兔舍环境空气微生物气溶胶的检测

采用国际标准ANDERSEN6级微生物空气样品收集器,选用血葡萄糖琼脂培养基,分别对两个不同种兔舍环境空气微生物进行监测。其舍内需氧菌含量分别为4.19×103～5.55×104CFU/m3、6.35×103CFU/m3空气,需氧革兰氏阴性细菌含量分别为3.04×102～3.27×103CFU/m3、4.68×102CFU/m3空气。根据微生物气溶胶颗粒在ANDERSEN-收集器不同层级上的分布情况得知,约有50%的需氧细菌气溶胶颗粒和革兰氏阴性细菌气溶胶颗粒分布在3、4层上,空气动力学直径(Dae50)在2～6μm之间,它们能进入人、畜的气管、支气管,甚至细支气管,对饲养员和动物的呼吸道构成严重威胁。     

兔舍内气载革兰氏阴性菌群的检测

采用ANDERSEN-6级空气微生物样品收集器,以5%公绵羊血琼脂和麦康凯3号培养基为采样介质,分别对3个不同兔场环境中气载需氧菌含量、气载革兰氏阴性菌含量与菌群组成进行了检测。结果表明:兔舍内气载需氧菌含量在0.78×103~20.10×103 CFU/m3之间,气载需氧革兰氏阴性菌含量在0.39×102~10.30×102 CFU/m3之间,占需氧菌总数的2.12%~10.20%;革兰氏阴性菌群包括肠杆菌、奈瑟氏菌、巴氏杆菌和假单胞菌,肠杆菌科细菌中大肠埃希氏菌占多数。在其中2个兔舍中还检测到可导致兔发生肺炎的肺炎克雷伯氏菌。     

冬季不同建筑类型奶牛舍内外气载微生物的比较研究

本研究旨在比较冬季不同建筑类型奶牛舍内外气载细菌和真菌的含量变化.选择3种建筑类型的奶牛舍,对舍内、运动场、净道、凉棚及场外上风向和下风向5和50 m处的气载微生物进行同期采样分析.结果显示,不同建筑类型奶牛舍内微生物含量不同,气载细菌的含量变化为1 540~10 487 CFU/m³,只设顶棚的棚舍细菌含量最高;气载真菌的含量变化为169~731 CFU/m³,卷帘舍的真菌含量最高,且所有舍晚上的细菌和真菌含量均高于早上和中午.从舍内外微生物的空间分布得出,舍内或运动场的细菌含量高于净道,场外下风向处的细菌含量高于上风向处,但真菌的空间分布变化不明显.本研究结果可为奶牛舍环境的改善和奶牛疾病预防提供参考.     

乳牛舍内外环境空气中需氧菌,厌氧菌以及产气荚膜杆菌的定量分析

应用Andersen-多层级微生物收集器和KS-92 液体喷冲器,对乳牛舍内、外空气细菌含量,即厌氧菌、需氧菌总数以及产气荚膜杆菌(魏氏梭菌)进行了定性定量分析。结果表明,舍内空气中厌氧菌总数达到2098～4 295 个/m 3 ,其中魏氏梭菌为0～5.5 个/m 3 (Andersen-收集器);同时在舍内空气中,需氧菌总数为2050～18 094 个/m 3 。在舍邻近(4 m 处)的环境空气中厌氧菌总数为239～2 282 个/m 3 ,其中魏氏梭菌0～2.0个/m 3 ;需氧菌总数为297～4 276 个/m 3 。结果证明,舍内环境的细菌能向舍外环境传播,舍内、外环境微生物含量的高低浮动反映了舍内的卫生状况。     

全封闭式兔舍空间细菌监测

为监测重庆兔管家科技发展有限公司的全封闭式兔舍空间细菌含量,采用自然沉降法测定。结果:璧山兔场监测了3次,其中仅商品兔舍1有1次监测结果为101 900 CFU/m~3,其余都是25 000 CFU/m~3以下。铜梁兔场监测了4次,其中3号舍有两次监测结果分别为132 100 CFU/m~3、153 400 CFU/m~3,其余兔舍都是25 000 CFU/m~3以下。渝北兔场监测了1次,3栋兔舍空间细菌含量都小于25 000 CFU/m~3以下。细菌含量超标的兔舍养满了商品兔,对满负荷运行时应加强通风,每周喷雾消毒2次以上效果更好。     

