共查询到20条相似文献,搜索用时 656 毫秒
1.
David D Yakobson B Rotenberg D Dveres N Davidson I Stram Y 《Veterinary microbiology》2002,87(2):111-118
2.
K K Kalicharran V S Springthorpe S A Sattar 《Canadian journal of veterinary research》1992,56(1):28-33
Human adenovirus type 5 containing the rabies virus glycoprotein gene (rHAd-RG1) has potential for the oral vaccination of animals. The stability of this recombinant was tested indoors and outdoors by measuring the loss in virus infectivity. Under indoor conditions the stability of the recombinant virus was studied in an egg yolk-containing commercial stabilizer and a simple buffered salt solution (EBSS; Earle's balanced salt solution) at 4 degrees C and room temperature (24-25 degrees C). Over 16 days, there was a more rapid loss in virus titer at room temperature than at 4 degrees C in both suspending media; however, these differences were slight and may be significant when the overall stability of the vaccine is considered. When the virus was mixed with either 10% (w/v) fox or skunk feces or EBSS, placed on stainless steel disks and the disks kept under ambient conditions (air temperature 24-25 degrees C; relative humidity 45-50%), there was a more rapid decline in virus titer in the fecal suspensions (3% remained after 72 h) than in EBSS (26% remained after 72 h). When bait-coated blister packs of the vaccine were placed in an outdoor location in the fall (October) season, there was a larger drop in the virus titer for vaccines placed in the sun (54% over 32 days) than for those in the shade (40% over 32 days). Incorporating proteinaceous stabilizers in the vaccine samples for outdoor study showed virus stability was not enhanced in their presence.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
4.
Contents The aim of the present study was to compare the influence of room temperature (27 degrees C) and 4 degrees C during glycerol addition on canine semen cryopreservation and verify the effect of different post-thawing dilutions on canine semen. Ten ejaculates from five stud dogs were collected by digital manipulation. Semen samples were evaluated and further divided into two aliquots. The first aliquot was extended in Tris-egg yolk-glycerol at 27 degrees C and the second one received glycerol at 4 degrees C. Samples were frozen and stored in liquid nitrogen. After 1 week, samples were thawed and submitted to evaluations of progressive sperm motility, morphology, acrosomal integrity, hypo-osmotic swelling (HOST) and thermoresistance tests. For thermoresistance test, aliquots were divided in two portions: one portion was kept undiluted (1 : 0) and the other one was diluted in a 1 : 4 ratio (one part semen to four parts extender). No differences were observed between temperatures for glycerol addition regarding seminal parameters evaluated. Furthermore, post-thawing dilutions demonstrated similar effect on canine semen longevity. Correlations among post-thaw sperm motility and HOST and results from thermoresistance test were observed for both temperatures for glycerol addition. In conclusion, glycerol could be added to canine semen at room temperature (27 degrees C) or at 4 degrees C. Moreover, there is no need to extend canine semen after thawing for the thermoresistance test, but if we need to increase the inseminating volume for artificial inseminations, the addition of extender will not damage the semen. 相似文献
5.
The abilities of two isolates of Tritrichomonas foetus to survive and replicate in transport and Diamond's medium or in the InPouch TF system (Bio-Med Diagnostics) when exposed to different temperatures for different periods were determined in a series of experiments. Tubes containing thioglycollate transport medium or pouches were inoculated with 4000 to 5000 organisms and kept for up to seven days at 37 degrees C, 22 degrees C, 4 degrees C, or -20 degrees C. When the holding time had elapsed, the numbers of motile T foetus were counted. Samples in transport medium were transferred to Diamond's medium, and both the pouches and tubes containing Diamond's medium were incubated at 37 degrees C. The cultures were examined and counted four or five times during the 10 to 14 day culture period. The sensitivity of the test under the different conditions, expressed as the number of positive cultures/the total number of samples x 100, varied from zero to 100 per cent depending upon the combination of variables considered. In each medium, with both isolates of T foetus, all samples kept for up to four days at 22 degrees C or 37 degrees C were positive. All cultures of samples kept more than five days at 4 degrees C were negative. No positive cultures were detected when samples were kept more than three hours at -20 degrees C. The day on which the cultures reached mean peak concentration varied with the temperature at which the samples had been kept before they were cultured. 相似文献
6.
