MELS223 PANDEMICS Lec 3 7/17/2013 4:01:00 PM
Lecture objectives: To define the terms endemic, sporadic, epidemic,
To discuss the lessons learned from studying three of the great
To outline the role of the WHO in infectious disease surveillance.
Readings: Brock Biology of Microorganisms, 13th ed. syphilis pp.
997; plague pp. 1024–1025; influenza pandemics 987–988. (12th
ed. syphilis 871-873; plague 899; influenza 862-864.)
Endemic = infection is always present in the community
Sporadic = Occasional cases of infection (no common source)
Epidemic= Sudden increase in incidence of an infection locally
Example : influenza. Can fall into all 3 of categories
H1N1 swine flu epidemic 2009
Onset of winter – epidemic, locally within NZ Significant pandemics (global)
Syphilis is a sexually transmitted infection
Treponema pallidum ss. Pallidum
Primary stage: ulcer formation
Secondary stage: rash, widespread multiplication in body
T. pallidum can cross placenta – small microbe. 50% infants will
Tertiary stage ( 40%) : granulomatous lesions
Stays dormant in the body if lucky
Bone and cartilage gets destroyed – congenital syphilis. Flat nose
Hutchinson‟s teeth Blindness, blisters.
Very susceptible to antibiotics, never been resistant. Cured with
Columbus in 1492 sailed to America.
Dominican Republic: believed this is where sailors acquired
Syphilitic Osseotype recognized in skeleton bones – evidence of
If we go to new country, will encounter new microbes. Take them