The A,B,C’s of Influenza Virginia Dato MD MPH Public Health Physician Bureau of Epidemiology Pennsylvania Department of Health.

The A,B,C’s of InfluenzaThe A,B,C’s of Influenza

Virginia Dato MD MPHVirginia Dato MD MPH

Public Health PhysicianPublic Health Physician

Bureau of Epidemiology Bureau of Epidemiology Pennsylvania Department of HealthPennsylvania Department of Health

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A, B, C’s of InfluenzaA, B, C’s of Influenza

Influenza A - A should stand for Avian (Believed Influenza A - A should stand for Avian (Believed to originate in wild birds now wide range of to originate in wild birds now wide range of viruses infect a wide range of species.)viruses infect a wide range of species.)– H subtypes [1-16 ] H subtypes [1-16 ] – N subtypes [1-9] N subtypes [1-9]

Influenza BInfluenza B– Just humans, some epidemics, no pandemicsJust humans, some epidemics, no pandemics

Influenza C Influenza C – Mild illness no epidemics Mild illness no epidemics

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The Enemy - Influenza AThe Enemy - Influenza AHemagglutinin – Required for attachment to the host cell membrane

Neuramindase – Required for virus release

RNA – Subject to lots of random errors.polymerase (PB1)

PB2, PA

four amino acids of PA, one of PB1, and five of PB2 that are found in human

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Antigenic drift (if a mutation allows Antigenic drift (if a mutation allows it to jump a species it is a shift)it to jump a species it is a shift)

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SHIFT

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Where did it come from?Where did it come from?

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Geographically – Possible Haskell Geographically – Possible Haskell County, Kansas, County, Kansas,

““There the smell of manure meant There the smell of manure meant civilization. People raised grains, civilization. People raised grains, poultry, cattle, and hogs. Sod-houses poultry, cattle, and hogs. Sod-houses were so common that even one of the were so common that even one of the county's few post offices was located county's few post offices was located in a dug-out sod home. In 1918 the in a dug-out sod home. In 1918 the population was just 1,720, spread population was just 1,720, spread over 578 square miles. “ from John over 578 square miles. “ from John BarryBarry

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Could a virus this nasty happen Could a virus this nasty happen again? again?

Natural recombination/resortment of genesNatural recombination/resortment of genes Accidental or Intentional Accidental or Intentional

recombination/resortment of genesrecombination/resortment of genes Release from the past - Accidental release Release from the past - Accidental release

from a laboratory storing the 1918 virus or from a laboratory storing the 1918 virus or other pandemic strains which humans no other pandemic strains which humans no longer have immunity to. longer have immunity to.

12http://www.cdc.gov/flu/weekly/weeklyarchives2008-2009/bigpi04.htm

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Other significant Influenza Other significant Influenza pandemicspandemics

1957-1958 “Asian Flu” H2N2 – 70,000 US 1957-1958 “Asian Flu” H2N2 – 70,000 US deathsdeaths

1968-1969 “Hong Kong flu” H3N2- 34,000 1968-1969 “Hong Kong flu” H3N2- 34,000 US deaths (H3N2 viruses still circulating US deaths (H3N2 viruses still circulating today)today)

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Belshe, R. B. N Engl J Med 2005;353:2209-2211

The Two Mechanisms whereby Pandemic Influenza Originates

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Belshe, R. B. N Engl J Med 2005;353:2209-2211

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HPAI vs LPAI – a poultry definitionHPAI vs LPAI – a poultry definition

high pathogenic avian influenza (HPAI) high pathogenic avian influenza (HPAI) – HPAI viruses can cause severe illness and high HPAI viruses can cause severe illness and high

mortality in poultry. mortality in poultry. low pathogenic avian influenza (LPAI) low pathogenic avian influenza (LPAI)

– LPAI viruses are usually associated with mild LPAI viruses are usually associated with mild disease in poultry. disease in poultry.

Human’s usually don’t get either if they do Human’s usually don’t get either if they do tend to only get conjunctivitis from LPAItend to only get conjunctivitis from LPAI

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SO not all H5N1 are the sameSO not all H5N1 are the same

H5N1 in Ducks in Crawford County – H5N1 in Ducks in Crawford County –

The ducks were sampled August 28, 2006 in The ducks were sampled August 28, 2006 in Crawford County, Pennsylvania. THIS is Crawford County, Pennsylvania. THIS is NOT the HPAI H5N1 that we are worried NOT the HPAI H5N1 that we are worried about.about.

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 http://www.pandemicflu.gov/ ( February, 13 2009)

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"So far, despite a large number of samples from poultry being collected and laboratory tested, no evidence of infection in poultry has been found to explain these human cases," Martin said.

http://www.cidrap.umn.edu/cidrap/content/influenza/avianflu/news/feb0609avian.html

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http://www.fao.org/ag/againfo/subjects/en/health/http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian_hpairisk.htmldiseases-cards/avian_hpairisk.html

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http://www.fao.org/ag/againfo/http://www.fao.org/ag/againfo/programmes/en/empres/Images/programmes/en/empres/Images/

maps/2009/hpai_05jan_05feb_09.gifmaps/2009/hpai_05jan_05feb_09.gif

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What about canine influenza?What about canine influenza?

