Comparison of some biological characteristics of PRRS virus strain (KTY-PRRS-04) isolated in Viet Nam through passage culture

Abstract

The PRRSV strain in this study is KTY-PRRS-04. It was isolated from the “blue ear” disease pigs (PRRS) in Bac Giang province, Viet Nam. MARC-145 cell was used to culture and isolate KTY-PRRS-04 virus, this virus strain developed quickly in this cell and caused the typical symptom that was the cells gathered together and sloughed out of the culture jar bottom. CPE appeared early after 24 hours of infection. After 72 hours, all of the culture cells were sloughed out of the jar bottom. The numbers of virus from the 1st to the 10th passage were 105 (TCID50/25μl) and from the 20th to 40th passage were 106. The numbers of free virus in the media were higher than the numbers of virus in the cells. The number of virus (presented in value of log10TCID50/25μl) in the cells or in the media, in the 1st passage were smaller than in the 10th and 20th passages (2.66; 3.04 in comparison with 2.87; 3.66) and the number of virus in the 30th and 40th passage were the highest (3.61 and 3.71).