Safety of an attenuated West Nile virus vaccine, live Flavivirus chimera in horses

REASON FOR PERFORMING STUDY: West Nile virus (WNV) infection is endemic and able to cause disease in naive hosts. It is necessary therefore to evaluate the safety of new vaccines. OBJECTIVES: To establish: 1) the safety of a modified live Flavivirus/West Nile virus (WN-FV) chimera by administration of an overdose and testing for shed of vaccine virus and spread to uninoculated sentinel horses; 2) that this vaccine did not become pathogenic once passaged in horses; and 3) vaccine safety under field conditions. METHODS: There were 3 protocols: 1) In the overdose/shed and spread study, horses were vaccinated with a 100x immunogenicity overdose of WN-FV chimera vaccine and housed with sentinel horses. 2) A reversion to virulence study, where horses were vaccinated with a 20x immunogenicity overdose of WN-FV chimera vaccine. Horses in both studies were evaluated for abnormal health conditions and samples obtained to detect virus, seroconversion and dissemination into tissues. 3) In a field safety test 919 healthy horses of various ages, breeds and sex were used. RESULTS: Vaccination did not result in site or systemic reactions in either experimental or field-injected horses. There was no shed of vaccine virus, no detection of vaccine virus into tissue and no reversion to virulence with passage. CONCLUSIONS: WN-FV chimera vaccine is safe to use in horses with no evidence of ill effects from very high doses of vaccine. There was no evidence of reversion to virulence. In addition, administration of this vaccine to several hundred horses that may have been previously exposed to WNV or WNV vaccine resulted in no untoward reactions. POTENTIAL RELEVANCE: These studies establish that this live attenuated Flavivirus chimera is safe to use for immunoprophylaxis against WNV disease in horses.     

Effect of oxytocin on expression of cytosolic phospholipase A2 mRNA and protein in ovine endometrial tissue in vivo

The induction of endometrial prostaglandin (PG) F₂ synthesis by oxytocin is dependent upon activation of phospholipase (PL) A₂ and mobilization of arachidonic acid. The objective of this study was to determine if oxytocin stimulates PGF₂ synthesis by inducing synthesis of cytosolic PLA₂ (cPLA₂). In Experiment 1, 15 ovariectomized ewes were given progesterone and estradiol to simulate an estrous cycle. Ewes were then given an injection of oxytocin on Day 14 of the simulated estrous cycle. Jugular blood samples were collected and assayed for 13,14-dihydro-15-keto-prostaglandin F₂ (PGFM). Uteri were collected at 0, 7.5, 25, 90, or 240 min postinjection (n = 3 ewes/time point). Total RNA was isolated from caruncular endometrium and subjected to dot-blot analysis. Oxytocin induced a rapid and transient increase in serum PGFM (P < 0.01). However, endometrial concentrations of cPLA2 mRNA did not change following oxytocin administration (P > 0.10). In Experiment 2, 11 ovary-intact ewes were given oxytocin (n = 5) or saline (n = 6) on Day 15 after estrus. Jugular blood samples were collected and assayed for serum concentrations of PGFM. Uteri were collected at 15 min postinjection. Homogenates were prepared from caruncular endometrium and subjected to Western blot analysis. Concentrations of PGFM were higher in oxytocin treated ewes compared to saline treated ewes at 15 min postinjection (P < 0.01). Endometrial concentrations of cPLA₂ protein were greater in the cytosolic than in the microsomal fraction (P < 0.01). Oxytocin did not affect the amount of cPLA₂ protein in either fraction (P > 0.10). In conclusion, oxytocin did not effect expression of either cPLA₂ mRNA or protein in ovine endometrium. Oxytocin may stimulate PGF₂ synthesis by activating cPLA₂ protein that is already present in an inactive form.     

Vertical distribution, size and composition of the weed seedbank under various tillage and herbicide treatments in a sequence of industrial crops

