Distemper is one of the worst, and most common of the diseases that cats can get. It is caused by a parvo virus and is similar to that found in dogs.
Years ago, the disease was commonly referred to as distemper in dogs, too, but has more recently been differentiated from the cats' affliction by calling it simply, parvo. Technically, it could be called parvo in cats, too. However, the medical term used today is feline panleukopenia. Through the years, it's also been known as Feline Parvovirus (FPV), Feline Infectious enteritis, Feline distemper, Feline agranulocytosis, and Feline ataxia.
This is an extremely deadly and contagious (to cats) disease, and the virus itself is incredibly durable. It can live in a contaminated environment for years. In other words, if any animals have had distemper (parvovirus) in your home, or the barn, it would be very unwise to introduce a new cat into the area, unless they have been vaccinated well prior to their arrival. While that is no guarantee, it might mean they would get a less virulent form of the disease.
The disease has a high mortality rate - up to 60 percent of adults, and up to 90 percent of kittens. The incubation period is 3 to 7 days and then the victim begins with a fever, loss of appetite, weakness and depression. Diarrhea and vomiting are common. And while they remain thirsty, they usually suffer dehydration. Once infected, they seldom live longer than 5 or 6 days. If they survive, they usually have some brain damage (cerebellar hypoplasia) which results in a lack of coordination, called cerebellar ataxia.
The only good thing that ever comes of this is that survivors are solidly immune for life and never need to be vaccinated. However, if a survivor is vaccinated, their naturally acquired immunity protects them from any potential side effects of the vaccine. And make no mistake, some cats experience severe vaccine reactions and die from that - in effect, they were given distemper and were not able to recover. For this reason, it is best to wait until kittens are old enough, strong enough, and healthy enough to tolerate vaccination. Check with your vet on that. It's usually around 9 weeks, but it isn't always best to follow a schedule from a book, but rather, to observe the kitten to be sure it can handle the viral invasion, whether it's a killed or modified live virus. Remember, just like humans, they're all different.
Basically, never vaccinate a kitten that is still nursing, no matter what age it is. The kitten is receiving passive immunity from the mother and the vaccine is wasted, as the kitten will not develop its own immunity as desired.
Also be sure to have any vaccinations completed at least 2 weeks prior to any potential exposure (no matter how remote the possibility), such as what could occur if going to a farm, to a new home, a cat show, or anywhere that groups of unacquainted, unrelated cats may be present.
(Information taken from the Merck Veterinary Manual)
Copyright © 2009 - Dr. RJ Peters