In ovo protection against infectious bronchitis

Abstract

The present invention is directed to processes and compositions for protecting host animals (e.g., chickens) from exposure to virulent infectious bronchitis virus. In ovo administration of live, avirulent strains of IB at appropriate dosage levels on a per egg basis provides an effective and efficient vaccination having acceptable safety and efficacy features.

We claim:  
     
         1 . A process for protecting a host animal, comprising administering a vaccine in ovo to a fertile egg containing an embryo of the host animal; and wherein the vaccine comprises an immunogenically-effective amount of a live, avirulent strain of infectious bronchitis virus.  
     
     
         2 . The process of    claim 1   , wherein the immunogenically-effective amount is in the approximate range of from about 10 −1.0  EID 50  per egg to about 10 2.0  EID 50  per egg.  
     
     
         3 . The process of    claim 2   , wherein the immunogenically-effective amount is about 10 −1.0 EID 50  per egg.  
     
     
         4 . The process of    claim 2   , wherein the immunogenically-effective amount is about 10 1.0  EID 50  per egg.  
     
     
         5 . The process of    claim 2   , wherein the immunogenically-effective amount is about 10 1.0  EID 50  per egg.  
     
     
         6 . The process of    claim 2   , wherein the immunogenically-effective amount is about 10 2.0  EID 50  per egg.  
     
     
         7 . The process of    claim 1   , wherein said administering occurs during incubation.  
     
     
         8 . The process of    claim 7   , wherein: 
 said administering occurs on approximately day 18 of incubation.    
     
     
         9 . The process of    claim 1   , wherein the host animal is a chicken.  
     
     
         10 . The process of    claim 9   , wherein the chicken is maternal-anti body-positive.  
     
     
         11 . The process of    claim 10   , wherein the chicken is other than a SPF chicken.  
     
     
         12 . The process of    claim 11   , wherein the chicken originates from a commercial flock of broilers.  
     
     
         13 . A process for protecting chickens from exposure to virulent strains of infectious bronchitis virus, comprising administering in ovo to fertile chicken eggs a vaccine comprising, on a per egg basis, an immunogenically-effective amount of a live, avirulent strain of infectious bronchitis virus.  
     
     
         14 . The process of    claim 13   , wherein the immunogenically-effective amount is in the approximate range of from about 10−1.0 ElD 50  per egg to about 10 2.0  EID 50  per egg.  
     
     
         15 . A vaccine for protecting chickens from exposure to virulent infectious bronchitis virus, comprising: 
 a solution containing, on a per chicken egg basis, a live, avirulent strain of infectious bronchitis virus in an immunogenically-effective amount.    
     
     
         16 . The vaccine of    claim 15   , wherein the immunogenically-effective amount is efficacious against subsequent post-hatch exposure of the chicken to virulent infectious bronchitis virus and does not significantly decrease the percentage of in ovo vaccinated chicken eggs that hatch upon the expiration of the incubation period.  
     
     
         17 . The vaccine of    claim 15   , wherein the immunogenically-effective amount is in the approximate range of from about 10 1.0  EID 50  per egg to about 10 2.0  EID 50  per egg.  
     
     
         18 . The vaccine of    claim 17   , wherein the vaccine contains substantially no virus neutralizing factor.