Transcript History of Infectious Disease

 What disease killed 300-500 million people worldwide
but has since been eradicated from the human
population?
 Smallpox
 1157 BC; Egyptian pharaoh Ramses V mummy has
smallpox lesions.
 Progression:
 Rash
 Pus-filled blisters
 Disfiguration and/or
blindness
 Death rate = 30%
Man with smallpox; Public Health Images
Library. Source: CDC
 Queen Elizabeth 1
 Had 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 adopted
 Vacca = latin word for “cow”
 Vaccine made with cowpox virus
 Causes body to produce antibodies that
protect against smallpox
 Side 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 & France
 Russian 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 happen
 Today 50% of U.S. never vaccinated
 Routine vaccination discontinued in 1972
 Boosters needed at 10 years
 After 9/11/01, 150 million vaccines ordered
 Controversial
 Feb 2008:
 DoD switched to new


Goal: Develop a second generation
smallpox vaccine


“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 emergencystockpiled ~200 million
Ring around the rosy,
A pocket full of posies,
Ashes… Ashes,
We all fall down!
Written in London in 1665
 Bubonic Plague
 Ring 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 = death
 60% 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 earthquake
 Homeless rats and homeless people
 Anti-rat campaign lasted 4 years
 25 cents per rat
 Plague does still exist in parts of the world
 WHO reports 1,000 – 3,000 cases per year
 Usually where infected rodents live close to humans
 Recent 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 only
 With antibiotic treatment = 50% fatality rate
 Because of delayed treatment
 Caused by Salmonella – typhi (bacteria)
 Mostly spread through water
 Also food and from other infected people
 10% 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.