C14 Flashcards
The prefix “path” refers to
Disease
Pathogenicity means the ability to cause
Disease
refers to the steps or mechanisms
involved in the development of a disease.
Pathogenesis
Once an infectious process is initiated, the disease may remain localized or it may spread; examples are pimples, boils, and abscesses.
Localized infections
is a disease caused by a microbe, and the microbes that cause infectious diseases are collectively referred to as pathogens.
Infectious disease
When the infection spreads throughout the body, an example is miliary tuberculosis, caused by Mycobacterium tuberculosis.
Systemic infections
has a slow onset and lasts a long time; examples are tuberculosis, leprosy, and syphilis.
Chronic disease
is one that has a rapid onset, and is
usually followed by a relatively rapid recovery; examples are measles, mumps, and influenza.
Acute disease
is one that comes on more suddenly
than a chronic disease, but less suddenly than an acute disease; an example would be bacterial endocarditis.
Subacute disease
are infectious diseases that go from being
symptomatic to asymptomatic, and then,
later, go back to being symptomatic.
Latent infections
is sometimes used as a synonym for
pathogenic.
Virulent
Virulent example
Adhesin, Pili
Pathogens that must live within host cells in order to survive and multiply are referred to as
obligate intracellular pathogens (e.g., Rickettsia and Chlamydia
spp.).
Cause malaria
Plasmodium spp
Cause babesiosis
Babesia spp.
are capable of both an
intracellular and extracellular existence.
Facultative intracellular pathogens
are considered to be virulence
factors.
Capsules and flagella
The major mechanisms by which pathogens cause disease are the exoenzymes or toxins that they produce.
Necrotizing enzymes
Coagulase
Kinases
Hyaluronidase
Collagenase
Hemolysins
Lecithinase
are poisonous substances released by various pathogens.
Toxins
Part of the cell wall structure of Gram-negative bacteria
- Can cause serious, adverse physiologic effects such as fever and shock
Endotoxins
Poisonous proteins secreted by a variety of pathogens
- Examples: neurotoxins, enterotoxins, exfoliative toxin, erythrogenic toxin, and leukocidins
Exotoxins
Some pathogens evade the immune system by changing their surface antigensantigenic variation; examples, Neisseria gonorrhoeae and Borrelia recurrentis.
Antigenic Variation
Some organisms conceal their foreign nature by coating themselves with host proteinslike camouflage (e.g., adult
schistosomes).
Camouflage and molecular mimicry
Some pathogens produce IgA protease, an enzyme that destroys some of the host’s antibodies (e.g., H. influenzae).
Destruction of antibodies