infectious diseases Flashcards
pathogen
any microorganism or agent that is capable of producing disease
virulence
related to the frequency with which an agent causes disease or it’s degree of communicability.
normal flora
beneficial microorganisms that the body harbors. They often function to compete with and prevent infection from unfamiliar agents.
colonization
microorganisms that are often pathogenic are present in the tissues of the host but have not caused symptomatic disease because of normal flora.
surveillance
the tracking of infections and the ensuring of compliance with federal and local requirements as outlined by the Centers for Disease Control (CDC).
immunity
resistance to infection. Can be active or passive.
passive immunity
of short duration (days or months) and either natural by transplacental transfer or artificial by injection of antibodies.
active immunity
lasts for years and is nayural from infection or artificial stimulation of the body’s immune system like with vaccination.
toxin production
Continued multiplication of a pathogen is sometimes accompanied by toxin production.
Toxins are protein molecules released by the bacteria to affect host cells at a distant site.
exotoxins
produced and released by certain bacteria into the surrounding environment as in tetanus, botulism and E. Coli
endotoxins
produced and released only by cell lysis.
endotoxins
produced and released only by cell lysis.
transmission of infectious organisms
Need reservoir ( source of organisms ), susceptibility of host with a portal of entry, and a mode of transmission.
Microorganisms can be transmitted by:
a. Contact transmission ( direct or indirect )
b. Droplet transmission
c. Airborne transmission
direct contact transmission
With direct contact the source and the host have physical contact. Microorganisms are transferred directly from skin to skin or from mucous membrane to mucous membrane. Often is called person-to-person contact.
indirect contact transmission
Indirect contact involves the transfer of microorganisms from a source to the host by passive transfer from contaminated articles.
droplet transmission
Indirect contact can also involve contact with infected secretions or droplets. These are produced when a person sneezes or talks and can only travel short distances. CDC recommends that staff stay at least 3 feet from a patient with a droplet infection.
Influenza is an example of a droplet infection.
Droplets do not stay suspended in air.
airborne transmission
Occurs when small airborne particles containing pathogens leave the infected source and enter a susceptible host.
These pathogens can remain suspended in the air for a prolonged time. The particles containing the pathogens are usually contained in droplets or dust. An example would be tuberculosis.