Editing Cholera (section)

=== Susceptibility ===
About 100{{nbsp}}million bacteria must typically be ingested to cause cholera in a normal healthy adult.<ref name=Lancet2004 /> This dose, however, is less in those with lowered [[gastric acid]]ity (for instance those using [[proton pump inhibitors]]).<ref name=Lancet2004 /> Children are also more susceptible, with two- to four-year-olds having the highest rates of infection.<ref name=Lancet2004 /> Individuals' susceptibility to cholera is also affected by their [[blood type]], with those with [[type O blood]] being the most susceptible.<ref name=Lancet2004 /> Persons with [[immunodeficiency|lowered immunity]], such as persons with [[HIV/AIDS|AIDS]] or [[malnutrition|malnourished]] children, are more likely to develop a severe case if they become infected.<ref name=WHOpreventionandcontrolofoutbreaks>[http://www.emro.who.int/csr/Media/PDF/cholera_whopolicy.pdf Prevention and control of cholera outbreaks: WHO policy and recommendations] {{webarchive|url=https://web.archive.org/web/20111122092541/http://www.emro.who.int/csr/Media/PDF/cholera_whopolicy.pdf |date=2011-11-22 }}, World Health Organization, Regional Office for the Eastern Mediterranean, undated but citing sources from '07, '04, '03, '04, and '05.</ref> Any individual, even a healthy adult in middle age, can undergo a severe case, and each person's case should be measured by the loss of fluids, preferably in consultation with a professional [[health care provider]].{{medical citation needed|date=December 2013}}

The [[cystic fibrosis]] genetic [[mutation]] known as [[delta-F508]] in humans has been said to maintain a selective [[heterozygous advantage]]: [[heterozygous]] carriers of the mutation (who are not affected by cystic fibrosis) are more resistant to ''V.&nbsp;cholerae'' infections.<ref name="Bertranpetit_1996">{{cite book |doi=10.1002/9780470514887.ch6 |chapter=Genetic and Geographical Variability in Cystic Fibrosis: Evolutionary Considerations |title=Ciba Foundation Symposium 197 – Variation in the Human Genome |series=Novartis Foundation Symposia |year=2007 |last1=Bertranpetit |first1=Jaume |last2=Calafell |first2=Francesc |volume=197 |pages=97–118 |pmid=8827370 |isbn=978-0-470-51488-7 }}</ref> In this model, the genetic deficiency in the [[cystic fibrosis transmembrane conductance regulator]] channel proteins interferes with bacteria binding to the [[intestinal epithelium]], thus reducing the effects of an infection.