Chapter 10: Mechanisms of Infectious Disease Flashcards
Host
organism capable of supporting growth of another organism
Infectious disease
disease state due to interaction with another organism
Colonization
presence of a living organism on or within the host
Microflora
bacteria inhabiting exposed surfaces on the body
Virulence
the disease-inducing potential
Pathogens
virulent microorganisms that is rarely in absence of disease
Saprophytes
organisms obtaining growth from dead material in environment
Mutualism
interaction between microorganisms and the host both derive benefits from the interaction
Commensalism
bacteria acquire nutrition and shelter from safe host
Parasitic Relationship
infecting organism benefits from host
Agents of Infectious Disease
prions viruses bacteria rickettsiaceae chlamydiaceae fungi parasites
Viruses
- smallest pathogens
- have no organized cellular structure
- consist of a protein coat (capsid) surrounding a nucleic acid core of DNA or RNA
- are incapable of replication outside a living cell
- can penetrate host and remain dormant
Two Types of Bacteria
- Gram positive organisms
- Gram negative organisms
gram positive:
- diplococci
- staphylococci
- streptococci
gram negative:
- bacilli
- sprilla (spirochete)
Parasite definition \+ Types of Parasites \+ Methods of Infecting
An agent that derives benefit from its biologic relationship with another organism
+
- protozoa
- helminths
- arthropods
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- these are members of the animal kingdom infect and cause diseases in other animals
- these animals then transmit disease to humans
Epidemiology
the study of factors, events and circumstances that influence the transmission of infectious diseases among humans
Incidence
the number of new cases of an infectious disease that occur within a defined population
Prevalence
the number of active cases at any given time
Prevalence
the number of active cases at any given time
Endemic Disease
- found in a particular geographic region
- the incidence and prevalence are expected and relatively stable
Epidemic
abrupt and unexpected increase in the incidence of disease over endemic rates
Pandemic
spread of disease beyond continental boundaries
Symptomatology
- specific: reflex the site of infection (i.e. diarrhea, rash, convulsions hemorrhage, pneumonia
- non specific: can be share by a number of diverse infectious diseases (i.e. symptoms such as fever, myalgia, headache)
- obvious: predictable patterns (i.e. chickenpox, measles)
- covert: may require lab testing to detect (i.e. hepatitis, increase WBC count)
Disease Course in Infection
- incubation period: pathogens begins active replication but does not produce symptoms
- prodromal stage: initial appearance of symptoms in host
- acute stage: host experiences max s/s of pathogen, rapid proliferation and cell lysis, immune system respond, tissue damage + inflammation
- convalescent stage: containment of infection, elimination of pathogen, repair of tissue
- resolution stage: total elimination of pathogen from body without any s/s of disease
Disease Course in Infection
- incubation period: pathogens begins active replication but does not produce symptoms
- prodromal stage: initial appearance of symptoms in host
- acute stage: host experiences max s/s of pathogen, rapid proliferation and cell lysis, immune system respond, tissue damage + inflammation
- convalescent stage: containment of infection, elimination of pathogen, repair of tissue
- resolution stage: total elimination of pathogen from body without any s/s of disease
Bactericidal
if it causes irreversible and lethal damage to the bacterial pathogen
Bacteriostatic
if its inhibitory effects on bacterial growth are reversed when the agent is eliminated
Bacteriostatic
if its inhibitory effects on bacterial growth are reversed when the agent is eliminated
Antibiotic Mechanisms
- interference with a specific step in bacterial cell wall synthesis
- inhibition of bacterial protein synthesis
- interruption of bacterial nucleic acid synthesis
- interference with normal bacterial metabolism
Antibiotic Target Site
penicillin: cell wall
cephalosporin: cell wall
monobactams: cell wall
aminoglycoside: ribosome
tetracyclines: ribosome
macrolides: ribosome
glycopeptide: ribosome
sulfonamides: folic acid synthesis
quinolones: DNA synthesis
