Immunological investigation of rabies virus and oral vaccination effectiveness in raccoon dog population in Lithuania.
The study was conducted to determine the prevalence of Rabies virus in raccoon dogs (Nyctereutes procyonoides) from Luthuania between 2003 and 2008. Direct immunofluorescence rabies antigens were detected in 66.3% of 3291 raccoon dog brain samples tested. The highest number of infected animals was observed in 2006 at 89.40%. However, the number of cases significantly decreased in 2007 (37.77%) and 2008 (6.81%). This could be due to the oral vaccination (Lysvulpen live vaccine) performed in wild animals from Lithuania between 2006 and 2008. The efficacy of oral rabies vaccination in raccoon dogs was tested using indirect enzyme-linked immunoassay (ELISA) Platelia Rabies II produced by Bio-Rad (France). A total of 510 blood samples from raccoon dogs were examined and it was noted that 237 (46.47%) were positive between 2006 and 2008. There were 83 blood samples of raccoon dogs from ≤1-year-old and 24 or 28.91% animals had antibodies against rabies. It was observed that only 46.47% samples of hunted raccoon dogs had antibody titres of ≥0.5 IU/ml blood after oral vaccination. It is suggested that oral vaccination programme against rabies virus is effective in preventing and controlling the spread of Rabies virus in raccoon dogs.