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Week 8 Lecture

Environmental Science
Course Code
Jovan Stefanovic

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Biological Hazards and Human Health
Biological Hazards
Nontransmissible diseases (cardiovascular, cancer, diabetes, asthma)
oThe cause of disease is not a living thing, usually its a combination of
different factors, usually it takes a long time to develop, many causes
Transmissible diseases (infectious agent such as bacteria, viruses, protozoa or
oThe living thing is the cause living thing is called infectious agent
oSomething that carries the infectious agent can be water, air, food,
mosquitoes = vectors that transmit diseases
oCan be transferred from person to person
oIn history, we were not aware of the causes, but it took a long period of time
for diseases to spread (e.g. Europe plague took a month to spread; today
people are commuting and travelling, within a couple of hours diseases
Growing germ resistance to antibiotics germs/bacteria are able to multiply very
quickly within 24 hours
High reproductive rate allow them to become genetically resistant quickly
oBacteria can have mutations
Overuse of antibiotics
Antibiotics in food additives to boost livestock
oWe are exposed to antibiotics in food (meat production)
Biological Hazards
Bacteria cannot multiply outside the human body, need the human cell to
multiply, cannot survive outside
o Tuberculosis
o Anthrax
o Different forms of Plague
o Yellow Fever
o Bird Flu
o Smallpox
o West Nile Virus
o Malaria
BACTERIAL diseases
Tuberculosis in medieval times, was related to vampires because they cough out blood
1 in 3 who come into contact with the disease will get sick, the other 2 will not

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Most new cases were seen in Asia and Africa, but recently over the last decade, there
are numerous cases in the developed countries
In 2004, mortality statistics included:
o 14.6 million chronic active TB cases
o 8.9 million new cases
o 1.6 million deaths, mostly in developing countries
Differences in health care systems
Transmissions cough, sneeze, speak, kiss, or spit of ill person
Most commonly attacks the lungs
Symptoms include chest pain, coughing up blood, and a productive, prolonged
cough for more then three weeks, fever, chills, night sweats, appetite loss, weight
loss, paleness, and often a tendency to fatigue very easily
Tuberculosis - Growing Treat
Bacillus Anthracis (large, spore forming bacteria)
Produce toxin toxin is something that is really damaging to the body
Three major clinical forms
o Cutaneous on the skin
o Inhalation
o Gastrointestinal
All three may lead to septricemia and death
No smell or taste; To small to be seen by naked eye
Cannot be transmitted from person to person, but from animal to person
Cutaneous Anthrax can be transmitted from animal to person through wool, meat, etc.
The most common naturally occurring type (>95%)
After skin contact with contaminated meat, wool or leather from infected animals
The incubation period ranges from 1 - 12 days
Begins as a small raising bump, progresses into vesicle and then a painless ulcer
Fever, headache, lymph glands swell
20 % of untreated cases results in death
Treatment = antibiotics
Inhalation Anthrax
The most lethal form
Inhalation of spores of anthrax
Incubation period 1-60 days
Starts as viral respiratory illness: sore throat, mild fever, muscle aches
May progress to respiratory failure and shock with developing meningitis
75 % of cases result in death even with all possible supportive care
Gastrointestinal Anthrax in the food
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