funda rle

• Sepsis


  Presence of microorganisms
• Asepsis


  No presence of microorganisms
• Unsterile


  Contaminated (should not be touched)
• Clean


  Washed/there is no pathogenic materials
• Sterile


  There is no beneficial bacteria
• Types of microorganisms


  • Beneficial - lactobacilli
  • Harmless - e coli
  • Pathogenic - cause disease
  • Opportunistic - opportunity to attack (entamoeba hystolitica)
  • Flora
• Techniques


  • Clean Technique - handling clean instruments/handwash
  • Sterile Technique - no touching/need of tongs, gloves
  • Contaminated/Unclean Technique
• Types of contamination


  • Chemical
  • Microbial
  • Physical
  • Allergenic
• Chain of Infection


  • Direct Contact
  • Indirect Contact
  • Inhalation
  • Ingestion
  • Injection
  • Fomites
  • Vectors
• Chain of Infection


  1. Agent leaves its reservoir or host through a portal of exit

  2. Conveyed by mode of transmission

  3. Enters through a portal of entry to infect a susceptible host
• Human Reservoirs


  • Sexually transmitted diseases
  • Measles
  • Mumps
  • Streptococcal infection
  • Respiratory pathogens
• Carriers


  People with inapparent infection capable of transmitting pathogen to others
• Types of Carriers


  • Symptomatic
  • Asymptomatic/Passive/Healthy Carriers
  • Incubatory Carriers
  • Convalescent Carriers
  • Chronic Carriers
• Chronic Carriers

  • Hepatitis B virus
  • Salmonella Typhi - causative agent of typhoid fever
  • Mary Mallon/Typhoid Mary - an asymptomatic chronic carrier of salmonella typhi
• Animal Reservoirs


  Humans are subject to diseases that have animal reservoirs, transmitted from animal to animal, with humans as incidental hosts
• Zoonosis


  Infectious disease transmissible from vertebrae animals to humans
• Zoonotic Diseases


  • Brucellosis - cows & pigs
  • Anthrax - sheep
  • Plague - rodents
  • Trichinellosis/Trichinosis - swine
  • Tularemia - rabbits
  • Rabies - bats, raccoons, dogs, other mammals
• Zoonoses Emergent North America


  • Encephalitis - birds
  • Monkeypox - prairie dogs
• Newly Recognized Infectious Diseases in Humans

  • HIV (Human Immunodeficiency Virus)
  • AIDS (Acquired Immunodeficiency Syndrome)
  • Ebola Infection
  • SARS (Sever Acute Respiratory Syndrome) - thought to have emergent from an animal hosts that have not yet been identified
• Environmental Reservoirs


  Plants, soil, water in environment are reservoirs of infectious agents
• Legionnaires Disease


  • Outbreaks often traced to water supplies in cooling towers & evaporative condensers, causative organisms Legionella Pneumophila
• Portal of Exit


  Path by which a pathogen leaves its host, corresponds to the site where pathogen localized
• Examples of Portals of Exit

  • Influenza viruses, mycobacterium tuberculosis - respiratory tract
  • Schistosomes - urine
  • Cholera Vibrios - feces
  • Sarcoptes scabiei - scabies skin lesions
  • Enterovirus 70 - cause of hemorrhagic conjunctivitis, in conjunctival secretions
• Bloodborne Agents


  • Rubella, Syphilis, Toxoplasmosis - crossing placenta from mother to fetus
  • Hepatitis B - through cuts or needles in skin
  • Malaria - blood-sucking anthropods
• Modes of Transmission


  • Direct Transmission
  • Indirect Transmission
• Direct Transmission


  • Direct Contact
  • Droplet Spread
• Direct Contact


  Occurs through skin-to-skin contact, kissing & sexual intercourse
• Direct Contact Transmission


  • Infectious mononucleosis/Kissing disease, gonorrhea - spread from person to person by direct contact
  • Hookworm - spread by direct contact with contaminated soil
• Droplet Spread


  To spray with relatively large, short-range aerosols produced by sneezing, couhing, or even talking
• Droplet Spread Transmission


  • Pertussis, Meningococcal Infection - are transmitted from an infectious patient to a susceptible host by droplet spread
• Indirect Transmission


  • Airborne Transmission
  • Vehicle-borne/Vesicles
  • Vector-borne/Vectors (Mechanical or Biologic)
• Airborne Transmission


  Infectious agents are carried by dust or droplet nuclei suspended in air for long periods of time and may be blown over great distances
• Airborne Transmission


  • Measles - occurred in children who came into a physicians office after a child with measles had left, because the measles virus remained suspended in the air
• Vehicle-borne/Vesicles


  Vehicles that may indirectly transmit an infectious agent: food, water, biologic products (blood), & fomites
• Vehicle-borne Transmission


  • Production of Botulinum Toxin by Clostridium Botulinum - from improperly canned foods providing an environment
• Vector-borne/Vectors


  • Mechanical Transmission
  • Biologic Transmission
• Mechanical Transmission


  • Flies carrying Shigella on their appendages
  • Fleas carrying Yersinia Pestis, the causative agent of plague, in their gut
• Biologic Transmission


  • Causative agent of malaria or guinea worm disease - undergoes maturation in an intermediate host before it can be transmitted to humans
• Portal of Entry


  Pathogen enters a susceptible host, must provide access to tissues in which pathogen can multiply or toxin can act
• Portals of Entry


  • Influenza Virus - exits the respiratory tract of source host and enters respiratory tract of new host
  • Fecal-Oral Route - they exit source host in feces, are carried in inadequately washed hands to a vehicle such as food, water, or utensil, and enter a new host through the mouth
  • Hookworm - skin
  • Syphilis - mucous membranes
  • Hepatitis B, HIV - blood