Influenza

1. Influenza Karee Wasson

2. Influenza • Influenza viruses are encapsulated, negative-sense, single-stranded RNA viruses of the family Orthomyxoviridae. The core nucleoproteins are used to distinguish the 3 types of influenza viruses: A, B, and C. Influenza A viruses cause most human infections. In this presentation, I will cover the Influenza A virus.

3. Influenza • Influenza, commonly known as the “flu”, is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae. • It is a highly contagious viral infection that attacks your respiratory system. • It is the sixth leading cause of death among American adults. • The virus is complex and constantly changing, making it possible for people to become reinfected in subsequent years. • Vaccines are produced each year for new strains to effectively protect individuals. • These vaccines are 70-90 percent effective in preventing influenza in healthy people under the age of 65. • It is a common myth that the vaccine can cause influenza. • Symptoms include: fever, extreme fatigue, headache and body aches. • About 50 percent of infected people have no symptoms but are still contagious.

4. HistoryThe Spanish Flu • Spread during the winter of 1918 and lasting until 1919. • The deadliest and most well known flu pandemic. • Occurred before vaccines were available and flu transmission vectors were thoroughly understood. • Estimated to have killed 20 million to 50 million people worldwide. • Responsible for the death of approximately 500,000 people in the U.S.

5. HistoryThe Asian Flu • Outbreak occurred during the winter of 1957 and lasted until 1958. • Flu vaccines were available and public health systems applied lessons learned from the Spanish flu outbreak. • Estimated to have killed 2 million people worldwide. • Responsible for the death of approximately 70,000 people in the U.S. • Having a better understanding of the virus attributed to a reduced death toll of the Asian flu compared to the Spanish flu.

6. HistoryThe Hong Kong Flu • Outbreak occurred in 1968. • Death tolls were reduced by almost 50% from the previous Asian flu due to better management of public health systems and improved vaccinations. • Estimated to have killed 1 million people worldwide. • Responsible for the death of approximately 34,000 people in the U.S.

7. HistorySwine Flu • The potential flu epidemic of 1976. • This flu was not as virulent, deadly or widespread as anticipated. • Fear resulted in the vaccination of all people in the United States. • Unfortunately, problems with the vaccine cause more sicknesses than the actual virus itself.

8. HistoryThe H1N1 Flu • The most recently feared global pandemic, happened in the winter of 2009 and continues into 2012. • Originated in pigs and was commonly called the swine flu. • Started in Mexico, where many of the deaths occurred. • Unlike other flu viruses, the H1N1 virus continued to infect people during the summer of 2009, causing many more deaths. • A vaccine has since been developed to fight the H1N1 flu.

9. H1N1 Case • In the Winter of 2010, I myself became infected with the H1N1 flu virus. • Source: I believe I contracted the virus from my son. • Symptoms: They came on fast and hard, lasting for two weeks. • The first sign of symptoms: sore throat and a headache. • Acute phase symptoms: fever, cough, sore throat, runny nose, body chills, head and body aches, and fatigue. • Lasting symptoms: cough and fatigue. • Doctor and diagnosis: I did not visit the doctor in person but phoned her. She confirmed my symptoms were that of the H1N1 virus and advised me to stay home and nurse myself back to health. Although this was not an official diagnosis, she was confident that I had the flu virus. • Patient activities: I remained in bed for the first week and slowly progressed into slight activity by the second week. By the end of the second week my health had returned to normal. • Treatment: I took Dayquil and Nyquil for two weeks to control the symptoms. • Infected: I believe I infected my brother with the flu virus.

10. Virus Description • The virus particle is 80–120 nanometers in diameter and roughly spherical in shape, although filamentous forms are not uncommon. • The particle consists of a vital envelope containing two main glycoproteins wrapped around a central core. This core contains the viral RNA and other viral proteins that package and protect this RNA. This RNA is single stranded, but in special cases it is double. Its genome is not a single piece of nucleic acid but consists of seven or eight pieces of segmented negative-sense RNA. Each piece of the RNA contains one or two genes, the code for its production.

12. Virus Description Cont. • The influenza virus has two large glycoproteins on the outside: • Hemagglutinin- A lectin that mediates binding of the virus to target cells and entry of the viral genome into the target cell. • Neuraminidase- Involved in the release of daughter virus from the parent-infected cells. This process happens by cleaving sugars that bind the mature viruses. Thus, these proteins are drug targets and are the antigens for which antibodies can be made.

