Influenza

• type a
• type b

• potentially severe illness.
• Epidemics and Pandemics
• rapidly changing

• usually less severe illness.
• Epidemic
• Genetically more stable

• Human Influenza A viruses start as avion (bird) influenza viruses
• flu passes from migratory wild birds -->to Domestic Birds -->to Swine -->to Humans
• --->can also go straight from domestic birds to humans
• --->Humans can also pass the flu to swine like they can pass it to Humans

• hemagglutinin (H)
• Neuraminidase (N)
• M2 protiens (ONLY ON TYPE A)

:)

allows the virus to bond to host cells

RNA viruses

• helps the virus to release itself from the highjacked cell in which it has produced
• in other words, after the H binds the virus to your cell and the virus gets into your cell, N lets it get out to your other cells

• H1
• H2
• H3

• H1
• H3

all kinds of flu

• epidemic: local virus infection in a pretty small area
• pandemic: infection of virus nation wide or worldwide

• spanish flu was very similar to today's swine flu
• both H1N1
• swine flu wasnt as bad today because of past vaccinations we have been given

• N1
• N2

• N1
• N2

all types

• Antigenic Drift
• Antigenic Shift

• small changes in H or N protiens that occur from year to year
• population is partially immune, but may be re affected over time (periodic epidemics)
• if a vaccine is given, it will probably still work against the flu

• aquisition of a new H or N protien
• --->possibly from an animal virus
• Population isn't immune because it's new, everyone is susceptable and it could possibly become a pandemic

• viruses are parasotes that use your ribosomes and cells to carry out their work
• attatch themselves and release themselves using H and N protiens

• an immunological diversion
• a protien made in your immune cells
• 2 types
• 3 subtypes

• type 1
• type 2

• Interferon Alpha
• Interferon Beta

• leukocyte interferon
• about 20 related protiens
• made in leukocytes (all different types of leukocytes)

• fibroblast (fibers under your epithelial cells) interferon
• made in fibroblasts, epithelial cells

Interferon Gamma

• immune interferon
• made in certian activated T cells & natural killer cells

• fight against viral infection (especially RNA viruses), double stranded RNA, certian bacterial components
• have strong antiviral properties

• fights antigens
• causes mitogenic stimulation of lymphocytes (that means makes more lymphocytes)

• many consequinces, not fully understood
• ---> interferon does a lot of things in your body, most is good, some is bad

only when needed

• Increase MHC1 expression (expression means that the gene is expressed and the protien is made)
• ---> mRNA transcribes the code on the dna and makes the protien. makes more MHC1 cells causing increased number of cytotoxic t cells
• Interferon also activates natural killer cells
• --->these kill virally infected cells

• increases MHC II expression on antigen presenting cells
• --->this increases the number of helper T cells which can activate memory cells, cytotoxic T cells, etc
• increases antivira potential of macrophages (aka-macrophage activity)

• Anti-viral: ex: interferon alpha is currently approved for certian causes of acute and chronic HCV&Chronic HBV (Hepatitis)
• Macrophage Activation: interferon gamma has been tried for lepromatous leprosy, leishmaniasis& toxo plasmosis
• Anti-Tumor: interferons have been used in melanoma, kaposi's sarcoma, & CML (type of leukemia)
• Multiple Sclerosis- and auto immune disease, your immune system attacks your own body
• --->interferon beta

• block interferon binding
• inhibit or stop function of interferon induced protiens
• pretty much try to block what interferon is trying to do
• try to stop natural killer cells' functions
• interfere with MHC I or MHC II production

• fever
• malaise (you don't know what's going on)
• fatigue (tiredness)
• muscle pain
• ---> flu like symptoms

The m2 protein is an ion channel which allows H+ in to lower the pH of the host cell and allow the virus to uncoat itself and allow the RNA out to make more virus

• 1918-1919: Spanish flu- type A (H1N1)- 20 million killed world wide, 550,000 killed in US
• 1957-1958: Asian Flu- type A (H1N2)- 70,000 killed in US
• 1968-1969: Hong Kong Flu- type A (H3N2) 34,000 killed in US

• croup (occurs in young children)
• primary influenza virus pneumonia
• secondary bacterial infection

• coughing virus
• young children are susceptable
• needs steam from shower to help

• streptocuccus pneumoiae
• staph infection- staphlycoccus aureus
• hemophilus influenzae bacterial (bacterial influenza)

