Canine herpesviral infection is a severe, often fatal, disease of puppies. (It is sometimes referred to as fading or sudden death syndrome in puppies.) In adult dogs, it may be associated with upper respiratory infection or an inflammation of the vagina marked by pain and a pus-filled discharge (in females) or inflammation of the foreskin of the penis (in males).

The disease is caused by a canine her-pesvirus that occurs worldwide. Transmission usually occurs by contact between susceptible puppies and the infected oral, nasal, or vaginal secretions of their dam or oral or nasal secretions of dogs allowed to come in contact with puppies during the first 3 weeks of life. Transmission may also occur prior to birth.

Death due to the infection usually occurs in puppies 1 to 3 weeks old, occasionally in puppies up to 1 month old, and rarely in puppies as old as 6 months. Typically, the onset of illness is sudden, and death occurs after an illness of less than 24 hours. Infections in the womb may be associated with abortions, stillbirths, and infertility.

No vaccine is available. Infected female dogs develop antibodies, and litters born after the first infected litter receive antibodies from the mother in the colostrum. Puppies that receive these maternal antibodies may be infected with the virus, but show no signs of disease. The outlook for puppies that survive early infection with canine herpesvirus is guarded because the disease can cause irreparable damage to the lymph nodes, brain, kidneys, and liver.

Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); David A. Ashford, DVM, MPH, DS; Craig E. Greene, DVM, MS; Eugene D. Janzen, DVM, MVS; Bert E. Stromberg, PhD; Max J. Appel, DMV, PhD; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Kenneth R. Harkin, DVM, DACVIM; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD; Jodie Low Choy, BVMS; Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM