Single immunization with the attenuated strain “Volgograd/14c” of the ASF virus does not protect piglets from infection with the homologous strain “Stavropol 01/08”

After the introduction of the ASF virus to Georgia in 2007, the disease spread to many countries in Europe and Asia. In present time, ASF has been registered in 42 countries of the Eurasian continent. Strict anti-epizootic measures are used to eradicate the disease, including stamping out policies, bans on import and export of all types of animals, trade bans, etc. In order to prevent the disease, different vaccine candidates have been developed, such as inactivated, live attenuated, subunit, vector and DNA vaccines. Unfortunately, in many cases, trials of these vaccine candidates have been unsuccessful. The aim of the work was to study the immunobiological and protective properties of the attenuated ASF virus strain “Volgograd/14c” against infection with the homologous virulent strain “Stavropol 01/08” in vivo. A single intramuscular inoculation of the attenuated strain “Volgograd/14s” at a dose of 10 3,0 HAU 50 см 3 to six pigs caused 1–4 day hyperthermia (40.0-40.8 o C) without the development of other clinical signs. Viremia in the blood of inoculated pigs was detected from day 3–7 in titers of 2.0-3.0 lg HAU 50 см 3 , with a maximum accumulation of 3.75 lg HAU 50 см 3 on day 10, a decrease on days 14–21 to 1.75–2.75 lg HAU 50 см 3 and loss of infectivity by day 28. Virus-specific antibodies to the ASF virus were detected in the serum of vaccinated animals from day 10. Challenge with the homologous virulent strain “Stavropol 01/08” caused the development of clinical signs and the growth of viremia in the blood to 6.0–7.5 lg HAU 50 см 3 in all pigs of the experimental and control groups. The course of the disease was hyperacute, acute, subacute and chronic with the death of all control animals and 5 of 6 experimental pigs with clinical signs and pathological changes characteristic to ASF.