Influenza is caused by influenza viruses that mutate frequently, sometimes resulting in global pandemics. The document discusses three pandemics from the 20th century caused by the H1N1, H2N2, and H3N2 strains. The deadly 1918 Spanish Flu pandemic may have killed over 50 million people. Influenza spreads through respiratory droplets and causes symptoms like fever, muscle aches, and cough. While similar to the common cold, influenza onset is usually more sudden. Antiviral drugs and vaccines can help prevent and treat influenza, but drug resistance is a growing problem due to the virus's frequent mutations.

1. Influenza
Meghan Darnell
David Fenin
Slade Schell
Sergey Sovenok

2. What is Influenza?

3. Influenza

4. Transmission

5. Mutations
 Antigenic Drift
• Mutations occur very often
• Small gradual changes
• Different strains
 Antigenic Shift
• Mutations don’t occur often
• Major changes
• Different subtypes

6. History
 Influenza was not studied
intensively until the 20th century.
 1918 H1N1 Strain (Spanish Flu)
 1957-58 H2N2 Strain (Asian Flu)
 1968 H3N2 Strain

7. Pandemic Severity Index

8. 1918 Spanish Flu
 Originated in U.S. military camps or in
China, not in Spain
 In 1915 the strain was transferred from
swine to humans.
 “Third wave” was the most deadly, killing
several million in 1919.
 May have killed more people than the
Black Death, with 20-100 million fatalities
 Category 5 Pandemic

11. H2N2 Strain (1958 Asian Flu)
 Originated in China as a result of a
mutation of both the H2N2 avian virus and
the H1N1 human virus.
 Infected mostly youth between the ages
of 5 and 19
 Had low mortality rate
 Resulted in 1-4 million fatalities
 Category 2 Pandemic

12. 1968 H3N2 Strain
 Originated in Hong Kong in 1968
 Combination of H2N2 human strain and
H3 avian strain
 Human exposure to H2N2 lead to partial
immunity to this strain
 Much lower mortality rates than both the
1918 and 1958 strains
 Category 2 Pandemic

13. Epidemiology
 Swine Flu of February 2009 resulted in a 15-
25% infection rate.
 In Fall of 2010 the infection rate was 40% in
the U.S.
 2010 strain ranked as a pandemic
 10-20% infection rate is typical in an
epidemic

14. More Epidemiology than you
could ever want!

15. Epidemiology (cont.)
 Insert Graph here

16. Signs and Symptoms
 Fever over 100 F (38 C)
 Aching muscles, especially in your
back, arms and legs
 Chills and sweats
 Headache
 Dry cough
 Fatigue and weakness
 Nasal congestion

17. Pathology
 Most common symptoms are usually a
result of the body’s immune response
 Pro-inflammatory cytokines
 Immune response may cause Cytokine
Storm

18. Difference between Cold and
Influenza
 Have similar symptoms
 Influenza comes on quicker than the
Common Cold
 Influenza virus damages cells while Cold
virus symptoms are caused mainly by an
inflammatory response.

19. “Stomach Flu”
 Nota medical diagnosis
 Gastroenteritis NOT A FORM OF INFLUENZA
 Can be caused by multiple factors
• Adenovirus, Rotavirus, Calicivirus, and
Astrovirus
• Waterborne parasites such as Giardia
• Certain foods
• Escherichia
coli, Campylobacter, Shigella, and
Salmonella

20. Treatments
 AntiviralDrugs
 Over the Counter Medications
 Nutrition/herbs
 Interferons

21. Anti-viral Agents
 Adamantanes
• Treats influenza type A
 Neuraminidase inhibitors
• Treats both Influenza type A and B
• Not as Toxic

22. Tamiflu
 Neuraminidase Inhibitor
 E. coli is a key factor in production
 Side effects

23. Drug Resistance
 Since mutations occur in influenza viruses
very often the development of a drug
resistant strain is very common.
 More and more resistant viruses
 As read earlier some antivirals like Tamiflu
don’t really kill of the whole virus but do
contribute to the killing of most of the
viruses
 China incident

25. Vaccines

27. Prevention
 WASH YOUR HANDS!!!!!
 Disinfectants not very effective