Editing Leptospirosis (section)

===Transmission===
The bacteria can be found in ponds, rivers, puddles, sewers, agricultural fields and moist soil.<ref name="Karpagm2020"/> Pathogenic ''Leptospira'' have been found in the form of aquatic [[biofilms]], which may aid survival in the environment.<ref name=Barragan2017>{{cite journal | vauthors = Barragan V, Olivas S, Keim P, Pearson T | title = Critical Knowledge Gaps in Our Understanding of Environmental Cycling and Transmission of Leptospira spp | journal = Applied and Environmental Microbiology | volume = 83 | issue = 19 | date = October 2017 | pmid = 28754706 | pmc = 5601346 | doi = 10.1128/AEM.01190-17 }}</ref>

''Leptospira'' live in the kidneys of various wild and domestic animals. When animals ingest the bacteria, they circulate in the bloodstream, then lodge themselves into the kidneys through the [[Glomerulus|glomerulular]] or [[peritubular capillaries]]. The bacteria then pass into the [[Lumen (anatomy)|lumens]] of the [[renal tubules]] and colonise the [[brush border]] of the [[proximal convoluted tubule]]. This causes the continuous shedding of bacteria in the urine without the animal experiencing significant ill effects. This relationship between the animal and the bacteria is known as a [[commensal relationship]], and the animal is known as a [[Natural reservoir|reservoir host]].<ref name="Haake 2015">{{cite journal | vauthors = Haake DA, Levett PN | title = Leptospirosis in humans | journal = Current Topics in Microbiology and Immunology | volume = 387 | issue = 387 | pages = 65–97 | date = 25 May 2015 | pmid = 25388133 | pmc = 4442676 | doi = 10.1007/978-3-662-45059-8_5 | isbn = 978-3-662-45058-1 }}</ref>

''Leptospira'' are found mostly in mammals.<ref name="Zoey2020"/> However, reptiles and [[Poikilotherm|cold-blooded animals]] such as frogs, snakes, turtles, and toads have been shown to have the infection.<ref name="Ellis2015"/> Whether there are reservoirs of human infection  is unknown.<ref name="Haake 2015"/><ref name="Ellis2015"/> Rats, mice, and moles are important [[Host (biology)#Definitive and secondary hosts|primary hosts]], but other mammals including dogs, deer, rabbits, hedgehogs, cows, sheep, swine, raccoons, opossums, and skunks can also carry the disease.<ref name="Ellis2015"/> In Africa, a number of wildlife hosts have been identified as carriers, including the [[banded mongoose]], [[Fennec fox|Egyptian fox]], [[Rusa deer]], and [[shrews]].<ref name=Allan2015>{{cite journal | vauthors = Allan KJ, Biggs HM, Halliday JE, Kazwala RR, Maro VP, Cleaveland S, Crump JA | title = Epidemiology of Leptospirosis in Africa: A Systematic Review of a Neglected Zoonosis and a Paradigm for 'One Health' in Africa | journal = PLOS Neglected Tropical Diseases | volume = 9 | issue = 9 | pages = e0003899 | date = 2015 | pmid = 26368568 | pmc = 4569256 | doi = 10.1371/journal.pntd.0003899 }}</ref> There are various mechanisms whereby animals can infect each other. Dogs may lick the urine of an infected animal off the grass or [[soil]], or drink from an infected puddle.{{Citation needed|date=August 2020}} House-bound domestic dogs have contracted leptospirosis, apparently from licking the urine of infected mice in the house.{{Citation needed|date=August 2020}} Leptospirosis can also be transmitted via the semen of infected animals.<ref name="Ellis2015"/> The duration of bacteria being consistently present in animal urine may persist for years.<ref name="Ellis2015"/>

Humans are the [[Host (biology)#Dead-end hosts|accidental host]] of ''Leptospira''.<ref name="Zoey2020"/> Humans become infected through contact with water or moist soil that contains urine from infected animals.<ref name="Karpagm2020"/> The bacteria enter through cuts, abrasions,<ref name="Karpagm2020"/> ingestion of contaminated food, or contact with [[mucous membrane]] of the body (e.g. mouth, nose, and eyes).<ref name="Kin Chin 2019"/> Occupations at risk of contracting leptospirosis include farmers, fishermen, garbage collectors and sewage workers.<ref name="Zoey2020"/> The disease is also related to [[adventure tourism]] and recreational activities.<ref name="Zoey2020"/> It is common among water-sports enthusiasts in specific areas, including [[triathlon]]s, water [[rafting]], [[canoeing]] and swimming, as prolonged immersion in water promotes the entry of the bacteria.<ref name="Zoey2020"/> However, ''Leptospira'' are unlikely to penetrate intact skin.<ref name="Lane 2016"/> The disease is not known to spread between humans, and bacterial dissemination in [[Convalescence|recovery period]] is extremely rare in humans.<ref name="Lane 2016">{{cite journal|last1=Lane|first1=Alison B|last2=Dore|first2=Michael M|title=Leptospirosis: A clinical review of evidence based diagnosis, treatment and prevention|journal=World Journal of Clinical Infectious Diseases|volume=6|issue=4|year=2016|pages=61|issn=2220-3176|doi=10.5495/wjcid.v6.i4.61|doi-access=free}}</ref> Once humans are infected, bacterial shedding from the kidneys usually persists for up to 60 days.<ref name="Spickler 2013"/>

Rarely, leptospirosis can be transmitted through an organ transplant.<ref>{{cite journal | vauthors = Song AT, Abas L, Andrade LC, Andraus W, D'Albuquerque LA, Abdala E | title = A first report of leptospirosis after liver transplantation | journal = Transplant Infectious Disease | volume = 18 | issue = 1 | pages = 137–40 | date = February 2016 | pmid = 26671230 | doi = 10.1111/tid.12490 }}</ref> Infection through the [[placenta]] during pregnancy is also possible.<ref>{{cite journal | vauthors = Puliyath G, Singh S | title = Leptospirosis in pregnancy | journal = European Journal of Clinical Microbiology & Infectious Diseases | volume = 31 | issue = 10 | pages = 2491–6 | date = October 2012 | pmid = 22549729 | doi = 10.1007/s10096-012-1625-7 | s2cid = 14033595 }}</ref><ref>{{cite journal | vauthors = Carles G, Montoya E, Joly F, Peneau C | title = [Leptospirosis and pregnancy. Eleven cases in French Guyana] | journal = Journal de Gynécologie, Obstétrique et Biologie de la Reproduction | volume = 24 | issue = 4 | pages = 418–21 | date = 1995 | pmid = 7650320 }}</ref><ref>{{cite journal | vauthors = Koe SL, Tan KT, Tan TC | title = Leptospirosis in pregnancy with pathological fetal cardiotocography changes | journal = Singapore Medical Journal | volume = 55 | issue = 2 | pages = e20-4 | date = February 2014 | pmid = 24712035 | pmc = 4291937 | doi = 10.11622/smedj.2013194 }}</ref> It can cause [[miscarriage]] and infection in [[infant]]s.<ref>{{cite journal | vauthors = Shaked Y, Shpilberg O, Samra D, Samra Y | title = Leptospirosis in pregnancy and its effect on the fetus: case report and review | journal = Clinical Infectious Diseases | volume = 17 | issue = 2 | pages = 241–3 | date = August 1993 | pmid = 8399874 | doi = 10.1093/clinids/17.2.241 }}</ref>