Med Micro Essential terms 1 Flashcards
HPV
20 year incubation; infects keratinocytes via receptor-mediated endocytosis; spread by direct or indirect contact
Robert Koch
Koch’s postulates: present in every case of disease; isolated from diseased individual; can cause disease in a new individual; and be isolated again from new individual
Pathogenesis
steps involved in development of disease
Pathogenicity
ability to cause disease
Pathogen
microorganism capable of causing disease
Pathology
study of structural and functional manifestations of disease
Infection
colonization by a pathogen, not necessarily disease
Infectious disease
diseases caused by microbe
Triangle of relationships
Humans, drugs, microbes. All interacting, all evolving.
Spreading factors
Invasins, enzymes that help pathogens move/invade tissues and gain entry
Exotoxin
toxic but heat labile; some form pores in membranes
Endotoxin
Lipid A or LPS in cell wall of gram negative bacteria; weak immunogen, so it’s bad;
Immunogen
Something that creates an immune response??
A-B Toxins
Two parts: A chain inhibits some cell functions; B chain binds and helps A enter. In cholera
Virulence
combination of invasiveness and toxigenicity producing the ability to overcome host defenses and cause disease
LD50
Used to test virulence. the # of bacteria to kill half of a population
Mononuclear cells?
Monocytes in blood, dendritic cells in tissues. Secrete or are attracted by cytokines
Neutrophil
A type of granulocyte; lactoferrin, defensins, other chems; Phagocytize pathogens, Capable of diapedesis
Opsonizing
Done by ABs and other molecules, enhance phagocytosis
Agglutinating?
cells or particles are cross linked with specific antibodies, form an immune complex; becomes less soluble and eventually precipitate out of solution
Communicability?
Depends on: source (dormant - carriers); # infectious agents released from host; capability of surviving transit b/w hosts; Percent of host population susceptible
Mutualism
Both benefit, sometimes cannot live without the other (bacteria in colon)
Commensalism
One benefits but the other gets no pros and cons (bacteria on skin)
Parasitism
One benefits while harming the other (TB in lungs)
Resident flora
Usually mutualistic, don’t invade, just naturally present
Transient flora
Don’t stay very long body, eliminated by competition with others, can’t resist body’s defense, same locations as residents
Opportunistic pathogen
Lack virulence factors; only cause disease if introduced by parenteral route or if immune system is weakened
Symptoms
Subjective, how the patient feels etc like nausea, headache
Signs
Objective indications, like fever, vomiting, etc
Syndrome
Collection of signs and symptoms typical for a specific disease.
Dead end host
Doesn’t pass on the pathogen to someone else
Incubation period
Initial colonization, no symptoms, adaptive immunity starting; Depends on Infectious dose, site of infection, general health of host, nature of pathogen (some are fast, some slow), virulence factors
Prodromal period?
Mild symptoms and signs, not always present!
Illness
Peak of signs and symptoms,
Decline
Signs and symptoms decreasing, immune system is winning now
Convalescence
Cleaning up, length depends on energy needed to repair
Reservoir of infection
Where pathogens wait to infect: Soil and water; animals; humans.
Mode of disease transmission (contact, vehicle, vector)
Contact: direct (kissing, cough < 1m) and indirect (cough > 1m); vector; vehicle: dust, water, cough on a table then someone else touches it
Epidemiology
Study of where and when diseases occur and how they are transmitted within populations. Important when Koch’s postulates aren’t possible and to consider traveling etc.
Incidence
Incidence = number of new cases in an area per a population
Prevalence
Number of total cases
Descriptive epidemiology?
Tabulate data and cases and results
Analytical epidemiology?
Trying to find the index case, cause, mode of transmission
Experimental epidemiology
Testing Koch’s postulates, or testing a treatment
Zoonotic disease
Caught from animals
Nosocomial disease
Disease caught from a healthcare environment
Exogenous disease
Caught from being in the hospital
Endogenous disease
you have the pathogen but something in environment causes it to cause disease
Iatrogenic disease
from a surgery, etc
