Pathogenicity Flashcards
What is parasitism?
Invading organism benefits from host at expense of host
What is symbiosis?
Living together
When is commensalism?
Microbe benefits and host is unharmed
What is mutualism?
Both host and microbe benefit
What is a pathogen?
Organism or agent capable of causing disease
What is disease?
Illness that alters body structures and functions
What are symptoms?
Subjective changes in body function may not be obvious to an observer (pain malaise)
What are signs?
Objective changes, observable, measurable (liesions, swelling, fever, paralysis)
What is syndrome?
Specific group of symptoms and signs that always accompany a particular disease
What is a communicable disease?
Disease easily spread from one host to another either directly or indirectly. (Chicken pox, measles, genital herpes, TB)
What is a contagious disease?
A disease easily spread directly from one host to another (chicken pox, measles)
What is a non-communicable disease?
not spread from one host to another, it is caused by microbes that normally inhabit the body and only occasionally produce disease, or by microbes that normally reside outside the body and produce disease only when introduced to the body (tetanus)
Diseases can be classified according to four different types of incidences, what are they?
Sporadic, Endemic, Epidemic, and Pandemic
What is a sporadic disease?
occurs only occasionally (typhoid fever)
What is a Endemic disease?
constantly present in a population (cold) or native to a population
What is epidemic?
many hosts in a given area acquire a certain disease in a relatively short period of time (AIDs, Influenza)
What is pandemic?
epidemic disease that occurs in multiple parts of the world or a disease that effects the majority of the population of a large region
What is Virulence?
degree of pathogenicity
what is a vector?
intermediary hosts that carry the disease from one species to another (arthropods)
what are fomites?
aka vehicle, inanimate objects that transmit disease
what is a reservoir?
site where the infectious agent survives
what is a biological vector?
like a insect bite.
what is a mechanical vector?
something carried on the insect, not from the insect
what are some types physical barriers must a pathogen over come?
skin, mucus membranes
what are some ways pathogens enter?
wounds, ulcers, animal and insect bites
what is an acute disease?
one that develops rapidly but lasts only a short time
what is a chronic disease?
develops mroe slowly, body reactions may be less severe but disease is continued or recurrent for long periods
What is a subacute disease?
between acute and chronic
what are latent diseases?
causitive agent remains in the body but then becomes active to produce symptoms (shingles)
what is an infection?
organism growing and multiplying inside host
what is a primary infection?
acute infection, causes initial illness
what is a secondary infection?
opportunistic pathogen, occurs after primary infection has weakened the body defenses
what is a subclinical (inapparent) inefection?
does not cause any noticeable illness
What is bacteremia?
bacteria present in the blood
what is septicemia?
bacteria present in the blood causing inflammation throughout the body
what is toxemia?
presence of the toxin in the blood
what is viremia?
viruses in the blood
what is intoxication?
disease that is caused by a toxin, rather than the organism itself
what is a nosocomial disease?
aquired illness as a result of a hospital stay
what is an intermediate host?
harbors a parasite for a short transition period
what is a definitive host?
harbors a parasite while it matures and possibly reproduces
what are risk factors?
any condition that can increase the chance of infection, could be factors of the infectious agent, environment, or host
what is the incubation period?
interval of time between when the host first contacts the infectious agent and when clinical signs and or symptoms of the disease develop.
What is an asymptomatic carrier?
infected individual showing no clinical signs of disease but potentially infectious to others
what is morbidity?
refers to the incidence of ill health in a population
what is mortality?
refers to the incidence of death or the number of death in a population
what are four modes of transmission?
direct, indirect, horizontal, vertical transmission
what is direct transmission?
through intimate contact w/ infected host (lepto)
What is indirect transmission?
through an arthropod vector, fomite, or airborn pathogen
what is horizontal transmission?
between members of species that are not parent/child relation (friends, strangers)
What is vertical transmission?
from one generation to the next (mother/child infection passed during pregnancy)
What are exotoxins?
proteins produced by an organism secreted into the environment
what are two of the most toxic substances (exotoxins) known to man?
tetanus and botulism
what are 3 types of exotoxins?
neurotoxins, enterotoxins, and cytotoxins
how hot do tempuratures need to be to break down exotoxins?
60-80C
What are antitoxins?
antibodies produced by the body in response to the antigenicity of the toxins
what is a toxoid?
inactivated toxins that can be injected to create an immune response without causing the disease
what are seven organisms capable of producing exotoxins?
Staphylococcus Aureus Clostridium tetani E.Coli Salmonella typhi Vibric Chlorae Clostridium botulinium bacillus anthracics
What are Endotoxins?
lipid part of some G(-) organisms
How hot does it need to be to take remove an endotoxin from tissue cultures?
250F for 30 min
can endotoxins be dangerous?
at high doses
between an Endotoxin and exotoxin which has no vaccine?
endotoxins
what are the effects of endotoxins? (7)
low BP, Fever, shock, Blood Coagulation, Inflammation, Diarrhea, hard to remove.
what are 3 other types of exotoxins?
Leukocydines, Hemolysis, Streptokinase
What is leukocydines?
kills WBC, upsets wbc membrane and destroys it. it also decreases host resistance
what is hemolysis?
aka streptolysins, caused be streptococcus pyogenes. breaks down cells, especially RBC
what is streptokinase?
caused by streptococcus pyogenes, disolves blood clots and can cause internal hemorrhaging.
when is streptokinase used?
after heart surgeries