Editing Parasitism (section)

=== Bacteria ===

{{main|Pathogenic bacteria}}

Many bacteria are parasitic, though they are more generally thought of as [[Pathogenic bacteria|pathogens]] causing disease.<ref name=McFall-Ngai2007>{{Cite journal |last=McFall-Ngai |first=Margaret |date=January 2007 |title=Adaptive Immunity: Care for the community |journal=Nature |volume=445 |issue=7124 |pages=153 |doi=10.1038/445153a|pmid=17215830 |bibcode=2007Natur.445..153M |s2cid=9273396 |doi-access=free }}</ref> Parasitic bacteria are extremely diverse, and infect their hosts by a variety of routes. To give a few examples, ''[[Bacillus anthracis]]'', the cause of [[anthrax]], is spread by contact with infected [[domestic animal]]s; its [[spore]]s, which can survive for years outside the body, can enter a host through an abrasion or may be inhaled. ''[[Borrelia]]'', the cause of [[Lyme disease]] and [[relapsing fever]], is transmitted by vectors, ticks of the genus ''[[Ixodes]]'', from the diseases' reservoirs in animals such as [[deer]]. ''[[Campylobacter jejuni]]'', a cause of [[gastroenteritis]], is spread by the fecal–oral route from animals, or by eating insufficiently cooked [[poultry]], or by contaminated water. ''[[Haemophilus influenzae]]'', an agent of [[bacterial meningitis]] and respiratory tract infections such as [[influenza]] and [[bronchitis]], is transmitted by droplet contact. ''[[Treponema pallidum]]'', the cause of [[syphilis]], is [[sexually transmitted disease|spread]] by [[sexual activity]].<ref name=Lippincott>{{cite book |last1=Fisher |first1=Bruce |last2=Harvey |first2=Richard P. |last3=Champe |first3=Pamela C. |title=Lippincott's Illustrated Reviews: Microbiology (Lippincott's Illustrated Reviews Series) |publisher=Lippincott Williams & Wilkins |year=2007|pages=332–353 |isbn=978-0-7817-8215-9 }}</ref>

[[File:Tevenphage.svg|thumb|[[Enterobacteria phage T4]] is a [[bacteriophage]] virus. It infects its host, ''[[Escherichia coli]]'', by injecting its DNA through its tail, which attaches to the bacterium's surface.]]