Cryptosporidium muris oocysts suspended in 200 microl of water were pipetted into plastic microcentrifuge tubes which were stored at 4 degrees C or frozen at -5 degrees C for 1, 3, 5, 7, and 10 days and at -20 degrees C for 1, 3, 5, and 8h, respectively. Other samples of C. muris oocysts suspended in water were heated in the metal block of a thermal DNA cycler. Block temperatures were set at 5 degrees C incremental temperatures from 40 to 70 degrees C. At each high temperature setting microcentrifuge tubes containing C. muris oocysts were exposed for 1 min. Both, frozen and heated oocyst suspensions as well as untreated control oocyst suspensions were then inoculated into each of four ICR mice by gastric intubation. Untreated, freeze-thawed or heated oocysts were considered infectious when oocysts of C. muris were found microscopically in the faeces of mice after inoculation. All inoculated mice that received oocysts frozen at -5 degrees C for 3, 5, 7, and 10 days and -20 degrees C for 1, 3, 5, and 8h had no oocysts in faeces. In contrast, C. muris oocysts frozen at -5 degrees C for 1 day remained infective for inoculated mice. Our results also indicated that when water containing C. muris oocysts was exposed at a temperature of 55 degrees C or higher for 1 min, the infectivity of oocysts was lost. 相似文献
7.
The survival of the street rabies virus in a 10% suspension, prepared from the salivary gland of a naturally infected fox, was studied under various conditions. A bioassay and titration on mice were used for the identification of the virus in different intervals. The heat inactivation of the virus in a suspension kept in a test tube at the temperatures of 20 degrees C and 37 degrees C was performed in two stages. The rapid reduction of the titre within 24 hours was followed by a slower decrease, reaching total inactivation after 96 hours at both temperatures. When the virus was tested by means of the contamination of various substrates (glass, metal sheet, plant leaf) with 0.1 ml of infection suspension in a thin layer, the longest survival of the virus was recorded at the temperature of 5 degrees C--144 hours. At the temperature of 20 to 21 degrees C the virus kept its activity on the glass and plant leaf for 24 hours and on the metal sheet for 48 hours although the applied drops looked like having dried. The temperature of 30 degrees C combined with intensive sunshine devitalized the virus within 1.5 hours, whereas without sunshine the virus still remained active, at the temperature of 30 degrees C, after 20 hours. 相似文献
8.
Experimental rabies in skunks: effects of immunosuppression induced by cyclophosphamide. 总被引:1,自引:1,他引:0 下载免费PDF全文
Striped skunks (Mephitis mephitis) were inoculated with street rabies virus and immunosuppressed with several doses of cyclophosphamide. Control skunks were inoculated with street virus only. The skunks were killed in terminal stages of the disease and several tissues were collected for examination by immunofluorescence, light microscopy and viral titration. Sera collected at euthanasia from most of the principals did not contain detectable rabies neutralizing antibodies, whereas high titers occurred terminally in controls. Immunofluorescence was much more entensive in submandibular salivary glands of cyclophosphamide-treated than control skunks. Similarly, virus was isolated from this tissue more consistently and at higher titer from principals than from controls. Immunofluorescence was extensive in brains of all skunks (both groups), but virus was isolated consistently only from brains of cyclophosphamide-treated skunks. Most of the cyclophosphamide-treated skunks had very few inflammatory cells in brain and cerebrospinal ganglia. Neuronal degeneration occurred in dorsal root ganglia of both principals and controls. The results suggest that the immune response has no effect on the development of rabies-induced aggressive behavior, that the immune response may inhibit salivary gland infection and that it is not essential for the development of neuronal degeneration in dorsal root ganglia. 相似文献
9.
