An update on national recommendations for the use of the adjuvanted recombinant zoster vaccine

Background

The adjuvanted recombinant zoster vaccine (RZV), first approved in 2017, has high, long-lasting efficacy against herpes zoster (HZ) and a clinically acceptable safety profile. In addition to the prevention of HZ in adults aged ≥50 years, the non-live RZV can be used from age 18 years in individuals with immunocompromised (IC) conditions. We reviewed the evolving landscape of national recommendations for RZV use.

Methods

National health authority and vaccination committee websites of countries where RZV is approved were searched in March 2022.

Results

Of 41 countries where RZV is licensed, 14 (Australia, Austria, Canada, Czech Republic, Germany, Ireland, Italy, Netherlands, New Zealand, Saudi Arabia, Spain, Switzerland, UK, US) provide national recommendations related to RZV; the majority are preferential to RZV or only recommend RZV. Overall, seven and seven countries recommend immunisation from age 50 years or 60/65 years, respectively. Of the seven countries that recommend immunisation from age 60/65 years, five recommend immunisation in individuals from age 50 years with comorbidities/IC conditions. Five countries recommend immunisation from age 18/19 years in individuals at increased risk of HZ due to immunosuppressive disease/treatment. In addition, six national recommendations refer to RZV safety and nine address prior HZ vaccination and/or infection. All recommendations outlined the RZV administration schedule.

Conclusions

Although national recommendations can inform decision making in clinical practice, RZV recommendations are not available in all licensed countries. The recommendations highlight a trend in favour of the use of RZV for the prevention of HZ in older individuals and those with IC conditions.

Main messages: An increasing number of countries are providing recommendations for the use of RZV for the prevention of HZ in older individuals and those with IC conditions.

Key messages

• An increasing number of countries are providing recommendations for the use of RZV for the prevention of HZ in older individuals.

• An increasing number of countries are providing recommendations for the use of RZV for the prevention of HZ in IC conditions.

Pattern of skin disease in Ethiopian HIV-infected patients on combination antiretroviral therapy: A cross-sectional study in a dermatology referral hospital

Background

More than 90% of human immunodeficiency virus (HIV)-infected patients will develop at least one type of skin disorder during the course of the disease. The prevalence and severity of skin disease commonly seen in HIV-infected patients has decreased in the era of combination antiretroviral therapy (cART). Few studies in Ethiopia have shown the magnitude of skin problems among adult patients on cART. The aim of this study is to describe the pattern of skin disease among adult patients who are on cART.

Methods

Cross-sectional observational study at ALERT Hospital from April 2018 to November 2018. Patterns of clinically diagnosed skin diseases were summarized descriptively.

Result

A total of 572 patients were evaluated. In total, 412 (72%) were female and the mean age of study participants was 40 (SD = 10.4). The median CD4 count at the time of diagnosis and start of cART were 178 (R 5-2000) and 168 cells/μl (R 5-1327), respectively. The mean duration of cART was 8 (SD = 3) years. 89.3% of patients were on first line and 7% on second line of cART regimen. Noninfectious inflammatory skin disorders (40.9%) were the most common concomitant diagnosis followed by infectious diseases (34.9%), infestation (7.7%), pigmentary disorders (6.3%) and cutaneous drug eruption (0.7%), respectively. Among the inflammatory skin disorders, 56.5% presented with eczema. One patient had Kaposi sarcoma.

Conclusion

Noninfectious inflammatory skin disorders are the most common concomitant skin disease in HIV-infected patients, with eczema being most prevalent. Infectious skin diseases were also common presentations. In our study, AIDS-defining skin conditions were rare.

