Midterm 3

Question 1

Malaria: mentions in history

Answer 1

• 4700 ya: Chinese med texts
• 2nd c BC: Chinese describe Ginghae (artemisia) plant
• New World: quinine, medicinal bark

Question 2

Malaria: microorganisms

Answer 2

• Multi-cellular protozoa, genus Plasmodium spread by Anopheles mosquitoes
• P. vivax
• P. ovale
• P. malariae
• P. falciparum

Question 3

P. vivax

Answer 3

• Seldomly fatal
• Most ancient, also affects apes
• Infects young red blood cells
• Dormant liver phase

Question 4

P. ovale

Answer 4

• Rarest, W Af
• Infects young red blood cells
• Dormant liver phase

Question 5

P. malariae

Answer 5

• Mild, world wide
• 4 day fever
• Infects old red blood cells
• Can persist sub-clinically for many years

Question 6

P. falciparum

Answer 6

• Most prevalent and severe
• Infects red blood cells of all ages –> parasitemia
• Rapidly fatal (can -> cerebral hemorrhage/anemia)

Question 7

Malaria: mosquitoes

Answer 7

• Anopheles gambiae and fenestus

- Flourish in tropical, still, warm water; deforested habitats; ag; irrigation

Question 8

Malaria: Discoverers

Answer 8

• Charles Laveran: noticed parasites in blood

- Ronald Ross: demonstrated transmission by mosquitoe

Question 9

Malaria: Symptoms

Answer 9

Classic cyclical presentation:

• Cold stage
• Hot stage
• Sweating stage
• Feel well -> then start over again
• Can have many diff complications: renal failure, hypothermia, etc.
• Characteristic of malaria, allows for historical ID

Question 10

Malaria: causes of death

Answer 10

• Anemia: destroys red blood cells

- Cerebral: damages brain, other vital organs

Question 11

Malaria: life cycle

Answer 11

• Inoculation into human, grows in liver cells
• Infects red blood cells (clinical manifestation)
• Differentiates sexually, ingested by mosquito
• Starts over again
• Complex life cycle=long evolution

Question 12

Malaria: global distribution

Answer 12

• Mostly poor, sub/tropical areas
• 91% of deaths in Af, others in E Med, SE Asia
• 86% of deaths are children (no time to develop immunity)

Question 13

Af: why most affected by malaria?

Answer 13

• Still slash and burn ag
• Falciparum=most common
• Climate: year round transmission
• Socio-econ instability (can’t afford nets)

Question 14

Sickle cell anemia

Answer 14

• Long co-ev in Af -> high rates of sickle cell anemia
• Causes blood cells to change shape (can’t inhabit)
• Homozygous: die of anemia

Question 15

Malaria: who is vulnerable

Answer 15

• Children
• Pregnant women
• Travellers/migrants

Question 16

NA

Answer 16

• Was endemic, far north as Ottawa valley
• Anopheles mosquito brought w/slave trade
• Elimination: destroying breeding sties, screens, quinine treatment

Question 17

Malaria Eradication Programs

Answer 17

• WHO, 50/60s
• Drain swamps
• Larvacides
• DDT spraying
• Paris Green
• Domestic mods w/socio econ improvements: screens, AC, safe water, indoor plumbing, nutrition, campaigns

Question 18

Carson

Answer 18

Silent Spring

• Malaria eradication -> huge enviro probs
• May -> cancer
• Led to worldwide ban but only after eradication in NA

Question 19

Roadblocks to eradicated malaria

Answer 19

• Cultural trash -> breeding outside natural settings
• Airport malaria
• Politics: civil wars -> hard to treat
• Not well funded by W agencies

Question 20

Anti-malarial agents

Answer 20

• Chinchona: source of quinine (Peru)
• Chloroquine: artificial quinine (extremely effective)
• Artemisia: source of Artemnisinin (combo therapy for MDR strains)

Question 21

Origins of malaria

Answer 21

-Gorillas in W Af (Congo, Gabone, etc.)

