Investigation of suspected viral hepatitis outbreaks in North West India

• High concordance between HEV-antigen and HEV-RNA detection in serum samples.
• HEV-antigen and HEV-RNA can be an early diagnostic marker of HEV infection.
• Saliva can be an alternate diagnostic sample for HEV infection.
• Sewage contamination of drinking water suggested in both the outbreaks.
• Both clinical and environmental strains belong to HEV genotype 1, subtype 1a.

Hepatitis E (HEV) infection is diagnosed on the basis of serum anti-HEV IgM detection. In outbreaks, early diagnostic method is important for prompt control measures. This study compared 3 diagnostic methods in 60 serum samples collected in suspected HEV outbreaks. The suitability of saliva samples for antibody detection was also evaluated in 21 paired serum saliva samples. The anti-HEV IgM, HEV-Ag, and HEV-RNA were detected in serum samples of 52 (86.66%), 16 (26.66%), and 18 (30%) patients, respectively. The concordance between serum and saliva IgM was found to be 76.91%. The positivity of PCR and HEV-Ag detection was 100% within 1 week of illness which declined to 5–10% thereafter. The outbreak was attributed to HEV genotype 1, subtype 1a, and the clinical and environmental strains clustered together. HEV-antigen and RNA were an early diagnostic marker with 96.66% concordance. Saliva samples can be used as an alternative in outbreak setting.