Liver-expressed Cd302 and Cr1l limit hepatitis C virus cross-species transmission to mice

Hepatitis C virus (HCV) has no animal reservoir, infecting only humans. To investigate species barrier determinants limiting infection of rodents, murine liver complementary DNA library screening was performed, identifying transmembrane proteins Cd302 and Cr1l as potent restrictors of HCV propagation. Combined ectopic expression in human hepatoma cells impeded HCV uptake and cooperatively mediated transcriptional dysregulation of a noncanonical program of immunity genes. Murine hepatocyte expression of both factors was constitutive and not interferon inducible, while differences in liver expression and the ability to restrict HCV were observed between the murine orthologs and their human counterparts. Genetic ablation of endogenous Cd302 expression in human HCV entry factor transgenic mice increased hepatocyte permissiveness for an adapted HCV strain and dysregulated expression of metabolic process and host defense genes. These findings highlight human-mouse differences in liver-intrinsic antiviral immunity and facilitate the development of next-generation murine models for preclinical testing of HCV vaccine candidates.

The epidemiological status of African swine fever in domestic swine herds in the Tavush Province region, Armenia

KEEN The factors associated with the spread and persistence of African swine fever (ASF) in the Caucasus region remain to be fully identified. It is assumed that large naive populations of domestic free-ranging and wild pigs are critical to disease transmission and maintenance. Nonetheless, 11 years since its epidemic introduction into the region in 2007, ASF virus (ASFV) is still circulating, suggesting that an endemic cycle has been established based on contact between free-ranging domestic pigs and wild pigs, and that native Ornithodoros ticks probably serve as reservoirs for the virus. Therefore, research is required to gather information on the epidemiological status of ASF in the Caucasus region, focusing particularly on understanding modes of ASFV spread and persistence in this new virus environment. The authors established an ASFV survey targeting domestic pigs in the Tavush province of northern Armenia, an area of the country considered to be at high risk of disease incursion/occurrence. All tested samples collected for this survey were negative for ASF. The probability of observing no reactors by antibody enzyme-linked immunosorbent assay in a sample of this size (n = 1,506) from a population with an estimated disease prevalence of 1% is very low (< 0.0001). Therefore, it is possible but very unlikely for ASFV to be present among domestic pigs in the Tavush province region.

Accelerometer activity tracking in horses and the effect of pasture management on time budget

BACKGROUND

Accelerometry is an accepted means of quantifying human physical activity. Quantitative physical activity tracking could be beneficial for studies into equine health and disease prevention, for example in relation to obesity management.

OBJECTIVES

Validate accelerometer use in grazing horses, determine between-day repeatability, and assess the effects of pasture size on time budget (i.e. duration in each activity category).

STUDY DESIGN

Proof of concept.

METHODS

Accelerometers (ActiGraph) were positioned at the poll. Horses underwent 5 min of observed activity in three categories: standing, grazing and ambulating. Receiver-operating characteristic curve analysis, used on ten second data epochs, calculated cut points between the activities. A 20-day study was then undertaken on 6 horses at pasture. Time in each category (per day) was deduced; a Mann Whitney U test was performed to compare standard vs. small paddock and day vs. night turn out.

RESULTS

Cut-off values with the optimum sensitivity (94.7-97.7%) and specificity (94.7-96.8%) were found to be <127.6 counts for standing, 127.6-702.7 counts for grazing and >702.7 counts for ambulating. Repeatability was analysed descriptively: Median (IQR) of the between-day difference in minutes standing, grazing and ambulating were 46.9 (21.3-87.9), 77.3 (40.2-124.5) and 15.6 (6.8-40.2) respectively. Median times standing and ambulating were significantly different between standard and small paddocks: standing: 8.7 vs. 10.3 h (P<0.001); ambulating: 55.7 vs. 39.6 min (P = 0.002). There was no significant difference in the median time spent grazing. There were significant differences between day and night: standing: 32.95% vs. 50.97% (P = 0.001), grazing: 60.81% vs. 46.77% (P<0.001) and ambulating: 4.57% vs. 2.40% (P<0.001).

MAIN LIMITATIONS

Small sample size and lack of cross-validation of cut-off points on independent, 'unseen' data.

CONCLUSIONS

Accelerometry can differentiate standing, grazing and ambulating in horses. Our proof-of-concept study demonstrates modifying pasture size influences activity budgets; opening avenues into studying obesity management.

