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Viral Diseases

Viral Diseases. Common Cold Most common infection Caused by group of viruses called: * Rhinoviruses – RNA viruses Virus infects the cells of the Respiratory tract Other viruses that may cause a cold are: * Adenovirus * Coronavirus

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Viral Diseases

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  1. Viral Diseases Common Cold • Most common infection • Caused by group of viruses called: * Rhinoviruses – RNA viruses • Virus infects the cells of the Respiratory tract • Other viruses that may cause a cold are: * Adenovirus * Coronavirus * Influenza A and B

  2. Common Cold is Contagious • Virus is spread by droplets from nose and throat from coughs, sneezing or direct contact • Person may feel sick from 2 – 4 days • There is no cure or vaccines for cold • Treatment of a cold includes relieving the symptoms: * Grandma’s chicken soup * Aspirin * Throat lozenges

  3. Influenza A and B • Known as the “FLU” • Highly contagious infection • In the respiratory tract: * Nose * Lungs • Named by the proteins on the surface of the virus: H = Haemagglutinin N = Neuraminidase

  4. What is the Bird Flu? • H5N1 • Type/strain of Influenza A • Called“Avian”flu • Most wild ducks are the natural carries of the virus • How did it end up infecting humans?.......... • When poultry, such as chickens and turkeys became infected • The virus is found in chicken droppings……. • Farmers needs to wash their hands

  5. Swine Flu • H1N1:Influenza A • Normally only infects pigs, but… • The virus is able to mutate as it travels from host to host for years…….. • Then, if it happens to infect a human host, it can mutate…… • This is not good! Why?................ • Once it mutates in the human host then it can be transmitted from one person to another and • our immune system can’t fight the virus off

  6. Bird Flu • Bird flu remains a threat: (AFP) – Mar 24, 2010 “Bird flu outbreaks that have killed seven people in several countries so far this year show the virus remains a threat to humans” “Last week, a three-year-old Vietnamese girl stricken with the virus died of severe lung infection, authorities there said.” “Fatality rate for humans infected with bird flu remains high at 59 percent”

  7. Bird Flu • Luckily, we can’tget the virus by eating cooked chicken or eggs • It has notbeen proven that the virus can be spread from person to person • Most common in Asia and Indonesia • No cases have been seen in USA or North America • At present time there is no affective vaccine against H5N1. WHY?....... • Regular Flu vaccine doesn’t work

  8. The Influenza of 1918 • Known as the “Spanish Flu” • Killed close to 50 million people worldwide • That’s more than the Black Death Bubonic Plaguefrom 1347 to 1351 • An estimated 675,000Americans died during the pandemic • What is a“Pandemic” ?........... When an infectious disease spreads worldwide

  9. The Influenza of 1918 • Origin of the Spanish Flu is not known • Interestingly it killed healthy adults, not the usual population such as: * Young children * Elderly * The Sick • WHY?.............. • Do to their healthy, strong immune system, the the system overreacted to the virus destroying healthy tissues and organs as well

  10. The Influenza of 1918 • Some Scientists believe that the H1N1 virus of today is the mutated version of the1918 Flu virus • Also, interestingly enough, it was not the virus itself that caused so many deaths, BUT?.......... • A secondary bacterial infection in the LUNGS!!! • In the past 300 years there have been two other Flu pandemics: 1. The Asian Flu of 1957 2.The Hong Kong Flu of 1968

  11. The Herpes Virus • The word “herpein” comes from Greek word “to creep” • There are more that 100 herpes viruses but only 8 infect human host • Most adults worldwide are infected • DNA virus • “Hidden” virus • Once infected, it is your buddy for LIFE!!!

  12. Herpes Simplex 1 and 2 • HSV – 1 • HSV – 2 • HSV-1 infects the cells in the mouth, skin and cornea of the eye • HIGHLY CONTAGIOUS - by direct contact • Cause cold sores and severe blistering of the skin • HSV- 2is type of STD – also Highly contagious

  13. Varicella – Zoster Virus Causes 2 distinct diseases: • Chicken pox –Varicella * Common in children * In adults it is very serious * Virus remains dormant or “Hidden” in nerve cells of spinal cord • Shingles – Herpes zoster * Common in adults * Reactivation of Chicken pox virus * Virus becomes “Active” again

  14. Epstein – Barr Virus • EBV • Causes Mononucleosis or the “Kissing Disease” • Transmitted in saliva from person to person • Virus infects cells in the mouth • Next, virus infects B – cells * Type of white blood cells * Virus “Hides” in B – cells • More than 90% of people become infected • Can cause Cancer: * Burkitt’s Lymphoma - cancer of B-cells * Nasophyrangeal CA – nose and throat

  15. Hepatitis • 6 strains of Hepatitis virus: * A B C D E and F • Only 3 can make us sick: * A B and C • Infects the Liver • Each type/strain is transmitted differently: * Contaminated food or water * Blood * Sexually /STD • Causes Jaundice – yellowing of skin and eyes

  16. Hepatitis Virus A • HVA • Type of RNA virus • More common in developing countries with poor sanitation • Highly contagious – found in feces • Spreads by eating and drinking contaminated food and water • Children have mild or no symptoms * They develop life - long immunity • 75 % of adults develop jaundice

  17. Hepatitis Virus B • HVB • DNA virus • Close to 400 million are infected world - wide • Spread by contaminated blood by drug users sharing needles • Body fluids - STD • Health care workers • 90% of people recover • But…… • 10% of people develop chronic hepatitis

  18. Hepatitis Virus C • HVC • RNA virus • Mainly spread via contaminated blood • 75% of infected people develop Chronic Hepatitis • Only 50% of people with chronic hepatitis recover • There is no vaccine for HVC • Luckily, There is vaccine for HVA and HVB

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