Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya.
Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub KE, Nairobi, Kenya.
Sci Rep. 2021 Apr 23;11(1):8881. doi: 10.1038/s41598-021-88327-z.
Brucellosis, caused by several species of the genus Brucella, is a zoonotic disease that affects humans and animal species worldwide. Information on the Brucella species circulating in different hosts in Kenya is largely unknown, thus limiting the adoption of targeted control strategies. This study was conducted in multi-host livestock populations in Kenya to detect the circulating Brucella species and assess evidence of host-pathogen associations. Serum samples were collected from 228 cattle, 162 goats, 158 sheep, 49 camels, and 257 humans from Narok and Marsabit counties in Kenya. Information on age, location and history of abortion or retained placenta were obtained for sampled livestock. Data on age, gender and location of residence were also collected for human participants. All samples were tested using genus level real-time PCR assays with primers specific for IS711 and bcsp31 targets for the detection of Brucella. All genus positive samples (positive for both targets) were further tested with a speciation assay for AlkB and BMEI1162 targets, specific for B. abortus and B. melitensis, respectively. Samples with adequate quantities aggregating to 577 were also tested with the Rose Bengal Test (RBT). A total of 199 (33.3%) livestock and 99 (38.5%) human samples tested positive for genus Brucella. Animal Brucella PCR positive status was positively predicted by RBT positive results (OR = 8.3, 95% CI 4.0-17.1). Humans aged 21-40 years had higher odds (OR = 2.8, 95% CI 1.2-6.6) of being Brucella PCR positive compared to the other age categories. The data on detection of different Brucella species indicates that B. abortus was detected more often in cattle (OR = 2.3, 95% CI 1.1-4.6) and camels (OR = 2.9, 95% CI 1.3-6.3), while B. melitensis was detected more in sheep (OR = 3.6, 95% CI 2.0-6.7) and goats (OR = 1.7, 95% CI 1.0-3.1). Both B. abortus and B. melitensis DNA were detected in humans and in multiple livestock host species, suggesting cross-transmission of these species among the different hosts. The detection of these two zoonotic Brucella species in humans further underpins the importance of One Health prevention strategies that target multiple host species, especially in the multi-host livestock populations.
布鲁氏菌病是由布鲁氏菌属的几种物种引起的，是一种影响全球人类和动物物种的人畜共患病。肯尼亚不同宿主中循环的布鲁氏菌种的信息在很大程度上是未知的，因此限制了针对目标控制策略的采用。本研究在肯尼亚多宿主牲畜群体中进行，以检测循环的布鲁氏菌种并评估宿主-病原体关联的证据。从肯尼亚纳罗克和马萨比特县采集了 228 头牛、162 只山羊、158 只绵羊、49 只骆驼和 257 名人类的血清样本。为采样牲畜收集了年龄、位置和流产或胎衣滞留史的信息。还收集了人类参与者的年龄、性别和居住地的数据。所有样本均使用针对 IS711 和 bcsp31 靶标的属水平实时 PCR 检测试剂盒进行检测，以检测布鲁氏菌。所有属阳性样本（两个靶标均为阳性）均进一步用针对 B. abortus 和 B. melitensis 的 AlkB 和 BMEI1162 靶标特异性的种特异性检测试剂盒进行检测。具有足够数量的 577 个样本也用孟加拉玫瑰红试验 (RBT) 进行了测试。共有 199 份（33.3%）牲畜和 99 份（38.5%）人类样本检测出布鲁氏菌属阳性。动物布鲁氏菌 PCR 阳性状态与 RBT 阳性结果呈正相关（OR=8.3，95%CI 4.0-17.1）。21-40 岁的人类比其他年龄组更有可能（OR=2.8，95%CI 1.2-6.6）为布鲁氏菌 PCR 阳性。不同布鲁氏菌种检测的数据表明，B. abortus 在牛（OR=2.3，95%CI 1.1-4.6）和骆驼（OR=2.9，95%CI 1.3-6.3）中检测更为频繁，而 B. melitensis 在绵羊（OR=3.6，95%CI 2.0-6.7）和山羊（OR=1.7，95%CI 1.0-3.1）中检测更为频繁。B. abortus 和 B. melitensis 的 DNA 均在人类和多种牲畜宿主物种中检测到，表明这些物种在不同宿主之间发生了交叉传播。这两种人畜共患布鲁氏菌种在人类中的检测进一步强调了针对多种宿主物种的“同一健康”预防策略的重要性，尤其是在多宿主牲畜群体中。
