This_is_so_beautiful.jpg (554×411) Human pathogen. A human pathogen is a pathogen (microbe or microorganism such as a virus, bacterium, prion, or fungus) that causes disease in humans. The human physiological defense against common pathogens (such as Pneumocystis) is mainly the responsibility of the immune system with help by some of the body's normal flora and fauna. However, if the immune system or "good" microbiota are damaged in any way (such as by chemotherapy, human immunodeficiency virus (HIV), or antibiotics being taken to kill other pathogens), pathogenic bacteria that were being held at bay can proliferate and cause harm to the host.
Such cases are called opportunistic infection. Some pathogens (such as the bacterium Yersinia pestis, which may have caused the Black Plague, the Variola virus, and the Malaria protozoa) have been responsible for massive numbers of casualties and have had numerous effects on afflicted groups. Types[edit] Viral[edit] Bacterial[edit] Fungal[edit] Other parasites[edit] Prionic[edit] Animal pathogens[edit] Asymptomatic carrier. Typhoid Mary in a 1909 newspaper illustration An asymptomatic carrier (healthy carrier or just carrier) is a person or other organism that has contracted an infectious disease, but who displays no symptoms.
Although unaffected by the disease themselves, carriers can transmit it to others.[1] In humans, HIV goes through a long latency period, during which the host is asymptomatic.[2] Many carriers are infected with persistent viruses such as EBV and Cytomegalovirus that only rarely progress to a disease state. Herpes simplex viral infection may also be asymptomatic and can be spread without the originally infected person realising they are infected.[3] C. difficile has also been shown to be spread by asymptomatic carriers, and poses significant problems in care home settings.[4] Prion. A prion ( Prions are not considered living organisms but may propagate by transmitting a misfolded protein state. If a prion enters a healthy organism, it induces existing, properly folded proteins to convert into the disease-associated, prion form; the prion acts as a template to guide the misfolding of more proteins into prion form.
These newly formed prions can then go on to convert more proteins themselves; this triggers a chain reaction that produces large amounts of the prion form.[8] All known prions induce the formation of an amyloid fold, in which the protein polymerises into an aggregate consisting of tightly packed beta sheets. Amyloid aggregates are fibrils, growing at their ends, and replicating when breakage causes two growing ends to become four growing ends. All known mammalian prion diseases are caused by the so-called prion protein, PrP. Proteins showing prion-type behavior are also found in some fungi, which has been useful in helping to understand mammalian prions. Creutzfeldt–Jakob disease. Creutzfeldt–Jakob disease (/ˈkrɔɪtsfɛlt ˈjɑːkoʊb/ KROITS-felt YAH-kohb)[1] or CJD is a degenerative neurological disorder that is incurable and invariably fatal.[2] CJD is at times called a human form of mad cow disease (bovine spongiform encephalopathy or BSE).[3] However, given that BSE is believed to be the cause of variant Creutzfeldt–Jakob (vCJD) disease in humans, the two are often confused.[4] CJD is caused by an agent called a prion.
Prions are misfolded proteins that replicate by converting their properly folded counterparts, in their host, to the same misfolded structure they possess. The disease leads to rapid neurodegeneration, causing the brain tissue to develop holes and take a more sponge-like texture. Classification[edit] Types of CJD include: variant (vCJD):[5] This is thought to be caused by the consumption of food contaminated with prions, which also cause BSE. sporadic (sCJD):[6] This accounts for 85% of cases of CJD.[7] familial (fCJD):[8] iatrogenic: Cause[edit] Stanley B. Typhoid carrier polluting food - a poster.jpg.
Mallon-Mary 01.jpg. Io9. 5 Awesome Sci-Fi Inventions (That Would Actually Suck) Remember all those Star Trek gadgets you wished you had because they looked so cool? Well, it turns out looking cool is about all they'd be good for. Here's five inventions that will be available some day ... even if nobody wants them. As seen in:Blade Runner, The Fifth Element, Back to the Future II, Futurama, The Jetsons ... it's actually kind of difficult to list sci-fi that doesn't feature some variation of the flying car. Why we thought we wanted them: First, we don't mean some kind of sissy half-plane, half-car hybrid that some people will try to tell you is a flying car. No, we mean real, float off the ground, how the crap is that happening, Jetsons sort of flying cars.
Of course, once you learned to drive you wanted one even more. Why we were wrong: Well, guess what: They're not gonna let you do that. No, you'd have to fly according to a wussified autopilot, along pre-set pathways. That's not even the worst part.