Pet Connection: Even for indoor cats, leukemia vaccinations are prudent

Is your kitten vaccinated for feline leukemia virus?

You may not have thought to do so if you plan for him to be an indoor cat, but veterinary immunology expert Ronald Schultz, DVM, says that vaccination during kittenhood, followed by a single booster vaccination at 1 year of age, is the best way to prevent the spread of the disease and reduce its incidence.

Feline leukemia virus is the most common cause of cancer in cats and can cause various blood disorders. Some cats with the disease have poor immune systems and are unable to fight off infections. Signs of the disease include appetite loss, weight loss, poor coat condition, pale gums and persistent diarrhea. In the United States, 2 to 3 percent of cats have the virus.

That’s a low percentage, but it’s still a serious disease that is highly communicable. Infected cats shed the virus through bodily fluids such as saliva, milk, urine and feces. They can spread it when they groom other cats, share food and water bowls, or use the same litter box.

Nursing mothers can pass it on through their milk. Kittens younger than 4 months and sick cats have the highest risk of infection and a higher rate of infection – 13 percent or more. Cats who are vaccinated as kittens and boosted at 1 year will most likely have lifelong protection from the disease. Age-related resistance to the disease typically develops when cats are about a year old.

“If we could have as many cats immune as possible, we probably would start to see very little FeLV,” Schultz says. “Now some people say ‘Well, it’s not that common anyway,’ but it still creates some significant disease.”

Many cat owners whose pets don’t go outside skip this vaccine. But cats can be escape artists or experience changes in lifestyle.

“I know an awful lot of indoor kittens that became outdoor cats,” Schultz says. “Can we ever know when that animal is a kitten that it’s never going to go outside and never be in contact with a potentially persistently viremic cat?”

Other concerns include potential reactions to the vaccine, which can include swelling or pain at the injection site, lethargy or fever. Some cats develop granulomas (inflammatory nodules) or sarcomas (soft tissue tumors) at the injection site. The University of California at Davis’ School of Veterinary Medicine suggests using a recombinant FeLV vaccine, citing evidence that this type of vaccine is associated with a decreased risk of sarcoma formation.

The advisory panel of the American Association of Feline Practitioners seconds Schultz’s advice to vaccinate kittens and boost the vaccination when they are a year old, but it does not consider FeLV a core vaccine, meaning one that is recommended for all cats.

Adult cats should be vaccinated for FeLV only if they are at risk, according to the AAFP.

Cats are at risk if they go outdoors, live with other cats who are known to be infected with FeLV, or live with other cats whose disease status is unknown.

If you discover that one of your cats has FeLV, have any other cats in your home tested for the disease. If they are infection-free, it’s best to have them live separately from the infected cat so they don’t share food and water bowls or litter boxes.

Ask your veterinarian about the pros and cons of having the uninfected cats vaccinated, since vaccination doesn’t help cats who are already infected.