Introduction and Approach to studying ID Flashcards
What are three ways vaccinations are made?
produced from inactivated microbial strains
produced from live viruses
produced from viral particles
Chemotherapeutic agents are used for?
used to treat infectious disease can be synthetic drugs or antibiotics.
Antibiotics are used for?
are chemicals produced by bacteria and fungi that inhibit or kill other microbes.
Quinine is used for?
from tree bark was long used to treat malaria.
Biological stains for bacteria?
gram stains
Fungi stains?
4
KOH, lactophenol blue, India ink, silver stains in tissue
Mycobacteria stains? (TB)
acid fast stains
Parasite stains?
2
trichrome stain, Wright’s stain
Virus stains?
Viruses—antibody conjugated dyes
Disease definition?
an upset in the homeostasis of the host, resulting in generation of observable changes
Whats the normal host-parasite relationship?
Carrier state
Factors that influence infection multifactorial?
5
Host Factors Site specific Infections Virulence Factors Degree of Pathogenicity Toxin Production
A compromised immune system, however, presents an “opportunity” for the pathogen to infect
Common ones?
4
Pneumocystis
Candida
Disseminated HSV
TB
Factors Required for Infection to Occur
5
Contact the host - be transmissible
Colonize the host - adhere to and grow or multiply on host surfaces
Infect the host - proliferate in host cells or tissues
Evade the host defense system - by avoiding contact that will damage it
Damage host tissues - by physical (mechanical) or chemical means
Pathogenesis of Infection
has a consistant pattern. Describe it?
4
Consistent pattern:
- parasite enters body
- organisms adhere to site specific target tissue
- organisms multiply establishing local or primary lesions
- spread
- -fascial planes
- -tubular structures (bronchus/ureter)
- -hematogeneous/lymphatic
Whats the incubation period?
What can the length of the incubation period be affected by/dependant on?
Pathogen replicates without any recognizable symptoms
Length may be affected by the general health of host, portal of entry, infectious dose of the pathogen and the virulence of the organism
Describe the prodromal stage?
3
- Initial appearance of symptoms in host
- Clinical presentation may be VERY vague (general malaise)
- Fever, myalgia, headache and fatigue may be present but are very non-specific
Describe the acute stage?
3
- Host experiences maximum impact due to rapid proliferation and dissemination of pathogen
- Toxic byproducts of microbial metabolism, cell lysis, and immune response combine to produce tissue damage and inflammation
- Symptoms are usually more pronounced and focused than during prodrome pointing to site and possible pathogen
Describe the convalescent stage?
3
- Containment of infection, progressive elimination of pathogen, repair of damaged tissue, and resolution of associated symptoms
- Length is variable depending on host and pathogen (days to months)
- Total elimination of pathogen from the body without residual signs or symptoms of disease
What kind of infectious diseases have a protracted/irregular course?
Chronic infectious diseases
WHat are Subclinical or Subacute illness?
progresses from infection → resolution without symptoms
The prodromal period is lengthy?
Insidious
Abrupt onset of symptoms with little or no prodrome?
Fulminant
Portal of entry types?
Penetration Direct contact Ingestion Inhalation Port of entry does NOT mean that is final site of infection
What are the sources of infection?
4
- Endogenous = from patient’s own normal flora
- Exogenous = From outside source
- Zoonoses = diseases passed from other animals to humans
- Nosocomial = hospital acquired infections (pneumomias are more pathogenic these types)
Community Acquired
Source can also refer to the body substance that was the most likely vehicle for transmission. Examples?
feces, urine, sputum, blood, body fluids
What is the collection of signs and symptoms expressed by the host during the disease process?
Symptomatology
aka
“clinical picture” or “disease presentation”
What is the outward expression of the struggle between invading organisms and the retaliatory inflammatory and immune responses of the host?
Symptoms
Describe how different symtpoms prevent?
4
May be specific and show site of infection (diarrhea)
May be non-specific and reflect overall battle (fever)
May be overt (chickenpox lesions) or hidden (elevated WBC count)
Cinical features suggestive of infection?
6
Fever/Chills/Rigors Myalgia/Fatigue Lymphadenopathy Splenomegaly (mono) GI Upset (gram neg) Leukocytosis/Leukopenia (overwhelming infection)
GI upset is often precent with what kind of bacteria?
Gram Neg
Common Community Acquired Infections
13
Skin Sinusitis Pharyngitis Otitis Pneumonia Meningitis Encephalitis
Gastroenteritis Urethritis Cystitis Prostatitis PID Osteomyelitis
Common Hospital Acquired Infections
(Nosocomial)?
8
Bacteria: Staph Strep group E. coli Klebsiella Proteus Psuedomonas Serratia Candida
Diagnosis of Infectious Disease
Direct Microscopic evaluation
types? 5
Indirect evidence of infection?
3
Gram Stain Wet Mounts KOH Culture Electron Microscopy
Agglutination
Electrophoresis
RIA
What factors do we look at when deciding on epidemiology?
5
- Incidence = the number of new cases of an infectious disease that occur within a defined population over time (1:100,000 per year)
- Disease prevalence = number of active cases at any given time
- Endemic = disease numbers in a geographical area if the incidence and prevalence are expected and relatively stable
- Epidemic = An abrupt and unexpected increase in the incidence over endemic rates
- Pandemic = Spread of disease beyond continental boundaries
