Avian flu
By Sona Hamelin
History
The human influenza A virus was
discovered in 1933 soon after Shope
succeeded in isolating swine influenza A
virus in 1931
Influenza outbreaks were noticed as soon
as 1899
Influenza outbreak
Viruses
Obligatory intracellular parasites
Contain single type of nucleic acid (either
DNA or RNA)
Contain protein coat, some contain
envelop and spikes.
Structure of Influenza virus
N and H spikes
H spikes stand for hemagglutinin
N spikes stand for neurominidase
Influenza types
Influenza viruses are classified into major
groups according to the antigens of their
protein: A, B, C
The A-type viruses are responsible for
major pandemics
Avian influenza is influenza carried by the
birds
Viral infection can be blocked by
neutralizing antibodies
Virus-infected cells
Function if the type 1 interferons
Effector T cell
Antigenic drift
Antigenic shift
T and B cells interactions
Two disulfide –linked subunits: HA-1, and
HA-2
T cell specific for the M protein can help B
cells specific for HA, so that the relative
lack of HA-specific T cells may not limit the
level of help delivered to HA-specific B
cells
Sites of recognition
Transmission from birds to human
Infected birds shed flu virus in their saliva, nasal
secretions, and feces.
Transmission to humans happen through
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Direct contact with secretions from infected birds
Contaminated food, water, equipment and clothing
Clinically normal waterfowl and sea birds may
introduce the virus into flocks
Broken contaminated eggs may infect chicks in the
incubator
Symptoms
High fever
Pneumonia
Eye infection
Acute respiratory distress
Influenza like symptoms
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Cough
Sore throat
Muscle ache
Laboratory findings
Leukopenia (particularly lymphopenia)
Mild to moderate thrombocytopenia
Slightly or moderately elevated
aminotransferase levels
Hyperglycemia
Elevated creatinine levels
immunization
The "flu shot“ - an inactivated vaccine
(containing killed virus) that is given with a
needle, usually in the arm.
The nasal-spray flu vaccine - a vaccine
made with live, weakened flu viruses that
do not cause the flu
Treatment
Antiviral medications (oseltamivir and
zanamivir) that will:
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Reduce the severity and duration of
symptoms caused by infection with influenza
A or B virus
Shorten the length of the illness
Control outbreaks of the flu in nursing homes
Reduce the spread of the virus to people at
high risk for severe complications of the flu
Reduce complications from the flu
Summary
Avian flu is a virus carried by birds
Avian virus contain H and N spikes on
their surface
Avian virus interact with T and B cells
There is not a permanent vaccine since
influenza virus A changes its structures
Antiviral drugs can reduce symptoms
Work cited
Villarreal, Luis P. (2005). Viruses and The Evolution of Life. Washington, D.C.: ASM
The Writing Committee of the Health Organization. (2005). Avian Influenza A (H5N1)
Infection in Humans. The New England Journal of Medicine, 353, 1374-1385.
Retrieved October 11, 2005 from the World Wide Web:
http://content.nejm.org/cgi/content/full/353/13/1374
Male, D., & Champion, B., & Cooke, A. (1989). Advanced Immunology. Hong Kong:
Mandarin Offset.
Kolata, G. (1999). Flu: The Story of The Great Influenza Pandemic of 1918 and The
Search for The Virus That Cause. New York : Farrar, Straus and Giroux.
Ahmad, K. (2004). Increased Asian Collaboration in Fight against Avian Flu, Science
Direct, 5, (1), 9. Retrieved October 11, 2005 from the World Wide Web:
http://www.sciencedirect.com
Appenzeller, T. (2005). Tacking The Next Killer Flu. National Geographic, 208, 2-31.
Avian Influenza Frequently asked questions. (2005). World Health Organization.
Retrieved September 30, 2005 from the World Wide Web:
http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html