HLTB21H3 Lecture Notes - Esus, Afri, Nuclear Dna

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HLTA01 Test 2: Leprosy, Tuberculosis & Syphilis Date: Oct. 17, 2011
Leprosy (Hansen’s Disease)
Origin Far East 1400BC to West via trade routes, India Greece 4th C BC Mediterranean 0 AD (JESUS‟s time)
History
-saraath” (Hebrew) – defiled, accursed, scaly “lepros” “lepra” leprosy aka “satyriasis insatiable sex. appetite
-Pagan priests bathing in blood of sacrificed children = „cure‟
-Found in an Egyptian Papyrus doc(1550BC), Indian writing (600BC), facies leprosa (facial bone findings), Ancient Greece after Army (w/ Alexander the
Great) returned from India(320BC), Rome (62BC) Pompeii`s troops (Constantine caught it)
-Recognized as `disease of the soul`, earlier thought to be hereditary illness, caused by curse or punishment by God Bible Job in Leviticus
-Lepers stigmatized eg. Wear special clothes, arrival notification (bells), separate hospitals, leprosariums, lazaretto, leper colony, lazar house
-Christians cared for lepers (Lazar houses, lazarets), Muslims culture didn‟t really discriminate, Minorities targeted more
-12th C became epidemic, 13th/14th C peak in Europe, 14th C retreated b/c pulmonary TB = resistance to leprosy
-Crusades return to Europe Spain & Africa Americas
- 1873 Father Damien cared for lepers at Molokai island, til died fr. leprosy himself
-1st leper house: England 936AD. Mid 12th C: lepers lost civic status, removed from public office. 13th C: 19,000 leprosaria in use
-Mass of Separation rise during Middle Ages (13th/14th C), decline around 1350 AD, spread to North America
-a.k.a. Hansens Disease- 1873- Dr. Hansen of Norway discovers leprosy germ, Mycobacterium leprae (M. leprae)
Etiology
-M. leprae. Slow multiplying bacillus (rod-shaped) avg doubling time 12-14days. Incubation period of 3-5yrs a spectral disease (many manifestations)
-low infectivity, low virulence
-higher resistance in Blacks, lowest in White
-no known vectors/reservoir hosts, no way of detecting past/preventing
*(Discussion) Challenges in finding cause: no specific method of studying the agent since can‟t test/study animals unless infect human (armadillos don‟t
even develop human type), long incubation period (3-5 yrs) prevents knowing who contracted it, slow-multiplying bacillus takes avg of 12-14 days to
double, Transmission unclear takes close & frequent contact to spread
Transmission via droplets from nose & during close,frequent contact not highly infectious may be related to genetic susceptibility
-Affects skin, nerves and mucous membranes
Entry bacteria nose, open wounds Schwann cells, where temporarily protected by immune system…then immune system inevitable attacks infected
Schwann cells, destroying nerves in process (causing anesthetia), bones degraded
Entry into body uncertain, inhalation? since bact. can‟t penetrate skin directly
Epidemiology
-often endemic, prevalent in Africa, South America, Southeast Asia
-Target scale (WHO) 1 in 10,000
-new case detection rates high in: Brazil, Southeast Africa(Angola, Mozambique, Madagascar, Congo, Tanzania), India
-Risk: more common in males than females (2:1 ratio) can affect people of all races around the world. Most common in warm, wet areas around (sub)tropics.
-Most common b/w 10-14yrs (preteen), 35-44yrs (mid-aged) rarely infants (b/c 3-5 yr incubation period). Seen to have genetic susceptibility
-D‟Arcy Island, Vancouver, BC (1890s-1957) first case among Chinese railway labourers prison to Chinese. Supply ship every 3mth- food, clothing,
opium, coffins
-Sheldrake Island, Tracadie, NB (1815-1844) intro‟d by sailors. spread family-family-neighbour. Lepers abandoned, living in hut 1844-legislation passed
to prevent spread of disease Sheldrake Island chosen for Lazaretto
Clinical Manifestations increase in intensity dep. on host’s immunity; spectral disease
-Indeterminate Leprosy (IL)
-earliest, mildest form. Only few lesions. Loss of sensation is rare
-Tuberculoid Leprosy (TT)
-1-2 yrs after exposure, dvlpmt of large lesions, loss of sensation, severe nerve damage, nerves become thick, impaired function, progression can lead
borderline-type
-Borderline Tuberculoid Leprosy (BT)
-more but smaller lesions
-Borderline Lepromatous Leprosy (BL)
-many lesions, consist of papules, plaques and nodules. Punched out appearing lesions that look like inverted saucers. long period, can be last stage
-Lepromatous Leprosy (LL)
-most severe, „Lion face‟, irreversible (never reverts to less severe form). Early symptoms: nasal stuffiness, discharge & bleeding, swelling of
legs/ankles, skin thickens, loss of eyebrows/lashes, nose/digit deformation or collapses, earlobes thicken, photophobia(light sensitivity), blindness, enlarged
liver and lymph nodes, hoarse voice
Diagnosis
- based on clinical symptoms, lab studies. Cannot be grown in tissue culture. Grows slowly
- relies on microscopic examination + evaluation of patient‟s response to pinprick or heat
Treatment
- chaulmoogra nut (Hydnocarpus tree)- oral but caused nausea, Promin (1941)-oral, iv less painful, Dapsone (1950s)-smaller, oral doses,
- WHO recommends MDT (Multiple Drug Therapy)=Dapsone + Rifampicin + Clofazimine= DRC many side effects.
- (M. bovis) BCG vaccine for TB works
- Nine-banded armadillo important animal for research do not develop human type of leprosy. low body temp (28-33°C) allows M.leprae to manifest.
- Trude Mouse no immune system- bacilli grow best in its footpad
Prevention - handwashing, disinfection of fomites, handkerchiefs & nasal secretions. Young household contacts to be treated with drugs. Leprovac (india)
and BCG Vaccinations.
Factors of disappearance of Hansen’s disease: selective mortality of leprosy patients during plague pandemic, cross immunity with other mycobacteria (if
you get TB mycobacteria, less prone to leprosy), so an increase in TB=decrease in leprosy, loss of pathogenicity (virulence), genetic selection, climate,
improved quarantine, socio-economic conditions, housing & sanitation
Current Stats
-212,000 in 2008 (WHO). Brazil, Nepal & Timor Leste have not yet reached target of 1 in 10,000 set in 1991 by WHO. Although within target, India
reported 87,228 (2008), 137,685 new cases detected in 2007. Brazil (45, 847) and Indonesia (21,430) of concern.