What is feline parvovirus?
Also known as feline infectious enteritis (FIE) or feline panleukopenia, feline parvovirus (FPV) is a small, hardy virus. FPV was thought to be almost eliminated from the cat population because of vaccination. However, it is still causing problems for some cat rescuers, pet shops and cat breeders.
Can dogs or people catch FPV from infected cats?
No. FPV does not infect dogs or humans, although it can infect other large cats and mink.
Can cats catch canine parvovirus?
Recently it has been shown that occasionally canine parvovirus can infect cats.
How are cats infected with FPV?
FPV is a very tough virus, it survives for up to a year in the environment and requires special disinfectants, like Parvocide, to kill it. Most cats catch FPV from a contaminated environment, rather than from infected cats.
Which cats are vulnerable to FPV?
Kittens are most susceptible, especially when the protective antibodies they receive in their mother's milk have waned, which is usually somewhere between 4-16 weeks of age. Unvaccinated adult cats are also susceptible and allowing a cat to get behind with its booster vaccinations may be risky.
What clinical signs does FPV cause?
FPV affected cats or kittens become acutely ill. They may vomit, bringing up froth or they may just look wet around the lips. Despite the name 'infectious enteritis' the cats may not have diarrhoea. Temperature is variable, it may be raised in the early stages, but often by the time the cat is taken to see a vet it can be subnormal. Affected cats often appear hungry or thirsty, sitting hunched over a water or food bowl but unable to drink or eat. Sometimes they present as a sudden death, indeed cats which "go off to die somewhere" may be suffering from this condition. Cat rescuers and breeders who have a problem with 'fading kittens' should check whether or not they have this virus in their premises (see section on how FPV is diagnosed).
If a pregnant queen is infected with FPV, the brain of her unborn kittens may be affected. The part of the brain which becomes damaged is the part that controls balance, so that from about 2 weeks of age, when kittens first become really mobile, they can be seen to have a wobbly gait. At weaning they have difficulty feeding because their heads bob up and down.
How is FPV diagnosed?
From a living cat or kitten a sample of faeces and a sample of blood should be sent to the Feline Virus Unit at Glasgow Veterinary School where they will be tested for virus and antibodies respectively. From a dead cat or a faded kitten 3 samples of the intestines should be sent preserved in formalin and the contents of the intestines should be sent in a clean receptacle.
If you want to know if FPV is present in your premises but none of your cats are presently sick, test them for antibodies against FPV. The levels of antibodies (ie. their antibody titres) are much higher than they would be from just having been vaccinated, so testing healthy in-contact cats can reveal the presence of FPV in the environment.
How is FPV disease treated?
If sick cats are detected in time, they can be treated symptomatically by good nursing and drip feeding. Many cats do recover if treatment is instigated early enough.
How do you prevent FPV infection?
The main method for FPV control is by vaccination, kittens are normally vaccinated at 9 and 12 weeks of age, although any age of cat can be vaccinated and older cats may respond to a single dose of vaccine. It is usual to give boosters every year with cat 'flu vaccines; 'flu vaccines need to be boosted yearly, but FPV boosters can often be given only every other year.
Are there any side effects of the vaccine?
Two kinds of FPV vaccine are available - "live" vaccines, in which the virus can still grow in the vaccinated cat, so producing a better immune response, without producing disease, and "inactivated" or "killed" vaccines which do not grow in the vaccinated cat, but which can be used safely in pregnant queens. Live FPV vaccines should never be used in pregnant queens because there is a tiny risk that they can produce the brain damage in unborn kittens described above. Other than that, both types of vaccine have been widely used for many years without side effects.
What should a cat rescue worker do after FPV diagnosis?
The problem will be that their cat accommodation will be full of virus and very infectious for around a year following FPV diagnosis. There are two possible options: first: only foster cats which have already been fully vaccinated against FPV, and so are immune. Secondly, if kittens must be fostered, greatly reduce contamination of the environment by disinfection with a veterinary disinfectant such as Parvocide. Since parvovirus is excreted in the faeces, the litter trays should be particularly disinfected. Remember that disinfectants will only work when thorough cleaning has already been done. Reduce the number of kittens which are fostered and do not allow them into the room(s) which the diseased cat or kitten occupied.
Should a cat breeder stop breeding after FPV diagnosis?
The cat breeder has a number of options open after FPV diagnosis: first, no susceptible animals should be introduced to the contaminated environment for at least a year, so that all newcomers should have had a full vaccination course before entering the premises. Secondly, kittens will receive antibodies from their mother's milk which will protect them for a few weeks (the exact time will depend on how well the kittens suckled and how high the mother's antibody titre was when she gave birth: the higher the titre, the longer the kittens will be protected). Therefore, an option for cat breeders is to sell their kittens at 5-6 weeks of age, before they lose these antibodies, known as maternal antibodies, and become susceptible to infection. This option of course depends on all of the kittens suckling adequately to obtain the antibodies. Vaccinating kittens from an earlier age, say 6 weeks, usually doesn't work because the maternal antibodies may interfere with the vaccine, so that the kitten is not protected. If the breeder wants to keep a good kitten, perhaps it could be fostered at a friend's house from 5 weeks of age, vaccinated when old enough and brought back.
Third, the best thing a breeder can do to eliminate FPV is to considerably cut down the number of litters he or she has during the year following FPV diagnosis. Every new kitten which gets infected, even if it doesn't get ill, adds to the virus dose in the environment: reducing the number or even stopping having kittens for a year would allow the virus to die out completely from your premises.
Some breeders have special premises built for rearing their kittens, they may think that by thorough cleaning and disinfecting these with a very powerful disinfectant like Parvocide they will be able to safely rear kittens. However, they must remember that the virus will be present everywhere on their premises and can be transmitted from one place to another on their shoes and clothing.
Is there any point in revaccinating the adult cats after a parvovirus outbreak?
Probably not. Most will already have protective high antibody titres.