SCIENTIFIC ASSESSMENT ON DETERMINATION OF THE MOST APPROPRIATE PERIOD FOR PERFORMANCE OF TOTAL VACCINATION OF RUMINANTS AGAINST BLUETONGUE DISEASE ON THE TERRITORY OF THE REPUBLIC OF BULGARIA IN 2021

Abstract

Bluetongue (BT) is an acute, viral, vector-borne, non-contagious disease of ruminants caused by the Bluetongue virus (BTV). It is transmitted by insects of the genus Culicoides. It is characterized by some strong seasonal dynamics in the countries of temperate latitudes mid-latitude climates, associated with the period of active flight of vectors. With this study we set a goal to make a scientific assessment of the appropriate period for general vaccination against bluetongue in ruminants in the territory of the Republic of Bulgaria in 2021. Taking into account the life cycle of the vectors, the temperatures at which they begin to become active and the time to build active immunity in cattle and sheep, we recommend that vaccination in 2021 may begin in the first half of February 2021 at the earliest. It is more likely for Southern Bulgaria to start in the first half of March, and for Northern Bulgaria – in the second half of March 2021.