Active surveillance of African swine fever in domestic swine herds in Georgia, 2014

Since its introduction to the Republic of Georgia in 2007, African swine fever virus (ASFV) has spread across the Caucasus region, the Russian Federation, and some Eastern European countries. It is assumed that large populations of naïve, domestic, free-ranging and wild pigs are vital to the transmission of the disease. Since its epidemic emergence in the region in 2007, ASFV has continued to circulate, which suggests that an endemic cycle has been established and is maintained by contact between free-ranging domestic pigs, wild pigs, and possibly native Ornithodoros ticks, the most likely reservoirs for the virus. In 2014, a survey was conducted across the Republic of Georgia to determine ASFV prevalence among domestic swine herds. All 1,231 samples collected for this survey tested negative for ASF. The probability of observing no reactors in a sample of this size (n = 1,231) from a population with an estimated disease prevalence of 1% is very low (<0.0001). Therefore, it is possible but very unlikely that ASFV was present among domestic swine during the span of this survey. These data suggest that, in 2014, domestic pig herds were not the source of the virus, and that the ASF endemic cycle may be supported by the circulation of ASFV among feral pigs, wild pigs, and possibly native Ornithodoros ticks.

Use of positive contrast radiography to identify synovial involvement in horses with traumatic limb wounds

BACKGROUND

The diagnostic value of positive contrast radiography in the work-up of suspected synovial infection in horses with limb wounds near synovial structures has yet to be systematically evaluated.

OBJECTIVES

To determine the specificity, sensitivity and positive and negative predictive values of positive contrast radiography for identification of synovial infection in a population of horses with limb wounds.

STUDY DESIGN

Retrospective case study comparing the performance of positive contrast radiography to the gold standard of synovial fluid cytology in horses presenting with limb wounds in the vicinity of synovial structures.

METHODS

Case records of horses presenting to the Royal Veterinary College Equine Hospital between 2010 and 2015 with limb wounds that may have compromised adjacent synovial structures were analysed. Synovial fluid cytology results were used to categorise synovial structures in infected and noninfected groups. Positive contrast radiography results were compared between infected and noninfected groups and sensitivity, specificity, positive and negative predictive values were calculated.

RESULTS

Fifty horses with 66 synovial structures were included in the study. Positive contrast radiography had a high specificity (86.4%), but only a moderate sensitivity (59.1%) for the identification of synovial infection. In addition, a low positive predictive value (68.4%) and high negative predictive value (80.9%) were observed in this population of horses.

MAIN LIMITATIONS

Sensitivity, specificity and predictive values may differ between different synovial structures and cases. Different conclusions may be drawn from the results in a single population. Sensitivity and specificity of positive contrast radiography may also be influenced by different techniques used by examiners and by inherent characteristics of individual cases.

CONCLUSIONS

Positive contrast radiography should be used for the investigation of potential synovial infection in horses with limb wounds, particularly if no synovial fluid sample for laboratory analysis can be obtained. However, it appears that positive contrast radiography is best used in combination with other tests to ensure that a correct and timely diagnosis is made.

Does 'hacking' surface type affect equine forelimb foot placement, movement symmetry or hoof impact deceleration during ridden walk and trot exercise?

BACKGROUND

Both pleasure and competition horses regularly exercise on surfaces such as tarmac, gravel and turf during 'hacking'. Despite this, there is limited evidence relating to the effect of these surfaces upon foot-surface interaction.

OBJECTIVES

To investigate forelimb foot placement, hoof vibration and movement symmetry in pleasure horses on three commonly encountered hacking surfaces.

STUDY DESIGN

Quantitative gait study in a convenience sample.

METHODS

Six horses regularly partaking in hacking exercise were ridden in walk and trot on all surfaces. Horses were equipped with one hoof-mounted, accelerometer and four body-mounted inertial measurement units (IMUs) to measure foot impact and movement symmetry. High-speed (400 FPS) video footage of foot-placement was acquired (dorsal, palmar, lateral views). Foot-impact and movement symmetry were analysed with a mixed effects model and Bowker symmetry tests for foot-placement analysis.

