HLTB21H3 Lecture Notes - Selman Waksman, Pseudoephedrine, Pus

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18 Apr 2012
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Tuberculosis The White Plague/People’s Plague
History
-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
phthisis accepted)
-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
microorganism)
-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
unpasteurized milk
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
Infection (10-30%)
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
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