(Redirected from Infections)
An 'infection' is the detrimental
colonization of a host
organism by a foreign
species. In an infection, the infecting organism seeks to utilize the
host's resources to multiply (usually at the expense of the host). The infecting organism, or
pathogen, interferes with the normal functioning of the host and can lead to
chronic wounds,
gangrene, loss of an infected limb, and even
death. The host's response to infection is
inflammation. Colloquially, a pathogen is usually considered a
microscopic organism though the definition is broader, including
bacteria,
parasites,
fungi,
viruses,
prions, and
viroids. A
symbiosis between parasite and host, whereby the relationship is beneficial for the former but detrimental to the latter, is characterised as
parasitism. The branch of
medicine that focuses on infections and pathogens is '
infectious disease'.
Colonization
Wound colonization refers to nonreplicating microorganisms within the wound, while in infected wounds replicating organisms exist and tissue is injured. All
multicellular organisms are colonized to some degree by extrinsic organisms, and the vast majority of these exist in either a
mutualistic or
commensal relationship with the host. An example of the former would be the
anaerobic bacteria species which colonize the
mammalian colon, and an example of the latter would be the various species of
staphylococcus which exist on human
skin. Neither of these colonizations would be considered infections. The difference between an infection and a colonization is often only a matter of circumstance. Organisms which are normally non-pathogenic can become pathogenic under the right conditions, and even the most
virulent organism requires certain circumstances to cause a compromising infection. Some colonizing bacteria, such as ''
Corynebacteria sp.'' and ''
viridans streptococci'', prevent the adhesion and colonization of pathogenic bacteria and thus have a symbiotic relationship with the host, preventing infection and speeding
wound healing.
The variables involved in the outcome of a host becoming inoculated by a pathogen and the ultimate outcome include:
★ the route of entry of the pathogen and the access to host regions that it gains
★ the intrinsic
virulence of the particular organism
★ the quantity or load of the initial inoculant
★ the
immune status of the host being colonized
As an example, the
staphylococcus species present on skin remain harmless on the skin, but, when present in a normally
sterile space, such as in the capsule of a
joint or the
peritoneum, will multiply without resistance and create a huge burden on the host.
Occult Infection
An occult infection is medical terminology for a "hidden" infection, that is, one which presents no symptoms. Dr. Fran Giampietro discovered and coined the term "Occult Infection" in the late 1930's.
See also
★
Antiseptic
★
List of infectious diseases
★
Infectious diseases
★
Ubi pus, ibi evacua (Latin: "where there is
pus, there evacuate it")
External Links
★
Vaccine Research Center Information concerning vaccine research clinical trials for Emerging and re-Emerging Infectious Diseases.
★
aboutinfections.com