RESULTS

Vibration power and frequency parameters increase as perceived surface firmness increases from grass, to gravel, to tarmac (P≤0.001). Vibration power parameters were consistently greater at trot compared with walk (P≤0.001), but the same was not true for vibration frequency (P≥0.2). Greatest movement asymmetry was recorded during grass surface trotting. No significant difference in foot-placement was detected between the three surfaces.

MAIN LIMITATIONS

This was a field study using three commonly encountered hacking surfaces. Surface properties change easily with water content and temperature fluctuations so care must be taken when considering other similar surfaces, especially at different times of the year. Six leisure horses were used so the results may not be representative of horses of all types.

CONCLUSIONS

Vibration parameters generally increase as perceived surface firmness increases. Increasing speed alters vibration power but not frequency. Further investigations are required to determine the role that this may play in the development of musculoskeletal disease in horses.

Hepatitis C Virus Strain-Dependent Usage of Apolipoprotein E Modulates Assembly Efficiency and Specific Infectivity of Secreted Virions

Hepatitis C virus (HCV) is extraordinarily diverse and uses entry factors in a strain-specific manner. Virus particles associate with lipoproteins, and apolipoprotein E (ApoE) is critical for HCV assembly and infectivity. However, whether ApoE dependency is common to all HCV genotypes remains unknown. Therefore, we compared the roles of ApoE utilizing 10 virus strains from genotypes 1 through 7. ApoA and ApoC also support HCV assembly, so they may contribute to virus production in a strain-dependent fashion. Transcriptome sequencing (RNA-seq) revealed abundant coexpression of ApoE, ApoB, ApoA1, ApoA2, ApoC1, ApoC2, and ApoC3 in primary hepatocytes and in Huh-7.5 cells. Virus production was examined in Huh-7.5 cells with and without ApoE expression and in 293T cells where individual apolipoproteins (ApoE1, -E2, -E3, -A1, -A2, -C1, and -C3) were provided in trans All strains were strictly ApoE dependent. However, ApoE involvement in virus production was strain and cell type specific, because some HCV strains poorly produced infectious virus in ApoE-expressing 293T cells and because ApoE knockout differentially affected virus production of HCV strains in Huh-7.5 cells. ApoE allelic isoforms (ApoE2, -E3, and -E4) complemented virus production of HCV strains to comparable degrees. All tested strains assembled infectious progeny with ApoE in preference to other exchangeable apolipoproteins (ApoA1, -A2, -C1, and -C3). The specific infectivity of HCV particles was similar for 293T- and Huh-7.5-derived particles for most strains; however, it differed by more than 100-fold in some viruses. Collectively, this study reveals strain-dependent and host cell-dependent use of ApoE during HCV assembly. These differences relate to the efficacy of virus production and also to the properties of released virus particles and therefore govern viral fitness at the level of assembly and cell entry.IMPORTANCE Chronic HCV infections are a major cause of liver disease. HCV is highly variable, and strain-specific determinants modulate the response to antiviral therapy, the natural course of infection, and cell entry factor usage. Here we explored whether host factor dependency of HCV in particle assembly is modulated by strain-dependent viral properties. We showed that all examined HCV strains, which represent all seven known genotypes, rely on ApoE expression for assembly of infectious progeny. However, the degree of ApoE dependence is modulated in a strain-specific and cell type-dependent manner. This indicates that HCV strains differ in their assembly properties and host factor usage during assembly of infectious progeny. Importantly, these differences relate not only to the efficiency of virus production and release but also to the infectiousness of virus particles. Thus, strain-dependent features of HCV modulate ApoE usage, with implications for virus fitness at the level of assembly and cell entry.

Maturation of secreted HCV particles by incorporation of secreted ApoE protects from antibodies by enhancing infectivity

BACKGROUND & AIMS

Hepatitis C virus (HCV) evades humoral immunity and establishes chronic infections. Virus particles circulate in complex with lipoproteins facilitating antibody escape. Apolipoprotein E (ApoE) is essential for intracellular HCV assembly and for HCV cell entry. We aimed to explore if ApoE released from non-infected cells interacts with and modulates secreted HCV particles.

