Download Environmental Health 1

Environmental Health &
Toxicology
APES
2009
http://news.nationalgeographic.com/news/2009/01/090116-poison-video-wc.html
Some Vocab…
• WHO- World Health Organization
• Health- state of complete physical, mental, and social
well being (not just the absence of disease)
• Disease- change in the body’s condition in response to
an environmental factor
– Ex: nutritional, chemical, biological or psychological
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Morbidity- illness
Pathogen- disease-causing
Vector- organism that spreads disease
Emergent- new, not identified or absent for last 20 years
Zoonotic- transmitted from animal host to humans
PATHOGENIC VS.
NON-PATHOGENIC
• 43% of all diseaserelated deaths are
from pathogens
(insects, bacteria,
virus, worms)
• 57% from
cardiovascular
disease, cancer, lung
disease, injuries, etc.
Pathogenic
NonPathogenic
Morbidity & Quality of Life
• Not everyone dies from disease, but still can cause
severe suffering and debilitation
• When sick…
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Crops not planted/harvested
Animals not tended
Work not done
Kids not fed
• Poorest people are most affected because they live in
unhealthiest environments & don’t have $ for health
care.
• Lack of adequate housing, sanitation, safe drinking water
causes most cases of diarrhea which is made worse by
malnutrition.
PATHOGENIC THREATS TO
HUMAN HEALTH
Infectious Diseases
• Onchocerciasis (river
blindness)
– Vector: Black fly
– Many roundworms get
into eyes & die
causing blindness
– Control with
insecticide sprays
– Merck & Co. are
providing free
ivermectin to help
eradicate.
Infectious Diseases
• Elephantiasis
– Vector: Mosquitoes
– Roundworm gets into
lymph system and
blocks lymph vessels
causing fluid build up
in the extremities.
– SmithKline Beecham
is supplying free
albendazole to kill
worms in body to help
prevent spread.
Infectious Diseases
• Drancunculiasis– Guinea worm
– Vector: Drinking
Water contaminated
with Cyclops
– 3 meter long worm
that lives under skin.
Forms blister & must
be wound out of skin
to remove
Infectious Diseases
• Hemorrhagic Fever
– Some Types…
• Ebola: Vector- unknown
• Lassa: Vector- Mastomys
rat species
• Hanta: Vector- Deer mice
– All cause tissue
deterioration, bleeding,
pulmonary edema.
– Ebola has 90% mortality
rate.
– Highly contagious
Infectious Diseases
• Malaria
– Vector: Anopheles
Mosquitoes transmits
Plasmodium protist into
host blood stream
– 3 million die each year,
90% of them in Africa
– In 1950’s & 60’s, sprayed
DDT & knocked down from
millions cases each year to
thousands, now back to 2.5
million new cases
– Mosquitoes are developing
resistance
– Fever, chills, flu-like
symptoms
Infectious Diseases
• Cholera
– Cause: Bacteria in unclean
drinking water
– Severe stomach cramping,
severe diarrhea, vomiting
– Thought eradicated in
many places but has made
comeback in some due to
ships dumping bilges in
harbors of cities with
inadequate water treatment
Infectious Diseases
• Tuberculosis
– Cause: bacteria
– Eliminated but has
returned stronger than
ever
– Some strains drug
resistant
– Spreads rapidly by
respiratory droplets
(coughing, sneezing,
mucus)
– EX: Russian prisons
EMERGING DISEASES
Infectious
Diseases
• West Nile Virus
– Vector: mosquitoes or
blood transfusions, mother
to child via nursing
– Symptoms: nerve
problems, stiff neck,
headache, high fever, etc.
– Mammals are the “dead
end” infection as the virus
cannot multiple in
mammals
– Prevention: scan blood
donations; mosquito
prevention
Infectious Diseases
• SARS
– Severe Acute Respiratory
Syndrome
– Vector: can be passed
directly from animals
(usually birds) to humans,
also passed human to
human
– Highly contagious!
– Passed via respiratory
droplets (cough, mucus,
sneeze) from human to
human
– Prevention: wash hands,
destroy infected animals,
keep distance from
animals, quarantine
infected people.
SARS vs. Bird Flu
Similarities
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Both are potentially fatal viruses.
Both are respiratory diseases.
Both have first affected animals and then made the jump to humans.
Both have similar symptoms, including fever and difficulty breathing.
At present, there is no known cure for either virus.
Differences
• Bird flu is caused by a flu virus while the SARS virus is more closely
related to the common cold.
• SARS can be transmitted from person to person. So far, MOST
CASES of bird flu have only been transmitted from birds to humans.
H1N1 (Swine Flu)
• First showed in 2009
• First thought to be genetically
similar to flu virus seen in pigs
• Now know it has similarities to
viruses seen in pigs, birds, and
humans
• Very contagious- spread from
human to human
• Same symptoms of flu with
high fever
Difference between Endemic,
Epidemic & Pandemic
• Endemic- disease exists
permanently in a region
or population. EX:
malaria
• Epidemic is localized
outbreak of disease.
EX: west nile
• Pandemic is worldwide
outbreak of disease.
EX: H1N1, small pox
Methods of disease prevention
Insect-born diseases:
• Reduce mosquito population
– Use biological control- frogs, fish, bats,
birds
– Wear more clothing in mosquito infested
areas
– Use insect repellant
– Insecticides
– Mosquito netting
– Eliminate standing water
Water-born diseases (cholera):
• Wash hands
• Boil water
• Shut down shellfish beds
• Provide clean drinking water
• Introduce sanitation for sewage
Other diseases (tuberculosis, hemorrhagic fever)
• Quarantine infected individuals
• Use antibiotics on bacteria (tuberculosis)
What causes disease to spread so
rapidly?
• Population density , so contact 
• Moving into remote areas for
agriculture  exposure.
• Deforestation, pollution causing
local & global climate change ( in
temp =  in mosquito pop. And 
in mosquito range)
• Eliminating predators so  in
rodent, roach, mosquito pop.
•  in speed & frequency of travel
(airplanes, ships) to other countries
•  in resistance (Malaria) =
“Superbugs”
• Taking medication improperly
leads to “superbugs”
• Antibiotics given to farm animals
increases their resistance.