Question 22

Cholera: micro organism

Answer 22

• Bacteria Vibrio cholerae
• Diff strains code for diff enterotoxins (-> flushing, fluid loss)
• Biotypes: Classical, El Tor
• Genetics: most pathogenic strains are 01 (^), also 0139
• Evolution through horizontal gene transfer (switching genes, recombo)

Question 23

Cholera: symptoms

Answer 23

• Abdominal fullness, lack of appetite
• Circulatory collapse (sunken image)
• Vomitting
• Rice water stools

Question 24

Cholera: recovery and fatality

Answer 24

• Oral rehydration therapy (effective, cheap)
• Healthy carriers: shed back into water
• MR: treated <1%, untreated 50-75%

Question 25

Cholera: transmission and reservoirs

Answer 25

- Contamination of water/food - Ppl/water: only major reservoirs - Disease of social disparity: poverty (drinking water), developing economies (lack of infrastructure)

Question 26

Cholera: origins

Answer 26

- Unclear, associated w/growing pop density (could have been around before) - Ancient descriptions: Sanskrit, Chinese, Egyptian - Hard to distinguish f/other diarrheal diseases

Question 27

Early sanitation and cholera

Answer 27

- Rome: sewers and aqueducts, latrines well constructed (prob no cholera) - Medieval Eur: very poor sanitation (tout a la rue, limited access to clean water)

Question 28

Cholera: early endemic foci

Answer 28

- Late 15th c: Bengal region of India/Bangladesh | - Early 1800s: Ganges and Brahma Rivers (great diversity of vibrio here = origins?)

Question 29

Initial spread of cholera (outside India)

Answer 29

- Likely began in 1817 near Calcutta - Associated w/British imperialism, globalization - Moved to Europe after 1830s

Question 30

Pandemics of cholera outside India: rough dates, types

Answer 30

- First 4 (starting 1817): unknown biotypes - 5 and 6: 01 classical - 7 (1961+): El Tor - 8: 0139

Question 31

Second cholera pandemic: background, reached NA

Answer 31

- Industrial rev -> growth of slums, couldn't manage sanitation - Reached NA by 1831, Ham by 1832

Question 32

Role fracturing societies: 2nd pandemic

Answer 32

-Associated w/filthy places, inhabitants -> social unrest (ex: Paris)

Question 33

Responses to 2nd cholera pandemic:

Answer 33

- Maritime quarantines: opposition - Pre-mature burial - Helpless therapies: bloodletting, smoke - Public health: med journals, sanitary surveillance

Question 34

Cholera: third pandemic

Answer 34

- Waterborne transmission proposed (John Snow) but not accepted - Emphasis on sanitary improvements

Question 35

Cholera, third pandemic, Philadelphia

Answer 35

- Densely populated, between two rivers - Doesn't show on skeleton, but museum had gut samples (base of all known classical strains, origins during humidity drop in India, setting on waterways

Question 36

Cholera, 7th pandemic

Answer 36

- Spread f/Bay of Bengal, several waves - El Tor - Less virulent, but can survive longer out of water (fruit, etc.) - About socio-econ disparity

Question 37

Cholera: Peru

Answer 37

- 1991 + - El Tor Biotype - Relatively low case fatality rate (<1%): info, oral rehydration therapy

Question 38

Peru: Causative Factors

Answer 38

- Rapid urban growth --> shanti towns (lacked housing, water, sanitation, untreated waste going into water) - Econ crisis and structural poverty - Declining public health - Sewage as fertilizer when water is scarce (-> spread) - El Nino: warming -> increase in zoo plankton that carry it

Question 39

Cholera: what does/doesn't work for treatment

Answer 39

Doesn't: - Repressive controls (quarantine) --> hidden cases - Mass immunization: $, short term Does: - Safe water, excreta disposal - ID, investigation, case reporting (facilitated by good labs, public health systems) - Access to social, econ resources

Question 40

Peru: costs of cholera outbreak

Answer 40

- 300k cases that year - Low case fatality - Econ loss: $770m (tourism, trade embargoes)

Question 41

Background to Haiti cholera outbreak

Answer 41

- Structural poverty: 80% below poverty line - Decades of political violence (no infrastructure) - Poor sanitation, access to safe water - Post-earthquake: no cholera

Question 42

Haiti: type of cholera

Answer 42

- El Tor, sero group 01 | - Particularly virulent, higher fatality rate

Question 43

Haiti: how did it spread

Answer 43

- Traced f/UN base house in Meille, outbreak coincided w/their arrival - W/in two months, consumed entire country - Denied by UN, there for imperialist reasons (failed state, security risk)