Download Biological Hazards

Biological
Hazards
Chapter 20 Section 2
Global Warming Affects
 Wide
Spread of global warming allows
mosquitoes to flourish in regions of the
world they never could before.
 The mosquitoes bring a variety of diseases
with them .
The Environment’s Role in
Disease
 Infectious
diseases are caused by
pathogen, organisms that cause disease.
 These diseases spread through person to
person contact through the air or drinking
water.
 A host is an organism in which a
pathogen lives all or part of its life.
Waterborne Disease
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About ¾ of infectious diseases are transmitted
through water.
In developing countries, there is a shortage of
water so the water supply is used for drinking,
washing and sewage disposal.
These are good breeding grounds for
pathogens.
Organisms that transmit diseases are called
vectors.
Cholera
 Deadliest
waterborne diseases come from
drinking polluted water by human feces.
 Cholera causes the body to lose water by
diarrhea and vomiting.
 It causes the most infant mortality.
Malaria
 Once
the world’s leading cause of death.
 Caused by parasitic protists and is
transmitted by a bite from female
mosquitoes.
 No vaccine for malaria exists but there
are preventative measures to control
mosquitoes.
Environmental Change and
Disease
 We
alter the environment to make it more
suitable for pathogens to live and
reproduce.
 Many organisms spread through soil that is
contaminated with feces. Ex. Hookworm
 People are infected by walking
barefooted and contaminated food.
Antibiotic Resistance
 Antibiotics
cause pathogens to evolve
 Large quantities of antibiotics are feed to
live stock to speed growth causing
Salmonella and E.Coli to evolve.
 Treating human illnesses has also caused
diseases such as pneumonia and
tuberculosis to evolve
Emerging viruses
 Viruses
that were unknown 100 years ago.
Ex. HIV/AIDS, ebola virus, West Nile virus.
 We do not have any effective drugs to
treat viral diseases.
 Vaccines are only effective to a virus that
is already present.
Cross Species Transfers
 When
pathogens cross over from its
original host to a new host.
 Ex. HIV, West Nile
 Recent Examples include the bird flu and
the swine flu.