The Nature of Plagues and the Price of Being Sedentary
Plague: The sudden increase in a number of people in a population affected by a disease.
Epidemiologist: are disease forecasters who study patterns in the spread and control of a
disease by using statistic data and mathematical modeling also used to identify the causes,
modes, and likelihoods of the disease transmission.
For an infection to persist it must transmit the infection to someone else. The number of
individuals infected by an infected person i0 R .
The longer someone is infected and the greater number of contacts the greater the value of0R
and the faster it will spread
Type 1: pop is large, pattern shows regular outbreaks, and it never completely disappears.
Type 2: peaks are discontinuous, regular occurrences.
Type 3: occurs in smaller communities, increased # of cases, and long periods of time with no
The success of the individuals passing of genes to future generations, through survival and
Symptoms: high fever, chills, headache, muscle aches, dry cough, chest pains, breath shortness,
o Within 1 week, lungs filled with fluid & pus, confusion, disorientation, hallucinations,
Caused by Legionella
Infected water sources evaporate into small water droplets
o Legionella inside water droplet breathed in
Taken in through aspiration
o Protective mechanisms preventing aspiration defective in smokers, elderly, and lung
Toxic Shock Syndrome
Symptoms: vomiting, high fever, lightheadedness, sore throat, muscle aches. Prashanthan Sep/13/2012
o 3-4 days later: rash on thigh, blood-shot eyes, cool/moist skin, rapid heart rate, sudden
drop in blood pressure, rapid breathing, fatigue
o Low blood pressure eventually leads to circulatory collapse, causing shock
Gender-specific STI (sexually transmitted infection)
Caused by Staphylococcus aureus
Linked to tampon brand (bacteria breeding ground)
o Caused reflux of blood and bacteria into vagina
Severe Acute Respiratory Syndrome (SARS)
Symptoms: headache, dry cough, sore throat, fever
Transmission: droplet secretions from nose and mouth (direct)
Africa was home to humanity
The earliest evidence of hominids were unearthed 4.2 million years ago, they split from apes
and were called Australopithecus Anamensis
Evidence of an erect upright posture was found in Ethiopia and Tanzania 3.8-3.0 million years
ago in the A.afarensis
The descent from trees freed them of some diseases, yet introduced them to others, such as
ticks, flies, and other “ bloodsucking parasites”
Originated around 2.5-1.8 million years ago , appearing in fossil record with several other
hominids such as the Homo habilis
The Homo habilis aka the “handy man” was a scavenger and used simple stone tools.
The species had contact with diseases as they were nomadic allowed interactions