Hepatitis-Hydropericardium Syndrome (Angara Disease) in Poultry: A Comprehensive Review

Hepatitis-Hydropericardium Syndrome (HHS), also known as Angara disease, is an acute, highly contagious viral disease primarily affecting broiler chickens aged ۳–۶ weeks, posing a significant threat to global poultry production. First reported in Pakistan in ۱۹۸۷, HHS has since spread across Asia, the Middle East, the Americas, and Europe, driven by fowl adenovirus serotype ۴ (FAdV-۴) of species C. This non-enveloped, double-stranded DNA virus causes sudden mortality rates of ۱۰–۸۰%, characterized by hepatic inflammation, hydropericardium, and systemic lesions including hepatomegaly, pericardial effusion, renal pallor, and pulmonary edema. Transmission occurs via vertical (egg contamination) and horizontal (fecal-oral) routes, with FAdV-۴ replicating in intestinal epithelia before viremic dissemination to target organs such as the liver, heart, and kidneys. Pathogenesis involves hepatocellular necrosis, basophilic intranuclear inclusions, and immunosuppression, exacerbated by hypervirulent strains emerging since ۲۰۱۵, featuring genomic deletions in fiber-۲ and hexon genes. Clinical signs include lethargy, ruffled feathers, anorexia, and discolored droppings, with post-mortem hallmarks of friable livers and watery to gelatinous transudate straw-colored pericardial fluid. Diagnosis combines epidemiological patterns, gross pathology, histopathology, and molecular tools such as PCR for FAdV-۴ detection, differentiating HHS from Inclusion Body Hepatitis caused by other serotypes. Prevention relies on biosecurity (hygiene and pest control as a mechanical carrier), and vaccination of breeder flocks using inactivated or recombinant vaccines is important for transferring maternal antibodies. No specific antivirals exist; supportive antibiotics mitigate secondary infections. HHS inflicts substantial economic losses through mortality, impaired growth, poor feed conversion, and control costs. Enhanced surveillance, strain-specific vaccines, and host resistance research are crucial for sustainable mitigation, underscoring HHS's ongoing challenge to poultry health and industry viability.

کلیدواژه ها:

Hepatitis-Hydropericardium Syndrome ، Angara Disease ، Fowl Adenovirus Serotype ۴ ، poultry