Investigations were conducted during the 2003, 2004 and 2005 growing seasons in northern Greece to evaluate effects of tillage regime (mouldboard plough, chisel plough and rotary tiller), cropping sequence (continuous cotton, cotton–sugar beet rotation and continuous tobacco) and herbicide treatment on weed seedbank dynamics. Amaranthus spp. and Portulaca oleracea were the most abundant species, ranging from 76% to 89% of total weed seeds found in 0–15 and 15–30 cm soil depths during the 3 years. With the mouldboard plough, 48% and 52% of the weed seedbank was found in the 0–15 and 15–30 cm soil horizons, while approximately 60% was concentrated in the upper 15 cm soil horizon for chisel plough and rotary tillage. Mouldboard ploughing significantly buried more Echinochloa crus‐galli seeds in the 15–30 cm soil horizon compared with the other tillage regimes. Total seedbank (0–30 cm) of P. oleracea was significantly reduced in cotton–sugar beet rotation compared with cotton and tobacco monocultures, while the opposite occurred for E. crus‐galli. Total seed densities of most annual broad‐leaved weed species (Amaranthus spp., P. oleracea, Solanum nigrum) and E. crus‐galli were lower in herbicide treated than in untreated plots. The results suggest that in light textured soils, conventional tillage with herbicide use gradually reduces seed density of small seeded weed species in the top 15 cm over several years. In contrast, crop rotation with the early established sugar beet favours spring‐germinating grass weed species, but also prevents establishment of summer‐germinating weed species by the early developing crop canopy.     

Occurrence of Staphylococcus intermedius on the hair and skin of normal dogs.

Aerobic bacterial populations were studied on the distal hair coat and at the skin surface of the shoulder, rump and abdomen of 10 healthy dogs. Coagulase negative staphylococci (CNS) were more frequently isolated from the hair than the skin at the shoulder and rump. There was no difference in the isolation rate of coagulase positive staphylococci (CPS) (Staphylococcus intermedius) between the hair and skin. Total skin counts were greatest on the abdomen whereas CNS counts from the hair were least at this site. There were no differences between CPS counts at the three sites on either hair or skin. The populations on the relatively unfavourable microenvironment of the distal hair may represent contamination rather than colonisation. The low populations of CPS at the skin surface also indicate contamination or transient colonisation rather than true resident status.     

Detection of Invasive Borrelia burgdorferi Strains in North‐Eastern Piedmont,Italy

Following reports of human cases of Lyme borreliosis from the Ossola Valley, a mountainous area of Piemonte, north‐western Italy, the abundance and altitudinal distribution of ticks, and infection of these vectors with Borrelia burgdorferi sensu lato were evaluated. A total of 1662 host‐seeking Ixodes ricinus were collected by dragging from April to September 2011 at locations between 400 and 1450 m above sea level. Additional 104 I. ricinus were collected from 35 hunted wild animals (4 chamois, 8 roe deer, 23 red deer). Tick density, expressed as the number of ticks per 100 m², resulted highly variable among different areas, ranging from 0 to 105 larvae and from 0 to 22 nymphs. A sample of 352 ticks (327 from dragging and 25 from wild animals) was screened by a PCR assay targeting a fragment of the 16S rRNA gene of B. burgdorferi s.l. Positive samples were confirmed with a PCR assay specific for the 5S‐23S rRNA intergenic spacer region and sequenced. Four genospecies were found: B. afzelii (prevalence 4.0%), B. lusitaniae (4.0%), B. garinii (1.5%) and B. valaisiana (0.3%). Phylogenetic analysis based on the ospC gene showed that most of the Borrelia strains from pathogenic genospecies had the potential for human infection and for invasion of secondary body sites.     

Yield-height correlation and QTL localization for plant height in two lowland switchgrass populations

Switchgrass (Panicum virgatum L.), as a model herbaceous crop species for bioenergy production, is targeted to improve biomass yield and feedstock quality. Plant height is a major component contributing to biomass yield. Accordingly, the objectives of this research were to analyze phenotypic variation for biomass and plant height and the association between them and to localize associated plant height QTLs. Two lowland switchgrass mapping populations, one selfed and another hybrid population established in the field at Perkins and Stillwater, Oklahoma, were deployed in the experiment for two years post establishment. Large genetic variation existed for plant biomass and height within the two populations. Plant height was positively correlated with biomass yield in the selfed population (r = 0.39, P<0.0001) and the hybrid population (r = 0.41, P<0.0001). In the selfed population, a joint analysis across all environments revealed 10 QTLs and separate analysis for each environment, collectively revealed 39 QTLs related to plant height. In the hybrid population, the joint analysis across overall environments revealed 35 QTLs and the separate analysis for each environment revealed 38 QTLs. The findings of this research contribute new information about the genetic control for plant height and will be useful for future plant breeding and genetic improvement programs in lowland switchgrass.     