• myositis
• cadiac complications
• encphalopathy
• liver and central nervous system complications
• peripheral nervous system complications

most people with compromised or not fully developed immune systems such as babies and the elderly

• inflammation of your muscles
• rare, more common in children
• comes with type B flu which is rare

heart problems, heart disease, etc

• bad brain disease
• recent studies report that it is a non pulmonary complication
• studies of patients under 21 years in Michigan- 8 cases seen last season
• deadly

reye syndrome

Guillian Barre syndrome

• liver has fatty deposits
• brain edema (swelling)
• vomiting, lethargy, coma

• youth (adults usually don't get it)
• certian viral infections (influenza, chicken pox)
• giving kids asprin can cause it

• 1. The flu virus attaches to the carbohydrates or sugars on your cell's surface (epithelial cells) such as nose, throat and lungs of mammals and intestines of birds (these are the places where epithelial cells are located)
• 2. The virus gets into the cell. Hemagglutinin allows it to do this
• 3. In influenza A, m2 allows hydrogen into the cell, lowering the pH and making it more acidic
• 4. The acid allows the virus to uncoat itself and reveal the RNA
• 5. The RNA can then go through protien synthesis and make more viruses inside the cell
• 6. Then the viruses leave the cell with the help of Neuraminidase and attack new cells and the process starts over

• contains a "Best Guess" of main antigenic types (Each year we choose which variant of each suptype is the best to use for optimal protection)
• currently the vaccine has...
• ---> Type A H1N2
• ---> Type A H3N2
• ---> Type B
• vaccine is inactivated
• sub-unit vaccine for children

in an egg... like a chicken egg

reassortant live vaccine: for healthy people (those not at risk of complications from influenza injections) age 5-49 years because they have strong immune systems

October-November

January

• incubation period is the time between exposure and symptoms
• short 1-3 days

• infected person may shed (or spread) the virus for 12-24 hours before they get symptoms
• viral shedding peoaks on day 2 or 3 then declines

• virus may be present as long as there are symptoms
• usually 5-10 days

• nearly all is spread by person to person (sneezing, coughing on someone)
• spread by droplets (as from a cough or sneeze) inhaled by a suceptable person
• inanimate objects (doorknobs, towels) and physical contact (handshaking) may contribute to spread, but their role is minor

• abrupt onset of symptoms
• fever, usually over 100 degrees F
• cough with little or no sputum
• chills/sweats
• headache
• muscle aches
• sore throat
• potentially severe, persistant malaise (sleepiness, youre out of it)
• chest sores, light sensitivity, eye pain

• only animals have had it, no previous human exposure
• morbidity and mortality in both young and old
• potential for pandemic infection by little known pathogen

• pandemic readiness plan
• rapid detection and diagnosis of new viral strains
• veteranary survailence
• continuing research for new antiviral agents

• Typical influenza involves only the upper respiratory tract (bronchus and bronchioles but not lungs while H5N1 has the ability to infect the upper and lower respiratory tract (including the lungs
• People with underlying medical problems such as lung or heart disease or cancer, or the elderly are at increased risk of secondary bacterial pneoumonia while anyone who is susceptable to H5N1 can get pneumonia caused by the influenza virus
• In regular influenza the influenza viral pneumonia is rare and in H5N1's resulting pneumonia is severe and may be fatal

• total annual costs of influenza are estimated at $14.6 billion in the US
• 10% of cost is direct costs of increased medical care
• 90% of cost is indirect costs like lost productivity, people are out sick and don't go to work, money is lost

• History: First developed in the 1940s
• Content: updated yearly to protect against strains that doctors think will come up. consists of 2 versions of type A and one version of Type B
• Process: Grown in emryonated chicken eggs and formalin inactivated

young healthy people

infection, usually prevents serious disease

• the elderly
• --->many develop infection, but vaccine reduces the frequency of serious disease and death
• --->elderly's response is directly related to their overall state of health

Selective Neuraminidase inhabitors (that stop the virus from getting out of the cell)

• Relenza
• Tamiflu

• Indication: Treatment (may be given before you get sick)
• Spectrum: Type A and Type B
• Administration: Inhaled- 2 puffs a day for 5 days

• Indication: Treatment Prophylaxis (meaning you get treated after you get sick)
• Spectrum: Type A & Type B
• Administration: Oral- 1 tablet a day for 5 days