The determination that birds or poultry are infected with Newcastle disease must be made by either a Federal veterinarian or a State veterinarian. 1 They will base that determination on one or more of the following factors: clinical evidence (signs, post-mortem lesions, and history of the occurrence of Newcastle disease); diagnostic tests; 2 or epidemiological evidence (evaluation of clinical evidence and the degree of risk posed by the potential spread of Newcastle disease based on population and exposure factors, including evaluation of whether the birds and poultry have had the opportunity to be in contact with birds or poultry infected with Newcastle disease or with excrement from birds or poultry infected with Newcastle disease, or if the birds and poultry have shared feed or water with birds or poultry infected with Newcastle disease).

1 The location of Federal veterinarians and State veterinarians may be obtained by writing to Emergency Programs, Veterinary Services, Animal and Plant Health Inspection Service, 4700 River Road, Unit 41, Riverdale, MD 20737-1231, or by referring to the local telephone book.

2 A copy of the protocols for Newcastle disease diagnostic tests may be obtained by writing to Emergency Programs, Veterinary Services, Animal and Plant Health Inspection Service, 4700 River Road Unit 41, Riverdale, MD 20737-1231. The protocols are also found in “Recommended Uniform Diagnostic Procedures,” published by the Committee of the American Association of Veterinary Laboratory Diagnosticians.

The determination that birds or poultry are exposed to Newcastle disease must be made by either a Federal veterinarian or a State veterinarian. They will base that determination on an evaluation of all related circumstances, including: the proximity of the birds or poultry to birds or poultry infected with Newcastle disease, to excrement from birds or poultry infected with Newcastle disease, and to other material touched by birds or poultry infected with Newcastle disease; the number of birds or poultry infected with Newcastle disease to which the birds or poultry were exposed; the species involved; the virulence of the Newcastle disease to which the birds or poultry were exposed; and the length of time the birds or poultry were in contact with birds or poultry infected with Newcastle disease, and to material touched by birds or poultry infected with Newcastle disease. Birds or poultry determined to be exposed to Newcastle disease will continue to be treated as exposed unless they are subsequently determined to be infected with Newcastle disease or until either a Federal veterinarian or a State veterinarian finds them to be free of Newcastle disease based on one or more of the factors listed in paragraph (a) of this section.