Download Exam #2 F 3/30 in WCH 1.120 Review Th 3/29 at 5pm in GRG 102

Exam #2 F 3/30 in WCH 1.120
Review Th 3/29 at 5pm in GRG 102
Homework #3 is due 4/11.
Bonus #2 is due W 4/4.
Bonus #3 is due F 4/27.
Immune System Overview
CB 43.14
Influenza,
an ssRNA
envelope virus
Spanish flu of 1918-1919
Spanish flu of 1918-1919
•Killed between 20-50 million people
worldwide; 675,000 in the U.S.
(2.5%-5% of world population)
•Infected 1/5 to 1/4 of world population
•Was most lethal to people 20-40 years old
http://virus.stanford.edu/uda/
Spanish flu of 1918-1919
People on their way to work suddenly developing the flu and
dying within hours (Henig).
One physician writes that patients with seemingly ordinary
influenza would rapidly "develop the most viscous type of
pneumonia that has ever been seen" and later when cyanosis
appeared in the patients, "it is simply a struggle for air until
they suffocate," (Grist, 1979).
Another physician recalls that the influenza patients "died
struggling to clear their airways of a blood-tinged froth that
sometimes gushed from their nose and mouth," (Starr, 1976).
http://virus.stanford.edu/uda/
The high fatality rate
from the Spanish flu
was probably due to an
immune system overreaction
Spanish flu of 1918-1919
This influenza virus was similar to avian flu
Avian flu exists in two distinct forms:
High pathogenicity AI virus that produce
>75% mortality (HPAI)
Low pathogenicity is everything else (LPAI)
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES 49:317–327, 2005
Avian flu is maintained in wild birds as low
pathogenicity, and occasionally mutates to high
pathogenicity in domesticated birds.
Approximately 25 outbreaks since 1959
15 since 1990 and 6 since 2000
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES 49:317–327, 2005
Influenza viruses type A, B, and C.
Type A viruses are the most common and are
found in swine, horses, wild birds, domestic
poultry, and humans.
Sporadic infections have been reported in
farmed mink, wild whales and seals, dogs, and
captive populations of big cats (tigers and
leopards).
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES 49:317–327, 2005
Influenza,
an ssRNA
envelope virus
The influenza A virus
genome contains 8 genes
that code for 10 different
proteins.
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES
49:317–327, 2005
Influenza,
an ssRNA
envelope virus
The influenza A virus
genome contains 8 genes
that code for 10 different
proteins.
CB 18.8
Viral genetic material can
change allowing the virus to
infect different cells.
Membrane protein
Virus 1
Virus 2
During co-infection
viral genomes can be
mixed resulting in a
new hybrid virus.
Virus
1+2
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES 49:317–327, 2005
How is bird flu being spread?
Declan Butler NATURE Vol 439 pg 772 February 16, 2006
Bird Flu Spread
http://news.bbc.co.uk/1/shared/spl/hi/world/05/bird_flu_map/html/1.stm
Migratory wild birds
or
Poultry trade (black market)
Prevention efforts will only be effective if the
source can be defined
If the flu is being spread by migratory birds,
why are some migratory routes free of flu?
In 2004 an outbreak in Tibet was traced to
illegal poultry transport from China.
How should we spend resources to protect
poultry and humans?
Even with today’s vaccine technology and the
knowledge that vaccines will prevent severe illness
and death, only 300 million doses are produced and
used worldwide.
More than 95% of the world’s population remains at
risk for infection.
Each year an estimated 250,000 to 500,000 people
die worldwide as a result of influenza virus
infections.
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES 49:317–327, 2005
It can be estimated that in the United States, for
example, the yearly economic burden caused by
influenza deaths, infections, vaccinations, loss of
productivity, and attendant health care costs is equal
to 0.1%–0.5% of the gross domestic product.
Public Health Risk from Avian Influenza Viruses by Perdue and Swayne in AVIAN DISEASES 49:317–327, 2005
Exam #2 F 3/30 in WCH 1.120
Review Th 3/29 at 5pm in GRG 102
Homework #3 is due 4/11.
Bonus #2 is due W 4/4.
Bonus #3 is due F 4/27.