Impending Doom !The World Coming To An EndPart III
Disease OccurrenceEndemic normal levels within geographic regions.
Epidemic sudden severe outbreak within a region.
Pandemic epidemic becomes widespread (worldwide).
PandemicGlobal outbreak.Caused by new subtypes novel pathogen.High person-to-person susceptibility.Unusually high mortality.Cholera Pandemic Cartoon, 1883
EpidemicversusPandemicSeasonal (mainly winter)Known pathogenElderly affected mostVaccine availableLocalized occurrenceAny time of yearUnknown pathogenAtypical age groupsNo proven/available vaccineWorldwide occurrence
Most epidemics and pandemics caused by influenza.
InfluenzaThree TypesType ARegular outbreaksMost widespreadResponsible for pandemicsInfects humans and animals
InfluenzaThree TypesType BSporadic outbreaksMainly occurs in residential communities (e.g. nursing homes)Infects humans onlyCan cause epidemics, have not caused pandemics
InfluenzaThree TypesType CCommonCauses very mild symptoms or none at allNot a severe public health threat
Influenza A VirusssRNA virusContains two membrane proteinsHemagglutinin (H)- Initiates infection by binding to receptors on host cells membrane.Neuraminidase (N)- Enzymatic properties of N destroy host cell receptors and allows viral infection of cell.
Influenza A VirusSubtypes vary by types of H and N membrane proteins- 15 different H proteins identified (H1, H2, etc.)- 9 different N proteins identified (N1, N2, etc.)Virus identified and named by H and N membrane proteinsMany different combinations of H and N proteins possibleOnly some Influenza A subtypes currently cause human infection- H1N1, H2N2, and H3N2Others are common in animal speciesAll common in avian species
Pandemics of 20th CenturySpanish Flu 1918 A (H1N1)50 million dead worldwide500,000 dead in U.S.Asian Flu 1957 A (H2N2)70,000 dead in U.S.Hong Kong Flu 1968 A (H3N2)34,000 dead in U.S.
The Case of Harry Tyson54 year old male brought to Norfolk General Hospital
Patient presented with:Fever (103.2 degrees F) Productive cough with bloodSore throatMyalgia (General muscle pain)Dyspnea (Difficulty breathing) on day 5
Subsequent Complications:Respiratory failure on day 5 and ARDSRenal and Cardiac failure days 6 & 7Died on day 8Wife and son admitted on day 5 with similar symptoms
Initial Treatment & DiagnosisPatient given Oseltamivir on days 5-8 with no improvementWife and son also administered drugSon died on day 14 and mother recoveredInitial diagnosis: Influenza with complicating secondary bacterial pneumonia
Final DiagnosisFather owned chicken farm where family workedFather involved in breeding hybrid chicken Large Asian variety with fast producing American varietyFather imported eggs from S.E. Asia illegallyExposed to products of the eggs
Suspected Pathogen: Influenza Virus A (H5N1)Father, Mother, and son all test positiveChickens test positiveThe USDA and CDC contactedFarm QuarantinedChickens Destroyed
So, you have the fluVirus causes upper and or lower respiratory tract infection as the virus uses cells for lytic reproduction
Symptoms of the Flu
Fever Cough and runny noseMalaise with myalgiaHeadache, sore throatExtreme tiredness
What is the respiratory tract?
Respiratory Tract FunctionGas exchange- Take in oxygen and expel carbon dioxideSound- Movement of gas through mouth and over larynx and pharynx allows sound production
Respiratory Tract MicrobesNormal Flora - Regular inhabitants- Rarely cause diseaseStaphylococci sp. Cultured from Mr. Styers throat.Gram negative cocci and gram positive rods from Ms. Shepards throat.
Respiratory Tract MicrobesNoseStaphylococcus spp.Staphylococcus aureusStaphylococcus epidermidis
Mouth and OropharynxStaphylococcus epidermidisStreptococcus pneumoniaeOther Streptococcus spp.Neisseria spp.Haemophilus spp.Anaerobic bacteriaYeastsStaphylococcus aureus
Respiratory Tract InfectionsRespiratory tract constantly exposed to outside environment.Exposure to many airborne microbes.
Respiratory Tract DefensePhysical barriers URTMucusCiliaPhysical barriers LRTPhygocytosis killer white blood cells
Respiratory Tract PathogensUpper Respiratory TractVirusesCorona viridaeAdeno viridaeRhino viridaeGroup A StreptococcusCorynebacterium diptheriaeBordetella pertussis
Respiratory Tract PathogensLower Respiratory TractVirusesInfluenzaSARSHaantavirus
Bacterial PneumoniaStreptococcus pneumoniaeMycoplasma pneumoniaePseudomonas aeruginosaLegionella pneumophila
The Monster That Looms: H5N1Currently unable to transmit human-to-human (as seen with H1, H2 & H3 strains)Infection only with direct contact with infected animalCan infect across breeds: birds and mammalsCauses atypical immune responseCytokine Storm that body cannot handleFluid (blood) fills the lungs as body fails Secondary infections are rampant Seen in the Spanish Flu of 1918
Review and ReflectionDifferentiate Epidemic and Pandemic outbreaks:Give the parts and function of each part of the respiratory tract:Give our typical respiratory tract defense against infection: List two non-pathogenic and two pathogenic respiratory tract microbes:Describe how an H2N2 strain of virus differs from an H5N2 strain. For which one is there a vaccine available?Describe what is meant by a secondary bacterial infection and how would a hospital test for this?
Writing PromptWrite a one page, double-spaced essay on what you think would happen if there was, in fact, an influenza AH5N1 outbreak. How would we react to the threat both locally and globally ? What would we have to do to contain the disease, yet survive as a society? Examine the effect on things like the economy, travel, as well as on everyday life such as school and grocery shopping. Be thoughtful and creative!
CitationsCenters for Disease Control and Prevention (2005). Information About Influenza Pandemics [Internet]. Fact Sheet [cited July 28, 2005] http://www.cdc.gov/flu/avian/gen-info/pandemics.htm
Centers for Disease Control and Prevention (2005). Key Facts About Influenza and Influenza Vaccine [Internet]. Fact Sheet [cited July 28, 2005] http://www.cdc.gov/flu/keyfacts.htm
Centers for Disease Control and Prevention (2004). Update on Avian Influenza A (H5N1) [Internet]. Health Alert Network. [cited July 28, 2005] www.phppo.cdc.gov/han/archivesys/viewmsgv.asp?alertnum=00209
Images UsedCholera Pandemic Picture http://www.authentichistory.com/images/postcivilwar/cartoons/1883_cholera_pandemic_cartoon.html
Portrait of Harry Tysonhttp://ring.uvic.ca/98oct16/EXEC.html
ByTim Styer and Katie ShepardThis is an unfinished product!