At present, only one (intranasal) FIP vaccine is available, which is considered as being non-core. Kittens may profit from vaccination when they have not been exposed to FCoV (eg, in an early-weaning programme), particularly if they enter a FCoV-endemic environment.

At present, there is no FIV vaccine commercially available in Europe. Potential benefits and risks of vaccinating FIV-infected cats should be assessed on an individual cat basis. Needles and surgical instruments used on FIV-positive cats may transmit the virus to other cats, so strict hygiene is essential.

All cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8-9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3-4 years of age, a booster every 2-3 years suffices, in view of the significantly lower susceptibility of older cats.

To examine the mode of natural transmission and persistence of feline coronavirus (FCoV), FCoV strains shed by domestic cats were investigated over periods of up to 7 years. An RT-PCR that amplified part of the 39 end of the viral spike (S) gene was devised to distinguish FCoV types I and II. All but 1 of 28 strains of FCoV from 43 cats were type I. Nucleotide identities of the amplified 320 bp product from 49 type I FCoVs ranged from 79 to 100 %. The consensus partial S sequence of isolates recovered from persistently infected cats at time intervals spanning years was generally conserved. While most cats were infected with a single strain, a few may have been infected by more than one strain. Cats that were transiently infected and ceased shedding could be re-infected with either the same, or a different, strain. In most cases, whether a cat became persistently or transiently infected was independent of the virus strain. However, one strain was unusual in that it infected the majority of cats in the household simultaneously and was still being shed 18 months later. Factors that influence whether FCoV establishes lifelong infection in some cats and not others are determined mainly by the host response to infection.

Feline coronavirus is a common infection in cats, as indicated by the high prevalence of antibodies against the virus, especially in multicat households. Approximately 5 to 12 per cent of seropositive cats develop classical feline infectious peritonitis. A survey of kittens born into households of seropositive cats demonstrated the existence of healthy coronavirus carriers. Seronegative animals did not appear to excrete virus. No specific antibody titre could be linked to carrier status and some carrier cats subsequently became seronegative. The management of the kittens strongly influenced whether they became infected, and some degree of protection appeared to be conferred by maternally derived antibody. At present, feline infectious peritonitis virus and feline enteric coronavirus can only be differentiated by their different clinical histories in infected catteries. In this survey, cases of feline infectious peritonitis occurred in kittens from households where the initial presentation had been enteritis and vice versa. Therefore no difference in epidemiology could be found.

Two injections, at 9 and 12 weeks of age, are recommended, followed by a first booster 1 year later. In high-risk situations, a third vaccination at 16 weeks is recommended. Boosters should be given every 3 years. However, cats in high-risk situations should be revaccinated annually. Cats that have recovered from caliciviral disease are probably not protected for life, particularly if infected with different strains. Vaccination of these cats is still recommended.

The pattern of shedding of feline coronavirus (FCoV) was established in 155 naturally infected pet cats from 29 households over periods of up to five years. Viral RNA was detected in faeces by reverse-transcriptase PCR (RT-PCR), and plasma antiviral antibodies by immunofluorescence. The cats rarely shed FCoV in their saliva. Three patterns of FCoV shedding were observed. Eighteen of the cats shed virus continuously, so were persistent, and possibly lifelong, carriers; none of them developed feline infectious peritonitis. Fifty-six cats ceased shedding virus, although they were susceptible to reinfection, and 44 shed intermittently or were being continuously reinfected. Four of the cats were resistant to infection. Seventy-three per cent of the virus shedding episodes lasted up to three months and 95 per cent up to nine months. There was a correlation between shedding and antibody titre but the cats could remain seropositive for some time after they had ceased shedding virus. One-off testing for FCoV by RT-PCR is inappropriate. Identification of longterm carriers requires that a positive result be obtained by RT-PCR on faecal samples for at least eight consecutive months. A cat should be shown to be negative over five months, or to have become seronegative, to ensure that it has ceased shedding virus.

Canine parvovirus (CPV), which causes hemorrhagic enteritis in dogs, has 3 antigenic variants: types 2a, 2b, and 2c. Molecular method assessment of the distribution of the CPV variants in Europe showed that the new variant CPV-2c is widespread in Europe and that the viruses are distributed in different countries.