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 – 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

9. Peak Months of Influenza Activity

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

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

14. 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

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

16. Severe Acute Respiratory Syndrome (SARS)

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

18. SARS Symptoms High fever (>100.4⁰ F) Headache Discomfort Body aches Diarrhea Pneumonia

19. 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 or 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

20. 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

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

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

23. 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

24. Respiratory Syncytial Virus (RSV) Enveloped RNA virus Almost all children are infected with RSV by the time they reach 2 years old

25. RSV Symptoms Incubation period is 4-6 days Runny nose Decrease in appetite Coughing Sneezing Fever Bronchitis in infants Full recovery usually occurs in 1-2 weeks

26. RSV Transmission Spread through respiratory droplets Direct and indirect contact with nasal or oral secretions from a patient

27. Bieber Fever Symptoms Hyperventilation Feelings of euphoria Fainting Hysteria Uncontrollably jumping up and down

28. Human Parainfluenza Viruses (HPIVs) Single-stranded RNA viruses Four types of HPIVs – HPIV-1 causes croup (laryngotracheobronchitis) in children – HPIV-2 also causes croup, but is less often detected – HPIV-3 is associated with bronchiolitis and pneumonia – HPIV-4 is infrequently detected and doesn’t cause severe illness

29. HPIV Symptoms Similar symptoms as with the common cold – Runny nose – Fever Sore throat “Barking” cough “Squeaky” inhalation Hoarse voice

30. HPIV Transmission Spread through respiratory droplets Contact with contaminated objects 90-100% of 5 year old children have had HPIV-3

31. HPIV Prevention The virus is inactivated with soap and water No vaccine available HPIV-1 and HPIV-2 antibodies can be transmitted from mother to child through breast feeding