规模化猪场夏季各类猪舍环境气载细菌检测

旨在评价规模化猪场各类猪舍的环境卫生质量,选择河北省不同地区的5个规模化猪场,采用自然沉降法对夏季4类猪舍(共24个猪舍)的舍内外气载细菌数量进行检测分析。结果表明,产房的气载细菌数量最少,保育舍细菌数量最多,各类舍的气载细菌数量分别达到3.82×10~4~2.32×10~5 CFU/m~3(产房)、8.34×10~4~3.38×10~5 CFU/m~3(保育舍)、9.81×10~4~2.03×10~5 CFU/m~3(妊娠舍)和6.89×10~4~2.67×10~5 CFU/m~3(肥育舍)。96%的猪舍细菌数量超标,最高超出国家标准的5.6倍。各猪场场区的细菌数量虽然显著低于舍内(P0.05),介于4.88×103~2.87×10~4 CFU/m~3,但也应引起重视。此外,同一舍不同垂直空间(0.5m和1.0m)和不同时间段(早、中、晚)的细菌数量均差异不显著(P0.05)。除妊娠舍外,同类舍气载细菌数量间均差异显著(P0.05)。结果提示:猪舍的气载细菌数量不仅取决于猪群类型,还受建筑类型和通风条件等因素的影响,该研究结果可为完善猪场的环境调控和防疫制度提供参考。     

戊二醛和季铵盐复合消毒剂杀菌效果的试验

将金黄色葡萄球菌、大肠埃希氏菌、溶血性链球菌 C群和类炭疽杆菌实验室培养 ,用 PBS液稀释成 5× 1 0 6 CFU/ m L 细菌悬液或芽胞悬液 ,分别加入到不同浓度的消毒剂作用不同的时间 ,结果表明 :戊二醛和季铵盐复合消毒剂 1∶70 0稀释时 ,1 0 min能有效杀灭金黄色葡萄球菌、大肠埃希氏杆菌、溶血性链球菌 ,1∶ 1 0 0稀释时 ,在 5min可杀灭类炭疽芽胞杆菌。用 1 %浓度的消毒剂对鸡场进行现场消毒 ,结果表明 :该消毒剂在60 min可杀灭 99.96%的细菌     

不同类型肉牛舍内外空气中细菌含量的比较研究

通过检测河北省不同地区6种有代表性建筑类型的肉牛舍内外空气中的细菌含量,对夏季和冬季肉牛舍的空气环境质量进行分析。夏季各地区牛舍中不同检测高度的细菌数量没有表现出显著差异(P>0.05),而冬季3种密闭式牛舍内,1.2m高的细菌数量均显著高于0.6m(P<0.05),分别达到98.2CFU/m3和68.3CFU/m3;夏冬两季不同建筑类型的牛舍内细菌数量均显著高于舍外(P<0.05),且冬季密闭式牛舍内细菌数量达到75.5×103～88.1×103 CFU/m3,是舍外的2.6～9.6倍,远远超过夏季(83.2×103 CFU/m3)。该研究为肉牛舍的设计和牛舍环境的改善提供理论基础。     

冬季大棚养鸭模式中微生物气溶胶对肉鸭应激和生产性能的影响

本研究通过评估不同饲养卫生清洁状况下微生物气溶胶的浓度对肉鸭生产性能的影响,为建立家禽养殖环境微生物气溶胶标准提供参考。选用600只1日龄的樱桃谷肉鸭,随机平均分配到1个对照组(A组)和4个清洁卫生条件逐步变差的试验组(B、C、D、E组),每组3个重复,每个重复40只。使用国际标准的Andersen-6级和AGI-30空气微生物采集器收集各组空气样品,检测微生物气溶胶浓度。检测鸭血清促肾上腺皮质激素(ACTH)浓度变化,评估其应激强度。与此相应地对肉鸭生长性能、屠宰指标等进行检测与评定,分析微生物气溶胶对肉鸭机体的影响。结果显示:当肉鸭舍的微生物气溶胶浓度升高至气载需氧菌为2.96×105CFU/m3、气载真菌为2.63×104CFU/m3、气载革兰氏阴性菌为3.09×104CFU/m3、气载内毒素为41.78×103EU/m3时(D组),该组肉鸭的血清ACTH浓度、料重比、死淘率显著或极显著高于对照组(P0.05或P0.01),该组肉鸭的平均日增重、胸肌率、胸肌重、屠宰率、屠体重显著或极显著低于对照组(P0.05或P0.01)。由此可见,微生物气溶胶可显著降低肉鸭的生产性能,气载需氧菌2.96×105CFU/m3、气载真菌2.63×104CFU/m3、气载革兰氏阴性菌3.09×104CFU/m3、气载内毒素41.78×103EU/m3可初步作为肉鸭养殖环境中的微生物气溶胶上限标准。     

