Editing Hepatitis C (section)

=== Occult infection ===
Persons who have been infected with hepatitis C may appear to clear the virus but remain infected.<ref name=Sugden2012>{{cite journal | vauthors = Sugden PB, Cameron B, Bull R, White PA, Lloyd AR | title = Occult infection with hepatitis C virus: friend or foe? | journal = Immunology and Cell Biology | volume = 90 | issue = 8 | pages = 763–73 | date = September 2012 | pmid = 22546735 | doi = 10.1038/icb.2012.20 | s2cid = 23845868 }}</ref> The virus is not detectable with conventional testing but can be found with ultra-sensitive tests.<ref name="Carreño2006">{{cite journal | vauthors = Carreño V | title = Occult hepatitis C virus infection: a new form of hepatitis C | journal = World Journal of Gastroenterology | volume = 12 | issue = 43 | pages = 6922–5 | date = November 2006 | pmid = 17109511 | pmc = 4087333 | doi = 10.3748/wjg.12.6922 | doi-access = free }}</ref> The original method of detection was by demonstrating the viral [[genome]] within liver biopsies. Still, newer methods include an antibody test for the virus' core protein and the detection of the viral genome after first concentrating the viral particles by [[ultracentrifugation]].<ref name="CarreñoGarcía2011">{{cite journal | vauthors = Carreño García V, Nebreda JB, Aguilar IC, Quiroga Estévez JA | title = [Occult hepatitis C virus infection] | journal = Enfermedades Infecciosas y Microbiologia Clinica | volume = 29 | pages = 14–9 | date = March 2011 | issue = Suppl 3 | pmid = 21458706 | doi = 10.1016/S0213-005X(11)70022-2 }}</ref> A form of infection with persistently moderately elevated serum liver enzymes but without antibodies to hepatitis C has also been reported.<ref name=Pham2010>{{cite journal | vauthors = Pham TN, Coffin CS, Michalak TI | title = Occult hepatitis C virus infection: what does it mean? | journal = Liver International | volume = 30 | issue = 4 | pages = 502–11 | date = April 2010 | pmid = 20070513 | doi = 10.1111/j.1478-3231.2009.02193.x | s2cid = 205651069 }}</ref> This form is known as cryptogenic occult infection.

Several clinical pictures have been associated with this type of infection.<ref name="Carreño2012">{{cite journal | vauthors = Carreño V, Bartolomé J, Castillo I, Quiroga JA | title = New perspectives in occult hepatitis C virus infection | journal = World Journal of Gastroenterology | volume = 18 | issue = 23 | pages = 2887–94 | date = June 2012 | pmid = 22736911 | pmc = 3380315 | doi = 10.3748/wjg.v18.i23.2887 | doi-access = free }}</ref> It may be found in people with anti-hepatitis-C antibodies but with normal serum levels of liver enzymes; in antibody-negative people with ongoing elevated liver enzymes of unknown cause; in healthy populations without evidence of liver disease; and in groups at risk for HCV infection including those on hemodialysis or family members of people with occult HCV. The clinical relevance of this form of infection is under investigation.<ref name="Carreño2008">{{cite journal | vauthors = Carreño V, Bartolomé J, Castillo I, Quiroga JA | title = Occult hepatitis B virus and hepatitis C virus infections | journal = Reviews in Medical Virology | volume = 18 | issue = 3 | pages = 139–57 | date = May–June 2008 | pmid = 18265423 | doi = 10.1002/rmv.569 | s2cid = 12331754 }}</ref> The consequences of occult infection appear to be less severe than with chronic infection but can vary from minimal to hepatocellular carcinoma.<ref name="CarreñoGarcía2011" />

The rate of occult infection in those apparently cured is controversial but appears to be low.<ref name=Nicot2011>{{cite book| vauthors = Nicot F |title=Occult hepatitis C virus infection: Where are we now?|year=2004|isbn=978-953-307-883-0|chapter=Chapter 19. Liver biopsy in modern medicine.|publisher=BoD – Books on Demand }}</ref> 40% of those with hepatitis but with both negative hepatitis C serology and the absence of detectable viral genome in the serum have hepatitis C virus in the liver on biopsy.<ref name=Scott2007>{{cite journal | vauthors = Scott JD, Gretch DR | title = Molecular diagnostics of hepatitis C virus infection: a systematic review | journal = JAMA | volume = 297 | issue = 7 | pages = 724–732 | date = February 2007 | pmid = 17312292 | doi = 10.1001/jama.297.7.724 | doi-access =  }}</ref> How commonly this occurs in children is unknown.<ref name=Robinson2008>{{cite journal | title = Vertical transmission of the hepatitis C virus: Current knowledge and issues | journal = Paediatrics & Child Health | volume = 13 | issue = 6 | pages = 529–541 | date = July 2008 | pmid = 19436425 | pmc = 2532905 | doi = 10.1093/pch/13.6.529 | last1 = Robinson | first1 = JL }}</ref>