Canine herpesvirus causes a fatal illness in puppies 1 to 2 weeks of age. It usually does not causes illness in puppies older than 3 weeks of age. The reason is that the body temperature of puppies younger than 3 weeks of age is below 98°F (36.6°C), and the virus replicates only at the lower temperatures.
Herpesvirus is acquired by the mother during breeding and takes up residence in her vagina. Puppies acquire the virus while in utero, during passage through the birth canal, or by direct contact with their dam and infected littermates.
This is an insidious disease. The dam is healthy and the puppies nurse in a normal manner until shortly before death. The illness begins with abrupt cessation of nursing, followed by abdominal distention, chilling, lack of coordination, and a yellow-green diarrhea. Puppies are in agony and cry out pitifully. Death usually occurs in 24 hours.
Treatment: There is no specific treatment, but survival is possible. Unaffected littermates should be placed in a homemade incubator in a room with an ambient temperature of 100°F (37.8°C). Since the virus does not multiply well at temperatures above 98°F (36.6°C), this may prevent it from reproducing and causing infection.
Puppies who recover may develop irreversible neurological symptoms, including lack of coordination, dizziness, and blindness.
Prevention: There is no available vaccine in North America at this time (there is one in Europe). Infected dams develop immunity and subsequent litters are rarely affected. Ideally, pregnant bitches should be isolated for three weeks before and after whelping – meaning no contact with dogs going to and from shows, kennels, training classes, sporting events, and so on.