powers to heal scrofula (lymph TB) during Middle Ages (500-1500AD), England
-1546-Fracastorius describes modern Theory of Contagion. (phthisis from germ in lung) 1626 – Consumption= leading cause of death in London (17/18th C
at its peak)
-1679-Franciscus Sylvius discovers lung nodules (small knots in lungs), “tubercles” (germ infects lungs).
-1720-Benjamin Marten speculates TB may be communicable 1-1
-19th century-TB rest of Europe N.America by 1900.
-1839-term “Tuberculosis” first used.
-Mid 19th C-TB romanticized (erotic, sexual, symptoms welcomed i.e. thinness, palor, beauty, long necks, shiny eyes, red cheeks) e.g. operas/novel: La
Traviata, La Boheme, Camille
- 1854 Dr. Brehmer – Doctoral dissertation “TB is curable” (sanatoriums- Davos, Switzerland; Trieste, Italy) via isolation, nutrition, rest, air
-1865 or 54?-Jean Antoine Villemin – specific microorganism as cause. breaking point: miasmas (contaminated air) vs. Contagion (transmissive
-1880s – Laennec ontological theory that all tb phenomena= single disease/cause
-1882-Dr. Robert Koch discovered tubercle bacillus, Mycobacterium tuberculosis (causing agent) . 1890- discovered tuberculin (PPD-purified protein
derivative) - Developed „tuberculin‟ test (what we use today for TB skin test = Diagnostic test instead of a cure)
-1895-Wilhelm Konrad von Rontgen - uses radiation (lung Xray - complements Tuberculin test)
Etiology (Cause) – TB caused by microbes called ‘mycobacteria’
-Agent: tubercle bacillus germ Mycobacterium tuberculosis – acid-fast bacillus (rod shaped; doesn‟t decolorize in certain dyes) – Koch+Erlich, grows where
oxygen-rich, specific to humans, ppl-ppl via droplets fr. saliva/mucus, possibly evolved from M. bovis after domestication of cattle
- M. bovis - cattle parasite, close relative of M. tuberculosis (>99.5 % identical), grows where low oxygen(vs. M. tuberculosis) spinal TB, from
Forms: several animal forms of bacillus, but only Bovine (cows; fr. unpasteurized milk) type infects humans; may lead to pulmonary TB or Miliary,
Commonly affects young children, fatal w/in few weeks,days.
Pott’s disease- spinal TB – fusion of vertebrae and deformation of spine hunchback, „lupus vulgaris‟ skin, effects kidneys
Pulmonary TB – most common
Miliary TB – small grainy tubercles look like millet seeds and spread to body via blood; acute, fatal
Addison’s disease – adrenal cortex TB
-3 main types of Human bacillus:
Type 1: found in India,least virulent
Type A: Africa, China, Japan, Europe, N.America
Type B: Exclusively in Europe, N.America
Transmission – inhalation (not so much oral since stomach acids kill bacteria) via air by cough, sneeze. Each droplet nuclei (airborne particles) can contain
b/w 1-3 bacilli. Each sneeze: 100,000 nuclei droplets = very contagious!! 3x 100,000= very contagious!
-What happens when TB enters body: Tubercle bacilli can remain viable throughout host‟s lifetime. Infection can remain dormant until immunity/resistance
fails. Can cause active TB (as opposed to just infection of TB)
- incubation period: Indefinite, variable
-10% risk of developing active TB in their lifetime.
-Only those w/ ACTIVE TB in lungs are infectious. Left untreated, each person w/active TB will infect 10-15ppl/yr (Ro=10?)
-other TB e.g. in kidney, spine(Potts disease) cannot easily be spread to others.
-No acquired resistance to tubercle bacillus (cured ppl are equally prone to getting it again)
Clinical Manifestations: can infect meninges, intestines, bones, larynx, lymph nodes surrounding neck (pig swelling– “scrofula”), skin, spine,
kidneys&genitals. Pulmonary tb causes violent cough, purulent sputum streaked w/blood, cough blood/phlegm, sneeze, emaciation, loss of appetite (weight
loss), irregular menses, fever, sweats, persistent coughing for 3 wks = active, chest pain ….which parts of body affected?
Course of Infection:
Exposure Non-Infection (70-90%) OR
Dormant TB (90%) -never dvlp TB, not infectious OR
Active TB (10% = ill) -5% dvlp TB w/in 2yrs, 5% dvlp TB many yrs later