New perspectives in occult hepatitis C virus infection

Table 1 Prevalence and hepatitis C virus genotype distribution of occult hepatitis C virus infection

Type	Country	Prevalence1	Genotype	Cohort/setting	Ref.
Anti-HCV negative
	Spain	57/100 (57%)	1b	Cryptogenic chronic hepatitis	[9]
	Japan	Not applicable	Not reported	Cryptogenic cirrhosis with HCC	[18]
	Italy	2/5 (40%)	Not reported	Cryptogenic cirrhosis with HCC	[19]
	Egypt	4/40 (10%)	Not reported	Cryptogenic chronic hepatitis	[20]
	Colombia	Not applicable	1a	Liver retransplantation	[21]
	Pakistan	23/31 (74%)	1a, 3a, 3b	Cryptogenic chronic hepatitis	[22]
	Iran	7/69 (10%)	1a, 1b, 3a	Cryptogenic chronic hepatitis	[23]
	Italy	9/276 (3.3%)	1a, 1b, 2a	General population without liver disease	[26]
Anti-HCV positive
	United States/Poland	11/11 (100%)2	1a, 1b	Asymptomatic anti-HCV carrier	[10]
	Cuba/Mexico	17/18 (94%)	Not reported	Asymptomatic HCV carrier and therapy response	[11]
	Spain	10/12 (83%)	1b	Asymptomatic anti-HCV carrier	[12]
	Canada	16/16 (100%)2	1a, 1b, 2a	Spontaneous recovery and therapy response	[13]
	United States/Poland	15/17 (88%)2	1a, 1b, 2a, 3a	Therapy response	[14]
	Spain	19/20 (95%)	1b, 2, 3	Therapy response	[15]
	Canada	24/24 (100%)2	1, 1a, 3a	Therapy response	[16]
	Egypt	7/62 (11%)	Not reported	Therapy response	[20]

¹Hepatitis C virus (HCV) RNA detection in liver and/or peripheral blood mononuclear cells;

²Including HCV RNA detection in serum with nested reverse-transcription polymerase chain reaction-nucleic acid hybridization assay. HCC: Hepatocellular carcinoma.