title: Seroepidemiology of a second epidemic of hepatitis E in a population that had recorded first epidemic 30 years before and has been under surveillance since then.
abstract: Large-scale waterborne epidemics of hepatitis E occur in developing countries. It is not known why these epidemics occur repeatedly and selectively in adult population?
  
  
  
  We studied seroepidemiology of an outbreak of hepatitis E in one of 15 villages that had recorded first epidemic of hepatitis E 30 years back. Another village not affected by the second epidemic was taken as a control. Overall, 1,216 sera were collected (638 from the epidemic village and 578 from the control village) for serological markers of both hepatitis A virus (HAV) and hepatitis E virus (HEV).
  
  
  
  The seroprevalence of anti-HEV in this population following the first epidemic in 1978 was 29.4%. Antibodies were detected in only 47% of the 45 patients affected by icteric HEV infection 14 years after the first epidemic. At 30-year follow-up, the seroprevalence of anti-HEV was only 4.5% (26/578). In the village affected by second epidemic, 138 (21.6%) subjects had serological evidence of recent HEV infection. The attack rate was 23.6% (78/330) in children (≤14 years) and 19.4% (60/308) in adults (P = 0.21). The attack rate of anicteric HEV infection was 21.8% (72/330) in children and 14.6% (45/308) in adults (P = 0.02).
  
  
  
  Following hepatitis E epidemics, there is a gradual loss of antibodies in the community over the decades and poor exposure to HEV infection in the cohort of population born during the interepidemic period. The next epidemic occurs when antibody levels fall to critically low levels and there is associated gross fecal contamination of water resources. During epidemic, persons of all age groups are exposed to infection, with predominant anicteric disease in children.
authors.forename: Mehnaaz Sultan
authors.initials: MS
authors.lastname: Khuroo
authors.forename: Mohammad Sultan
authors.initials: MS
authors.lastname: Khuroo
references.citation: J Viral Hepat. 2003 Jan;10(1):61-9
references.pmid: 12558914
references.citation: Science. 1990 Mar 16;247(4948):1335-9
references.pmid: 2107574
references.citation: Ann Intern Med. 2007 Jul 3;147(1):28-33
references.pmid: 17606958
references.citation: N Engl J Med. 2007 Mar 1;356(9):949-51
references.pmid: 17329703
references.citation: Curr Opin Infect Dis. 2008 Oct;21(5):539-43
references.pmid: 18725805
references.citation: Am J Med. 1981 Feb;70(2):252-5
references.pmid: 6781338
references.citation: J Infect Dis. 1995 Feb;171(2):447-50
references.pmid: 7844387
references.citation: Lancet. 1993 May 22;341(8856):1355
references.pmid: 8098491
references.citation: Lancet. 1980 Jul 12;2(8185):97-8
references.pmid: 6105287
references.citation: J Med Virol. 2008 Apr;80(4):646-58
references.pmid: 18297720
references.citation: Am J Trop Med Hyg. 2000 Apr;62(4):519-23
references.pmid: 11220771
references.citation: Intervirology. 1983;20(1):23-31
references.pmid: 6409836
references.citation: Rev Med Virol. 2007 May-Jun;17(3):151-80
references.pmid: 17051624
references.citation: Am J Med. 1980 Jun;68(6):818-24
references.pmid: 6770682
references.citation: Lancet. 1980 Oct 25;2(8200):876-9
references.pmid: 6107544
references.citation: N Engl J Med. 2007 Mar 1;356(9):895-903
references.pmid: 17329696
references.citation: J Med Virol. 1992 May;37(1):58-60
references.pmid: 1619398