First isolation and characterization of caprine parainfluenza virus type 3 from cattle in China

Caprine parainfluenza virus type 3 (CPIV3) is an enveloped single-stranded negative-sense RNA virus, commonly found in respiratory tract infections of goats and sheep. However, there have been no reports of CPIV3 infection in cattle. In this study, a strain of CPIV3 named HB2304S3 was isolated from a cattle with respiratory symptoms using Madin-Darby bovine kidney cells. The strain was verified by PCR and high-throughput sequencing, and the complete genomic sequence was obtained. After purification of the virus, hemagglutination tests and physicochemical property tests were conducted on this CPIV3 strain. The hemagglutination titer of the isolate was 1:40, and it was sensitive to ether, trypsin, temperature, and pH. To further investigate CPIV3 epidemiology in Chinese cattle populations, we conducted molecular surveillance across multiple provinces. The results revealed that 52 samples were positive for CPIV3, with a total positive rate of 34.21 % (52/152). Moreover, CPIV3 was detected in 12 cattle farms, with a farm positive rate of 70.59 % (12/17). These findings provide the first conclusive evidence of CPIV3 cross-species transmission to cattle and reveal its significant prevalence within cattle populations in China.