10.
Thomovsky EJ Backus RC Mann FA Richmond CK Wagner-Mann CC 《American journal of veterinary research》2008,69(5):652-658
OBJECTIVE: To determine whether lipid particle coalescence develops in veterinary parenteral nutrition (PN) admixture preparations that are kept at room temperature (23 degrees C) for > 48 hours and whether that coalescence is prevented by admixture filtration, refrigeration, or agitation. SAMPLE POPULATION: 15 bags of veterinary PN solutions. PROCEDURES: Bags of a PN admixture preparation containing a lipid emulsion were suspended and maintained under different experimental conditions (3 bags/group) for 96 hours while admixtures were dispensed to simulate IV fluid administration (rate, 16 mL/h). Bags were kept static at 4 degrees C (refrigeration); kept at 23 degrees C (room temperature) and continuously agitated; kept at room temperature and agitated for 5 minutes every 4 hours; kept static at room temperature and filtered during delivery; or kept static at room temperature (control conditions). Admixture samples were collected at 0, 24, 48, 72, and 96 hours and examined via transmission electron microscopy to determine lipid particle diameters. At 96 hours, 2 samples were collected at a location distal to the filter from each bag in that group for bacterial culture. RESULTS: Distribution of lipid particle size in the control preparations and experimentally treated preparations did not differ significantly. A visible oil layer developed in continuously agitated preparations by 72 hours. Bacterial cultures of filtered samples yielded no growth. CONCLUSIONS AND CLINICAL RELEVANCE: Data indicated that the veterinary PN admixtures kept static at 23 degrees C are suitable for use for at least 48 hours. Manipulations of PN admixtures appear unnecessary to prolong lipid particle stability, and continuous agitation may hasten lipid breakdown. 相似文献
11.
U Biermann W Herbst T Schliesser 《Berliner und Münchener tier?rztliche Wochenschrift》1990,103(3):88-90
The tenacity of viruses in liquid manure of cattle was examined in a total of five samples inoculated with ECBO-virus (strain LCR-4) representing viruses without envelope and Aujeszky virus (field isolate) representing enveloped viruses. The titers were examined at regular intervals over a period of 26 weeks. On the day of inoculation each sample had a titer of 10(5) ID50/ml. After 16 weeks complete inactivation was observed in the Aujeszky virus sample stored at 20 degrees C. The Aujeszky virus sample wich was kept at 4 degrees C at 26 weeks had a titer of 10(1,75) ID50/ml. In the samples inoculated with ECBO virus after 26 weeks of inoculation a titer of 10(3) ID50/ml was found in the manure stored at 20 degrees C. No influence on the virus titers in the liquid manure samples was observed either from pH or the number of bacteria (3,4 x 10(7)-1.16 x 10(8)/ml during the examination period. 相似文献
12.
The objective of this study was to assess the stability of ELISA plates prepared with one of three blocking agents and used with one of two conjugates at various time intervals after preparation of the plates. Two of the blocking agents used were commercially available: one termed stabilgaurd (stab) and one manufactured by SVANOVA Biotek AB Inc. (svan). The third blocking agent used was bovine serum albumin (bsa). A polyclonal rabbit anti-bovine IgG (poly) and an anti-bovine IgG monoclonal (mono) conjugate were used. Eighteen composite individual cow milk samples collected late in lactation (200-400 days in milk) were used in this study. An indirect microtitre plate ELISA that used the Ostertagia ostertagi antigen was used to quantify antibodies against the parasite, present in the milk samples. Each of six blocking agent/conjugate combinations (called systems) were used to test 18 milk sub-samples at 1, 4 and 24 weeks after blocking the plates. Plates blocked with stab and svan were kept at room temperature and an additional set were incubated at 37 degrees C so as to mimic long term storage (about 1 year) and tested only once at 4 weeks. Those blocked with bsa were frozen at -20 degrees C. Concordance correlation coefficients (CCC) and reproducibility were used to assess the agreement between test results conducted on the same milk sample at the various test-times using a particular system. Generally, there was good agreement between tests conducted at different times for all systems. However, the svan-mono and bsa-poly systems had the best agreement with overall CCC values of 96% and 93%, respectively. The svan-poly system had the lowest CCC of 75%. The CCC and reproducibility ranked the systems in a similar way. The high CCC between tests done using plates kept at room temperature and ones incubated at 37 degrees C, suggested that plates would be stable up to a year after blocking. The storage of plates blocked with svan and stab agents under room temperature, makes them more convenient to use and transport relative to bsa-blocked plates that have to be frozen. 相似文献
13.
