Mbugi Erasto V, Katale Bugwesa Z, Lupindu Athumani M, Keyyu Julius D, Kendall Sharon L, Dockrell Hazel M, Michel Anita L, Matee Mecky I, van Helden Paul D
Department of Biochemistry, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
Departments of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
East Afr Health Res J. 2017;1(1):19-30. doi: 10.24248/EAHRJ-D-16-00319. Epub 2017 Mar 1.
Cross-species tuberculosis (TB) transmission between humans and animals has been reported for quite a long time in sub-Saharan Africa. Because humans and animals coexist in the same ecosystem, exploring their potential for cross-species transmission and the impact the disease may have on the health of humans, animals, and their products is critical.
This study aimed to identify risk factors for transmission of TB () and to assess the potential for zoonotic TB () transmission in the Serengeti ecosystem where humans and animals are in intense contact. Our aim is to create a base for future implementation of appropriate control strategies to limit infection in both humans and animals.
We administered a semi-structured questionnaire to 421 self-reporting patients to gather information on risk factors and TB occurrence. In a parallel study, researchers screened sputum smears using Ziehl-Neelsen staining and confirmed by mycobacterial culture. We then performed descriptive statistics (Pearson's chi-square test) and logistic regression analysis to establish frequencies, association, and quantification of the risk factors associated with TB cases.
Our findings showed 44% (95% confidence interval [CI], 0.40-0.49) of the results were positive from sputum samples collected over a 1-year duration in areas with a high TB burden, particularly the Bunda district, followed by the Serengeti and Ngorongoro districts. Of the culture-positive patients who also had infections other than TB (43/187 patients), 21 (49%) were HIV positive. Contact with livestock products (odds ratio [OR] 6.0; 95% CI, 1.81-19.9), infrequent milk consumption (OR 2.5; 95% CI, 1.42-4.23), cigarette smoking (OR 2.9; 95% CI, 1.19-7.1.2), and alcohol consumption (OR 2.3; 95% CI, 1.22-4.23) were associated with a higher likelihood of TB infection.
There was no evidence of direct cross-species transmission of either or between humans and animals using the study methods. The absence of cross-species TB transmission could be due to limited chances of contact rather than an inability of cross-species disease transmission. In addition, not all people with presumptive TB are infected with TB, and therefore control strategies should emphasise confirming TB status before administering anti-TB drugs.
在撒哈拉以南非洲，人类与动物之间的跨物种结核病（TB）传播已有很长时间的报道。由于人类和动物共存于同一生态系统中，探索它们跨物种传播的可能性以及该疾病可能对人类、动物及其产品健康产生的影响至关重要。
本研究旨在确定结核病（TB）传播的风险因素，并评估在人类与动物密切接触的塞伦盖蒂生态系统中人畜共患结核病（TB）传播的可能性。我们的目标是为未来实施适当的控制策略以限制人类和动物感染奠定基础。
我们向421名自我报告的患者发放了一份半结构化问卷，以收集有关风险因素和结核病发生情况的信息。在一项平行研究中，研究人员使用齐尔-尼尔森染色法筛查痰涂片，并通过分枝杆菌培养进行确认。然后我们进行了描述性统计（Pearson卡方检验）和逻辑回归分析，以确定与结核病病例相关的风险因素的频率、关联和量化。
我们的研究结果显示，在结核病负担较高的地区，特别是邦达区，其次是塞伦盖蒂和恩戈罗恩戈罗区，在为期1年收集的痰样本中，44%（95%置信区间[CI]，0.40 - 0.49）的结果呈阳性。在同时患有结核病以外其他感染的培养阳性患者中（43/187名患者），21名（49%）为艾滋病毒阳性。接触畜产品（比值比[OR] 6.0；95% CI，1.81 - 19.9）、不经常饮用牛奶（OR 2.5；95% CI，1.42 - 4.23）、吸烟（OR 2.9；95% CI，1.19 - 7.12）和饮酒（OR 2.3；95% CI，1.22 - 4.23）与结核病感染的可能性较高相关。
使用本研究方法未发现人类与动物之间存在结核分枝杆菌或牛分枝杆菌直接跨物种传播的证据。不存在跨物种结核病传播可能是由于接触机会有限，而非跨物种疾病无法传播。此外，并非所有疑似结核病患者都感染了结核病，因此控制策略应强调在使用抗结核药物之前确认结核病状态。
