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infection
the invasion and multiplication of microorganisms in or on the body tissue that produce signs and symptoms as well as an immunologic response
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role of microorganisms in infection
pathogens
microorganisms capable of harming people by producing disease
sepsis
poisoning of tissues by presence of infection
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types of infections
subclinical
- silent or asymptomatic infection
- laboratory verified infection that causes no signs or symptoms
- carrier-can transmit infection to others
latent infection
occurs after a microorganism has been dormant in the host(may be for years)
exogenous infection
results from environmental pathogens - pathogen-any microorganism capable of disease
endogenous infection
from the hosts normal flora
microorganisms that live on or within a body to compete with disease producing microorganisms and provide a natural immunity against certain infections
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Agents causing infection
bacteria
- airborne
- soilborne/vectorborne(via animals)
viruses
reproduce inside living cells
fungi include mold, yeasts
parasites
- live on another organism without contributing to host
- EX: tapeworms, hookworms, mites, fleas,ticks
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chain of infection
pathogenicity
ability of organism to cause disease
virulence
vigor with which an organism grows and multiplies
specificity
attraction of organism to specific host
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source
reservoirs, elements in the environment
inanimate objects: medicines, air, food, water, blood
human sources: clients, other health care personnel, visitors
- may be from those infected actively
- in incubation stage of disease
- carriers
- endogenous
animals: rats, insects, mosquitoes, ticks
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portal of exit
MEANS FOR MICROOGANISMS TO LEAVE SORCE
sputum, emesis-vomit, blood, urine/feces, wound drianage, genital secretions
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modes of transmission
contact/ direct transmission
the susceptible host comes into direct contact or indirect contact with the sosurce
- direct
- indirect-dressing, needle, surgical instrument
- droplet-mucous membranes exposed to secretions airborne less than 3 feet
- ex. veneral disease
airborne transmission
results from
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