Rhinotracheitis

 

 
A 3-dimensional representation of the Feline Panleukopenia Virus
http://www.tulane.edu/~dmsander/WWW/335/Herpescapsid.GIF

Like other members of the Herpesviridae family, FHV-1 is species specific and therefore normally only infects other felids.  Cats can become infected through contact with infected animals, through transmission of nasal or respiratory secretions, or via fomites. The virus is not very resistant in the environment and is easily inactivated by most disinfectants.

The virus infects the animal through epithelial cells on mucous membranes.  The virus replicates in the cell nucleus and kills the cell resulting in the relase of the virus to adjacent cells.  The death of cells resulting from viral replication causes blisters on epithelial surfaces and ulcers or erosions on mucous membranes.  Although most animals recover from the clinical disease associated with this virus, few eradicate the virus from their body.  The virus moves into adjacent nerves and remains latent until stimulated by a stressor to move out of the neuron and infect another cell.  This can produce another lesion, clinical signs with upper respiratory or ocular irritation.  This latent carrier state allows for animals to be persistent carriers and shedders of FHV-1, which accounts for its high incidence. 

 
A young kitten displaying severe ocular and nasal discharge as a result of FHV Infection.
http://www.marvistavet.com/assets/images/cat_with_herpes.gif

In kittens, FHV-1 is characterized by a sudden onset of sneezing, coughing, nasal and ocular discharge and frothing salivation.  The kitten may also be having trouble breathing, have unexplained weight loss, corneal ulcers and a fever.  Occasionally tongue ulcers are seen.  In unvaccinated kittens less than 4 weeks of age, there may be extensive upper respiratory inflammation which may spread to the lungs causing a pneumonia.

In general, most cats with FHV-1  that are older than 6 months of age will have mild disease that may not be associated with any clinical signs.  Pregnant queens may abort their kittens.  The abortions observed are suspected to be secondary to toxemia and fever of the queen and not a direct effect of the virus on the kittens.

The disease associated with FHV-1 usually resolves in 10-21 days.  However, many cats will remain latent carriers of the disease and may spread the virus to other cats.  In rare cases in which very young kittens are infected and develop a pneumonia, the disease may be fatal.

The disease associated with FHV-1 is usually resolved in 10-21 days with supportive care.  Antimicrobial drugs may be administered to reduce the risk of a secondary bacterial infection.  In cases with severe corneal ulceration, anti-viral medicated drops may be prescribed. 

Both inactivated virus and attenuated virus vaccines are available and are used for control, but not prevention of this disease.  The vaccines have short-lived protection and help reduce shedding and clinical disease associated with feline rhinotracheitis (Vaccination Program for Cats).