Deka Ram Pratim, Shome Rajeswari, Dohoo Ian, Magnusson Ulf, Randolph Delia Grace, Lindahl Johanna F
Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), 750 07 Uppsala, Sweden.
Department of Animal & Human Health, International Livestock Research Institute (ILRI), Nairobi 00100, Kenya.
Microorganisms. 2021 Apr 9;9(4):783. doi: 10.3390/microorganisms9040783.
This study assessed seropositivity of Brucella infection in dairy animals and risk factors associated with it. The cross-sectional study used multi-stage, random sampling in the states of Bihar and Assam in India. In total, 740 dairy animals belonging to 534 households of 52 villages were covered under this study. Serological testing was conducted by indirect enzyme-linked immunosorbent assay (iELISA). Animal-level Brucella seropositivity was found to be 15.9% in Assam and 0.3% in Bihar. Seropositivity in urban areas (18.7%) of Assam was found to be higher than in rural areas (12.4%). Bihar was excluded from the risk factor analysis, as only one Brucella seropositive sample was detected in the state. A total of 30 variables were studied for assessing risk factors, of which 15 were selected for multivariable regression analyses following a systematic process. Finally, only three risk factors were identified as statistically significant. It was found that animals belonging to districts having smaller-sized herds were less likely ( < 0.001) to be Brucella seropositive than animals belonging to districts having larger-sized herds. Furthermore, the chance of being Brucella seropositive increased ( = 0.007) with the increase in age of dairy animals, but decreased ( = 0.072) with the adoption of artificial insemination (AI) for breeding. We speculated that the identified risk factors in Assam likely explained the reason behind lower Brucella seropositivity in Bihar, and therefore any future brucellosis control program should focus on addressing these risk factors.
本研究评估了奶牛布鲁氏菌感染的血清阳性率及其相关风险因素。这项横断面研究在印度比哈尔邦和阿萨姆邦采用多阶段随机抽样。本研究共涵盖了52个村庄534户家庭的740头奶牛。通过间接酶联免疫吸附测定法（iELISA）进行血清学检测。结果发现，阿萨姆邦奶牛布鲁氏菌血清阳性率为15.9%，比哈尔邦为0.3%。阿萨姆邦城市地区的血清阳性率（18.7%）高于农村地区（12.4%）。比哈尔邦被排除在风险因素分析之外，因为该邦仅检测到一份布鲁氏菌血清阳性样本。总共研究了30个变量以评估风险因素，其中15个变量经过系统筛选后用于多变量回归分析。最终，仅确定了三个具有统计学意义的风险因素。研究发现，与属于牛群规模较大地区的奶牛相比，属于牛群规模较小地区的奶牛布鲁氏菌血清阳性的可能性更低（<0.001）。此外，奶牛布鲁氏菌血清阳性的几率随着奶牛年龄的增长而增加（=0.007），但随着采用人工授精（AI）进行繁殖而降低（=0.072）。我们推测，在阿萨姆邦确定的风险因素可能解释了比哈尔邦布鲁氏菌血清阳性率较低的原因，因此未来任何布鲁氏菌病防控计划都应侧重于解决这些风险因素。
