The A B C s of Influenza Virginia Dato

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

A, B, C’s of Influenza n n Influenza A - A should stand for Avian (Believed to originate in wild birds now wide range of viruses infect a wide range of species. ) – H subtypes [1 -16 ] – N subtypes [1 -9] Influenza B – Just humans, some epidemics, no pandemics n Influenza C – Mild illness no epidemics 2

The Enemy - Influenza A Hemagglutinin – Required for attachment to the host cell membrane polymerase (PB 1) PB 2, PA four amino acids of PA, one of PB 1, and five of PB 2 that are found in human RNA – Subject to lots of random errors. Neuramindase – Required for virus release 3

Antigenic drift (if a mutation allows it to jump a species it is a shift) 4

SHIFT 5

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Where did it come from? 9

Geographically – Possible Haskell County, Kansas, “There the smell of manure meant civilization. People raised grains, poultry, cattle, and hogs. Sod-houses were so common that even one of the county's few post offices was located in a dug-out sod home. In 1918 the population was just 1, 720, spread over 578 square miles. “ from John Barry 10

Could a virus this nasty happen again? Natural recombination/resortment of genes n Accidental or Intentional recombination/resortment of genes n Release from the past - Accidental release from a laboratory storing the 1918 virus or other pandemic strains which humans no longer have immunity to. n 11

http: //www. cdc. gov/flu/weeklyarchives 20082009/bigpi 04. htm 12

Other significant Influenza pandemics 1957 -1958 “Asian Flu” H 2 N 2 – 70, 000 US deaths n 1968 -1969 “Hong Kong flu” H 3 N 2 - 34, 000 US deaths (H 3 N 2 viruses still circulating today) n 13

The Two Mechanisms whereby Pandemic Influenza Originates Belshe, R. B. N Engl J Med 2005; 353: 2209 -2211 14

Belshe, R. B. N Engl J Med 2005; 353: 2209 -2211 15

HPAI vs LPAI – a poultry definition n high pathogenic avian influenza (HPAI) – HPAI viruses can cause severe illness and high mortality in poultry. n low pathogenic avian influenza (LPAI) – LPAI viruses are usually associated with mild disease in poultry. n Human’s usually don’t get either if they do tend to only get conjunctivitis from LPAI 16

SO not all H 5 N 1 are the same H 5 N 1 in Ducks in Crawford County – The ducks were sampled August 28, 2006 in Crawford County, Pennsylvania. THIS is NOT the HPAI H 5 N 1 that we are worried about. n 17

http: //www. pandemicflu. gov/ ( February, 13 2009) 18

http: //www. cidrap. umn. edu/cidrap/content/influ enza/avianflu/news/feb 0609 avian. html "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. 19

http: //www. fao. org/ag/againfo/subjects/en/health/dis eases-cards/avian_hpairisk. html 20

http: //www. fao. org/ag/againfo/progr ammes/en/empres/Images/maps/200 9/hpai_05 jan_05 feb_09. gif 21

What about canine influenza? H 3 N 8 n Known to circulate in horses for 40 years. n Probably jumped from a single horse to a single greyhound. Evidence that it has been in greyhounds at least as early as 2000 (or earlier). n First caught attention in deadly outbreaks 2004 in Florida racing greyhounds. n 22

Human Implications of Canine Influenza n n Morbidity and mortality for our pet and service dogs. No known human cases (which is why we are not as worried about this as H 5 N 1) Recombination (shift) with another influenza A theoretically possible if the same organism is infected with H 3 N 8 and another strain at the same time (H 5 N 1 ? ? ? ) H 3 N 8 vaccination when available for dogs will significantly decrease that chance. 23

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. 24

How does avian influenza (H 5 N 1) spread? (as of 4/04/2007) n Bird to Bird - very easy – Through feces and other secretions – Facilitated by crowded conditions and mixing of birds in bird markets. n Bird to Mammal (human, cat, dog) – Through eating uncooked bird – Through extremely close contact (sleeping with birds in same small area. ) n Mammal to Mammal – Very rare human to human associated with extremely close intimate contact. No known cat to human. – Will the virus mutate to make spread easier? ? ? ? 25