Direct immunofluorescence on impression smears of brain and pharynx was compared with virus isolation in cell culture for the diagnosis of Aujeszky's disease in experimentally and naturally infected pigs. Pharyngeal impression smears were more sensitive than virus isolation in two pigs killed 10 and 12 days after experimental infection. Both methods were of similar sensitivity in the detection of virus from field cases of disease. Smears of brain and pharynx were more sensitive than virus isolation for tissue which had been stored at room temperature (approximately 20 degrees C) for up to 48 hours. Some reduction in the amounts of virus recovered from tissues and the intensity of fluorescent staining occurred in these samples. 相似文献
14.
Quan M Mülders MS Meltzer DG 《Journal of the South African Veterinary Association》2002,73(3):111-114
Investigaltions to determine the effect of sample storage on the concentration of copper in liver tissue and on the activity of erythrocyte superoxide dismutase were undertaken in preparation for a study of blesbok (Damaliscus pygargus phillipsi) that were suspected to be suffering from copper deficiency. Two liver samples were collected from each of 20 culled blesbok in a manner that simulated the collection of biopsies from the live animal. These samples were stored either in 10% formalin or frozen at -20 degrees C until analysed 4 1/2 months later. The effect of different methods of sample storage on superoxide dismutase activity was determined. Erythrocytes collected from 3 Jersey cows and 5 culled blesbok were washed and divided into 0.5 ml portions, stored at room temperature (approximately 20 degrees C), in a refrigerator (4 degrees C), frozen at -20 degrees C in a freezer, and in liquid nitrogen (-200 degrees C). An analysis of superoxide dismutase activity was undertaken using a commercial assay kit at intervals of 2-4 days until the levels of activity had fallen significantly. The copper concentration in formalin-preserved liver samples was significantly lower than that measured in frozen liver tissue apparently as a result of leaching. The activity of superoxide dismutase in cattle blood was unchanged for 4 days at room temperature but fell appreciably after 2 days at 4 degrees C and -20 degrees C. Enzyme activity remained unchanged for 200 days in erythrocytes stored in liquid nitrogen. Superoxide dismutase activity levels in healthy blesbok were considerably lower than those measured in Jersey cows and remained unaffected for up to 6 days in samples stored at 4 degrees C and 20 degrees C. The level of activity fell significantly thereafter. Samples stored in liquid nitrogen were unchanged after 40 days. 相似文献
15.
湖南湘西地区外观健康犬携带狂犬病病毒的调查研究 总被引:3,自引:0,他引:3
为了解湖南湘西地区外观健康犬携带狂犬病病毒的情况,我们于2005年9月从湘西狂犬病疫点采集38份扑杀的外观健康的犬脑组织,并于2006年1月在湘西农贸市场采集了168份外观健康的犬脑组织。RT-PCR和直接荧光抗体试验(FAT)检测表明共有5份犬脑标本为阳性,并用乳鼠脑内接种的方法分离得到了5株狂犬病病毒毒株,分子流行病学分析表明这5株病毒均为野毒。在这5份阳性标本,疫点有4份,检出率为10.5%,市场1份,检出率为0.59%。我们的调查结果表明疫点的外观健康犬携带狂犬病病毒的检出率与国内的其它报道接近,而从市场采集的标本的检出率却要低很多。 相似文献
16.