METHODS

ApoE secreted from non-infected cells was incubated with HCV from primary human hepatocytes or Huh-7.5 cells. Co-immunoprecipitation, viral infectivity and neutralization experiments were conducted.

RESULTS

Physiological levels of secreted ApoE (10-60µg/ml) enhanced the infectivity of HCV up to 8-fold across all genotypes, which indirectly decreased virus neutralization by antibodies targeting E1 or E2 up to 10-fold. Infection enhancement was observed for particles produced in primary human hepatocytes and Huh-7.5 cells. Selective depletion of ApoE ablated infection enhancement. Addition of HA-tagged ApoE to HCV particles permitted co-precipitation of HCV virions. Serum ApoE levels ranged between 10-60µg/ml, which is ca 100-fold higher than in Huh-7.5 conditioned cell culture fluids. Serum-derived HCV particles carried much higher amounts of ApoE than cell culture-derived HCV particles. Serum ApoE levels correlated with efficiency of co-precipitation of HCV upon exogenous addition of HA-ApoE. ApoE-dependent infection enhancement was independent of the hypervariable region 1 and SR-B1, but was dependent on heparan sulfate proteoglycans (HSPGs).

CONCLUSIONS

Physiological quantities of secreted ApoE stimulate HCV infection and increase antibody escape, by incorporating into virus particles and enhancing particle interactions with cellular HSPGs. Thus, secreted particles undergo ApoE-dependent maturation to enhance infectivity and to facilitate evasion from neutralizing antibodies. Lay summary: This study shows that HCV particle infectivity is remodeled by secreted ApoE after particle release from cells. Fluctuation of the availability of ApoE likely influences HCV infectivity, antibody escape and transmission.

Ebola Virus Disease Is Characterized by Poor Activation and Reduced Levels of Circulating CD16+ Monocytes

A number of previous studies have identified antigen-presenting cells (APCs) as key targets of Ebola virus (EBOV), but the role of APCs in human Ebola virus disease (EVD) is not known. We have evaluated the phenotype and kinetics of monocytes, neutrophils, and dendritic cells (DCs) in peripheral blood of patients for whom EVD was diagnosed by the European Mobile Laboratory in Guinea. Acute EVD was characterized by reduced levels of circulating nonclassical CD16⁺ monocytes with a poor activation profile. In survivors, CD16⁺ monocytes were activated during recovery, coincident with viral clearance, suggesting an important role of this cell subset in EVD pathophysiology.

Technical innovation changes standard radiographic protocols in veterinary medicine: is it necessary to obtain two dorsoproximal-palmarodistal oblique views of the equine foot when using computerised radiography systems?

Since the 1950s, veterinary practitioners have included two separate dorsoproximal-palmarodistal oblique (DPr-PaDiO) radiographs as part of a standard series of the equine foot. One image is obtained to visualise the distal phalanx and the other to visualise the navicular bone. However, rapid development of computed radiography and digital radiography and their post-processing capabilities could mean that this practice is no longer required. The aim of this study was to determine differences in perceived image quality between DPr-PaDiO radiographs that were acquired with a computerised radiography system with exposures, centring and collimation recommended for the navicular bone versus images acquired for the distal phalanx but were subsequently manipulated post-acquisition to highlight the navicular bone. Thirty images were presented to four clinicians for quality assessment and graded using a 1-3 scale (1=textbook quality, 2=diagnostic quality, 3=non-diagnostic image). No significant difference in diagnostic quality was found between the original navicular bone images and the manipulated distal phalanx images. This finding suggests that a single DPr-PaDiO image of the distal phalanx is sufficient for an equine foot radiographic series, with appropriate post-processing and manipulation. This change in protocol will result in reduced radiographic study time and decreased patient/personnel radiation exposure.

