Avian fluAvian flu

By Sona HamelinBy Sona Hamelin

HistoryHistory

The human influenza A virus was The human influenza A virus was discovered in 1933 soon after Shope discovered in 1933 soon after Shope succeeded in isolating swine influenza A succeeded in isolating swine influenza A virus in 1931 virus in 1931

Influenza outbreaks were noticed as soon Influenza outbreaks were noticed as soon as 1899as 1899

Influenza outbreakInfluenza outbreak

VirusesViruses

Obligatory intracellular parasitesObligatory intracellular parasites

Contain single type of nucleic acid (either Contain single type of nucleic acid (either DNA or RNA)DNA or RNA)

Contain protein coat, some contain Contain protein coat, some contain envelop and spikes.envelop and spikes.

Structure of Influenza virusStructure of Influenza virus

N and H spikesN and H spikes

H spikes stand for hemagglutininH spikes stand for hemagglutinin

N spikes stand for neurominidaseN spikes stand for neurominidase

Influenza typesInfluenza types

Influenza viruses are classified into major Influenza viruses are classified into major groups according to the antigens of their groups according to the antigens of their protein: A, B, Cprotein: A, B, C

The A-type viruses are responsible for The A-type viruses are responsible for major pandemicsmajor pandemics

Avian influenza is influenza carried by the Avian influenza is influenza carried by the birdsbirds

Viral infection can be blocked by Viral infection can be blocked by neutralizing antibodiesneutralizing antibodies

Virus-infected cellsVirus-infected cells

Function if the type 1 interferonsFunction if the type 1 interferons

Effector T cellEffector T cell

Antigenic driftAntigenic drift

Antigenic shiftAntigenic shift

T and B cells interactionsT and B cells interactions

Two disulfide –linked subunits: HA-1, and Two disulfide –linked subunits: HA-1, and HA-2HA-2

T cell specific for the M protein can help B T cell specific for the M protein can help B cells specific for HA, so that the relative cells specific for HA, so that the relative lack of HA-specific T cells may not limit the lack of HA-specific T cells may not limit the level of help delivered to HA-specific B level of help delivered to HA-specific B cellscells

Sites of recognitionSites of recognition

Transmission from birds to humanTransmission from birds to human

Infected birds shed flu virus in their saliva, nasal Infected birds shed flu virus in their saliva, nasal secretions, and feces.secretions, and feces.

Transmission to humans happen through Transmission to humans happen through Direct contact with secretions from infected birdsDirect contact with secretions from infected birds Contaminated food, water, equipment and clothingContaminated food, water, equipment and clothing Clinically normal waterfowl and sea birds may Clinically normal waterfowl and sea birds may

introduce the virus into flocksintroduce the virus into flocks Broken contaminated eggs may infect chicks in the Broken contaminated eggs may infect chicks in the

incubatorincubator

SymptomsSymptoms

High feverHigh fever

PneumoniaPneumonia

Eye infectionEye infection

Acute respiratory distressAcute respiratory distress

Influenza like symptomsInfluenza like symptoms CoughCough Sore throatSore throat Muscle acheMuscle ache

Laboratory findingsLaboratory findings

Leukopenia (particularly lymphopenia)Leukopenia (particularly lymphopenia)

Mild to moderate thrombocytopeniaMild to moderate thrombocytopenia

Slightly or moderately elevated Slightly or moderately elevated aminotransferase levelsaminotransferase levels

HyperglycemiaHyperglycemia

Elevated creatinine levelsElevated creatinine levels

immunizationimmunization

The "flu shot“The "flu shot“ - an inactivated vaccine - an inactivated vaccine (containing killed virus) that is given with a (containing killed virus) that is given with a needle, usually in the arm. needle, usually in the arm.

The nasal-spray flu vaccineThe nasal-spray flu vaccine - a vaccine - a vaccine made with live, weakened flu viruses that made with live, weakened flu viruses that do not cause the flu do not cause the flu

TreatmentTreatment

Antiviral medications (oseltamivir and Antiviral medications (oseltamivir and zanamivir) that will:zanamivir) that will: Reduce the severity and duration of Reduce the severity and duration of

symptoms caused by infection with influenza symptoms caused by infection with influenza A or B virus A or B virus

Shorten the length of the illnessShorten the length of the illness Control outbreaks of the flu in nursing homes Control outbreaks of the flu in nursing homes Reduce the spread of the virus to people at Reduce the spread of the virus to people at

high risk for severe complications of the flu high risk for severe complications of the flu Reduce complications from the flu Reduce complications from the flu

SummarySummary

Avian flu is a virus carried by birdsAvian flu is a virus carried by birds

Avian virus contain H and N spikes on Avian virus contain H and N spikes on their surfacetheir surface

Avian virus interact with T and B cellsAvian virus interact with T and B cells

There is not a permanent vaccine since There is not a permanent vaccine since influenza virus A changes its structuresinfluenza virus A changes its structures

Antiviral drugs can reduce symptomsAntiviral drugs can reduce symptoms

Work citedWork cited

Villarreal, Luis P. (2005). Villarreal, Luis P. (2005). Viruses and The Evolution of Life.Viruses and The Evolution of Life. Washington, D.C.: ASM Washington, D.C.: ASM

The Writing Committee of the Health Organization. (2005). Avian Influenza A (H5N1) The Writing Committee of the Health Organization. (2005). Avian Influenza A (H5N1) Infection in Humans. Infection in Humans. The New England Journal of Medicine, 353,The New England Journal of Medicine, 353, 1374-1385. 1374-1385. Retrieved October 11, 2005 from the World Wide Web: Retrieved October 11, 2005 from the World Wide Web: http://content.nejm.org/cgi/content/full/353/13/1374http://content.nejm.org/cgi/content/full/353/13/1374

Male, D., & Champion, B., & Cooke, A. (1989). Male, D., & Champion, B., & Cooke, A. (1989). Advanced Immunology.Advanced Immunology. Hong Kong: Hong Kong: Mandarin Offset.Mandarin Offset.

Kolata, G. (1999). Kolata, G. (1999). Flu: The Story of The Great Influenza Pandemic of 1918 and The Flu: The Story of The Great Influenza Pandemic of 1918 and The Search for The Virus That Cause.Search for The Virus That Cause. New York : Farrar, Straus and Giroux. New York : Farrar, Straus and Giroux.

Ahmad, K. (2004). Increased Asian Collaboration in Fight against Avian FluAhmad, K. (2004). Increased Asian Collaboration in Fight against Avian Flu,, Science Science Direct, Direct, 55, (1), 9. Retrieved October 11, 2005 from the World Wide Web: , (1), 9. Retrieved October 11, 2005 from the World Wide Web: http://www.sciencedirect.comhttp://www.sciencedirect.com

Appenzeller, T. (2005). Tacking The Next Killer Flu. Appenzeller, T. (2005). Tacking The Next Killer Flu. National Geographic, 208,National Geographic, 208, 2-31. 2-31.

Avian Influenza Frequently asked questions. (2005). World Health Organization. Avian Influenza Frequently asked questions. (2005). World Health Organization. Retrieved September 30, 2005 from the World Wide Web:Retrieved September 30, 2005 from the World Wide Web:

http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.htmlhttp://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html