How will Pandemic Influenza Spread? n Droplet like seasonal influenza? n Direct or Indirect contact like seasonal influenza? n Feces and other secretions like avian influenza? n Airborne like measles? 26

Seasonal Influenza Spreads Via Droplet Transmission Courtesy of Centers for Disease Control and Prevention 27

Direct exposure to droplets n Direct mucous membrane (eyes, mouth, nose) exposure to flu virus. Since droplets fall out of the air quickly this usually happens if you are in the path of a cough, sneeze or breath. . Stay out of the droplet zone Courtesy of Centers for Disease The Droplet zone Control and Prevention 28

Seasonal Influenza spreads via Indirect Exposure n Indirect contact via your hands or something else picking up virus and getting it onto your mouth, eyes or nose. Courtesy of Centers for Disease Control and Prevention 29

Airborne Transmission Tiny Infectious droplet nuclei less than 5 microns. n The small virus particles hang in the air – sometimes for hours. Important for smallpox, measles, chicken pox. n Less important for SARS and most Influenza (but if you are trying to contain a rare or highly fatal disease every little bit counts. ) n 30

Foodborne or Fecal-Oral Transmission? n n n Existing commercial precautions already excellent Restaurants have hand washing sinks in kitchens Poultry and eggs already need to be well cooked No bare hand contact with ready to eat food already in place. Good agriculture practices related to produce being put in place 31

Vaccination – The Best Defense n n Vaccination is the best defense because it prepares the immune system to rapidly respond when exposed to the virus. This rest of this lecture is for when a person can’t get a vaccine because: – an effective safe vaccine does not exist or there are shortages – the person has a medical reason that keeps him/her from getting vaccinated. – The person has an immune deficiency that makes the vaccine less effective. 32

Anti- viral/anti-microbial agents are nice but… Can there be an adequate supply? n Will the agents develop resistance? n Can people afford them? n Single drug agent resistance is currently widespread. 33

Results as of 2/13 Nationwide H 1 N 1 190 tested 185 (97. 4%) resistant to Oseltamivir, 2 (1. 1% resistant to the Adamantanes) H 3 N 2 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 34

NON-Pharmaceutical Interventions Things people can do to keep from getting and giving infections. n Policy’s institutions can make to decrease infections n Engineering changes institutions can make to decrease infections. n 35

Individuals can decrease personal exposure Keep hands clean n Stay out or get out of the air space of the infectious or potentially infectious – wear a protective mask if you can’t n Limit intimate contacts (human, animal, avian, infectious surface) n Don’t share (toothbrushes, glasses, towels, etc. ) 36 n Watch what you eat or drink n

What about Masks? n Basic surgical masks for the person who is sick. – These masks catch the droplets of virus even if the person is not fast enough to cover their cough themselves. In Japan many people wear masks to work when they have a cold as a curtsey to those around them. (Can’t find one to buy – making one probably works too. – 2 ply T-shirt material tested by the military) 37

For the individual who is well – Surgical mask will keep you from getting droplets directly on your face and nose, but not your eyes (consider glasses) if you are in the droplet zone and get a direct hit. – Surgical masks will NOT keep you from breathing in droplets so move back if you are in the droplet zone. Or make sure you get a mask that filters all of the air you breath. (Fit is most important. When you breath in you pull air around a typically fitting surgical mask. ) 38

Examples of Institutional Policy Changes Make sure that supplies are in place to help stop the spread of respiratory infections (tissues, hand sanitizer, soap) n Educate employees about disease transmission. n Liberal tele-commuting/ sick leave policies n Extend hours. n 39

Institutional Engineering Changes Increase building air exchanges n Air filtration systems n Air flow away from potentially sick individuals n Clear plastic or other barriers that separate individuals n Spread desks to increase spacing between individuals n 40

Stay informed; be prepared to change. n Multiple websites are available with the latest information including – http: //www. pandemicflu. gov – www. cdc. gov – http: //www. pandemicflu. state. pa. us/ – www. promedmail. org – http: //www. cidrap. umn. edu/ 41