Milk Merchant Survey Data.

Brucellosis, a neglected zoonotic disease, is endemic in many sub-Saharan African countries, including Cameroon. Recent studies have shown that Brucella abortus infects multiple livestock species throughout Cameroon. While the presence and risk to humans have been identified at farms and abattoirs, the bacterium has never been detected in milk intended for human consumption. In Cameroon, milk is commonly sold at open-air markets for human consumption without regulation. This study investigates the presence of Brucella spp. in milk sold at these markets in three regions: the Far North, North, and West. Cow milk samples and surveys were collected from 380 merchants in each region, totaling 1,140 samples and surveys. Each sample underwent iELISA, culture, real-time PCR, and next-generation sequencing (NGS). Surveys assessed the knowledge, attitudes, and practices (KAP) of milk merchants. Results indicate that B. abortus is not only endemic in livestock but present in milk sold for human consumption. Culture results show a countrywide positivity of 1.3% (1.1% Far North, 1.1% North, 1.8% West). Real-time PCR results indicate a 4.0% positivity rate (2.4% Far North, 5.5% North, 4.0% West). iELISA indicates 21% of the milk samples contained anti-Brucella antibodies, with significant regional variations (38.4% Far North, 15.5% North, 8.9% West). Finally, NGS revealed that the bacterial isolates from milk are epidemiologically linked to those obtained from animals across the region. KAP analysis shows that only 26.4% of merchants boil and 91.2% mix the milk from multiple cattle before sale. All surveyed merchants selling culture-positive milk engaged in risky behaviors, resulting in the sale of contaminated milk to approximately 720 people each week. This study highlights the risk of human brucellosis extending beyond farms and abattoirs to the general public. Future research should investigate milk consumers’ habits and prevalence to better understand brucellosis risk in Cameroon.

布鲁氏菌病（Brucellosis）是一种被忽视的人畜共患病，在包括喀麦隆在内的诸多撒哈拉以南非洲国家均呈地方性流行。近期研究表明，流产布鲁氏菌（Brucella abortus）可感染喀麦隆境内的多种畜禽物种。尽管已在农场与屠宰场确认该病菌的存在及其对人类的感染风险，但此前从未在供人类食用的牛奶中检出此病菌。在喀麦隆，牛奶通常在露天市场无监管售卖以供人饮用。本研究针对远北、北部及西部三个地区的露天市场售卖牛奶，调查布鲁氏菌属（Brucella spp.）的存在情况。研究人员从每个地区的380名商户处采集牛奶样本与调查问卷，总计获得1140份样本及问卷。对每份样本均开展了间接酶联免疫吸附试验（iELISA）、分离培养、实时荧光定量PCR（real-time PCR）以及下一代测序（NGS）。调查问卷评估了奶商的知识、态度与实践（KAP）情况。研究结果显示，流产布鲁氏菌不仅在畜禽中呈地方性流行，还存在于供人食用的售卖牛奶中。分离培养结果显示，全国范围内阳性率为1.3%（远北地区1.1%、北部地区1.1%、西部地区1.8%）。实时荧光定量PCR检测结果显示阳性率为4.0%（远北地区2.4%、北部地区5.5%、西部地区4.0%）。间接酶联免疫吸附试验显示，21%的牛奶样本含有抗布鲁氏菌抗体，且存在显著区域差异（远北地区38.4%、北部地区15.5%、西部地区8.9%）。最后，下一代测序结果表明，从牛奶中分离得到的菌株与该区域内从动物体内分离得到的菌株存在流行病学关联。知识、态度与实践分析显示，仅有26.4%的商户会对牛奶进行煮沸处理，且91.2%的商户会在售卖前混合多头牛的牛奶。所有售卖培养检测呈阳性牛奶的受访商户均存在危险操作行为，这导致每周约有720人购买到受污染的牛奶。本研究强调，人类布鲁氏菌病的感染风险已不仅限于农场与屠宰场，而是延伸至普通民众。未来研究应调查牛奶消费者的习惯与感染率，以更全面地了解喀麦隆境内的布鲁氏菌病感染风险。