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Pathogens
Eco-Science
Chapter 21
Water Pollution and disease are
closely related
Many disease-causing organisms
spend at least part of their life cycle in
the water
Examples: parasites, bacteria, and
viruses
What is a pathogen?
Pathogens- Parasites, bacteria, and
viruses that cause disease in living things
How do these ‘guys’ get into the water?
Through raw sewage or animal waste
they are then passed on to others who come in
contact with the contaminated water
Pathogens result in more human illness
and deaths than any other environmental
factor!
Typhoid Fever
Spread by contaminated
food, drink or water
Affects intestines, lymph nodes, spleen,
etc.
Symptoms: Fever, Rash, Weakness,
Diarrhea, etc.
Cholera
Cholera occurs in places with poor
sanitation, crowding, war, and famine
caused by a bacterium that releases a
toxin that increases the release of
water in the intestines
causes a large amount of watery
diarrhea.
Schistosomiasis
Spread by a microscopic worm that enters the skin
of people who walk in contaminated water (water
infected with human waste)
Worms attack the liver, urinary bladder, and
intestines
Symptoms: fever, chills, lymph node enlargement,
itchy rashes
FACT: Causes more than 1 million deaths each
year
Malaria
Transmitted to humans by the bite of an
infected mosquito
Note: that it is not transferred via direct
contact with contaminated water BUT
water is the breeding ground for the
mosquito…
A parasitic disease that involves high
fevers, shaking chills, flu-like symptoms,
and anemia.
FACT: Malaria kills more than 3,000
children under the age of five each year
and more than 1.5 million each year.