Infections

Infections are invasions of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to these organisms and the toxins they produce. 

Infectious diseases, also known as transmissible diseases or communicable diseases, are illnesses resulting from infections.

Infections are caused by infectious agents including viruses, viroids, prions, bacteria, nematodes such as parasitic roundworms and pinworms, arthropods such as ticks, mites, fleas, and lice, fungi such as ringworm, and other macroparasites such as tapeworms and other helminths.

Hosts can fight infections using their immune system. Mammalian hosts react to infections with an innate response, often involving inflammation, followed by an adaptive response. 

Specific medications used to treat infections include antibiotics, antivirals, antifungals, antiprotozoals, and antihelminthics. Infectious diseases resulted in 9.2 million deaths in 2013 (about 17% of all deaths). The branch of medicine that focuses on infections is referred to as Infectious Disease.

Source adapted from: Infection. (2016, January 18). In Wikipedia, The Free Encyclopedia. Retrieved 08:33, January 31, 2016, from https://en.wikipedia.org/w/index.php?title=Infection&oldid=700503524