Infectious diseases

Annotations:

• 1. caused by infectious agents (generate spontaneous/from air)

1. Definition
   1. Infectious disease

      Annotations:

      • -disease caused by infectious agents(bacterium, virus, protozoan, fungus) -can be passed to other host
   2. Infection

      Annotations:

      • -occurs when the infectious agent enter the body and start reproduction -may or may not lead disease
      1. Pathogen

         Annotations:

         • -a type of infectious agent can cause disease
      2. Host

         Annotations:

         • -an organism infected by another organism
      3. Virulence

         Annotations:

         • the relative ability of an agent can cause rapid and severe disease in a host
   3. Prevalence

      Annotations:

      • -number of cases at a given time -expressed as a percent at a given time =product of incidence x duration of disease(long duration:hepatitis B)
   4. Contamination

      Annotations:

      • The presence of an infectious agent on different kinds of material/substances(e.g. water, a body surface, clothes)
   5. Disease

      Annotations:

      • -a pathological condition -characterized by signs and symptoms
   6. Immunogenicity

      Annotations:

      • The ability of an organism to produce immune response after an infection: -providing protection against a similar or the same organism(e.g. infectious agents)
   7. Vector of infection

      Annotations:

      • an insect or any living carriers:transport an infectious agent from an infected individual/its wastes to other susceptible individuals/food/surroundings.
   8. Reservoir

      Annotations:

      • any person,animal, arthropod, plant, soil or substance or combination of these:allow an infectious agent to live and multiplies. -an infectious agent are transmittable to other susceptible(natural habitat)
   9. Imapparent infection

      Annotations:

      • -no detectable clinical symptoms -can be documented by :    1.isolation of a pathogen,     2. detection of it component(DNA)    3. produce a specific immune response in                 person(asymptomatic)
   10. Incidence

       Annotations:

       • 1.number of new cases in a given time period 2.expressed as percent infected per year/number per person time of observation
   11. Special terms
       1. Nosocomial

          Annotations:

          • 1. an infection originating in a patient while in a hospital 2. not related to the patient's primary condition-e.g. infection of surgical wound, hepatitis B, urinary tract infection
          1. Opportunistic infections

             Annotations:

             • infection by organisms -take opportunity provided by a defect in host defense -organism infect the host and cause disease. 
       2. Eradication

          Annotations:

          • -aims to termination of all transmission of infection(extermination of the infectious agent) -absolute process(an all or non phenomenon)
          1. Elimination

             Annotations:

             • It is used to describe eradication of a disease(e.g. measles/polio) from a large geographic  region.
       3. Reproductive rate

          Annotations:

          • It describes the potential for an infectious disease to spread. Influential factors: 1.probability of transmission 2.frequency of population contact 3.virulence of the organism 4.population immune proportion 5.duration of infection
2. Causes
   1. Genetic
   2. Biological
   3. Physical
   4. Environment
   5. Chemical
3. Early history

   Annotations:

   • 1.Smallpox-trigger epidemic in ancient Greece and Egypt 2.Plague-coinfect with measles and smallpox  3.Syphilis- spreadly rapidly through europe in 1490s and cause high mortality
4. Koch's Postulates(a particular agent can cause a specific disease)

   Annotations:

   • 1. specific agent must be associated with every case of the disease. 2. the agent can be isolated from a diseased host and grown in culture 3. the culture-grown agent is introduced into a healthy species must cause the same disease 4.the same agent must be again isolated from the infected host
5. Caused by infectious disease agents

   Annotations:

   • 1.microbes/microorganisms -bacteria -viruses -protozoa -fungi -Helminths(animals)
   1. MOA for induceing disease

      Annotations:

      • 1.production of poisons(enzymes or toxins) 2.direct invasion and destruction 3.trigger immune responsed
6. Phases
   1. Incubation period

      Annotations:

      • Time between infection and apparent of symptoms
      1. Prodromal period

         Annotations:

         • mild,non specific symptoms that signal onset of some disease
         1. Clinical phase

            Annotations:

            • a person experiences typical signs and symptoms
            1. Decline phase

               Annotations:

               • subsidence of symptoms
               1. Recovery phase

                  Annotations:

                  • symptoms have disappeared -tissue heal -body remains strength
7. Classifications
   1. By duration

      Annotations:

      • 1. Acute 2.Chronic 3.Latent -characterized by periods of no symptoms between outbreaks of illness
   2. By location

      Annotations:

      • 1. Local- confined to a specific area of body 2. Systemic- infects most of the body with pathogens distributed widely in tissues
   3. By Timing

      Annotations:

      • 1. Primary:initial infection in a healthy person 2. Secondary:infection that occurs in a person weakened by a primary infection
   4. Clinical

      Annotations:

      • 1. Diarrheal diseases 2. Respiratory diseases 3. Central nervous system infection 4. Cardiovascular infection 5.Sepsis
   5. Microbiological

      Annotations:

      • 1. Bacterial 2. Viral 3. Fungal 4. Parasitic 5. Prion
   6. Transmission

      Annotations:

      • 1. Contact(direct/indirect) 2. Food/water borne 3. Airborne 4. Vecter borne 5. Perinatal:occurs during pregnancy
   7. Reservoir

      Annotations:

      • 1. Human:HIV, HBV 2. Animals: Rabies 3. Soil 4. Water:Pseudomonas aeruginosa
8. The severe level
   1. Endemic

      Annotations:

      • The constant of a disease or infectious agent within a given geographic area
   2. Pandemic

      Annotations:

      • an worldwide epidemic affect high proportion of global population
   3. Epidemic

      Annotations:

      • The occurrence of a disease/illnesses excess of what may be expected on the basis of past experience for a given population
9. Transmission

   Annotations:

   • 1.air 2.contaminated food/water 3. body fluids 4.Direct contact 5.animal vectors
   1. Reducing spreading

      Annotations:

      • 1.Vaccines 2.Antimicrobial drugs 3.Good personal hygiene 4.Protection against vectors 5.Quarantine