A natural outbreak of Avian Influenza H5N1 (AI-H5N1) in Muscovy ducks, with nervous signs, eye opacity, high mortality as well as necrosis, and hemorrhage in pancreas. The infection was confirmed by RT-PCR. Injection of IgY revealed stopped mortality and signs with improvement in general health conditions in birds injected with dilution 1/5 and 1/10 as compared with noninjected. Examined tissue sections from AI-H5N1 naturally infected ducks showed area of hemorrhages in the brain and hemorrhage and necrosis in the liver—pancreas showing areas of hemorrhages and focal area of coagulative necrosis characterized by lymphocytic infiltration. Severe depletion of the splenic lymphoid follicle. The trachea is suffering from moderate to severe submucosal hemorrhages. IgY-injected ducks showed milder lesions than infected non-treated. Birds injected with 1/5 diluted IgY showed milder lesions than those injected with 1/10.
The results suggest that administering IgY antibodies against the HPAI H5N1 virus can mitigate the severe signs, lesions, mortality, and histopathological changes observed in ducks naturally infected with the virus. The IgY antibodies may neutralize the virus and reduce the viral load, thereby limiting the extent of tissue damage and inflammatory response, indicating its potential as a therapeutic approach for managing avian influenza outbreaks. The usage of IgY appears to confer protection against signs, mortality, and pathological changes induced by the AI-H5N1 infection.