what disease killed 300-500 million people worldwide but has since been eradicated from the human...
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What disease killed 300-500 million people worldwide but has since been eradicated from the human population?
Smallpox1157 BC; Egyptian pharaoh Ramses V mummy
has smallpox lesions.
Progression:RashPus-filled blistersDisfiguration and/or
blindnessDeath rate = 30%
Man with smallpox; Public Health ImagesLibrary. Source: CDC
Queen Elizabeth 1Had smallpox in
1562
Source: Google images
Take pus from a lesion and put into vein or scratch in arm of a healthy person.Amount of virus varied, and some would
die.George Washington had his army
“variolated” during America’s War of Independence
The first vaccine
Edward Jenner 1749 - 1823
Physician who heard milkmaids say they never got smallpox if they had cowpox
In 1796, put pus from cowpox into cut on boy; 8 weeks later exposed him to smallpox.
Slow acceptance, then widely adoptedVacca = latin word for “cow”
Vaccine made with cowpox virusCauses body to produce antibodies
that protect against smallpoxSide effects: red spot, pustules,
scabs, leaves a scar. Fever is common, swelling.
Fatal complications are rare:1 death per million vaccines
1967: WHO announces global smallpox eradication program.Still 15 million new cases a year then
1977: Last reported naturally occurring case in Somalia.Smallpox is the only disease totally
eradicated in humans
Virus kept in labs in US, Russia & FranceRussian scientists claimed they could make
smallpox in large amounts in “scatter bombs.”Later: Where did the Russian scientists go?May not know for days – until symptoms
happenToday 50% of U.S. never vaccinated
Routine vaccination discontinued in 1972Boosters needed at 10 years
After 9/11/01, 150 million vaccines ordered Controversial
Feb 2008:DoD switched to new
“biodefense vaccine.”Grown in lab cell
cultures (monkey kidney cells) instead of on cow skin.
Similar to old vaccine but advanced production capabilities.
Used only for those at “high risk”.
CDC emergency-stockpiled ~200 million
Goal: Develop a second generation smallpox vaccine
Ring around the rosy,A pocket full of posies,
Ashes… Ashes,We all fall down!
Written in London in 1665
Bubonic PlagueRing around the rosy = dark-ringed red
spots in the skin from infected flea bites.Pocket full of posies = belief that
disease carried by putrid-smell of the lesions made people carry posies close to their nose
Ashes…Ashes = Bodies were cremated (not the norm in those days)
All fall down = death60% of London died
Great fire of London finally killed the rats
The brown rat, house rat, sewer rat, Norway rat = carriers of Bubonic Plague
Gangrene caused by plague
Excessive sneezing of plague sufferers led Pope Gregory VII to coin “God Bless You” as a holy response when someone sneezes.
Plague (bacteria) infects both people & rodents.Fleas (vector) transmit to people.Infected people transmit by coughing, sneezing,
close talking
Came closest to wiping out the human race.50 million people died from 1347-1352
(~50-60% of Europeans)
San Francisco 1907-1908
After the 1906 earthquakeHomeless rats and homeless peopleAnti-rat campaign lasted 4 years
25 cents per rat
Plague does still exist in parts of the worldWHO reports 1,000 – 3,000 cases per yearUsually where infected rodents live close to
humansRecent outbreaks: Russia, China, Kenya, Zaire,
Bolivia
Have there been any human cases in the U.S.?
CDC
13 cases reported in Oregon (5 fatal) since 1970.
Mostly spread from fleas of infected rodents.
In the news over the summer.
WWII: Japanese army dropped plague-infected fleas over China.
Both US and Soviet Union developed techniques to aerosolize the Plague bacteria.Pneumonic Plague = most severe threat
Most deadly form – rapid symptoms and close to 100% fatality rate.
Vaccine (3 doses) is for bubonic plague onlyWith antibiotic treatment = 50% fatality rate
Because of delayed treatment
Caused by Salmonella – typhi (bacteria)Mostly spread through water
Also food and from other infected people10% death rate in early 1900’s
Clean water supply prevents typhoid; there is also a typhoid vaccine
Carrier = person who has a disease-causing organism on their skin or in their body.
Carriers may not be sick, but can spread disease if come in contact with others.
6 of 11 people in a house got typhoid fever in 1906
Bad water & food ruled out; Mary refused to be tested
Mary tested against her will when 22 more people got typhoid
Mary put into isolation, released after 3 years.