兔舍内气载需氧菌和气载葡萄球菌的检测

本研究采用A ndersen-6级空气微生物样品收集器,选用血-葡萄糖-琼脂培养基为采样介质,对两个不同种兔舍环境空气中需氧菌总数和葡萄球菌总数进行了检测,并对葡萄球菌的菌群组成进行了分析。结果表明,两个兔舍内需氧菌含量分别为1.73~85.8×103CFU/m3、2.71~9.66×103CFU/m3空气,葡萄球菌含量分别为0.94~7.84×103CFU/m3、1.02~6.54×103CFU/m3空气。兔舍空气中葡萄球菌主要包括金黄色葡萄球菌、腐生葡萄球菌、表皮葡萄球菌、科氏葡萄球菌、头状葡萄球菌和马胃葡萄球菌,其中金黄色葡萄球菌的含量占葡萄球菌总数的26.3%~29.6%,其次是腐生葡萄球菌和表皮葡萄球菌。另外,还对需氧菌和金黄色葡萄球菌在A ndersen-6级收集器不同层级上的分布情况进行了统计分析,结果表明,约有56.4%的需氧菌和49%金黄色葡萄球菌分布在3~6层上,空气动力学直径(A erody-nam ic d iam eter,D ae)在6~0.2μm,它们能进入人、畜的气管、支气管,甚至细支气管,对饲养员和动物的呼吸道构成严重危害。     

禽舍微生物气溶胶含量及其空气动力学研究

采用Andersen-微生物空气样品收集器，选用普通营养琼脂和金黄色葡萄球菌选择培养基对一个种鸡场舍环境空气进行监测。其需氧菌含量从3.12×104到9.01×105，金黄色葡萄球菌含量波动于2.0×103～3.3×104CFU/m3之间。根据微生物气溶胶颗粒在Andersen-收集器不同层级上的分离情况得知，22.5%的需氧菌、1.8%的金黄色葡萄球菌气溶胶颗粒的空气动力学直径(d50)为Φ0.65～2.1μm，它们能进入人、畜的肺泡，对人畜呼吸道构成感染威胁。     

Concentration of airborne endotoxins and airborne bacteria in Chinese rabbit houses

Concentration of airborne endotoxins, airborne aerobic bacteria and airborne aerobic gram-negative bacteria were measured in 3 rabbit houses. Further, the species composition of the airborne gram-negative bacterial flora was investigated. The total amount of airborne endotoxin ranged from 22 to 774 EU/m3 (Endotoxin Units/m3). The number of total airborne aerobic bacteria varied between 780 and 20100 CFU/m3, the number of airborne aerobic gram-negative bacteria between 39 and 1030 CFU/m3. Most gram-negative bacterial isolates belonged to the family Enterobacteriaceae with E. coli as primary species. In two rabbit houses also airborne Pasteurella multocida spp. multocida, the most common respiratory pathogen of rabbits, was isolated.     

Comparative Study of Indoor and Outdoor Airborne Microorganism of Different Styles of Cowsheds in Winter

The present objective of the study was to investigate the concentrations of indoor and outdoor and airborne fungi of three styles of dairy cowsheds in winter.The sampled sites included the shed,exercise yard,net road,sunshade,5 or 50 m distance upwind or downwind outside each dairy farm.The results showed that the indoor microorganism concentration varied from the shed styles.The concentrations of airborne bacteria ranged from 1 540 to 10 487 CFU/m³ in all three sheds,and among all sheds,the bacteria concentration in the shed with only roof was the highest.The concentrations of airborne fungi ranged from 169 to 731 CFU/m³ in all sheds,and the fungi concentration in the shed with curtain was the highest.Moreover,both bacteria and fungi concentrations in the evening were higher than that at noon and in the morning.From the spatial distribution of indoor and outdoor microorganisms,the bacteria concentrations in the sheds or at the exercise yard were higher than that at the net road in each farm,and the bacteria concentration in downwind was higher than in upwind,while the spatial distribution of fungi showed no significant difference among all sampled sites.The research results would provide some references for improving environment of cowshed and preventing from diseases.     