Comparison of a standalone consumer grade smartphone with a specialist inertial measurement unit for quantification of movement symmetry in the trotting horse

REASONS FOR PERFORMING STUDY

Equine inertial measurement unit (IMU) gait analysis has gained in popularity for use in horses. Similar transducers are now found in consumer grade smartphones. However, to date there are no scientific data evaluating their use for assessment of movement (a)symmetry in the horse.

OBJECTIVES

To establish limits of agreement (LoA, mean difference ±2 s.d.) between a validated specialist IMU system and IMU data collected with a consumer grade smartphone for quantification of movement symmetry and range of motion (ROM) of pelvic movement in the trotting horse.

STUDY DESIGN

Method comparison study based on quantitative gait data.

METHODS

Twenty horses were equipped with a specialist IMU (MTw, Xsens) and a consumer grade smartphone (Apple iPhone6), both securely attached immediately in front of one another in the midline over the sacrum. Horses were trotted in-hand and lunged on both reins on a soft arena surface. Median values for movement symmetry and ROM were determined over a series of strides for each exercise condition. Data collection was repeated in 6 horses to determine the effect of mediolateral sensor positioning on outcome parameters.

RESULTS

Valid data from 17 horses resulted in LoA values of -3.7 ± 9.2 mm for MinDiff (difference between left and right hind mid stance), -0.6 ± 6.0 mm for MaxDiff (difference between left and right hind propulsion) and -0.8 ± 7.4 mm for ROM across horses and exercises. LoAs were narrower for straight line exercise and the negative bias was considerably reduced when moving the smartphone to the right of the midline.

CONCLUSIONS

The consumer grade smartphone provided meaningful gait data in horses: LoAs in particular for in-hand exercise and when adjusting the mediolateral positioning are similar to published asymmetry thresholds. Owing to the sensitivity to mediolateral positioning, particular care should be taken when placing an IMU over the midline of the horse.

Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015

REASONS FOR PERFORMING STUDY

Training and rehabilitation techniques which improve core muscle strength are beneficial for improvement of dynamic stability of the equine vertebral column. The Equiband™ system, consisting of resistance bands attached to a customised saddle pad, is suggested to provide constant proprioceptive feedback during motion to encourage recruitment of abdominal and hindquarter musculature.

OBJECTIVES

To quantify the effect of the Equiband™ system on back kinematics and movement symmetry.

STUDY DESIGN

Longitudinal intervention study.

METHODS

Quantitative analysis of back movement and gait symmetry before/after a 4-week exercise programme. Inertial sensor data was collected from 7 horses at Weeks 0 and 4 of a fixed exercise protocol. Analysis with and without the Equiband™ system was completed at trot in hand on a hard surface, and for both reins on the lunge on a soft surface. Six back kinematic and 3 movement symmetry parameters were calculated according to published methods. Movement symmetry values were side-corrected to allow comparison between reins on the lunge. A mixed model (P<0.05) evaluated the effects of the Equiband™ system over time, and trotting direction on back kinematic and movement symmetry parameters.

RESULTS

The Equiband™ system significantly reduced (all P<0.02) roll, pitch and mediolateral displacement in the cranial-mid thoracic region. Across all horses, back displacement and range of motion values were significantly greater (P<0.01) on the lunge than in a straight line, movement symmetry was consistent with having corrected all horses to be left-sided.

CONCLUSION

Preliminary results suggest the Equiband™ system may aid dynamic stabilisation of the vertebral column. Ethical animal research: This study was authorised by the Ethics and Welfare Committee of the Royal Veterinary College, London (URN Approval Number 1238). Written consent was obtained from the owner/keeper of each animal.

SOURCE OF FUNDING

Royal Veterinary College. Competing interests: N.C. Stubbs and N. Rombach developed the Equiband™ system. The remaining authors have no competing interests.

