Simkute et al.
The prevalence, seroprevalence, and risk factors of tick-borne encephalitis virus in dogs in Lithuania, a highly endemic state
Viruses. 202315(11):2265. doi:10.3390/v15112265
Studies about TBE in dogs are rare, and it is often suggested that TBE virus infections are mostly asymptomatic. However, clinical symptoms can be similar to those in humans, but it is assumed that TBE is underdiagnosed in dogs.
In Lithuania, a country which is highly endemic for TBE, a study has been carried out in two veterinary clinics in Kaunas to assess the prevalence of TBE virus-specific RNA and antibodies in dogs and to evaluate risk factors for severe disease and mortality. Randomly collected blood samples from 473 dogs with various diseases were obtained and analyzed for TBE and detection of Anaplasma phagocytophilum and Babesia spp.
TBE viral RNA could be detected in 88/473 (18.6%) serum/blood samples of dogs, and TBE ELISA antibodies were found in 102/473 (21.6%) of the samples, of which 86.3% were tested positive in a neutralization assay. TBE antibodies were found in 26.1% of PCR-positive dogs. The rate of death/euthanasia in TBE virus PCR-positive dogs was 18.2%.
Lethal outcome was associated with older age and dogs with neurological symptoms had a higher risk for worse outcome. Dogs with other tick-borne infections like A. phagocytophilum or Babesia had significantly higher levels of TBE antibodies. TBE-related neurological symptoms were noticed in 31.8% of PCR-positive dogs. TBE virus could be isolated from serum and CSF.
In 34.2% of ticks collected from dogs, TBE virus-specific RNA could be detected (in Ixodes ricinus and Dermacentor reticulatus).
The authors concluded that TBE is a clinically important disease in TBE endemic countries like Lithuania. However, TBE in dogs is underdiagnosed due to a lack of awareness.