Foot-and-mouth disease - quantification and size distribution of airborne particles emitted by healthy and infected pigs

There is strong evidence to suggest that foot-and-mouth disease (FMD) can be transmitted by airborne virus up to many kilometres from a virus source. Atmospheric dispersion models are often used to predict where this disease might spread. This study investigated whether FMD virus (FMDV) aerosol has specific characteristics which need to be taken into consideration in these models. The characteristics and infectiousness of particles emitted by 12 pigs have been studied pre- and post-infection with O UKG 2001 FMDV. Aerosol generated by individual pigs was found log normally distributed in the range 0.015-20.0microm with concentrations between 1000 and 10000cm(-3) at the smallest size and <1cm(-3) above 10microm. No differences in either the total number of particles produced or their size distribution were detected between uninfected and infected pigs. However, a correlation between aerosol concentration and animal activity was found with a more active pig producing significantly greater concentrations than those that were less active. Viable virus was found up to a maximum of 6.3 log TCID(50)/24h/animal. The virus was distributed almost equally across the three size ranges; <3, 3-6 and >6microm. No correlation could be established between the production of virus and animal activity. In general the production of airborne virus closely followed the detection of viraemia in the blood and the presence of clinical symptoms. However, in one instance a pig excreted as much airborne virus as the other animals in the study, but with less virus detected in its blood. The results suggest that there is little merit in including a sophisticated virus release pattern based on physical activity periods or FMDV aerosol size spectrum, together with the appropriate dry deposition calculations, in models used to predict airborne spread of FMD. An estimate of the total daily virus production based on the clinical assessment of disease and virus strain is sufficient as input.     

Air hygiene in a pullet house: effects of air filtration on aerial pollutants measured in vivo and in vitro

1. The natural history of air hygiene in a pullet house was assessed at three-weekly intervals using a combination of in vitro and in vivo assays. The performance of an internal air filter was also examined as an experimental technique for providing clean air. 2. Overall, air hygiene was poor by comparison with occupational standards for human health. The mass concentrations of respirable and inspirable dust were 1.4 and 11.3 mg/m3 compared to human exposure limits of 5 and 10 mg/m3 respectively. The concentration of ammonia was typically about 20 ppm. 3. The majority (greater than 99%) of airborne particles were non-viable. Commensal bacteria from the skin were the most numerous airborne bacteria. Scopulariopsis and Aspergillus spp. were the most prevalent fungi recovered from the air and bird's lungs respectively. The concentrations of airborne and lung fungi were positively correlated with ammonia concentrations. 4. The differences between in vivo and in vitro assays of airborne microorganisms suggest that an aerosol sampler should be devised which better mimics the physical and biochemical environment of the respiratory tract.     

山西省东南部羊舍气载真菌浓度变化及空气动力学特征

试验研究了山西省东南部羊舍气载真菌浓度变化规律和真菌气溶胶的空气动力学特征,以期为羊场的环境控制提供依据。应用Andersen-6级空气微生物采样器,以孟加拉红培养基为采样介质,于春、夏、秋、冬分别采集了山西省东南部3个羊场羊舍的真菌气溶胶,分析其气载真菌浓度和真菌气溶胶的粒径特点。结果表明,羊舍气载真菌一年中以秋季浓度最高,显著高于其他季节（P<0.05）,且秋季一天上午、中午、下午3个时间段中,浓度差异显著（P<0.05）;羊舍真菌气溶胶粒子4个季节在采样器上的分布基本相同,高峰出现在第Ⅳ级,主要分布在Ⅲ~Ⅴ级,占各级总数的72.66%~83.87%,可进入人和动物的肺泡;羊舍真菌气溶胶粒子计数中值直径（CMD）为1.3~2.9 μm,粒径分布的离散度（GSD）为1.6~2.7 μm;夏季CMD显著低于其他季节（P<0.05）。综合以上结果,羊舍气载真菌浓度与季节密切相关,80%左右气溶胶粒子可进入人和动物肺泡,且CMD小于其他动物圈舍,潜在危害较大。     

