Protective role of humoral immune responses during an outbreak of hepatitis E in Egypt

Although the seroprevalence of hepatitis E virus (HEV) is approximately 80% in adult Egyp- tians living in rural areas, symptomatic HEV-caused acute viral hepatitis (AVH) is sporadic and relatively uncommon. To investigate the dichotomy between HEV infection and clini- cal AVH, HEV-specific immune responses in patients with symptomatic and asymptomatic HEV infection during a waterborne outbreak in Egypt were examined. Of 235 acute hepati- tis patients in Assiut hospitals screened for HEV infection, 42 (17.9%) were hepatitis acute hepatitis patients confirmed as HEV-caused AVH; 37 (88%) of the 42 patients were residents of rural areas, and 14 (33%) were from one village (Kom El-Mansoura). Another 200 AVH contacts of AVH cases in this village were screened for HEV and 14 (7.0%), all of whom were family members of AVH cases, were asymptomatic HEV IgM-positive. HEV infections in this village peaked during the summer. Asymptomatic HEV seroconverters had significantly higher levels of epitope-specific neutralising (p=0.006) and high avidity (p=0.04) anti-HEV antibodies than the corresponding AVH cases. In conclusion, naturally acquired humoral immune responses appear to protect HEV-exposed subjects from AVH during an HEV outbreak in Egypt

Genotypic characterization of symptomatic hepatitis E virus (HEV) infections in Egypt

Background: Hepatitis E virus (HEV) is a common cause of acute viral hepatitis (AVH) in many developing countries. In Egypt, HEV seroprevalence is among the highest in the world; however, only a very limited number of Egyptian HEV sequences are currently available. Objectives: The objectives were to determine the HEV genotype(s) currently circulating in Egypt. Study design: AVH patients without serologic evidence of hepatitis A, B, and C viruses were evaluated for possible HEV infection using serologic assays for anti-HEV IgM and anti-HEV IgG and real-time PCR for HEV RNA. Stool suspensions from suspected cases were inoculated into rhesus macaques to confirm the presence of HEV. Sequence analysis was utilized to determine HEV genotype. Results: Of 287 subjects with AVHenrolled, 58 had serologic evidence of acute HEVinfection. Stool samples for two of these patients were repeatedly positive for HEVRNAby real-time PCR. Macaques experimentally inoculated with these human stools also developed viremia. Sequence analysis of open reading frame (ORF) 1 demonstrated that these isolates belonged to HEV genotype 1 and were 3.9–9.5% divergent from other genotype 1 isolates. ORF2 was 5.3–8.7% divergent from previously reported Egyptian isolates. Conclusions: This study strongly suggests that genotype 1 HEV related to other North African isolates is circulating in acute symptomatic patients in Egypt. Further evaluation of genotypic variability is underway in this highly endemic cohort and is considered an important component of our increased understanding of HEV pathogenesis