1. Plate 85 Viral Diseases of the Respiratory System

2. Respiratory System The respiratory system is responsible for oxygenating the blood and removing waste carbon dioxide from the blood

3. Respiratory System Alveoli are the final branches of the “respiratory tree” Allow gases to exchange between the lungs and the blood Tissue between alveoli and capillaries is very thin – allowing for easy gas exchange

4. Viral Diseases of the Respiratory System Most viral diseases do not directly kill the host organism Rather, the viruses destroy cells within the respiratory system, making them susceptible to bacterial infection – Staphylococci – Streptococci

5. Influenza Human influenza viruses (helical, RNA viruses) Type A – Causes seasonal epidemics – Found in ducks, chickens, pigs, whales, horses, and seals – Categorized into subtypes based upon surface proteins Hemagglutinin (H) – 16 variations Neuraminidase (N) – 9 variations Current strains include H1N1 and H3N2 Type B – Causes seasonal epidemics – Only found in humans Type C – Causes mild respiratory illness

6. Novel H1N1 – “Swine Flu” Caused by “antigenic shift” – a major change in the virus with a new combination of hemagglutinin and neuraminidase proteins So different from other influenza viruses that most people don’t have immunity to it Pigs can be infected with human and avian influenza viruses, and they can mix It’s thought that “Swine Flu” has genes mostly from a human virus, but surface proteins from an avian virus

7. Influenza Symptoms Fever Cough Sore throat Runny or stuffy nose Muscle or body aches Headaches Fatigue

10. Peak Months of Influenza Activity

11. Influenza Complications Bacterial pneumonia Ear infections Sinus infections

12. Influenza Vaccinations CDC recommends “universal” flu vaccinations Especially the following groups: – Pregnant women – Children younger than 5 – People 50+ years old

13. Influenza Transmission Spread through respiratory droplets Also possible to get by touching a surface that has the virus on it, then touching your eyes, mouth, or nose May be able to infect others 1 day before symptoms appear and 5-7 days after becoming sick

14. http://www.flu.gov/video/psa/stay_healthy_a merica.html http://www.flu.gov/video/psa/stay_healthy_a merica.html

15. Severe Acute Respiratory Syndrome (SARS)

16. Caused by a coronavirus (SARS-associated coronavirus) Coronaviruses have been linked pneumonia The virus may survive in the environment for several days

17. SARS Symptoms High fever (>100.4° F) Headache Discomfort Body aches Diarrhea Pneumonia

18. SARS Transmission Spread through respiratory droplets Spread through touching a contaminated object, then touching your mouth, nose, or eyes “Close contact” – living with someone with SARS, having direct contact with body fluids from a patient Incubation period is between 2-7 days, but the disease is only contagious while symptoms are present

19. Global SARS Outbreak (2003) Between November 2002 – July 2003 – 8,098 people became infected worldwide – 774 died – 8 people in U.S. were confirmed to have SARS, 0 deaths

20. Common Cold More than 200 viruses cause the “common cold” Rhinoviruses and adenoviruses are the most common

21. Common Cold - Symptoms Sneezing Stuffy or runny nose Sore throat Coughing Mild headache Mild body aches

22. Common Cold – Runny Nose Nose makes clean mucus when infected to wash the virus from the sinuses Immune cells begin to fight the virus, changing the mucus to a white or yellow color As bacteria in nose grow back, they may change the mucus to a greenish color