Dear Dr. John,

I have owned many cats over the years, including fostering a few. Adoption includes testing for things such as FeLV and FIV. Another virus is something called FIP. It has almost always signaled a death sentence, as far as I am aware. Apparently, there is now a new treatment and I wonder if you have any information. T.H.

Dear T.H.,

All three of the viruses that you mention can be devastating and fatal to cats. Feline Leukemia (FeLV) has a vaccine available to prevent it whereas Feline Immunodeficiency Virus (FIV) and Feline Infectious Peritonitis (FIP) do not. Once contracted, all of them can take varying amounts of time before cats succumb to active infection, illness, and/or death. Supportive care can sustain cats with any of these however, once clinical signs of illness set in, prognosis has typically been bad.

FIP is an enteric coronavirus that manifests in a dry form and a wet form with most being of the wet form. In these cases, large amounts of fluid develop in the abdomen cavity but the thorax or pericardium can also be affected. Typically seen in younger cats, stress can also be a contributing factor especially in multi-cat households. Until more recently, supportive care with the use of corticosteroids was practiced.

The drug you ask about is an antiviral known as Remdesivir (marketed as Veklury), given by injection only. It is currently used in people for treatment of Covid-19. The oral option active form for cats is known as GS-441524 and protocols call for 12 weeks of treatment costing a few thousand dollars. This therapeutic regime is readily available in Europe but is seeing more use in the US since the FDA is not keen on prosecuting for use of this drug due to the promise it holds while not yet approved. There is a legal means for veterinarians to use it, the challenge is getting access. Improvement of sick cats is seen in a few days and with a greater than 80% success rate.

Dr. John de Jong is President of the World Veterinary Association. He owns and operates the Boston Mobile Veterinary Clinic and can be reached at 781-899-9994.