In the current poultry industry, diseases involving enlarged and necrotic livers and spleens in chickens are often encountered. In addition to bacterial causes such as Vibrio and nutritional problems, there is another viral culprit behind liver and spleen enlargement: hepatitis E virus.
Hepatitis E is also known as hepatitis-splenomegaly syndrome. It has been occurring in China for many years, but to date, people know little about it. Infection with avian hepatitis E virus (HEV) can cause hepatitis-splenomegaly in laying hens and broiler breeders, leading to decreased egg production and even death.
Under natural conditions, dead chickens typically show ovarian regression, red fluid in the abdomen, an enlarged liver, and hemorrhage or blood clots in the abdominal cavity. The liver is usually friable, with spots and red, yellow, and/or yellowish-brown lesions; subcapsular hematomas may be present, as may blood clots attached to the surface. Infected chickens have mild to severe splenomegaly. White histological lesions in the liver may also be present, ranging from multifocal hemorrhage to extensive necrosis and hemorrhage.
Blood clots in the abdominal cavity and liver hemorrhage are often confused with hemorrhagic fatty liver syndrome (HFLS). HFLS usually occurs in laying hens, but the liver in hepatitis-liver hemorrhagic syndrome (HS syndrome) is not fatty.
Prevention and control measures:
1, To date, there is no particularly effective treatment for hepatitis E. The use of medications that support liver and kidney function and enhance immune function can help chickens recover from this disease.
2, Strict implementation of biosecurity measures on poultry farms can limit the spread of the virus. Maintain environmental disinfection, especially disinfection of chickens while they are in the poultry house. Alternating iodic acid preparations and glutaraldehyde preparations is preferable; if hepatitis E occurs, in addition to strengthening disinfection, affected chickens should be culled as early as possible to minimize opportunities for transmission.
3, Because hepatitis E can be transmitted vertically, when sourcing chicks, investigate whether the breeder farm has had cases of hepatitis E. Carefully select the source farm for the chicks to prevent vertical transmission.
4, Strengthen husbandry management and use high-quality, complete feed. Add vitamin E, vitamin C, and liver-protective medication to the feed and drinking water.
5, Control immunosuppressive diseases to reduce avian HEV infections.