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Dis-ease
May you live long, share much
kindness, and always talk nicely to
yourself
Bacteria
Bacteria grow in a wide variety of habitats and
conditions.
• When most people think of bacteria, they think of disease-causing
organisms, like the Streptococcus bacteria growing in culture in this
picture, which were isolated from a man with strep throat.
• While pathogenic bacteria are notorious for such diseases as
cholera, tuberculosis, and gonorrhea, such disease-causing
species are a comparatively tiny fraction of the bacteria as
a whole.
• Bacteria are so widespread that it is possible only to make the most
general statements about their life history and ecology.
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They may be found on the tops of mountains,
The bottom of the deepest oceans,
In the guts of animals, and even
In the frozen rocks and ice of Antarctica.
One feature that has enabled them to spread so far, and last so long
is their ability to go dormant for an extended period (forming
capsides to prevent desiccation or hard-coated materials
creating a bacterial spore.
Virus
Viruses
• Viruses are particles of nucleic acid, protein, and some
cases lipids that can reproduce only by infecting living
cells.
• A typical virus is composed of a core of either DNA or
RNA, surrounded by a protein coat.
1. A virus’s outer protein coat is called its capsid.
2. The capsid includes protein that enables a virus to
enter a host cell.
3. The capsid proteins of a typical virus bind to the
surface of a cell and “trick” the cell into allowing it
inside.
4. Once inside, the viral genes take over, eventually.
– The cell transcribes the viral genes, putting the
genetic program of the virus into effect.
– The virus may become part of the host’s genome
– Sometimes that genetic program may simply
cause the cell to make copies of the virus, but
often it destroys the host cell.
Pathogen Disease
Type
Viruses
Agent that
Methods of Transmission
Causes Disease
Common Cold Rhinovirus
Airborne, direct contact
with infected person
Influenza
Two types (A,B),
plus subtypes
Chicken Pox
Varicella –
Herpes virus
Airborne, direct contact
with infected person
Measles
Paramyxovirus
Airborne, direct contact
with infected person
Acquired
Immune
Deficiency
Syndrome
Human
Immunedeficiency Virus
Body fluids
Direct sexual contact
Pathogen
Type
Disease
Agent that Causes
Disease
Methods of
Transmission
Bacteria
Tuberculosis
Mycobacterium
tuberculosis
Droplets in air, direct
contact with secretions
of infected person
Meningitis
Neisseria
meningitides
Direct contact with a
carrier
Cholera
Vibrio cholerae
Contaminated drinking
water
Tetanus
Clostridium tentani
Contaminated wound,
usually puncture wound
African
sleeping
sickness
Trypanosoma
Spread by tsetse fly
Malaria
Plasmodium
Spread by Anopheles
mosquitoes
Amoebic
dysentery
Entamoeba
histolytica
Contaminated drinking
water
Protists
Malaria Infection
Roll down your sleeves to
cover exposed skin and
avoid mosquito bites,
especially in evening and
early morning.
One more reason to hate
mosquitoes –
West Nile Virus
CNS infecting virus –West Nile Virus
Human Disease Cases by
County - California, 2004
Butte County - 7
Fresno County- 11
Glenn County - 3
Imperial County - 1
Kern County - 59
Lake County - 1
Lassen County - 1
Los Angeles County - 305
Merced County - 1
Orange County - 62
Placer County - 1
Riverside County - 109
Sacramento County - 3
San Bernardino County - 187
San Diego County - 2
San Joaquin County - 2
San Luis Obispo County - 1
Santa Clara County - 1
Shasta County - 5
Tehama County - 10
Tulare County - 3
Ventura County - 2
Yolo County - 1
• Cumulative 2004 Data as of 3 am,
Apr 30, 2005*
West Nile Virus is transmitted to humans through mosquito bites.
Mosquitoes become infected when they feed on infected birds that
have high levels of West Nile Virus in their blood. Infected
mosquitoes can then transmit West Nile Virus when they feed on
humans or other animals.
Since West Nile virus (WNV) was first isolated in 1937, it has been known to
cause asymptomatic infection and fevers in humans in Africa, West Asia, and
the Middle East.
These data are provisional and may be revised or adjusted in the future.
More about the dreaded WNV
• Human and animal infections were not documented in the Western
Hemisphere until the 1999 outbreak in the New York City metropolitan
area. Since then, the disease has spread across the United States. In
2003, WNV activity occurred in 46 states and caused illness in over
9,800 people.
• Less than 1% of infected people develop severe illness that includes
meningitis (inflammation of one of the membranes covering the brain
and spinal cord) or encephalitis.
• The symptoms of these illnesses can include headache, high fever, neck
stiffness, stupor, disorientation, coma, tremors, convulsions, muscle
weakness, and paralysis. Of the few people that develop encephalitis, a
small proportion die but, overall, this is estimated to occur in less than 1
out of 1000 infections.
2004 West Nile Virus Activity in the United States
(reported as of January 11, 2005)*
State
Neuroinvasiv
e disease
California
156
269
346
771
23
900
1017
553
2470
88
Total
Fever
Other Clinical/
Unspecified
Total Human
Cases
Reported
to CDC
Deaths
Polio
• And we thought it was over……
Thanks for the cartoon
http://www.pbs.org/wgbh/aso/onth
eedge/polio/