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PULSE

PULSE. Upper Respiratory Infections Wednesday, October 31 st 2012. What Is A Virus? . Virus Structure. Viral Genome Double-stranded DNA Single-stranded DNA Double-stranded RNA Single-stranded RNA Protein Coat Capsid – built from large number of protein subunits called capsomeres

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PULSE

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  1. PULSE • Upper Respiratory Infections • Wednesday, October 31st 2012

  2. WhatIsAVirus?

  3. Virus Structure • Viral Genome • Double-stranded DNA • Single-stranded DNA • Double-stranded RNA • Single-stranded RNA • Protein Coat • Capsid – built from large number of protein subunits called capsomeres • Envelope • Derived from membrane of host cell ~ contain host cell phospholipids and membrane proteins • Also contain proteins and glycoproteins of viral origin • Non-eveloped – ‘Naked Virus’

  4. Influenza • Orthomyxoviridae Family • Influenza Viruses: A, B, or C • Spherical or Longitudinal • average diameter of 80 to 120 nanometers • Glycoproteins • Hemagglutinin – primary protein responsible for binding to receptor sites on the cell membrane, allowing the virion to enter the cell • Neuraminidase – enables the virus to be released from the host cell ~ enzymes that cleave sialic acid groups from glyocoproteins and are required for influenza virus replication

  5. Avian & Swine H5N1 H1N1 Bird flu you need to seek TWEETMENT, and for swine flu you can just apply OIKMENT!

  6. Culture and Diagnosis • Rapid Influenza Diagnostic Test (RIDT) • Direct Fluorescent Antibody Stain (FDA) • Viral Culture • Real-time Polymerase Chain Reaction (RT-PCR) • Influenza A or B Antibody Test

  7. Treatment • Influenza A • Amantadine • Rimantadine • Influenza A and B • Zanamirvir (Relenza) • Oseltamivir (Tamiflu)

  8. Vaccination

  9. Myth: You can get the flu, or a mild case of it, from the flu vaccine.

  10. Myth: Antibiotics can fight the flu if you get it.

  11. Myth: You don’t need to get the flu vaccine if you got it last year – the strains are basically the same.

  12. Myth: The flu vaccine contains thiomerosal, which may be harmful.

  13. Myth: Getting the flu can be a pain, but it’s not really a serious disease, so vaccination isn’t helpful.

  14. Influenza Summary

  15. Upper Respiratory Tract 1 2 • Includes • Mouth, Nose, Throat, Nasal Cavity, • Sinuses, Larynx 1 http://health.rush.edu/healthinformation/care%20guides/28/000141.aspx 2 http://www.ohiosinus.com/patient-info/sinus-anatomy-and-function

  16. Lower Respiratory Tract 1 • Includes • Trachea • Bronchi and Bronchioles in Lungs 1 http://health.rush.edu/healthinformation/care%20guides/28/000141.aspx

  17. Respiratory Tract Defenses 3 1 2 4 2 1 http://www.thegeminigeek.com/why-do-we-have-nose-hair/ 2 http://www.sciencephoto.com/media/311125/enlarge 3 http://pathmicro.med.sc.edu/ghaffar/innate.htm 4 http://pathmicro.med.sc.edu/mayer/stru-11.jpg

  18. Symptoms of the Common Cold • … or Rhinitis • How an affected person feels: • Malaise • Nasal Congestion • Runny Nose (rhinorrhea) • Excessive Sneezing • Coughing • Sore Throat • Mild Fever http://www.nhs.uk/conditions/Rhinitis---non-allergic/Pages/Introduction.aspx

  19. Symptoms of the Common Cold • Inflammation • Redness (erythema) • Pain to touch • Swelling • Nasal Discharge • Mild Fever • Swollen lymph nodes – less common • What a physician notes on examination: http://www.virtualmedicalcentre.com/diseases/perennial-allergic-rhinitis/30

