Y. S. LU1 , Y. MIURA2 , G. Y. SHU 3 , G. Y. WANG', Y. L. LEE1 , T. F. LIN', P. C. LIN4
Respiratory signs and blood-tinged diarrhea were observed in cow of two dairy farms at Chia-Li, Tainan county in February, 1982. Sixteen out of 44 cows, 36.4%, in K farm. and 100% in S farm showed clinical signs of depression, anorexia, fever (39-41.2° C), severe diarrhea, reduced milk production, watery or purulent nasal discharge, coughing, and salivation. The course prolonged for about four days.
No virus was isolated from samples cultured on bovine embryo kidney or bovine testis cell cultures. Sera samples were subjected to serological tests against six kinds of viruses. The level of hemagglutination-inhibition antibodies against bovine Coronavirus increased significantly in three weeks, i.e., geometric mean of HI antibody of I :26 (IO 160) at zero week, I :250 (80-1,280) at a week post-infection, I :357 (80-1,280) at 2 weeks PI and I :230 (10-1,280) at 3 weeks PI. It was concluded that the infection was caused by bovine Coronavirus.
The sera samples were also positive against Rota virus (I 00% in HI test), PI-3 virus (100% in neutralization test), Adeno-7 type virus (5%), and BYD virus (10%), while were negative against IBR virus.
During the outbreak of the diesase, the daily temperature change in the dairly farm area was 9.5-l l .3° C. It seems that the big variation of temperature in a day was related to the outbreak of the disease, bovine Coronavirus infection.