Several Human Liver Cell Expressed Apolipoproteins Complement HCV Virus Production with Varying Efficacy Conferring Differential Specific Infectivity to Released Viruses

Apolipoprotein E (ApoE), an exchangeable apolipoprotein, is necessary for production of infectious Hepatitis C virus (HCV) particles. However, ApoE is not the only liver-expressed apolipoprotein and the role of other apolipoproteins for production of infectious HCV progeny is incompletely defined. Therefore, we quantified mRNA expression of human apolipoproteins in primary human hepatocytes. Subsequently, cDNAs encoding apolipoproteins were expressed in 293T/miR-122 cells to explore if they complement HCV virus production in cells that are non-permissive due to limiting endogenous levels of human apolipoproteins. Primary human hepatocytes expressed high mRNA levels of ApoA1, A2, C1, C3, E, and H. ApoA4, A5, B, D, F, J, L1, L2, L3, L4, L6, M, and O were expressed at intermediate levels, and C2, C4, and L5 were not detected. All members of the ApoA and ApoC family of lipoproteins complemented HCV virus production in HCV transfected 293T/miR-122 cells, albeit with significantly lower efficacy compared with ApoE. In contrast, ApoD expression did not support production of infectious HCV. Specific infectivity of released particles complemented with ApoA family members was significantly lower compared with ApoE. Moreover, the ratio of extracellular to intracellular infectious virus was significantly higher for ApoE compared to ApoA2 and ApoC3. Since apolipoproteins complementing HCV virus production share amphipathic alpha helices as common structural features we altered the two alpha helices of ApoC1. Helix breaking mutations in both ApoC1 helices impaired virus assembly highlighting a critical role of alpha helices in apolipoproteins supporting HCV assembly. In summary, various liver expressed apolipoproteins with amphipathic alpha helices complement HCV virus production in human non liver cells. Differences in the efficiency of virus assembly, the specific infectivity of released particles, and the ratio between extracellular and intracellular infectivity point to distinct characteristics of these apolipoproteins that influence HCV assembly and cell entry. This will guide future research to precisely pinpoint how apolipoproteins function during virus assembly and cell entry.

Foot placement of the equine forelimb: Relationship between foot conformation, foot placement and movement asymmetry

REASONS FOR PERFORMING STUDY

Hoof conformation, foot placement and movement asymmetry are routinely assessed as part of the lameness examination. However, to date, few studies have described these parameters, or the interplay between them, in the general horse population.

OBJECTIVES

To assess foot conformation and foot placement in the forelimbs of a group of general purpose horses and investigate the relationships between foot placement, foot conformation and movement asymmetry.

STUDY DESIGN

Observational cross-sectional study.

METHODS

Forty-three horses were included in the study. Measurements were taken from photographs of each forelimb to assess foot conformation. Video footage was recorded simultaneously from perpendicular cameras at both walk and trot and used to categorise foot placement. Inertial sensor data were used to assess head movement asymmetry in trot.

RESULTS

There was a high degree of variation in foot placement between and within horses, but a 'lateral heel' placement was most common in walk and a 'lateral' placement most common in trot. Foot placement was associated with dorsal and palmar hoof angles but there was no relationship between foot placement and the other conformation parameters, nor with movement asymmetry. Moderate negative correlations were found between several of the conformation parameters and movement asymmetry.

CONCLUSIONS

A relationship exists between foot conformation and movement asymmetry with decreasing hoof width and hoof length related to increasing amount of movement asymmetry. In the population of horses studied here--deemed to be 'well functioning' by their owners/riders--foot placement was found to be independent of movement asymmetry and, to a large extent, independent of foot conformation.

Lungeing on hard and soft surfaces: Movement symmetry of trotting horses considered sound by their owners

REASONS FOR PERFORMING STUDY

Lungeing is often part of the clinical lameness examination. The difference in movement symmetry, which is a commonly employed lameness measure, has not been quantified between surfaces.

OBJECTIVES

To compare head and pelvic movement symmetry between surfaces and reins during lungeing.

STUDY DESIGN

Quantitative gait analysis in 23 horses considered sound by their owners.

