- Highly infectious
- In unvaccinated populations will be enzootic.
- Primarily a disease of young kittens as they lose maternal antibody.
- Morbidity generally 100%, but in many cases only mild or subclinical disease occurs.
- Seasonal incidence with summer and autumn peaks noted in some areas because of seasonal birth rate.
The virus is perpetuated in the cat population in three main ways ( See Picture )
- By contact spread from acutely infected to susceptible animals; this depends on sufficient numbers of susceptible animals in the population and sufficient opportunities for contact between them.
- By persisting in the recovered cat, i.e. immune carriers.
- By persisting in the environment.
Of these, (1) and (3) are by far the most important.