Virus isolation and vaccination of mediterranean tortoises against a chelonid herpesvirus in a chronically infected population in Italy

A chelonid herpesvirus was isolated from a group of tortoises in Italy with a history of increased mortality and upper digestive and respiratory tract disease. The isolated virus was inactivated with formalin and used to prep are a nonadjuvanted vaccine and a vaccine adjuvanted with aluminum hydroxid e. 57 tortoises, 26 Testudo hermanni, 25 T. graeca, and 6 T. marginata, wer e included in the study. The animals were vaccinated 3 times at 45 day inte rvals. Blood was collected from the animals 14 days prior to the first vacc ination, and on day 0, 25, 45, 90, 113 and 369 after the first vaccination. Plasma antibody titers to the homologous chelonid herpesvirus were determi ned using a virus neutralization test (VNT). No significant rise in antibod y titer was noted in the vaccinated animals. Antibody titers measured dropp ed below the cutoff-level sporadically in all positive animals. Repeat sero logical testing may therefore be necessary in order to detect seropositive animals.