H3N8H3N8 Known to circulate in horses for 40 years.Known to circulate in horses for 40 years. Probably jumped from a single horse to a Probably jumped from a single horse to a

single greyhound. Evidence that it has been single greyhound. Evidence that it has been in greyhounds at least as early as 2000 (or in greyhounds at least as early as 2000 (or earlier). earlier).

First caught attention in deadly outbreaks First caught attention in deadly outbreaks 2004 in Florida racing greyhounds.2004 in Florida racing greyhounds.

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Human Implications of Canine Human Implications of Canine InfluenzaInfluenza

Morbidity and mortality for our pet and service Morbidity and mortality for our pet and service dogs.dogs.

No known human cases (which is why we are not No known human cases (which is why we are not as worried about this as H5N1)as worried about this as H5N1)

Recombination (shift) with another influenza A Recombination (shift) with another influenza A theoretically possible if the same organism is theoretically possible if the same organism is infected with H3N8 and another strain at the same infected with H3N8 and another strain at the same time (H5N1 ???) time (H5N1 ???)

H3N8 vaccination when available for dogs will H3N8 vaccination when available for dogs will significantly decrease that chance. significantly decrease that chance.

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What about Swine Influenza? What about Swine Influenza?

The CDC typically receives about one report of a human swine flu case a year, the SDDH statement said. In late November the CDC, in one of its seasonal influenza activity updates, reported on a patient from Texas who was infected with swine influenza after exposure to pigs, including a sick one.

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How does avian influenza How does avian influenza (H5N1) spread? (as of (H5N1) spread? (as of

4/04/2007) 4/04/2007) Bird to Bird - very easyBird to Bird - very easy

– Through feces and other secretionsThrough feces and other secretions– Facilitated by crowded conditions and mixing of birds in bird Facilitated by crowded conditions and mixing of birds in bird

markets.markets. Bird to Mammal (human, cat,dog)Bird to Mammal (human, cat,dog)

– Through eating uncooked birdThrough eating uncooked bird– Through extremely close contact (sleeping with birds in same Through extremely close contact (sleeping with birds in same

small area.) small area.) Mammal to MammalMammal to Mammal

– Very rare human to human associated with extremely close Very rare human to human associated with extremely close intimate contact. No known cat to human.intimate contact. No known cat to human.

– Will the virus mutate to make spread easier???????Will the virus mutate to make spread easier???????

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How will Pandemic Influenza How will Pandemic Influenza Spread?Spread?

Droplet like seasonal influenza?Droplet like seasonal influenza? Direct or Indirect contact like seasonal Direct or Indirect contact like seasonal

influenza?influenza? Feces and other secretions like avian Feces and other secretions like avian

influenza?influenza? Airborne like measles? Airborne like measles?

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Seasonal Influenza Spreads Via Seasonal Influenza Spreads Via Droplet TransmissionDroplet Transmission

Courtesy of Centers for Disease Control and Prevention

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Direct exposure to dropletsDirect exposure to droplets

Direct mucous membrane (eyes, mouth, nose) exposure to Direct mucous membrane (eyes, mouth, nose) exposure to flu virus. Since droplets fall out of the air quickly this flu virus. Since droplets fall out of the air quickly this usually happens if you are in the path of a cough, sneeze or usually happens if you are in the path of a cough, sneeze or breath..breath..

Courtesy of Centers for Disease

Control and Prevention

Stay out of the droplet zone

The Droplet zone

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Seasonal Influenza spreads via Seasonal Influenza spreads via Indirect Exposure Indirect Exposure

Indirect contact via your hands or Indirect contact via your hands or something else picking up virus and getting something else picking up virus and getting it onto your mouth, eyes or nose. it onto your mouth, eyes or nose.

Courtesy of Centers for Disease Control and Prevention

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Airborne TransmissionAirborne Transmission

Tiny Infectious droplet nuclei less than 5 Tiny Infectious droplet nuclei less than 5 microns.microns.

The small virus particles hang in the air – The small virus particles hang in the air – sometimes for hours. Important for sometimes for hours. Important for smallpox, measles, chicken pox.smallpox, measles, chicken pox.

Less important for SARS and most Less important for SARS and most Influenza (but if you are trying to contain a Influenza (but if you are trying to contain a rare or highly fatal disease every little bit rare or highly fatal disease every little bit counts.)counts.)

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Foodborne or Fecal-Oral Foodborne or Fecal-Oral Transmission?Transmission?

Existing commercial precautions already excellentExisting commercial precautions already excellent Restaurants have hand washing sinks in kitchens Restaurants have hand washing sinks in kitchens Poultry and eggs already need to be well cookedPoultry and eggs already need to be well cooked No bare hand contact with ready to eat food No bare hand contact with ready to eat food

already in place.already in place. Good agriculture practices related to produce Good agriculture practices related to produce

being put in placebeing put in place

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Vaccination – The Best DefenseVaccination – The Best Defense

Vaccination is the best defense because it prepares Vaccination is the best defense because it prepares the immune system to rapidly respond when the immune system to rapidly respond when exposed to the virus.exposed to the virus.

