Equine recurrent airway obstruction and insect bite hypersensitivity: understanding the diseases and uncovering possible new therapeutic approaches

Recurrent airway obstruction (RAO) and insect bite hypersensitivity (IBH) are allergic conditions that are commonly encountered in the horse. Whilst complete allergen avoidance is an effective management strategy for both diseases, this may not be achievable in all cases and treatment options are therefore required. The inflammatory response is the main therapeutic target for glucocorticoids given to horses with RAO and severe cases of IBH, whilst the bronchodilators used in RAO primarily target airway smooth muscle. Such drugs are effective in most but not all individuals and there may be unwanted adverse effects. This article will review how knowledge of drug action and the pathogenesis of RAO and IBH can be utilised to identify potential targets for novel therapeutic agents that, in the longer term, may be safer and/or more effective in managing the allergic horse.     

Injuries in the event horse: training versus competition

Two related studies on injuries sustained by event horses during competition and during training are reported. During the cross-country phase of competition, the most common injuries were lacerations and abrasions to the carpus and stifle. Superficial digital flexor tendonitis and exertional rhabdomyolysis were significantly more common during Cours Complete Internationale (CCI) competitions compared to one-day event (ODE) competitions. The difference in injury types at ODEs and CCI competitions probably relates to the increased athletic demands of the CCI and the closer veterinary observation at these competitions. The results of the training study indicate that 21% of horses intending to compete in a CCI did not start due to injury. Forty-three percent of these injuries involved soft tissue structures with injuries to the superficial digital flexor tendon and the suspensory ligament each accounting for 33%. The most important area for future research is investigation of the risk factors for these career-threatening soft tissue injuries.     

Effect of the interfacial layer composition on the properties of emulsion creams

We have quantified observed differences in the microstructure and rheology of creaming emulsions stabilized by protein and low molecular weight surfactants. In this study, we made two sets of emulsions from a single parent emulsion, which differed only in their interfacial composition (i.e., either protein or surfactant). The protein studied was whey protein isolate. The zeta potential of the surfactant-stabilized emulsion was controlled by mixing anionic (SDS) and nonionic (Brij 35) surfactants to match the zeta potential of the protein-stabilized emulsion. Despite this, ultrasonic creaming measurements and confocal microscopy showed that the structures within the cream layers were different between the two sets of emulsions. The protein-stabilized emulsions appeared to slow or arrest the packing within the cream, leading to a lower density network of emulsion droplets, whereas the surfactant emulsion droplets rearranged more quickly into a well-packed, concentrated cream layer. Rheological analysis of the creams showed that despite the protein-stabilized emulsions having a lower dispersed phase volume fraction, their elastic modulus was approximately 30 times greater than that of a comparable surfactant-stabilized emulsion. These differences were caused by the ability of the protein to form a highly viscoelastic interfacial network around the droplets which may include intermolecular covalent cross-links. At close range the adhesive nature of the interaction between the layers contributes to the microstructure and rheology of concentrated emulsions. This is the first time that such well-defined emulsion systems have been studied in detail both noninvasively to look at the impact on creaming and also invasively to look at the impact on bulk rheological properties.     

Involvement of Parachlamydia in bovine abortions in Scotland

Bovine abortion represents a major animal welfare issue and a cause of substantial economic loss yet the rate of successful diagnosis remains low. Chlamydia-related organisms including Parachlamydia have recently emerged as putative cattle abortifacients. Placental tissue samples and fetal lung from bovine abortion submissions across Scotland in Spring 2011 were investigated by histopathology for the presence of suspect Chlamydia-related organisms. Evidence of Chlamydia-related organisms was observed in 21/113 (18.6%) placenta samples. Thirteen of the suspect cases and 18 histopathology negative cases were analysed by molecular and immunohistochemical methods. All samples were PCR positive for Parachlamydia but sequencing revealed high homology between identified environmental 16S sequences in all but three cases. Parachlamydial antigen was detected in 10/31 placental samples (32.2%) with pathology consistent with chlamydial infection. This work supports the need for further surveillance investigations and experimental studies to determine the role of Parachlamydia in bovine abortion.     

Acceptability and compliance of atenolol tablet, compounded paste and compounded suspension prescribed to healthy cats*

This study was designed to evaluate the cats' acceptance and compliance of the owners and cats towards an extemporaneously prepared palatable compounded atenolol (paste and suspension) formulation in comparison to the commercially obtained tablet, in a randomised, cross-over study design.The three formulations were prescribed twice daily for 6 days to 13 healthy privately-owned cats of 13 different owners, with varying levels of experience in medicating cats. Daily compliance was evaluated via an owner-completed diary, completed after each dose administered. Owner's experience and preference of the formulation was evaluated via questionnaires given prior to, at the end of each treatment protocol, and upon completion of the study. Although compounded suspension was association with fewest missed doses, the majority of cat owners expressed a preference for the divided tablet. Atenolol tablets, compounded paste and suspension acceptance and compliance were comparable. Further work is now required to assess the amount and stability of the active ingredient and the robustness of the paste and suspension formulations prior to any bioavailability comparisons between the formulations.     

A tool for rapid assessment of erosion risk to support decision-making and policy development at the Ngenge watershed in Uganda

This study tests a rapid, user-friendly method for assessing changes in erosion risk, which yields information to aid policy development and decision-making for sustainable natural resources management. There is currently a lack of timely, up-to-date and current information to support policy development on sustainable natural resources management in Uganda. The study was carried out in the Ngenge watershed, a typical catchment in the Ugandan Highlands, characterised by deforestation in favour of subsistence agriculture without adequate soil and water conservation measures. The watershed is experiencing soil erosion, sedimentation and flooding problems which are threatening agricultural productivity and food security. Sustainable management of environmental resources is needed to ensure a livelihood for the rural population which is dependent on the land. Historical erosion risk was evaluated in three steps using multi-temporal satellite data. First, current erosion risk was assessed by combining slope and vegetation cover during periods of high intensity rainfall. The data used for the assessment was obtained from public (free) satellite images. Erosion risk was then linked to land use and finally to the change in vegetation cover over the years 1980-2000. The analysis of erosion risk using rainfall, slope and NDVI (Normalised Difference Vegetative Index) as a proxy for vegetation cover gives an indication of the current erosion risk in the area. The results of historical vegetation cover change analysis indicate an overall increase in areas under erosion risk in the study area from 1980 to 2000. This method of erosion risk mapping provides a quick and straightforward means for identifying priority areas for interventions for soil and water resource management. Considering that resources are limited, the interventions to be appropriate have to be focused mainly on areas affected by degradation.