Infection 37220 225373151 2008-07-13T10:05:24Z 81.184.152.228 iw {{Refimprove|date=December 2007}} {{otheruses}} 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 (biology)|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 wound]]s, [[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 [[feces]], [[parasite]]s, [[Fungus|fungi]], [[Virus|viruses]], [[prion]]s, and [[viroid]]s. 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]]'''. A '''secondary infection''' is an infection that occurs during or following treatment of another already existing primary infection. ==Colonization== [[Wound]] colonization refers to nonreplicating microorganisms within the wound, while in infected wounds replicating organisms exist and tissue is injured. All [[multicellular organism]]s are colonized to some degree by extrinsic organisms, and the vast majority of these exist in either a [[mutualism|mutualistic]] or [[commensal]] relationship with the host. An example of the former would be the [[Anaerobic organism|anaerobic bacteria]] species which colonize the [[mammal|mammalian]] [[colon (anatomy)|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 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 system|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 technique|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 this type, and coined the term "occult infection" in the late 1930s. ==Bacterial or viral== Bacterial and viral infections can both cause similar symptoms such as [[malaise]], [[fever]], and chills. It can be difficult, even for a doctor to distinguish which is the cause of a specific infection. <ref name=nipa> [http://www.antibiotics-info.org/bact02.asp Bacterial vs. Viral Infections - Do You Know the Difference?] National Information Program on Antibiotics</ref> It's important to distinguish, because viral infections cannot be cured by [[antibiotics]]. {|class="wikitable" |+Comparison of viral and bacterial infection |- ! Characteristic ! Viral ! Bacterial |- || Typical symptoms | In general, viral infections are systemic. This means they involve many different parts of the body or more than one body system at the same time; i.e. a runny nose, sinus congestion, cough, fever, body aches etc.They can be local at times as in viral conjunctivitis or "pink eye" and herpes. Only a few viral infections are painful, like herpes. The pain of viral infections is often described as itchy or burning.,<ref name=nipa/> | The classic symptoms of a bacterial infection are localized Redness, Heat, Swelling and Pain. In ancient Rome the terms were; Rubor, Calor, Turgor, and Dolor. One of the hallmarks of a bacterial infection is local pain, pain that is in a specific part of the body. For example,if you get cut and the cut gets infected with a bacterium, it will be painful right where the infection is. If you have a sore throat and the infection is bacterial, one side of the throat is often more sore than the other. An ear infection is usually bacterial if one ear hurts and the other doesn't. An infection that produces pus is not always bacterial. <ref name=nipa/> |- | Cause || [[Pathogenic viruses]] || [[Pathogenic bacteria]] |} ==See also== * [[Antiseptic]] * [[List of infectious diseases]] * [[Infectious disease]]s * [[Staphylococcus aureus]] * [[Ubi pus, ibi evacua]] (Latin: "where there is [[pus]], there evacuate it") * [[Routes of infection]]s ==References== {{reflist}} * [http://www.vrc.nih.gov Vaccine Research Center] Information concerning vaccine research clinical trials for Emerging and re-Emerging Infectious Diseases. *[http://www.aboutinfections.com aboutinfections.com] {{pathology}} [[Category:Infectious diseases]] [[ar:عدوى]] [[ay:Añata]] [[ca:infecció]] [[cs:Infekční onemocnění]] [[da:Infektion]] [[de:Infektion]] [[el:Λοίμωξη]] [[es:Infección]] [[eo:Infekto]] [[eu:Infekzio]] [[fr:Surinfection]] [[it:Infezione]] [[he:זיהום (רפואה)]] [[la:Infectio]] [[lv:Infekcija]] [[nl:Infectie]] [[ja:感染]] [[no:Infeksjon]] [[pl:Zakażenie]] [[pt:Infecção]] [[ru:Инфекция]] [[simple:Infection]] [[fi:Infektio]] [[uk:Інфекція]] [[yi:אינפעקציע]] [[zh:感染]]