Infectious disease Flashcards
define infectious disease
disease caused by bacterium, virus, protozoan, or fungus
define infection
occurs when infectious agent enters the body and begins to reproduce
define pathogen
infectious agent that causes disease
define host
an organism infected by another organism
define virulence
relative ability of agent to cause rapid and severe disease
categories of infectious agents
-prion
-viruses
-bacteria
-fungi
-protozoa
-helminths
-ectoparasites
prions are characterized by …
spongiform change caused intracellular vacuoles in neurons and glia
prions are composed of
abnormal forms of host protein
prions cause what type of disease
transmissible spongiform encephalopathies (neurodegenerative disorder)
creutzfeldt Jakob disease has symptoms of
loss of cognitive ability, decrease in ability to move and memory loss
what is seen in Creutzfeldt Jakob disease
prions build up and cause brain to shrink and tissue fills with holes
viruses are defined as
obligate cellular parasites that replicate inside living cells
viruses replicate by doing what
by replicating nucleic acid and synthesis of viral protein
how are bacteria classified
- by gram staining
- by shape
- by need of O2
gram positive bacteria have
thick wall that retains crystal violet stain
gram negative bacteria have
thin cell wall surrounded by an outer membrane
types of bacteria are
- cocci
- bacilli
- spiral
characteristics of cocci bacteria
- round shaped and cause pneumonia and sepsis
characteristics of bacilli bacteria
- rod shaped
- single, pairs, or in chains
- causes serious diseases