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Disease Process septicemia

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Disease Process septicemia Powered By Docstoc
					PRINCIPLES OF DISEASE
               Symbiosis
• Relationship between 2 or more species

• Mutualism- both benefit,
              Symbiosis
• Commensalism-one benefits and other
  unaffected
                 Parasitism
• One benefits at expense of other

•   Pathogen-causes disease
•   Metabolically unstable relationship
•   Host dies or eliminates pathogen
•   Most successful parasites
                 Parasitism
• Host under continuous pressure from infection


• Battle between host & parasite


• Emergence of new & return of old infectious
  diseases
                Pathogenicity
• Capacity to produce disease
  –   Adherence
  –   Multiply on host
  –   Ability to invade host or cause damage
  –   Avoid being damaged by host’ defenses
  –   Depends upon # of organisms
                Virulence
• Intensity of disease produced
                      Terms

• Contamination

• Infection- multiples and invades tissue

• Disease- disrupts state of health
                Normal Flora
• 1 x10 13 body cells with 1 X1014 bacterial cell


• Resident flora always present
              Normal Flora
• Resident flora



• Transient flora
              Opportunists

• Usually cause no disease
• Conditions allow them to cause disease
               Opportunists

• Intro of bug into unusual body sites

• Disturbance of normal flora
    Advantage of Normal Flora
• Ensures normal development of immune
  system
• Prevent over growth of harmful organism-
  microbial antagonism
       Microbial Antagonism
• Normal flora in colon prevents overgrowth
  of C. difficile
• E. coli produces bacteriocins
  Disadvantage of Normal Flora
• Potential for spread into sterile parts of
  body
• Intestine may perforate
• Skin broken
• Extraction of tooth
• Perianal skin flora enters urinary tract
                  Etiology
• Cause of disease
• Koch’s postulates-organism causes disease
        Frequency of Disease
• Endemic
  – Always present in population

• Epidemic
  – Occurs in unusually high number of people

• Pandemic-
  – Epidemics world wide
   Types of Infectious Diseases

• Acute -develops rapidly but lasts for short
  time- influenza
• Chronic disease -develops more slowly and
  continues or recurs for long periods -TB,
  hepatitis B
• Latent- agent remains inactive for a time
  and later becomes active-shingles
            Herd Immunity
• Proportion of people in community who are
  immune
• Important in cyclic diseases
• If high, disease can only spread among
  susceptible people

• Loss of herd can lead to reemergence of
  disease
           Extent of Disease
• Local infection-limited to small area of
  body- boils
• Focal - starts as local infection (sinus or
  teeth) then enter blood or lymph and
  spreads
• Systemic -organisms or products spread
  through out body-measles
• Bacteremia- presence of bacteria in blood
           Extent of Disease
• Septicemia-bacteria multiplies in blood
• Toxemia-toxins in blood
• Viremia-virus in blood
• Subclinical (inapparent )- no noticeable
  illness-hepatitis A
• Primary disease- initial acute infection
• Secondary infection -opportunistic infection
          Stages of Disease

• Incubation period-time between initial
  infection and first appearance of S&S
          Prodromal Period
• Short period–only in some diseases
             Invasive Period

• Period of illness-most acute
• Overt signs and symptoms
• Cough, sore throat
      Decline/Convalescence
• S&S subside
• Regain strength and recovery
            Epidemiology
• Study of mechanism and factors involved in
  the frequency and spread of disease
• Incidence of diseases
• Prevalence of diseases
                         Chain of Infection
                              Infecting
     Susceptible               Agents
       Host                     Bacteria
   Elderly & Young              Parasites
Pts w/ Chronic Illness           Viruses
                                                  Reservoir
       Diabetic                                  People Food
Use of Invasive Equip                             Equipment




     Entry
                                               Portal of Exit
    Broken Skin                                Respiratory System
 Respiratory System                             GI & GU System
  GI & GU System             Direct Contact
                            Indirect Contact
                           Transmission
                               Airborne
                               Droplet
             Spread of Disease
•   Chain of infection
•   Agent- pathogen
•   Reservoir-source/site of organism
•   Human reservoirs

• Animal reservoirs -zoonoses
                    Humans
• Sick people
• Carriers
  – Incubatory or asymptomatic carriers
     • HIV but not AIDS
     • Hepatitis C
  – Chronic carriers
     • Typhoid Mary excreted salmonella for years in feces
     • S. pyogenes in throat
                    Animals
•   Domestic and wild
•   Mammals carry rabies-exposure to saliva
•   Consume contaminated animals or products
•   Arthropod borne-West Nile
•   Zoonoses
    – Lyme disease: wild deer and mice
    – Hantavirus pulmonary disease: rodents
     Environmental Reservoirs
• Able to survive in nonliving reservoirs
• Soil: C. tetani
  – Humans produces toxin
  – Survives in soil by forming endospores
• Contaminated water
                Portal of Exit
• Via body fluid or feces
  –   Respiratory tract
  –   GI
  –   GU
  –   Nonintact skin-lesions, wounds
        Modes of Transmission
• Airborne
  –   Tiny droplet nuclei vs large droplets
  –   Dust particles
  –   Suspended in air don’t fall
  –   More likely to reach lower resp tract
  –   Resistant to drying
       • TB, measles and chicken pox
  – Spread rapidly in crowded conditions
                   Droplet
•   Large droplets, short distances
•   Mucous droplets -coughing , sneezing
•   Pertussis, influenza, SARS
•   Talking less transmission
                   Contact
• Direct- person to person, touching ,sex,
  colds
  – Horizontal transmission
  – Fecal-oral transmission especially if public
    health & hygiene lacking
                    Contact
• Vertical
  – Parent to offspring-birth canal, breast milk,
    placenta
• Indirect-via fomites-tissues, diapers , door
  knobs- hands
  – Normal person sheds skin atrr rate of 5 x10 8
    per day
• Hep B, C, D, lice, STDs
                 Vehicle
• Via medium-water, food, blood - Shigella in
  water or food, S. aureus
• Vector-arthropod
  – Mechanical-passive
  – Biological- active
     •
             Portals of Entry

•   Respiratory
•   GI - in food and water
•   GU-sexually transmitted microbes
•   Non intact skin- parenteral
           Susceptible Host
•   Imunocompromised
•   Old age or young
•   Not vaccinated
•   Large inoculum
        Healthcare Infections
• Healthcare acquired
  – Exogenous

  – Endogenous
             Consequences
• Serious illness or death

• Prolonged hospital stay
• Need for antimicrobial therapy
• Foci for spreading infection
 Controlling Disease Transmission

• Standard precautions-everyone

• Isolation for communicable diseases or bugs
                Prevention
• SSIs –prophylactic antibiotics

• Devices- central lines & ventilators
               Prevention
• Quarantine

• Immunization- influenza & pneumococcal
• Vector control

				
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posted:1/19/2011
language:English
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