An aerosolized Brucella spp. challenge model for laboratory animals

To characterize the optimal aerosol dosage of Brucella abortus strain 2308 (S2308) and B. melitensis (S16M) in a laboratory animal model of brucellosis, dosages of 10(3)-10(10) colony forming units (CFU) were nebulized to mice. Although tissue weights were minimally influenced, total CFU per tissues increased beginning at 10(6)-10(7) CFU dosages, with 10(9) CFU appearing to be an optimal dosage for S16M or S2308 aerosol delivery. At 12 weeks after vaccination with 10(7) CFU of B. abortus strain RB51 (SRB51) or saline (control), mice were challenged intraperitoneally (i.p.) (6.4 x 10(4) CFU) or via aerosol (1.76 x 10(9) CFU) with S2308. Mice vaccinated with SRB51 had reduced (P < 0.05) splenic, liver and lung colonization (total CFU and CFU/g) after i.p. challenge with S2308 as compared with control mice after i.p. S2308 challenge. Control and SRB51-vaccinated mice did not differ (P > 0.05) in splenic, liver or lung colonization after aerosol S2308 challenge. Failure to demonstrate vaccine protection was not because of a high aerosol challenge dosage as colonization of spleen and liver tissues was lower (P < 0.05) after aerosol challenge when compared with control mice after i.p. S2308 challenge.     

Comparison of two formaldehyde administration methods of in ovo-injected eggs

Formaldehyde administration in the hatchery can be very useful in decreasing microbial numbers. However, its use is controversial because of the adverse effects that can occur to chicks and people. This study was designed to look at alternative methods of application of formaldehyde in the hatchery. In addition, the study compared the effects of these methods of application on in ovo-and non-in ovo-injected eggs. All in ovo-injected eggs were given diluent only with no vaccine or antibiotic added. In hatchers containing both in ovo-injected eggs and non-in ovo-injected eggs, formaldehyde was administered two ways, dose (DOSE) and constant rate infusion (CRI). In the DOSE hatcher, 12 ml of formaldehyde was administered at one time every 12 hr, whereas in the CRI hatcher, the same volume was administered at a rate of 1 ml/hr over a 12-hr period. A control (CONT) hatcher received 12 ml of distilled water at the same time that the DOSE hatcher was given formaldehyde. In the DOSE hatcher, a peak concentration of formaldehyde of 102 ppm was reached. The CRI was maintained at approximately 20 ppm of formaldehyde. At pipping, the aerosol bacterial load in the hatchers receiving formaldehyde (DOSE, 130 colony-forming units [CFU]/m3; CRI, 82.5 CFU/m3) was significantly less than in the CONT hatcher (235 CFU/m3). At hatch, the CRI (337.5 CFU/m3) was not able to control bacterial levels and only the DOSE hatcher (150 CFU/m3) had a significantly lower aerosol bacterial count. The CRI non-in ovo-injected eggs (93.39%) had a significantly higher percentage of hatch of fertile compared with non-in ovo-injected eggs exposed to water (84.27%). In ovo-injected eggs in CONT and DOSE treatment groups contained significantly higher percentages of visual contamination than non-in on-injected eggs in the same hatchers. This difference had numerical significance only in the treatment groups within the CRI hatcher. The chicks were then placed into replicate treatment groups and grown for 14 days. Chicks from the CRI in ovo-injected eggs had a statistically significant improvement in feed conversion ratio (1.24) at 14 days when compared with chicks from CONT non-in ovo-injected eggs (1.29). All formaldehyde-exposed chicks had numerically lower feed conversion ratios compared with the CONT exposed chicks.     

Emissions of dust and microbes from animal housing

The content of airborne dust and germs in animal houses is described qualitatively and quantitatively. After having left the animal house by way of the exhaust air the microorganisms suffer a decay which is caused by dispersion and death-rate. The dispersion can be demonstrated by models. The boundary of the dispersion of germs and dust is about 200 m from source under normal conditions. Epidemiologic studies indicate that some virus particles can be transported over several miles by way of the air. Control of airborne dust and germ levels in animal houses is still poor.