Synthesis and Cytopathogenesis of African Swine Fever Virus in Porcine Cell Cultures

Abstract

Porcine buffy coat (Be) cells infected with African swine fever (ASF) virus had chromosomal, nucleolar, and cytoplasmic degeneration and developed intracytoplasmic inclusion bodies beginning 12 hours after infection. Cytolysis began 20 hours after infection and was widespread 40 hours after infection. The inclusions stained specifically for deoxyribonucleic acid (DNA) with the Feulgen and acridine orange techniques, resisted deoxyribonuclease digestion, localized fluorescent antibody, and incorporated 3H-Iabeled thymidine. Similar cytologic and cytochemical changes were observed in porcine kidney (PK) 2a cells infected with cell culture-attenuated strains of the virus, but the time sequence of changes was extended. Viral synthesis in Be cells was partially inhibited with 5-iododeoxyuridine (IUDR), 5-fluorodeoxyuridine (FUDR), 5- bromodeoxyuridine (BUDR), and hydroxyurea. Thlaed dition of BUDR to Be cultures at intervals between 2 and 20 hours and ation after 24 hours of infection indicated that viral DNA was synthesize tween 6 and 7 hours, and infectious virus, between 10 and 11 hours.