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Swine Flu and You

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  1. Swine Flu and You Don Skillman, M.D. Infectious Diseases / Internal Medicine St Peter’s Hospital

  2. Swine Flu • Where does the name come from? • Where is it spreading? • How bad is it? • Is there a treatment or vaccine? • What’s the situation in Helena?

  3. It’s scaring people all over the world.

  4. Swine Flu • They’ve changed the name of it: • Swine-origin Influenza A (H1N1) Virus • “S-OIV”

  5. Swine Flu • A respiratory disease of pigs, caused by type A influenza viruses. • They cause regular outbreaks in pigs. • People do not normally get swine flu, but human infections can happen. • Swine flu viruses can spread from person-to-person. • In the past, this transmission was limited and not sustained beyond three people.

  6. Swine Flu in the USA • 1976: • A swine flu outbreak in Fort Dix, New Jersey • More than 200 cases. • Serious illness in several people and one death. • September 1988: • A previously healthy 32-year-old pregnant woman in Wisconsin got infected and died 8 days later. • 2005 to January 2009 • 12 human cases of swine flu were detected. • No deaths.

  7. Influenza ABC’s • There are three types of Influenza viruses, Influenza A, B, and C . • Influenza C: Causes mild disease in humans and is not associated with epidemics. • Influenza B: Causes disease in humans, but it is usually mild. It occurs during annual epidemics, but has not been associated with pandemics. • Influenza A is associated with annual epidemics and with prior pandemics. • “Bird Flu” and “Swine Flu” are influenza A viruses.

  8. Influenza H’s and N’s • These are two surface proteins • They affect viral spread. • H = Hemagglutinin: it helps the virus get into cells. • 16 different H proteins have been identified. • N = Neuraminidase: it facilitates the release of new viral particles from the infected cells. • 9 different N proteins have been identified. • Circulating strains are identified by the H and N proteins present, for example: H1N1 or H2N3.

  9. An example of an Influenza A virus and its official name.

  10. Swine Flu (H1N1) • Influenza A viruses • 16 different HA’s • 9 distinct NA’s

  11. Hemagglutinin has 4 major variable regions. • They are involved in what animal species the influenza A virus can infect. Humans Swine Horses Birds Mink Ferrets Marine animals Whales

  12. How do virus types get mixed together? • Large swine breeding farms. • Large chicken ranches. • Families with pigs or chickens/ducks/geese. • Close relationships between animals and humans.

  13. Influenza A • Only a few of the 16 HA and 9 NA types can usually infect Humans. • Only affected by subtypes with H1, H2, H3 and N1, N2. • And possibly N8 • In late 1997 a new strain of influenza A crossed from chickens into humans, H5N1.

  14. Antigenic Drift • Changes in H and N proteins occur continuously. • These small changes make you susceptible to the new virus that’s circulating each year. • Called “Seasonal Influenza” • That’s why you need a new influenza vaccine each year, to protect you from the new circulating strain.

  15. Antigenic Shift • This is a larger change in the H and N surface proteins. • When Antigenic Shift occurs, there may be little or no protection from prior infections. • For example, infection with H1N1 virus confers little resistance to infection with an H3N2 virus. • These larger changes, or shifts, may result in influenza pandemics, infecting much larger numbers of people than the annual epidemics.

  16. Pandemic Influenza • 1918 - Spanish Flu, H1N1 • 1957 - Asian Flu, H2N2 • 1968 - Hong Kong Flu, H3N2 • 1977 – Russian Flu • An H1N1 influenza strain that had not been seen since 1957 re-emerged. • Older people were less frequently affected by it. • They had been exposed to H1N1 before. • Younger people who had not been previously exposed to the H1N1 strain were more frequently infected.

  17. Influenza Pandemics • “Pandemic” means that a virus is circulating widely. • It’s about geography, not death tolls. • Calling it a pandemic it doesn’t automatically mean that it will be like the flu pandemic of 1918, which killed 20 to 50 million people worldwide.

  18. Influenza Pandemics • Worldwide, the Asian flu pandemic of 1957 killed about 2 million. • The Hong Kong flu of 1968 killed about 1 million. • “Ordinary flu” kills about 250,000 to 500,000 people each year. • Within the United States, the 1968 flu pandemic killed about 34,000 people. • This is about how many die from seasonal influenza every year in the USA.

  19. Pandemic Influenza Phases

  20. Pandemic Influenza Phases • Phase 5 • Most countries will not be affected at this stage. • Phase 5 is a strong signal that a pandemic is imminent. • The time to finalize the organization, communication, and implementation of the planned mitigation measures is short.

  21. Swine Flu - Where is it Now?

  22. 11 O’clock, Eastern Daylight Time 6 May 2009 Swine Flu Confirmed in 41 states 642 total cases 2 deaths 12 other states had 1 or 2 cases. Montana has had none.

  23. Global Cases of Swine Flu • 6 May 2009: 23 countries with 1,893 cases. • Mexico has reported 942 cases, including 29 deaths. • Austria (1) Canada (165) Hong Kong (1) Colombia (1) Costa Rica (1) Denmark (1) • El Salvador (2) France (5) Germany (9) Guatemala (1) Ireland (1) Israel (4) • Italy (5) Netherlands (1) New Zealand (5) Portugal (1) South Korea (2) Spain (73) • Sweden (1) Switzerland (1) United Kingdom (28) • WHO is not recommending travel restrictions.

  24. Swine Flu - How Bad Is It?

  25. Swine Flu - How bad is it? • Each year, “ordinary” influenza kills about 36,000 Americans. • Swine flu has killed 2. • A Mexican man who came to Texas for treatment. • A Texan woman, pregnant, with underlying chronic diseases.

  26. Uncomplicated Swine Flu • Fever • Headache • Upper respiratory tract symptoms • cough, sore throat, runny nose • Sore muscles • Fatigue • Vomiting, or diarrhea.

  27. Mild Influenza Sounds a Lot like the Common Cold!

  28. Influenza vs. the Common Cold Influenza Common Cold Onset Fever Sore Muscles Fatigue Sore Throat Headache Sneezing Stuffy Nose Cough Nasal Discharge Abrupt Virtually always, >101oF often Common, often severe Severe, near exhaustion Sometimes Prominent Sometimes Sometimes Dry, nonproductive, may be severe Clear, modest amounts Gradual Practically never Mild, or nonexistent Mild Common Rare Usually Usually Hacking, possibly productive Clear or green/yellow, possibly lots

  29. Complicated Swine Flu • With previous variants of swine flu viruses, clinical syndromes have ranged from mild respiratory illness, to lower respiratory tract illness, dehydration, or pneumonia. • Deaths caused by previous variants of swine influenza viruses have occasionally occurred.

  30. Complicated Swine FluExpect complications to be similar to seasonal influenza. • Worsening of underlying chronic medical conditions • Upper respiratory tract disease • sinusitis, otitis media, croup • Lower respiratory tract disease • pneumonia, bronchiolitis, status asthmaticus • Cardiac • myocarditis, pericarditis

  31. Complicated Swine FluExpect complications to be similar to seasonal influenza • Musculoskeletal • myositis, rhabdomyolysis • Neurologic • acute and post-infectious encephalopathy, encephalitis, febrile seizures, status epilepticus • Toxic shock syndrome • Secondary bacterial pneumonia with or without sepsis.

  32. Groups at higher risk for seasonal influenza complications. • Children less than 5 years old; • Persons aged 65 years or older; • Children and adolescents (less than 18 years) who are receiving long-term aspirin therapy and who might be at risk for experiencing Reye’s syndrome after influenza virus infection; • Pregnant women; • Adults and children who have chronic pulmonary, cardiovascular, hepatic, hematological, neurologic, neuromuscular, or metabolic disorders; • Adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV); • Residents of nursing homes and other chronic-care facilities.

  33. Swine Flu – Hopeful Signs • It appears to lack the traits that made previous flu viruses so deadly. • Cases in the USA don’t appear to be more severe than ordinary flu. • Most people older than 55 have already faced a similar kind of flu virus, so their immune systems may already be primed to resist severe disease. • The outbreak in Mexico, which began earlier than in the United States, appears to be waning.

  34. Swine Flu Testing in Montana • About 400 samples were sent in from around the state in the past week. • 20% were positive for influenza A. • None, so far, have been Swine Flu • This tells us that seasonal influenza is still active in Montana.

  35. Swine Flu - Is there a treatment or vaccine?

  36. Swine Flu – Who Needs Treatment? • Everyone with suspected swine flu doesn’t need to be seen by a health care provider. • Patients with severe illness, and those at high risk for complications from influenza should contact their medical provider or seek medical care.

  37. Groups at higher risk for seasonal influenza complications. • Children less than 5 years old; • Persons aged 65 years or older; • Children and adolescents (less than 18 years) who are receiving long-term aspirin therapy and who might be at risk for experiencing Reye’s syndrome after influenza virus infection; • Pregnant women; • Adults and children who have chronic pulmonary, cardiovascular, hepatic, hematological, neurologic, neuromuscular, or metabolic disorders; • Adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV); • Residents of nursing homes and other chronic-care facilities.

  38. Swine Flu – Treatment? • This swine flu virus is susceptible to oseltamivir and zanamivir. • Tamiflu® and Relenza®

  39. Treatment of influenza does no good if started more than 48 hours after onset of symptoms.Don’t waste the drug or the expense!!!

  40. Therapy • More than a quarter-million prescriptions for Tamiflu pills were filled at retail U.S pharmacies in the week ending May 1st. • That's 34 times higher than the week before — as the regular influenza season wound down — and more than double the peak of last winter's flu season.

  41. Infectious Period • The duration of shedding with this virus is unknown. • The estimated duration of viral shedding is based upon seasonal influenza virus. • Infected persons are assumed to be shedding virus from one day prior to illness onset until resolution of symptoms.

  42. Infectious Period • In general, persons should be considered potentially infectious from one day before to 7 days following illness onset. • Children, especially younger children, might be infectious for up to 10 days.

  43. Swine Flu - Vaccine • Work is already under way. • Making a completely new influenza vaccine can take five to six months. • The seasonal vaccines will confer little or no protection against this swine flu virus.

  44. Vaccine Availability? • A conservative estimate of global capacity for flu vaccine production is at least 1 to 2 billion doses per year. • The current annual demand for seasonal influenza vaccine, globally, is for less than 500 million doses per year.

  45. Prevention / Avoidance of the Flu • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it. • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective. • Avoid touching your eyes, nose or mouth. • Try to avoid close contact with sick people. • If you get sick with influenza, stay home from work or school and limit contact with others to keep from infecting them.

  46. Human Influenza Transmission • Influenza viruses are spread from person to person through respiratory droplets. • The virus infects through the nose and throat, and is expelled by coughing and sneezing. • Droplets are believed to fall to the ground within 3 ft from an infected person. More distant spread is unlikely.