Vaccination against Feline Panleukopenia: implications from a field study in kittens

64 kittens from 16 litters were vaccinated against FPL at the age of 8, 12 and 16？weeks using three commercial polyvalent vaccines. Blood samples were taken before each vaccination and at the age of 20？weeks. Sera were tested for antibodies against Feline Panleukopenia Virus (FPV) by hemagglutination inhibition test and serum neutralisation assay in two independent diagnostic laboratories.There was a good correlation between the results obtained in different laboratories and with different methods. Despite triple vaccination 36.7% of the kittens did not seroconvert. Even very low titres of MDA apparently inhibited the development of active immunity. The majority of kittens displayed significant titres of MDA at 8 and 12？weeks of age; in some animals MDA were still detected at 20？weeks of age. Interestingly, the vaccines tested differed significantly in their ability to overcome low levels of maternal immunity.In the given situation it is recommended to quantify antibodies against FPV in the serum of the queen or kittens before primary vaccination of kittens. The beginning of primary vaccination should be delayed until MDA titres have declined. Unprotected kittens that have been identified serologically should be revaccinated.Feline Panleukopenia (FPL) is a contagious, serious disease of cats. The causative agent, Feline Panleukopenia Virus (FPV), belongs to the genus Parvovirus of the virus family Parvoviridae [1]. FPV is highly stable in the environment and endemic in many cat populations [2]. In a retrospective study FPL was identified as cause of death in 25% of kittens sent in for pathological examination [3]. The virus predominantly replicates in rapidly dividing cells. In newborn kittens, high mortality (>90%) with peracute deaths and neurological disorders like ataxia and blindness are the main clinical signs. Older kittens develop panleukopenia, neutropenia and diarrhoea due to infection of bone marrow, lymphatic tissue and intestinal epithelial cells. Clini