Current perspectives of viral hepatitis

Table 1 Characteristics of hepatitis viruses

Virus	Hepatitis A	Hepatitis B	Hepatitis C	Hepatitis D	Hepatitis E
Family	Picornaviridae	Hepadnaviridae	Flaviviridae	Deltaviridae	Calciviridae
Nucleic acid structure	Positive sense, single-stranded RNA	Circular, double-stranded DNA with single-stranded portions	Positive sense, single-stranded RNA	Negative-stranded circular RNA	Positive sense, single-stranded RNA
Genome size (kb)	7-9	3-4	10-12	1.7	7-8
Envelope	No	Yes	Yes	Yes	No
Epidemics	Yes	No	No	No	Yes
Route of infection	Fecal-oral, sexual, and parenteral	Blood, sexual, and parenteral	Blood, sexual, and parenteral	Blood, sexual, and parenteral	Fecal-oral, parenteral, and zoonotic
Examinations	Anti-HAV IgM in blood and stool	HBs antigen	Anti-HCV IgM, anti-HCV IgG	Anti-HDV IgM, delta antigen	Anti-HEV IgM
Course in pregnancy	Benign and self-limiting	Acute and chronic infections	Acute and chronic infections	Requires HBV coinfection for propagation	Acute
Risk of VT	Probable and rare	Yes, 30%, related to maternal VT	Yes, 3%-10%, related to maternal VT	Exceptional	Yes, 46%
Preventing VT	Avoid infection by public hygienic measures	Antenatal antiviral therapy; active and passive immunization to neonate	Reducing maternal VT with therapy	Reducing HBV VT	Avoid infection by public hygienic measures
Breastfeeding	Yes, safe	Yes, safe	Yes, safe	Yes	Not safe in acute phase
Infant follow-up	Not needed	Serology 3 months after completing vaccination course, usually at age 9 months	Anti-HCV testing at 12-18 months to clear passively transferred maternal antibodies	Not needed	Intensive monitoring of consequences for VT, if occurs
Vaccine	Yes	Yes	No	No	Two vaccines are in trial

VT: Vertical transmission; HAV: Hepatitis A virus; HBV: Hepatitis B virus; HCV: Hepatitis C virus; HDV: Hepatitis D virus; HEV: Hepatitis E virus.