Protection against Infectious Bronchitis Virus, a Corona Virus Infection, Using Ostrich Antibodies

Abstract

In chickens, infectious bronchitis (IB) is a major respiratory disease. The respiratory system is the primary multiplication site of IB virus (IBV), a coronavirus, after which the virus is distributed to other organs. Poultry farms sustain considerable economic damage due to IB outbreaks in flocks, since IB causes a severe reduction in weight gain in chicks. In the present study, we produced the ostrich IgY against IBV by immunizing female ostriches with the IB viral antigens. The resultant purified IgY showed a strong neutralizing activity against IBV infection of cultured primary chick kidney cells. The infectivity of IBV was markedly inhibited in the trachea of chicks when ostrich IgY was injected intra-muscularly into newly hatched chicks prior to viral inhalation challenge at two weeks of age. Furthermore, the infection was strongly blocked in the tracheae when IgY was injected into chicks at one day and one week of age, with viral inhalation performed at three weeks of age. These findings suggest that the injection of ostrich IgY can help protect young chicks from IBV infections. In south Asian and African countries, broiler chicks are sent to poultry market around 30 days of age, so it is important to prevent IB outbreaks in very young flocks. We strongly believe that ostrich IgY will be a powerful weapon against IB infection in poultry farms on a wide scale and also hope that these findings will aid in the development of antibody vaccines for new type corona viruses, SARS-CoV and MERS-CoV.