13. Virulence Factors • Evolves rapidly • Antigenic shift- virus acquires a new genome segment from another influenza virus • Antigenic drift- virus’s rapid evolution • Encapsulated • Have unique antigens that the human body have no immune defenses for • Can be transmitted from one species to another • Easily transmitted • Air-borne • Directly • Indirectly (hand to eyes, mouth, or nose)

14. Pathophysiology • Inhibition of adrenocorticotropic hormone (ACTH) resulting in lowered cortisol levels. • Infected cells produce proinflammatory cytokines and chemokines as an immune response, causing symptoms of the flu such as fever, headaches, and fatigue. • The hemagglutinin protein determines which species the virus can infect and also where in the human respiratory tract it will bind. • Hemagglutinin binds to respiratory epithelial cells, allowing cellular infection. • Neuraminidase cleaves the bond that holds newly replicated virions to the cell surface, permitting the spread of the infection.

15. Outward Symptoms • Fever and chills • Cough • Nasal congestion • Body aches (especially in joints and throat) • Fatigue • Headache • Irritated/watering eyes • Sometimes diarrhea and abdominal pains, especially in children Incubation Time • Usually two days but can range from one to four days

16. Transmission • Virus shedding: • Begins the day before symptoms appear and ends between day 5-7 • Modes of transportation: • Airborne • Directly • Indirectly (hand to eyes, mouth, or nose)

17. Diagnosis • Usually doctors will diagnose influenza based on a patient's symptoms. • A doctor can perform a diagnostic test and get the results back within 15 to 30. These tests can be administered a number of ways including throat swab, nasal swab, or nasal wash.

18. Prevention • Annual vaccinations • Good personal health and hygiene • Not touching your eyes, nose or mouth • Frequent hand-washing • Covering coughs and sneezes • Avoid close contact with those infected • Stay home yourself if you are sick

19. Treatment • Management • Get plenty of rest • Drink lots of water • Avoid alcohol and tobacco use • If necessary, take over the counter medication to relieve symptoms • Antivirals (use is uncommon) • Neuraminidase inhibitors • M2 protein inhibitors

20. Cases • Case numbers are hard to determine because many people infected do not seek medical help and recover on their own • Estimated number of cases in the U.S. today is around 60 million per year according to the Centers of Disease Control and Prevention • From Sep. 1st, 2009 to Aug. 31st 2010, influenza associated hospitalizations in Oregon totaled 1,315 patients and influenza associated deaths totaled 67.

21. Every year, 5-20% of Americans are infected with the flu virus. Of those infected, 200,000 are hospitalized and 36,000 die. Influenza is responsible for a total cost of over $10 billion in the U.S. annually. It is crucial for our well being to understand this virus as well as how to successfully prevent and properly treat it.

22. Works Cited "Estimating Seasonal Influenza-Associated Deaths in the United States: CDC Study Confirms Variability of Flu." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 24 June 2011. Web. 30 Oct. 2012. <http://www.cdc.gov/flu/about/disease/us_flu-related_deaths.htm>. "Influenza (disease)." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 30 Oct. 2012. <http://www.britannica.com/EBchecked/topic/287790/influenza>. "Influenza Facts." Influenza Facts. N.p., n.d. Web. 30 Oct. 2012. <http://www.stjude.org/stjude/v/index.jsp?vgnextoid=166b0307f6e70 110VgnVCM1000001e0215acRCRD>. "Influenza ." Influenza. N.p., n.d. Web. 30 Oct. 2012. <http://emedicine.medscape.com/article/219557-overview>. "Influenza." Wikipedia. Wikimedia Foundation, 24 Oct. 2012. Web. 30 Oct. 2012. <http://en.wikipedia.org/wiki/Influenza>. "Pathophysiology and Mechanism of the Influenza Virus." Pathophysiology and Mechanism of the Influenza Virus. N.p., n.d. Web. 30 Oct. 2012. <http://www.influenzavirusnet.com/pathophysiology.html>. Staff, Mayo Clinic. "Definition." Mayo Clinic. Mayo Foundation for Medical Education and Research, 10 Aug. 2012. Web. 30 Oct. 2012. <http://www.mayoclinic.com/health/swine-flu/DS01144>. "Swine Flu Symptoms - What Is Swine Flu - H1N1 Influenza A - Swine Flu Treatment." WebMD. WebMD, n.d. Web. 30 Oct. 2012. <http://www.webmd.com/cold-and-flu/features/swine-flu-faq- 1?page=2>.