High clinical manifestation rate in an imported outbreak of hepatitis E genotype 1 infection in a German group of travellers returning from India

Background. There are only few reports about travel-associated, imported tropical hepatitis E virus (HEV) genotype 1 infections within Western travellers. We describe the clinical course of a single outbreak of hepatitis E in a German travellers group returning from India and compare the results of two commercial HEV-seroassays.

MATERIAL AND METHODS: After identifying hepatitis E in an index patient returning from a journey to India all 24 members of this journey were tested for anti-HEV-IgG and IgM using two commercial seroassays (Wantai and Mikrogen), for HEV-RNA by PCR and HEV-Ag by an antigen-assay (Wantai).

RESULTS: 5/24 (21%) individuals were viraemic with viral loads between 580-4,800,000 IU/mL. Bilirubin and ALT levels in these patients ranged from 1.3-14.9 mg/dL (mean 7.3 mg/dL, SD 5.6 mg/dL) and 151-4,820 U/L (mean 1,832U/L, SD 1842U/L), respectively and showed significant correlations with viral loads (r = 0.863, p < 0.001; r = 0.890, p < 0.001). No risk factor for food-borne HEV-transmission was identified. All viraemic patients (5/5) tested positive for anti-HEV-IgG and IgM in the Wantai-assay but only 4/5 in the Mikrogen-assay. Wantai-HEV-antigen-assay was negative in all patients. Six months later all previously viraemic patients tested positive for anti-HEV-IgG and negative for IgM in both assays. However, two non-viremic individuals who initially tested Wantai-IgM-positive stayed positive indicating false positive results.

CONCLUSIONS: Despite the exact number of exposed individuals could not be determined HEV genotype 1 infections have a high manifestation rate of more than 20%.The Wantai-antigen-test failed, the Wantai-IgMrapid- test and the Mikrogen-IgM-recomblot showed a better performance but still they cannot replace real-time PCR for diagnosing ongoing HEV-infections.