Third Eyelid Syndrome and Torovirus ~ Pawprints and Purrs, Inc.

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Third Eyelid Syndrome and Torovirus

Third eyelid syndrome has long been recognized in cats, but until recently, nothing was known about the cause.

What are the symptoms?

The symptoms of this disease are generally mild. Guardians often panic that their cats are suffering from Feline Influenza (Feline Viral Rhinotracheitis - FVR), but this is not the case - it's more like an upper respiratory infection than the flu.

Protruding nicitating membranes (haws, third eyelids): These usually only protrude part of the way across the eyes, rather than covering the eyeball completely. The eyes may seem watery, perhaps with a little clear discharge (like tears).
Diarrhea: This is not always obvious in a cat unless he always uses a litter box (i.e. never go outside unaccompanied), has fecal soiling of the fur around the anus or has an accident in the house. It may persist for days, weeks or months.
Sneezing: This is not a universal symptom, and often manifests as single, rather than repeated, sneezes.
Other General Signs. These include vomiting, drowsiness, slight fever, irritability, anorexia (loss of appetitie), and the cat not feeling quite himself.

What is the causative agent?

The cause of this condition is a virus. The Torovirus is a member of the same family of viruses as the Coronaviruses. A Coronavirus is the cause of Feline Infectious Peritonitis (FIP), but the Torovirus is much milder. The condition is usually mild and self limiting.

Can Torovirus cause disease in other mammals?

Toroviruses cause diseases in man and many animals, including cows and cats. It is disputed whether the diarrhea in the feline infection is caused by secondary bacterial infection or the virus. More than likely, it is caused by the virus, simply because Toroviruses causes gastrointestinal symptoms in other animals.

As with any viral illness, there is a possibility of secondary bacterial infection - this may manifest itself as rhinitis, conjunctivitis, pneumonia or gastroenteritis most commonly, although as the cat will be run down, any infection is more likely to develop.

What is the treatment of Torovirus?

Treatment of Torovirus infection is generally supportive - that is, keeping the cat comfortable by providing plenty of fresh water to drink (prevent dehydration from the diarrhea and fever), a bland diet (eg: chicken or white fish, rice, or a prescription diet) to rest the gut following a 24 hour fast if diarrhea is severe and there is any discharge from the eyes. Some veterinarians will prescribe antibiotics to prevent or treat a secondary bacterial infection. If diarrhea is persistant, then corticosteroid tablets may be used to dampen the gut inflammation.

However, like the common cold in their guardians, Torovirus infection is usually mild and self limiting, lasting 5 to 10 days.

Page URL: http://www.sniksnak.com/cathealth/torovirus.html

Resource References:
The information on this page is provided by Andy Dann and his cats Frazzle, Oscar, and Dana.
Oscar suffered with Torovirus in 1998; Mr. Dann spent countless hours researching this information to gain knowledge and better understand the condition.

A New Family of Vertebrate Viruses: Toroviridae
Horzinek MC, Flewett TH, Saif LJ, Spaan WJ, Weiss M, Woode GN
Intervirology 1987 27:1 17-24

Toroviridae: A Proposed New Family of Enveloped RNA Viruses
Horzinek MC, Weiss M, Ederveen J
Ciba Found Symp 1987 128: 162-74

A New Group of Gastrointestinal Viruses ("Toroviridae")
Weiss M
Schweiz Arch Tierheilkd 1987 Mar 129:3 139-56

The Proposed Family Toroviridae: Agents of Enteric Infections
Weiss M, Horzinek MC
Arch Virol 1987 92:1-2 1-15

A Clinical and Microbiological Study of Cats with Protruding Nictitating Membranes and Diarrhea: Isolation of a Aovel Virus
Muir P, Harbour DA, Gruffydd-Jones TJ, Howard PE, Hopper CD, Gruffydd-Jones EA, Broadhead HM, Clarke CM, Jones ME
Vet Rec 1990 Sep 29 127:13 324-30