Salat et al.
Experimental and natural infections of tick-borne encephalitis virus in dogs
Viruses. 2021;13(10):2039. doi: 10.3390/v13102039
In TBE endemic areas, dogs are frequently infected with the TBE virus, but only a few dogs get TBE.
A Czech group carried out a study by experimentally infecting subcutaneously six three-month-old beagle dogs with i) a high dose (108 pfu), ii) a low dose (106 pfu) of TBE virus strain 9001 and iii) culture medium as control. Clinical observations were evaluated daily for four weeks.
None of the dogs showed either clinical signs of disease or increase in rectal temperature. Virus titers in the serum were low in one dog infected with a high dose and in one dog infected with the low dose. No significant changes were measured in most hematological and biochemical parameters. No significant pathological changes were found after necropsy on day 28 p.i.
Infected dogs developed a robust antibody response and on day 21 p.i., all infected dogs had TBE IgG antibodies and neutralizing antibodies.
In a seroprevalence study, with a total of 453 sera from dogs across the Czech Republic, the rate of positive sera in healthy dogs or in dogs with health problems was in the same range (12% and 13% in NT test). A significant correlation between the age of the dogs and NT positivity was observed.
It remains unknown why most infected dogs develop no disease, but why sporadic cases can be severe or even lethal. As in human TBE cases, there is no specific treatment with an antiviral drug available for dogs.