Feline Herpesvirus I

Information/Facts
Infection
Clinical Signs
Diagnosis
Treatment
Prognosis
Prevention

       herpesvirus (b)        sillyfacecat (i)        herpesvirus (b)
                                                                                                    

Information/Facts
Feline Herpesvirus I (FHV-I) is also known as feline rhinotracheitis virus.  This virus belongs to the viral family Herpesviridae, subfamily Alphaherpesvirinae.  (7)

FHV-I is an enveloped double-stranded DNA virus with surface projections or spikes, dispersed evenly over all the surface.  (7)

FHV-I causes acute respiratory illness called rhinotracheitis, which is part of the feline upper respiratory infection complex (a group of feline viral and bacterial infections).  Cats often have two or more of these upper respiratory infections at the same time, and FHV-1 is one of the most common.  (7)

FHV-I is found worldwide and it is likely that most cats will be exposed to infection at some point during their lifetime.  FHV-I is not a zoonotic disease.  (7) 
                                                                                                                       
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hammackcat (i)


Infection
Cats shed FHV-I through the discharge from infected eyes, nose, and mouth: therefore, transmission is by direct contact with discharge, though several days of close contact are necessary for infection.  Sneezing and coughing can spread the virus as far as 4 feet, though this transmission is not of major importance.  The virus remains infectious in the environment for about 24 hours on items that an infected cat has touched or sneezed on, including cages, food and water bowls, litter trays, pet owner's clothing, and the pet owner's hands.  (3)

All ages and breeds are susceptible, disease may be more severe in young kittens and susceptible cats (those with other illness, not vaccinated or living in high risk situations).  The virus can affect the reproductive tract of cats and cause complications during pregnancy.  (3, 7)

pregnantcat (n)


Acutely infected cats shed the virus for 1-3 weeks, after which time most become lifelong, latently infected carriers.
Even though these cats show no symptoms, they harbor the virus in their nerve cells.   The virus can be reactivated following periods of stress or corticosteroid treatment, and these cats may then transmit infection.  (3, 7)

nervecell (o)
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Clinical Signs
Infected cats may have a fever and may stop eating.  They will have common respiratory symptoms such as coughing, sneezing, and runny eyes and nose.  The cat will likely have rhinitis (inflammation of the nose) and conjunctivitis (inflammation of the membrane lining of the eyelid).  This may progress to ulcerative keratitis (inflammation and ulceration of the cornea, the transparent front portion of the eye that gathers light rays and directs them into the eye). Ulcerations on the cornea can cause a serious threat to eyesight.  Signs of corneal ulcers include discharge, squinting, turning away from light, obvious discomfort, and pawing at the eyes. (7)                                                                                             
                                                                                                     

herpeseye
(p)                        eyeulcer (p)                      nasaldischarge (q)
 
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Diagnosis
A presumptive diagnosis of FHV-I is usually made on the basis of the cat's medical history and clinical symptoms. Virus isolated from nasal or eye secretions can confirm the diagnosis.  Other tests such as immunofluorescence and the polymerase chain reaction (PCR) can also be used.  (3)
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Treatment
There is no cure for FHV-I, but sick animals can be treated with supportive therapy.  This may include intravenous (IV) fluids and/or feeding tubes for anorexic cats.  It is recommended to minimize stress, keep cats indoors while they are sick, make sure the cat is eating and drinking enough (offer foods that appeal to them), keep the cat's eyes and nose clean and clear of discharge, and use a humidifier or put the cat in a bathroom while the hot shower is running (this helps break up the mucus in the upper airway).

Medications may include oral antibiotics to prevent or treat secondary bacterial infections, eye ointments to treat ulcerative keratitis, decongestants (nasal drops) to decrease nasal discharge, or interferon to help control chronic infectious nasal dischared in kittens 3 to 8 weeks old.  (3)
                                                                                                                             
   eyeointment (r)           ngtube (s)        humidifier (t)

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Prognosis
Prognosis of cats infected with FHV-1 is good.  A flare up of symptoms is a fairly mild condition, even in its most severe form, as long as the cat receives adequate fluids and nutrition.  It often runs its course in 7 to 10 days without medical intervention. The infection usually lasts longer when secondary bacterial infections develop. Rarely, FHV-I causes death in young kittens and older cats.  Some cats may develop chronic symptoms such as chronic rhinosinusitis (sneezing and nasal discharge).  (7)
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Prevention
Vaccination is the best prevention method available for cats.  As FHV-I is highly prevalent and easily transmitted, and because disease may occasionally be severe and in some cases may lead to chronic clinical signs, the FHV-I vaccine should be considered as one of the core vaccines given to cats.  (3)

A modified-live vaccine (MLV) and an inactivated vaccine for injectables are commercially available.  A MLV for intranasal use is available and effective in some countries.  The vaccines provide reasonable protection against disease, but do not prevent infection, or the potential of the cat to become a carrier of the virus.

The MLV injectable is most commonly used.  This vaccine is usually combined with the vaccine for Feline Calicivirus.  The following parameters are recommended (3):

Kittens less than 16 weeks of age:
- first vaccination at 6 wks, repeated every 3-4 weeks until 16 wks
- booster 1 year later
- thereafter, no more than once every 3 years


Kittens/cats older than 16 weeks of age:
- 2 doses, 3-4 weeks apart
- booster 1 year later
- thereafter, no more than once every 3 years

In shelters during an outbreak:
- kittens:  at 4 weeks of age, then every 2 weeks to 16 weeks of age
- older kittens/cats: time of admission, repeated in 2 weeks


Pregnant cats:
- use only if necessary (high risk situations) – used the killed-virus vaccine

Cats with FeLV or FIV infections:
- use the killed-virus vaccine                                                                                                             Return to top


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