A 6-year-old child had acute onset of the disease that started as catarrhal nasopharyngitis. 2 days later the patient died. Autopsy of the body shows markedly plethoric and swollen pia mater that is soaked with thick turbid yellow-green fluid. The brain is swollen, the cerebellar tonsils are enlarged, and there is a clearly visible ligature mark on the brain. The described changes are characteristic of: