Editing Parasitism (section)

=== Fungi ===

{{further|Pathogenic fungus|Plant pathology}}

Parasitic [[fungi]] derive some or all of their nutritional requirements from plants, other fungi, or animals.

Plant pathogenic fungi are classified into three categories depending on their mode of nutrition: biotrophs, [[hemibiotrophs]] and necrotrophs. Biotrophic fungi derive nutrients from living plant cells, and during the course of infection they colonise their plant host in such a way as to keep it alive for a maximally long time.<ref>{{Cite journal |last1=Fei |first1=Wang |last2=Liu |first2=Ye |date=11 August 2022 |title=Biotrophic Fungal Pathogens: a Critical Overview |url=http://dx.doi.org/10.1007/s12010-022-04087-0 |journal=Applied Biochemistry and Biotechnology |volume=195 |issue=1 |pages=1–16 |doi=10.1007/s12010-022-04087-0 |pmid=35951248 |s2cid=251474576 |issn=0273-2289}}</ref> One well-known example of a biotrophic pathogen is [[Corn smut|''Ustilago maydis'']], causative agent of the corn smut disease. Necrotrophic pathogens on the other hand, kill host cells and feed [[saprophytic]]ally, an example being the root-colonising honey fungi in the genus ''[[Armillaria]].''<ref name="RHS">{{cite web |title=What is honey fungus? |url=https://www.rhs.org.uk/advice/profile?PID=180 |publisher=[[Royal Horticultural Society]] |access-date=12 October 2017}}</ref> Hemibiotrophic pathogens begin their colonising their hosts as biotrophs, and subsequently killing off host cells and feeding as necrotrophs, a phenomenon termed the [[biotrophy-necrotrophy switch]].<ref>{{Cite journal |last1=Chowdhury |first1=Supriyo |last2=Basu |first2=Arpita |last3=Kundu |first3=Surekha |date=8 December 2017 |title=Biotrophy-necrotrophy switch in pathogen evoke differential response in resistant and susceptible sesame involving multiple signaling pathways at different phases |url=http://dx.doi.org/10.1038/s41598-017-17248-7 |journal=Scientific Reports |volume=7 |issue=1 |page=17251 |doi=10.1038/s41598-017-17248-7 |pmid=29222513 |pmc=5722813 |bibcode=2017NatSR...717251C |issn=2045-2322}}</ref>

Pathogenic fungi are well-known causative agents of diseases on animals as well as humans. Fungal infections ([[Fungal infection|mycosis]]) are estimated to kill 1.6&nbsp;million people each year.<ref>{{cite journal |title=Stop neglecting fungi |journal=Nature Microbiology |date=25 July 2017 |volume=2 |issue=8 |pages=17120 |doi=10.1038/nmicrobiol.2017.120 |pmid=28741610 |doi-access=free}}</ref> One example of a potent fungal animal pathogen are [[Microsporidia]] - obligate intracellular parasitic fungi that largely affect insects, but may also affect vertebrates including humans, causing the intestinal infection [[microsporidiosis]].<ref name="Didier">{{cite journal |last1=Didier |first1=E. S. |last2=Stovall |first2=M. E. |last3=Green |first3=L. C. |last4=Brindley |first4=P. J. |last5=Sestak |first5=K. |last6=Didier |first6=P. J. |url=https://www.researchgate.net/publication/8159085 |title=Epidemiology of microsporidiosis: sources and modes of transmission |journal=Veterinary Parasitology |date=9 December 2004 |volume=126 |issue=1–2 |pages=145–166 |doi=10.1016/j.vetpar.2004.09.006 |pmid=15567583}}</ref>

[[File:Borrelia burgdorferi-cropped.jpg|thumb|upright|''[[Borrelia burgdorferi]]'', the bacterium that causes [[Lyme disease]], is transmitted by ''[[Ixodes]]'' ticks.]]