17.
Horney BS Honor DJ MacKenzie A Burton S 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1993,22(1):5-9
Serum sorbitol dehydrogenase (SDH) activities in 10 cows and nine horses were measured using an automated clinical analyzer. The serum samples were divided into aliquots that were stored at room temperature (21 degrees C), refrigerated (0-5 degrees C), or frozen (-30 degrees C). The stability of the SDH activity was monitored at various intervals. SDH activity in bovine sera remained stable for at least 5 hours at room temperature, 24 hours refrigerated, and 72 hours frozen without any significant (p < 0.05) differences from the initial serum values. In equine sera, SDH activity remained stable for at least 5 hours at room temperature and 48 hours frozen. The activity of the refrigerated equine sera was stable for at least 5 hours but less than 24 hours. An evaluation of fresh bovine serum and heparinized plasma samples indicated that there was no significant difference (p < 0.05) between the two sampling methods and that either may be employed for automated measurement of SDH activity following the established protocol. Sample type comparison indicated that there was a small but statistically significant (p < 0.05) difference between the results obtained comparing fresh serum and heparinized plasma samples for the horse. A reference range for Holstein cows was established using sera from 71 clinically healthy cattle (mean -/+ 2 SD = 32 -/+ 26 U/L). 相似文献
18.
Poxviruses are known to remain infectious in the scabs of patients for months to years. The aim of this study was to investigate viral stability in storm water, food or gauze spiked with vaccinia virus strain Munich 1 (VACV M1). Storm water, storm water supplemented with either fetal calf serum (FCS) or potting soil was stored at two different temperatures (refrigerator, room temperature; 4 degrees C/25 degrees C). In addition, we analysed the viability of VACV M1 on the surface of bread, salad, sausages and gauze bandages stored at 4 degrees C. Samples were titrated in MA 104 cells and the presence of viral DNA was demonstrated by orthopoxvirus-specific PCRs. After 2 weeks, reisolation of VACV M1 from all kinds of food, bandage and water samples except for storm water supplemented with potting soil was possible. Viral DNA was detected in almost all samples by PCR. Prolonged experiments with VACV M1-spiked storm water and storm water supplemented with FCS revealed that samples kept at 4.5 degrees C are infectious for up to 166 days. Our data demonstrate that VACV M1 has a longlasting stability in water and food. The results obtained during this study should be taken into account for risk assessment calculations for poxvirus transmission. Implying that variola virus and vaccinia virus behave in a similar way, our data call for sophisticated countermeasures in cases of a variola release in biological warfare. 相似文献
19.
20.
Sánchez A Contreras A Jiménez J Luengo C Corrales JC Fernández C 《Veterinary microbiology》2003,94(1):71-77
With the aim of evaluating the effect of freezing goat milk samples on recovery of intramammary pathogens, 1200 milk samples from udder halves with subclinical intramammary infection were studied. Samples (20 ml) were frozen at -20 and at -80 degrees C. Thawing was carried out at room temperature at 7, 14, 21, 28, 58, 118, 178, 236 and 730 days after collection and bacteriological analyses were carried out to determine the number of colony forming units/ml (CFU/ml). Mixed model statistical analysis showed that bacterial group, temperature of storage, interaction of bacterial group and temperature of storage and the interaction of bacterial group, time and temperature of storage were statistically significant effects. For coagulase negative staphylococci (CNS), least squares means of log CFU/ml recovered at -20 and -80 degrees C were not different. Nevertheless, for Gram negative bacilli (GNB) a significant decrease was detected in samples frozen at -20 vs. -80 degrees C. At both temperatures and at different times of storage, significant increases were detected between log CFU/ml of CNS and values on day zero. At -20 degrees C, a significant decrease in GNB recovery was detected between freezing days zero and 730. This difference was not detected when goat milk samples infected by GNB were frozen at -80 degrees C. The results show that frozen milk samples can be useful in goat subclinical mastitis control programs. 相似文献