METHODS

Twenty-three horses were assessed in-hand and on the lunge on both reins on hard and soft surfaces with inertial sensors. Seven movement symmetry parameters were quantified and used to establish 2 groups, namely symmetrical (n = 9) and forelimb-lame horses (n = 14), based on values from straight-line assessment. Movement symmetry values for left rein measurements were side corrected to allow comparison of the amount of movement symmetry between reins. A mixed model (P<0.05) was used to study effects on movement symmetry of surface (hard/soft) and rein (inside/outside with respect to movement symmetry on the straight).

RESULTS

In forelimb-lame horses, surface and rein were identified as significantly affecting all head movement symmetry measures (rein, all P<0.0001; surface, all P<0.042). In the symmetrical group, no significant influence of surface or rein was identified for head movement symmetry (rein, all P>0.245; surface, all P>0.073). No significant influence of surface or rein was identified for any of the pelvic movement symmetry measures in either group.

CONCLUSIONS

While more symmetrical horses showed a consistent amount of movement symmetry across surfaces/reins, horses objectively quantified as lame on the straight showed decreased movement symmetry during lungeing, in particular with the lame limb on the inside of a hard circle. The variation within group questions straight-line movement symmetry as a sole measure of lameness without quantification of movement symmetry on the lunge, ideally on hard and soft surfaces to evaluate differences between reins and surfaces. In future, thresholds for lungeing need to be determined using simultaneous visual and objective assessment.

Effect of turn direction on body lean angle in the horse in trot and canter

Turning is commonly used as a diagnostic aid in equine lameness examinations. Forces experienced on the circle differ from those in a straight line, necessitating an inward lean of the body and asymmetric head/pelvic excursion, which are important parameters for lameness investigations. To better understand gait adaptations to lungeing in normal horses, the effect of turn direction on body lean in trot and in canter warrants further investigation. In this study, it was hypothesised that, on average and independent of gait, the observed body lean angle would be consistent with the ratio between gravitational and centripetal acceleration, but with variations for individual horses showing differences between reins. Twenty horses were fitted with a global positioning system (GPS)-aided inertial measurement unit quantifying body lean angle, speed and circle radius in trot and canter in both directions. The difference between predicted (from speed and circle radius) and observed body lean (Δobs,pred) was compared between horses, directions and gaits using a generalised linear model. The mean speed and circle radius were 3.3m/s and 4.9 m in trot and 4.5m/s and 5.7 m in canter. Mean Δobs,pred was -1.1° (range -7.6° to 5.4°) in trot and -0.8° (range -7.6° to 8.3°) in canter and was significantly different between horses (P<0.0001) and directions (P<0.0001), but not between gaits (P=0.14). Interactions between horse and direction (P<0.0001) and horse and gait (P=0.011) were also significant. Horses leaned marginally less into the circle than predicted. However, this study provides additional evidence for horse specific adaptations, showing significant differences between horses and turn directions but not between gaits.

Development and validation of an equine nerve block simulator to supplement practical skills training in undergraduate veterinary students

Lameness is the most common presenting complaint in equine practice. Performing diagnostic nerve blocks is an integral part of any lameness work-up, and is therefore an essential skill for equine practitioners. However, the opportunities for veterinary students to practice this skill are limited. The aim of this study was to design and validate an equine nerve block simulator. It was hypothesised that the simulator would improve students' ability and enhance their confidence in performing nerve blocks. A simulator was built using an equine forelimb skeleton and building foam. Wire wool targets were placed under the foam in the positions corresponding to the anatomical location of the most palmar digital, abaxial and low four-point nerve blocks and attached to an electrical circuit. The circuit became complete when the operator placed a needle in the correct position and immediate audible feedback with a buzzer was provided. To validate the simulator, it was compared with two established teaching methods: cadaver training and theoretical training with a hand-out. Cadaver-trained students achieved the best results (73 per cent correct blocks), compared with simulator-trained students (71 per cent correct blocks), and a hand-out trained group (58 per cent correct blocks). Feedback obtained with a questionnaire showed that students enjoyed simulator training more, and that they felt more confident in performing diagnostic nerve blocks than the other two groups. The equine nerve block simulator provides a safe, cost-effective method to supplement the teaching of diagnostic analgesia to undergraduate veterinary students.