Isolation And Identification Of BHV-1 And Investigation Of IBRV Infection Among Shanghai Dairy Herds

Infectious bovine rhinotracheitis (IBR), caused by infectious bovine rhinotracheitis virus (IBRV) or bovine herpesvirus 1 (BoHV-1, BHV1 or BHV-1), Former is used in studies of the virus; and IBR is used in studies of the disease. Bovine herpesvirus 1 used to describe BHV-1 include’infectious bovine rhinotracheitis (IBR)-like’and’infectious pustular vulvovaginitis (IPV)-like’in the herds with cows. The IBR disease is characterised by clinical signs of the conjunctivits, abortion and brain fever. The IPV disease is characterised by clinical signs of miscarriage and stillbirth and so on. IBR is one of the major infectious diseases hindered seriously the healthy development of the feedlot cattle industry in our country. It had been a worldwide distribution and was classified as Class B animal disease by OIE. BHV-1 is maintained within the host animal by latent infection. It is very difficult to treat the disease which is caused by BHV-1. The disease would cause heavy economic losses among dairy herds.The study was about the prevalence of IBRV infection in Shanghai. ELISA kits were used for antibody detection detected in serum, which were made in SVANOVA company. The serum samples were from Holstein cattle in Shanghai. To collect the cows’tail venous blood into the anticoagulant blood sample tubes in 16 dairy herds. Cause the statistical methods and approaches of the cattle’datas were difference with each other herds, we chose 9 herds’cattle datas with better integrity. To make a summary of the 9 herds’cattle the second time ELISA result. To contrast the differences among the herds including months age, calving times, unnormal calving. There were 24,962 serum samples from 16 herds’cattle. There were 18,613 serum samples detected in the second time tests about the 9 herds’cattle. The results demonstrated 41.86% positive rate of antibodies detection to IBR (7,791 out of 18,613) from the 9 herds’cattle.We got the veterinarian’s record of the cattle from the NO.4 dairy herd. There was no sign showed the classical clinical sign of the cattle is IBR’s. To collect the cattle’s blood sample with the antibodies positive in the NO.4 farm. Preheral blood lymphocytes (PBL’s) were isolated by general method from the blood samples. PBL’s was co-cultured with Madin darby bovine kidney (MDBK) cells under stimulation with Concanavalin A (Con A). The cell cultures were observed daily for cytopathic effect (CPE). It is characterised by grapelike clusters of rounded cells gathered around a hole in the monolayer, sometimes giant cells with several nuclei may be observed, which is as the same as the BHV-1 infected the cell with CPE. Further study and identification by PCR, and this fragment was confirmed to be the expected portion of BHV-1 tk gene by DNA sequencing. The tk gene of BHV-1/SH7 shared 99% nucleotides identities to others. The isolated virus strain was identified as a BHV-1 strain, and was named as BHV-1/SH7 strain.It should be useful to get the whole picture of the prevalence of IBRV infection in Shanghai, which was the large number of the samples and variety multifarious the cows data. It would provide a theoretical tool for the epidemic comprehensive control of the infection and spreading of the virus, which was the investigation of IBRV infection among Shanghai dairy herds. It could provide a new endemic strain for our self-developed efficient diagnostic kits and vaccines, which was the result of isolation and identification of the BHV-1/SH7 strain. It had a great signficance to diagnose and prevent of IBR in Shanghai.