  20. Pathogens Responsible for the Common Cold • >60% Cases • Rhinoviruses • Highly variable serotypes • Nonenveloped, Icosahedral • linear + stranded ssRNA genome • Binds Intercellular Adhesion Molecule -1 • Coronaviruses • Fewer serotypes – Alpha implicate • Enveloped, Spherical • linear + stranded ssRNA genome • Binds Aminopeptidase N/CD13 http://www.nature.com/news/2009/090212/full/news.2009.98.html http://phil.cdc.gov/phil/details.asp?pid=4814

  21. Transmission of the Common Cold • How? • Aerosolized Droplets – Sneezing/Coughing • Fomites – inanimate objects or substances that can carry the pathogen • Direct Contact – eg. small children • To Where? http://www.sos03.com/Diseases/Lung/Common_Cold • Infection initiates in uppermost throat & nasal cavity

  22. Treatment of the Common Cold • Instead, treat the symptoms: • No cure actually targets the virus

  23. Immune Response to the Common Cold • And let your immune system do the rest … • Adaptive Immune Response • Cytotoxic & Natural Killer T Cells • B Cells • Innate Immune Response • Macrophages • Eosinophils http://www.cancer.gov/cancertopics/understandingcancer/immunesystem/AllPages

  24. What is Pneumonia? • An anatomical diagnosis – • inflammatory condition of lung where fluid fills the alveoli http://www.britannica.com/EBchecked/media/107200/The-alveoli-and-capillaries-in-the-lungs-exchange-oxygen-for

  25. Symptoms of Pneumonia • How an affected person might feel: • Short of Breath - dyspnea • Frequent Cough • Fever • Chills • Chest Pain • Fatigued

  26. Symptoms of Pneumonia What a physician notes on examination: Fever Rapid shallow breathing – tachypnea Reduced breath sounds Crackling Pleural rub against chest wall Chest X-ray infiltrate R L http://www.uptodate.com.medjournal.hmc.psu.edu:2048/contents/image?imageKey=PEDS/86360&topicKey=PEDS%2F5986&source=preview&rank=undefined

  27. Pathogens Responsible for Pneumonia Viral: Hantavirus Betacoronavirus Influenzavirus Rhinovirus Bacterial: Streptococcus Pneumoniae Legionella Pneumophilia Mycoplasma Pneumophilia

  28. Pathogens Responsible for Pneumonia Streptococcus Pneumoniae - small, paired, gram + cocci - about 2/3 of community acquired cases - more common among immuno-compromised - binds monosaccharide - sialic acid - upper throat - binds disaccharide - N-acetylgalactosamineb1-4 galactose- in lower respiratory tract http://textbookofbacteriology.net/S.pneumoniae.html

  29. Pathogens Responsible for Pneumonia Legionella Pneumophilia - gram -, rod-like - aerobic - more common in aqueous habitats in association with amoeba - infects macrophages in alveoli http://phil.cdc.gov/phil/details.asp?pid=11150

  30. Pathogens Responsible for Pneumonia Mycoplasma Pneumophilia - genus lacks cell walls - smallest free-living organism - variable shape - binds to carbohydrate antigen on respiratory epithelium - aerobic & anaerobic http://www.nejm.org/doi/full/10.1056/NEJM199411243312105

  31. Pathogens Responsible for Pneumonia Hantavirus - negative sense ssRNA - composed of 4 proteins Nucleocapsid G1 & G2 – envelope RNA polymerase - envelope glycoproteins may attach to integrin cell-surface molecule, which is found on endothelial cells and platelets throughout the body http://www.nlm.nih.gov/medlineplus/ency/imagepages/17201.htm

  32. Pathogens Responsible for Pneumonia SARS - Coronavirus Enveloped, Spherical linear + stranded ssRNAgenome Binds Angiotensin-Converting Enzyme-2 as a receptor/mode of entry into cells no new cases since 2004 http://www.cdc.gov/sars/lab/images.html

  33. Transmission of Pneumonia Bacterial: • How? • Commonly as Aerosolized Droplets – Sneezing/Coughing • Less common as Fomites • – although S. pneumoniaemay survive dessication • Rarely during casual contact Viral: • How? • Commonly as Aerosolized Droplets – Sneezing/Coughing • Hantavirus is spread via airborne dust contaminated by excretory products of infected rodents

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