Canine herpesvirus

Canine herpesvirus
Virus classification
Group:	Group I (dsDNA)
Order:	Herpesvirales
Family:	Herpesviridae
Subfamily:	Alphaherpesvirinae
Genus:	Varicellovirus
Species:	Canine herpesvirus 1 (CHV-1)

Canine herpesvirus (CHV) is a virus of the family Herpesviridae which most importantly causes a fatal hemorrhagic disease in puppies (and in wild Canidae) less than two to three weeks old. It is known to exist in the United States, Canada, Australia, Japan, England and Germany. CHV was first recognized in the mid-1960s from a fatal disease in puppies.

The incubation period of CHV is six to ten days. CHV is transmitted to puppies in the birth canal and by contact with infected oral and nasal secretions from the mother or other infected dogs, but it is not spread through the air. The virus replicates in the surface cells of the nasal mucosa, tonsils, and pharynx. Low body temperature allows the virus to spread and infect the rest of the body. Symptoms include crying, weakness, depression, discharge from the nose, soft, yellow feces, and a loss of the sucking reflex. CHV also causes a necrotizing vasculitis that results in hemorrhage around the blood vessels. Bruising of the belly may occur. Eye lesions include keratitis, uveitis, optic neuritis, retinitis, and retinal dysplasia. There is a high mortality rate, approaching 80 percent in puppies less than one week old, and death usually occurs in one to two days.

In puppies three to five weeks old, the disease is less severe due to their ability to properly maintain body temperature and mount a febrile response. More puppies survive, but they can develop a latent infection. Some later get neurologic disease and have symptoms like difficulty walking and blindness. Reactivation of a latent infection may be caused by stress or immunosuppressive drugs such as corticosteroids. The site of latency has been shown to be the trigeminal ganglion and possibly the lumbosacral ganglion.

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Wikipedia