Prevalence and risk factors of mycobacterial infections in farm and trade cattle in southwestern Nigeria

We evaluated the prevalence of mycobacterial infections (i.e., Mycobacterium bovis and non-tuberculous mycobacteria [NTM]) and their associated risk factors among cattle herds and trade cattle in southwestern Nigeria. Through cross-sectional study design, cattle herds from three locations were screened using the single intradermal comparative cervical tuberculin test based on two diagnostic standards; more than 4 mm (? 4 mm) and more than 2 mm (? 2 mm) cut-off points. Abattoir study involved screening trade cattle for tuberculous lesions. Overall, 515 cattle from 45 herds were screened. Using >?4 mm, animal level and herd prevalence of 11.7 and 46.7% were recorded, respectively. Applying the ? 2 mm cut-off, animal level and herd prevalence increased to 31.1 and 60.0%, respectively. Significantly, using the ? 2 mm cut-off, cattle in medium size herds/extensive management system (OR?=?1.6; 95% CI 1.1–2.5) and Sokoto Gudali (OR?=?2.3; 95% CI 1.4–3.8) were more at risk of being positive reactors, while Rahaji (OR?=?0.3; 95% CI 0.1–0.7) breeds of cattle and cows in the peri-urban area (OR?=?0.4; 95% CI 0.2–0.9) were less at risk of being positive reactors. Again, M. avium reactor of 21.7% was observed. In the abattoir, 1797 cattle were examined with 126 lesions suggestive of tuberculosis (TB). Culture/molecular analyses confirmed 2.2% M. bovis and 0.9% NTM infections. Risk factors associated with bovine TB among trade cattle were sex (OR?=?4.0; 95% CI 1.2–13.5) and age (OR?=?0.3; 95% CI 0.1–0.9). We confirm 11.7% prevalence of mycobacterial infections among populations of cattle screened with breed and herd size being major risk factors.     

PCR鉴定沙门氏菌血清分型方法的建立与应用

为建立快速有效、经济适用的沙门氏菌血清型鉴定方法,利用Primer Plex软件设计畜禽中常见沙门氏菌的菌体(O)抗原和鞭毛抗原(H)的引物,优化引物比例和退火温度等反应条件,建立沙门氏菌血清型鉴定的PCR法,并对46株沙门氏菌分离株进行血清型鉴定,同时与传统玻片凝集法和美国CDC的液相芯片(Luminex-x MAP)法进行比较。优化后获得了O抗原中B、C1、D和E1群的多重PCR引物,以及鞭毛抗原H1相抗原基因(fli C)和H2相抗原基因(flj B)的2对引物;建立了一套基于沙门氏菌O和H抗原的多重PCR血清型鉴定法;PCR法和Luminex-x MAP法鉴定出7种沙门氏菌血清型,传统玻片凝集法鉴定出6种血清型;PCR法与传统玻片凝集法和Luminex-x MAP鉴定结果的符合率均为95.65%。本研究建立的PCR沙门氏菌血清型鉴定法简便、快速,预期可在沙门氏菌的血清分型研究中发挥作用。     

肉鸡屠宰加工过程中沙门菌污染定量风险评估

为了构建肉鸡屠宰加工过程中沙门菌污染定量风险评估模型,分析鸡肉中沙门菌的消长变化规律,明确关键风险防控点,采用2015年部分肉鸡屠宰场沙门菌污染监测和调研数据,构建以烫煺后为评估过程起点,包括净膛、清洗预冷和分割传送的模块化过程风险评估模型,以不同分布描述各变量,并通过@RISK软件模拟运行。结果显示,通过构建的模型模拟屠宰加工后终端鸡肉产品中的沙门菌污染量,90%的可能分布在0~9MPN之间,而依据实际监测数据换算为5.3 MPN,说明模型可信。根据过程中各环节的模拟数据,分析了肉鸡携带的沙门菌消长变化,发现预冷后沙门菌污染总量明显下降,但分割传送后污染总量又有所回升。通过拟合的相关系数分析,明确了传送带上的沙门菌是影响终端鸡肉沙门菌污染的最关键风险点。本研究构建的肉鸡屠宰加工全过程沙门菌定量风险评估模型,可为肉鸡屠宰场沙门菌污染的卫生监管和风险管理提供理论依据。     

广西边境地区活禽批发市场禽流感流行病学监测

为了给广西边境地区重大动物疫病防控阻截带建设提供数据支持,以及了解中越边境地区家禽禽流感病毒生态学,2012年12月—2017年12月,对广西边境地区主要活禽批发市场家禽及市场环境进行了系统监测。结果显示:广西边境地区活禽批发市场内禽流感病毒污染较重,呈多亚型病毒共存状态;家禽样品的平均病毒分离率为15.95%,环境样品则高达23.65%,明显高于家禽样品。市场调查发现:广西9个边境县(市、区)中,年活禽交易量在100万只以上的有5个;市场交易活禽主要为本地散养或规模场养殖家禽、从其他地区批发转运来的家禽以及边境走私家禽;大部分活禽市场没有配备消毒和无害化处理设施,也未严格执行休市制度。监测和调查结果表明,广西边境地区活禽批发市场家禽交易量大且频繁,来源复杂;市场中禽流感病毒污染严重,多亚型病毒在市场内常年蓄积循环,且存在家禽隐性带毒现象,因而有病毒散播风险。污染严重主要是因市场管理水平不高和生物安全措施不到位造成的,因此需要加强市场的动物卫生监管,提高禽流感监测力度。     

黄菠萝与红松混交林生长情况研究

通过对比黄菠萝与红松不同混交生长的影响,以及分析了二者混交林种间的树冠结构关系,以此制订相应的经营措施。     

Symbiotic N<Subscript>2</Subscript> fixation and nitrate utilisation in irrigated lucerne (<Emphasis Type="Italic">Medicago sativa</Emphasis>) systems

Symbiotic N₂ fixation by lucerne (Medicago sativa) has capacity to provide significant inputs of N to agro-ecosystems, and the species has also been shown to scavenge soil mineral N and thus act as a sink for excess reactive N. The balance between these two N cycle processes was investigated in an extensive irrigated lucerne growing region where nitrate contamination of groundwater has been reported. We sampled 18 permanent pure lucerne stands under irrigation for standing dry matter, total shoot N, and N₂ fixation using ¹⁵N natural abundance along with activity of the inducible enzyme nitrate reductase as indicators of use of soil NO₃⁻ by lucerne. On average 65% of lucerne N was obtained from symbiotic N₂ fixation. Converting standing dry matter estimates to annual N₂ fixation amounts we calculated average N₂ fixation of 311 kg N/ha, including N in roots and nodules. Uptake of N from soil by lucerne was calculated to be 181 kg N/ha/year. We were not able to identify the source of this soil mineral N, although nitrate reductase activity of lucerne was higher than that of non-N₂ fixing species examined.     

Performance evaluation of forest co-management: a case study of Chunati Wildlife Sanctuary,Bangladesh

The objective was to evaluate the performance of the co-management of Nishorgo Support Project at Chunati Wildlife Sanctuary in Bangladesh. I adopted the Focus Groups Discussion method for opinion survey and applied the SWOTAHP technique for data analysis. Local people did not participate in the decision-making process of forest management and they perceived co-management as a threat to their livelihoods. Moreover, mistrust and misunderstanding among different stakeholders, political and ethical conflicts, lack of property rights of tribal communities, and lack of accountability and transparency were identified as the drawbacks of co-management.