College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China.
PLoS One. 2013 Jul 10;8(7):e68230. doi: 10.1371/journal.pone.0068230. Print 2013.
Lack of clear risk factor identification is the main reason for the persistence of brucellosis infection in the Chinese population, and there has been little assessment of the factors contributing to Brucella contamination of raw whole milk. The purpose of this study was to identify risk factors affecting Brucella contamination of raw milk, and to evaluate effective measures for disease reduction in order to determine preventive strategies.
A nationwide survey was conducted and samples were obtained from 5211 cows corresponding to 25 sampling locations throughout 15 provinces in China. The prevalence of Brucella in the raw milk samples averaged 1.07% over the 15 Chinese provinces, while the prevalence of positive areas within these regions ranged from 0.23-3.84% among the nine provinces with positive samples. The survey examined factors that supposedly influence Brucella contamination of raw whole milk, such as management style, herd size, abortion rate, hygiene and disease control practices. A binary logistic regression analysis was carried out to determine the association between risk factors for Brucella and contamination of milk samples. Furthermore, a relative effect decomposition study was conducted to determine effective strategies for reducing the risk of Brucella contamination of raw whole milk. Our data indicate that disease prevention and control measures, abortion rate, and animal polyculture are the most important risk factors. Meanwhile, culling after quarantine was identified as an effective protective measure in the current Chinese dairy situation.
These results indicate that, although there is a low risk of contamination of milk with Brucella nationwide in China, there are individual regions where contamination is a significant problem. Controlling three factors-culling after quarantine, maintaining a low abortion rate, and avoiding mixing groups of cattle and small ruminants-could effectively reduce the risk of Brucella contamination of raw whole milk.
在中国人群中，缺乏明确的危险因素识别是布鲁氏菌病感染持续存在的主要原因，而且对导致原料生牛乳布鲁氏菌污染的因素评估甚少。本研究旨在确定影响原料生牛乳布鲁氏菌污染的危险因素，并评估有效的减少疾病的措施，以确定预防策略。
进行了一项全国性调查，从中国 15 个省的 25 个采样点采集了 5211 头奶牛的样本。15 个中国省份的原料生牛乳样本中布鲁氏菌的流行率平均为 1.07%，而在有阳性样本的 9 个省份中，这些地区的阳性区域流行率在 0.23%-3.84%之间。该调查检查了一些据称会影响原料生牛乳布鲁氏菌污染的因素，如管理方式、牛群规模、流产率、卫生和疾病控制措施。进行了二项逻辑斯谛回归分析，以确定布鲁氏菌与牛奶样本污染之间的风险因素的关联。此外，进行了相对效果分解研究，以确定降低原料生牛乳布鲁氏菌污染风险的有效策略。我们的数据表明，疾病预防和控制措施、流产率和动物混养是最重要的危险因素。同时，检疫后淘汰被认为是当前中国奶牛场情况下的一种有效保护措施。
这些结果表明，尽管中国全国范围内原料生牛乳中布鲁氏菌污染的风险较低，但个别地区的污染问题较为严重。控制三种因素——检疫后淘汰、保持低流产率和避免牛群和小反刍动物混合——可以有效地降低原料生牛乳布鲁氏菌污染的风险。
