capable of being spread to plants from other plants or organisms.
|False-colored electron micrograph showing a malaria sporozoite migrating through the midgut epithelium of a rat|
Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce.Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.
Infections are caused by infectious agents (pathogens) including:
- Viruses and related agents such as viroids and prions
- Fungi, further subclassified into:
- Parasites, which are usually divided into
- Arthropods such as ticks, mites, fleas, and lice, can also cause human disease, which conceptually are similar to infections, but invasion of a human or animal body by these macroparasites is usually termed infestation. ( Diseases caused by helminths, which are also macroparasites, are sometimes termed infestations as well, but are sometimes called infections.)
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.