Mittal Mitesh, Sharma Vikas, Nehra Kapil, Chakravarti Soumendu, Kundu Krishnendu, Bansal V K, Churamani C P, Kumar Anil
Central Military Veterinary Laboratory (CMVL), Sardhana Road, Meerut Cantt, Meerut, Uttar Pradesh, India.
Defence Institute of Bio-Energy Research (DIBER), Project Site Secunderabad, Military Farm Road, Old Bowenpally, Secunderabad, Telangana State, India.
One Health. 2017 Nov 6;5:1-5. doi: 10.1016/j.onehlt.2017.11.001. eCollection 2018 Jun.
The present study was undertaken over a three year period (2012-2014) in an organized dairy farm located in North India to ascertain as the putative cause of abortion. The dairy farm maintained cattle of Frieswal, Crossbred and Sahiwal breeds and followed calf-hood vaccination with Strain 19 live vaccine in all the heifers. Even with the recommended vaccination schedule and good managemental practices in place, 88 cases of abortions clinically suspected of bovine brucellosis (40 from Frieswal breed, 17 from Crossbred cattle and 31 from Sahiwal breed) were reported from this farm. From these abortion cases, bacteriological isolation was possible in only four dams while 16 dams were found to be serologically positive in Serum Tube Agglutination Test (STAT). Molecular screening by PCR assay (specific for the gene of ) revealed that 24 dams were positive, out of which 20 were from Frieswal breed and rest four were from Crossbred herd. Prominently, all Sahiwal dams were found to be negative in bacteriological isolation and also in PCR assay. These results thus indicate towards the possibility of breed predisposition to abortions due to infection. Statistical analysis by Fischer exact test ( < 0.01) too substantiated that breed susceptibility exists among these PCR positive cases. This study is novel as breed variation in abortions due to in cattle is being documented for the first time. Seven representative PCR amplicons generated during the study were also sequenced and submitted to NCBI GenBank. Moreover, this study also accentuates the importance of PCR screening especially in vaccinated herd and raises concerns on over-dependence of serological assays when intensive vaccination is practised without any concomitant DIVA strategy. Thus, besides assisting in planning pragmatic control strategies against bovine brucellosis these findings are also imperative from 'One Health' context, also.
本研究在印度北部一个有组织的奶牛场进行，为期三年（2012 - 2014年），以确定流产的假定原因。该奶牛场饲养弗里斯瓦尔、杂交和萨希瓦尔品种的牛，并对所有小母牛进行19号菌株活疫苗的犊牛期接种。即使有推荐的疫苗接种计划和良好的管理措施，该农场仍报告了88例临床疑似牛布鲁氏菌病的流产病例（弗里斯瓦尔品种40例，杂交牛17例，萨希瓦尔品种31例）。从这些流产病例中，仅在4头母畜中实现了细菌分离，而在血清试管凝集试验（STAT）中发现16头母畜血清学呈阳性。通过PCR检测（针对[具体基因]基因特异性）进行分子筛查显示，24头母畜呈阳性，其中20头来自弗里斯瓦尔品种，其余4头来自杂交牛群。值得注意的是，所有萨希瓦尔母畜在细菌分离和PCR检测中均为阴性。这些结果表明，由于[感染原因]感染，存在品种易感性导致流产的可能性。费舍尔精确检验（P < 0.01）的统计分析也证实了这些PCR阳性病例中存在品种易感性。这项研究具有创新性，因为首次记录了牛因[感染原因]导致流产的品种差异。研究期间产生的7个代表性PCR扩增子也进行了测序并提交至NCBI基因库。此外，本研究还强调了PCR筛查的重要性，特别是在接种疫苗的牛群中，并引发了对在没有任何配套鉴别诊断策略的情况下进行强化疫苗接种时过度依赖血清学检测的担忧。因此，这些发现除了有助于制定针对牛布鲁氏菌病的实用控制策略外，从“同一健康”的角度来看也至关重要。