This rest of this lecture is for when a person can’t This rest of this lecture is for when a person can’t get a vaccine because:get a vaccine because:– an effective safe vaccine does not exist or there are an effective safe vaccine does not exist or there are

shortagesshortages– the person has a medical reason that keeps him/her from the person has a medical reason that keeps him/her from

getting vaccinated.getting vaccinated.– The person has an immune deficiency that makes the The person has an immune deficiency that makes the

vaccine less effective. vaccine less effective.

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Anti- viral/anti-microbial agents are Anti- viral/anti-microbial agents are nice but…nice but…

Can there be an adequate supply? Can there be an adequate supply? Will the agents develop resistance?Will the agents develop resistance? Can people afford them? Can people afford them?

Single drug agent resistance is currently widespread.

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Results as of 2/13 Nationwide Results as of 2/13 Nationwide

H1N1 190 tested 185 (97.4%) resistant to Oseltamivir, 2 (1.1% resistant to the Adamantanes)

H3N2 41 tested 0 resistant to oseltamivr, 41 (100% resistant to the adamantanes)

Influenza B – The adamantanes have never had activity against B

No known zanamivir resistance,

No known double resistance – yet

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NON-Pharmaceutical Interventions

Things people can do to keep from getting Things people can do to keep from getting and giving infections. and giving infections.

Policy’s institutions can make to decrease Policy’s institutions can make to decrease infectionsinfections

Engineering changes institutions can make Engineering changes institutions can make to decrease infections.to decrease infections.

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Individuals can decrease Individuals can decrease personal exposurepersonal exposure

Keep hands cleanKeep hands clean Stay out or get out of the air space of the Stay out or get out of the air space of the

infectious or potentially infectious – wear a infectious or potentially infectious – wear a protective mask if you can’tprotective mask if you can’t

Limit intimate contacts (human, animal, avian, Limit intimate contacts (human, animal, avian, infectious surface)infectious surface)

Don’t share (toothbrushes, glasses, towels, etc.)Don’t share (toothbrushes, glasses, towels, etc.) Watch what you eat or drinkWatch what you eat or drink

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What about Masks? What about Masks?

Basic surgical masks for the person who is Basic surgical masks for the person who is sick. sick. – These masks catch the droplets of virus even if These masks catch the droplets of virus even if

the person is not fast enough to cover their the person is not fast enough to cover their cough themselves. In Japan many people wear cough themselves. In Japan many people wear masks to work when they have a cold as a masks to work when they have a cold as a curtsey to those around them. (Can’t find one curtsey to those around them. (Can’t find one to buy – making one probably works too. – 2 to buy – making one probably works too. – 2 ply T-shirt material tested by the military) ply T-shirt material tested by the military)

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For the individual who is well For the individual who is well

– Surgical mask will keep you from getting Surgical mask will keep you from getting droplets directly on your face and nose, but not droplets directly on your face and nose, but not your eyes (consider glasses) if you are in the your eyes (consider glasses) if you are in the droplet zone and get a direct hit. droplet zone and get a direct hit.

– Surgical masks will NOT keep you from Surgical masks will NOT keep you from breathing in droplets so move back if you are breathing in droplets so move back if you are in the droplet zone. Or make sure you get a in the droplet zone. Or make sure you get a mask that filters all of the air you breath. (Fit is mask that filters all of the air you breath. (Fit is most important. When you breath in you pull most important. When you breath in you pull air around a typically fitting surgical mask. ) air around a typically fitting surgical mask. )

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Examples of Institutional Policy Examples of Institutional Policy ChangesChanges

Make sure that supplies are in place to help Make sure that supplies are in place to help stop the spread of respiratory infections stop the spread of respiratory infections (tissues, hand sanitizer, soap)(tissues, hand sanitizer, soap)

Educate employees about disease Educate employees about disease transmission.transmission.

Liberal tele-commuting/ sick leave policiesLiberal tele-commuting/ sick leave policies Extend hours. Extend hours.

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Institutional Engineering ChangesInstitutional Engineering Changes

Increase building air exchangesIncrease building air exchanges Air filtration systems Air filtration systems Air flow away from potentially sick Air flow away from potentially sick

individualsindividuals Clear plastic or other barriers that separate Clear plastic or other barriers that separate

individualsindividuals Spread desks to increase spacing between Spread desks to increase spacing between

individualsindividuals

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Stay informed; be prepared to Stay informed; be prepared to change.change.

Multiple websites are available with the Multiple websites are available with the latest information includinglatest information including– http://www.pandemicflu.govhttp://www.pandemicflu.gov

– www.cdc.govwww.cdc.gov– http://www.pandemicflu.state.pa.us/http://www.pandemicflu.state.pa.us/

– www.promedmail.orgwww.promedmail.org– http://www.cidrap.umn.edu/http://www.cidrap.umn.edu/