Bluetongue virus serotype 20 infection in pregnant Merino sheep.
Eleven maiden Merino ewes, free of antibody to bluetongue virus serotype 20 (BTV-20) in agar gel immunodiffusion and serum neutralisation tests, were mated once with a ram. Ten ewes were inoculated with BTV-20 35 to 42 days after service, and one ewe was left as an uninoculated control. One of the inoculated ewes and the control ewe remained uninfected throughout the experiment. Eight of the remaining 9 ewes showed clinical signs ranging from mild to moderate, and the other showed no clinical signs of infection. BTV-20 viraemia was detected in ewes between days 3 and 11 post inoculation, and the serum antibody response was followed. The control ewe and 5 of the 9 infected ewes were pregnant when examined 90 to 97 days after service. Each of these animals produced a normal lamb. There was no evidence of abortion in the remaining 5 ewes, and no transplacental transfer of virus was detected in the lambs of the 5 infected ewes. At necropsy, 46 days after the birth of the last lamb, no gross or microscopic lesions were observed in either the ewes or lambs.
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D001819:Bluetongue / Q000276:immunology* / Q000382:microbiology; D001820:Bluetongue virus / Q000145:classification / Q000276:immunology*; D003168:Complement Fixation Tests / Q000662:veterinary; D005260:Female; D005779:Immunodiffusion / Q000662:veterinary; D009500:Neutralization Tests; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology / Q000662:veterinary*; D012087:Reoviridae / Q000276:immunology*; D012703:Serotyping; D012756:Sheep
D000914:Antibodies, Viral