Infection

 "An infection is that the invasion of an organism's body tissues by disease-causing agents, their multiplication, and therefore the reaction of host tissues to the infectious agents and the toxins they produce. An infectious disease, also known as transmissible disease or communicable disease, is an illness resulting from an infection Infections are caused by infectious agents (pathogens) including Viruses and related agents like viroids and prions Bacteria, Fungi, further subclassified into Ascomycota, including yeasts like Candida, filamentous fungi like Aspergillus, Pneumocystis species, and dermatophytes, a gaggle of organisms causing infection of the skin and other superficial structures in humans. Basidiomycota, including the human-pathogenic genus Cryptococcus. Parasites, which are usually divided into Unicellular organisms (e.g. malaria, Toxoplasma, Babesia). Macroparasites (worms or helminths) including nematodes like parasitic roundworms and pinworms, tapeworms (cestodes), and flukes (trematodes, like schistosomiasis)"