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Hepatitis-splenomegaly Syndrome

Hepatitis-splenomegaly (HS) syndrome is a disease of adult chickens, caused by infection with the avian hepatitis E virus (HEV). The virus is found worldwide, and is widespread among clinically healthy laying hens in the United States. HS syndrome is often associated with another condition known as amyloidosis.

HEV is transmitted by the fecal-oral route.


Reduced egg production
Reduced feed consumption
Reduced body weight gain


  • History - Slight increased mortality (up to 1% per week) and a severe drop in egg production (up to 40%)
  • HEV serum antibody testing
  • RT-PCR


Supportive care


Scientific References