Long-term study of partial arytenoidectomy with primary mucosal closure in 76 Thoroughbred racehorses (1992-2006)

REASON FOR PERFORMING STUDY: The effectiveness and best method to perform a partial arytenoidectomy in racehorses is unclear. This study was performed to evaluate the success of and complications that can occur after a unilateral partial arytenoidectomy with primary mucosal closure in Thoroughbred racehorses. HYPOTHESIS: Partial arytenoidectomy is an effective surgical procedure to return Thoroughbred racehorses, afflicted by arytenoid chondropathy or a failed laryngoplasty, to preoperative levels of performance. METHODS: Seventy-six Thoroughbred racehorses admitted to the New Bolton Centre between 1992 and 2006 were assessed. Information was obtained from the medical records about the horse, laryngeal abnormalities, surgery and other findings during hospitalisation. Racing information was evaluated relative to those independent variables by an analysis of variance with a level of significance of P<0.05. RESULTS: Arytenoid chondropathy was the presenting complaint in 54 horses and failed laryngoplasty in 22 horses. Thirteen horses (17%) underwent a second surgery for laser excision of intralaryngeal granulation tissue at the arytenoidectomy site. Seventy-three horses were discharged from the hospital and racing outcome was evaluated. Sixty horses (82%) raced after surgery and 46 horses (63%) raced 5 or more times after surgery. The median time from surgery to the first start was 6 months. The average earnings/start was not significantly different before and after surgery. There was no association between earnings after surgery and age, gender, location of lesion, type of lesion, duration of tracheal intubation or undergoing a second surgery. CONCLUSIONS AND POTENTIAL RELEVANCE: A Thoroughbred racehorse is likely to race after a unilateral partial arytenoidectomy with primary mucosal closure and return to a preoperative level of performance.     

Growth,feed efficiency and blood profile of buffalo calves consuming high levels of fluoride

Twelve male buffalo calves of 10 to 12 months of age were divided into 3 groups of four each. They were fed wheat straw+concentrate mixture +3 Kg greens. The chemical composition of the diet was same in all the three groups except fluoride which was added (as NaF) in concentrate mixture of group B and C to make the final fluoride concentration 30 ppm and 60 ppm respectively. The animals were kept on scheduled diet for a period of 90 days. Body weights were recorded at the start of the experiment and at fortnightly interval thereafter. Analysis of data revealed that the dry matter intake decreased non significantly in group B and C as compared to control group. A significant decrease in serum calcium and a significant increase in phosphorus concentration were observed in group C animals. A significant increase was observed in alkaline phosphatase activity in group C animals. A non significant decrease was observed in T₄ values in group C animals. On the basis of these results it could be concluded that fluoride in the diet of buffalo calves @ 30 ppm is a safe level whereas 60 ppm has affected the blood metabolites.     

Evaluation of Methods to Determine Sperm Density for the European eel,Anguilla anguilla

European eel, Anguilla anguilla, is a target species for future captive breeding, yet best methodology to estimate sperm density for application in in vitro fertilization is not established. Thus, our objectives were to evaluate methods to estimate European eel sperm density including spermatocrit, computer‐assisted sperm analysis (CASA) and flow cytometry (FCM), using Neubauer Improved haemocytometer as benchmark. Initially, relationships between spermatocrit, haemocytometer counts and sperm motility were analysed, as well as the effect of sperm dilution on haemocytometer counts. Furthermore, accuracy and precision of spermatocrit, applying a range of G‐forces, were tested and the best G‐force used in method comparisons. We found no effect of dilution on haemocytometer sperm density estimates, whereas motility associated positively with haemocytometer counts, but not with spermatocrit. Results from all techniques, spermatocrit, CASA and FCM, showed significant positive correlations with haemocytometer counts. The best correlation between spermatocrit and haemocytometer counts was obtained at 6000 ×  g (r = 0.68). Of two CASA variants, one or three photographic fields (CASA‐1 and CASA‐2), CASA‐2 showed a very high accuracy to haemocytometer counts (r  =  0.93), but low precision (CV: CASA‐2 = 28.4%). FCM was tested with and without microfluorospheres (FCM‐1 and FCM‐2), and relationships to haemocytometer counts were highly accurate (FCM‐1: r  =  0.94; FCM‐2: r  =  0.88) and precise (CV: FCM‐1 = 2.5; FCM‐2 = 2.7%). Overall, CASA‐2 and FCM‐1 feature reliable methods for quantification of European eel sperm, but FCM‐1 has a clear advantage featuring highest precision and accuracy. Together, these results provide a useful basis for gamete management in fertilization protocols.