[Doping relevant substances in horse feed]. / Dopingrelevante Substanzen in Futtermitteln für Pferde.

INTRODUCTION: Horse feed material of Swiss and foreign production available on the Swiss market was tested with regard to possible contamination with 7 different alkaloids, atropine and colchicine. Twenty-eight feed samples as well as 2 poppy seed samples were analyzed. Out of 28 feed samples 18 were positive for prohibited substances in Equestrian sports. The concentration of prohibited substances was in none of the samples high enough to cause an effect on the body of the horse. The poppy seed sample, which was obtained by conventional harvesting and cleaning methods, contained a very high Morphine concentration compared to the sample which was harvested by hand. Despite high quality standards a contamination with prohibited substances in horse feed cannot be excluded.

INTRODUCTION: Divers aliments pour chevaux de provenance indigène et étrangère disponibles sur le marché suisse ont été examinés quant à une éventuelle contamination par 7 alcaloïdes différents ainsi que par l'atropine et la colchicine. On a analysé 28 échantillons de fourrages ainsi que 2 échantillons de graines de pavot provenant de cultures suisses. Dix-huit des vingt-huit échantillons contenaient des substances pouvant avoir une importance en matière de dopage dans les sports équestres. La concentration des substances recherchées n'était, dans aucun des échantillons de fourrages, assez élevée pour qu'on puisse tabler avec un effet sur le corps du cheval. L'échantillon de graines de pavot produites avec les techniques usuelles de récolte et de nettoyage présentait, par rapport à celui composé de graines récoltées à la main, un taux de morphine inhabituellement élevé. La présente étude de 28 échantillons d'aliments démontre qu'une contamination avec des substances ayant une importance en matière de dopage ne peut pas être exclue, même avec des standards de qualité élevés.

Efficacy of the repellent N,N-diethyl-3-methyl-benzamide (DEET) against tabanid flies on horses evaluated in a field test in Switzerland.

Female tabanid flies (Diptera: Tabanidae) can be a serious nuisance for horses because of their painful bites during blood feeding. They also play a primary role in mechanical transmission of a lentivirus causing Equine Infectious Anemia (EIA), a virus that has spread within Europe in recent years. According to the European law for products intended for use as a repellent on horses (recreational and sport horses), a field test is mandatory to demonstrate sufficient repellency of such a substance against the specific target fly species, but currently no agreed protocols are available for testing of potential repellents. The aim of the present study was to establish a protocol for a field test to investigate the efficacy of N,N-diethyl-3-methyl-benzamide (DEET, Brum®, Huebeli-Stud Horse Care AG) in a 15-17% oil-water emulsion against tabanid flies on horses up to four hours. Between July and August 2015, four horses on three farms each were tested on two consecutive days in a cross-over design. The four horses on Farm A were used in the pre-test as well as in the main test. Two and a half hours after repellent application the horses were lunged until sweating. Tabanid fly infestations were both photographed and directly counted during five minutes 3 and 4h after repellent application on the right side of the horses in the area from the head to the flank, belly and first third of the foreleg. Without repellent application, up to 29 tabanid flies were counted on a horse, whereas the maximum for the repellent treated horses was four. In 50% of the horses treated with DEET there were no Tabanids observed (efficacy 100%), and in all horses the tabanid fly counts were lower than in the control horses with one exemption at 4h. The efficacy of the DEET repellent was at least 80% and 71% respectively, three or four hours after application (with a confidence level of 89%). A fly trap (Horse Pal) revealed the presence of the tabanid species Tabanus brominus and Haematopota pluvialis, but also non-specified arthropods. The design of the present study simulated practical conditions, allowed to quantify the number of tabanids flies and to demonstrate repellency of DEET in horses.

Protection of horses against Culicoides biting midges in different housing systems in Switzerland.

Species belonging to the Culicoides complexes (Diptera, Ceratopogonidae), obsoletus and pulicaris, in Switzerland, are potential vectors of both bluetongue virus (BTV) and African horse sickness virus (AHSV). The epidemic of BTV in 2006 and 2007 in Europe has highlighted the risk of introduction and spread of vector-borne diseases in previously non-endemic areas. As a measure of prevention, as part of an integrated control programme in the event of an outbreak of African horse sickness (AHS), it is of utmost importance to prevent, or substantially reduce, contact between horses and Culicoides. The aim of the present study was to compare the effect of three protection systems, net, fan, repellent, or combinations thereof, with regard to their potential to reduce contact between horses and Culicoides. Three different equine housing systems, including individual boxes (BX), group housing systems (GR), and individual boxes with permanently accessible paddock (BP) were used. The efficacy of the protection systems were evaluated by comparing the total number counts of collected female Culicoides, of non-blood-fed and blood-fed Culicoides, respectively, with UV black light traps. The study was conducted over 3 summer months during 2012 and 2013 each and focused on the efficacy and practicality of the protection systems. The repellent was tested in 2012 only and not further investigated in 2013, as it showed no significant effect in reducing Culicoides collected in the light traps. Net protection system provided the best overall protection for the total number of female Culicoides, non-blood-fed and blood-fed Culicoides in all tested housing systems. The net, with a pore size of 0.1825 mm(2), reduced the total number of Culicoides collected in the housing systems BP, GR and BX by 98%, 85% and 67%, respectively. However, in the GR housing system, no significant difference between the effectiveness of the fan and the net were determined for any of the three Culicoides categories. The results of the present study demonstrated that horse owners can substantially reduce their horses' exposure to Culicoides, by using net protection in the housing systems BX, BP and GR. In GR housing systems, protection against Culicoides using a fan is also recommended.

[African horse sickness and equine encephalosis: must Switzerland get prepared]. / Afrikanische Pferdepest und equine Encephalosis: Muss sich die Schweiz vorbereiten?

African horse sickness (AHS) of equines is partly transmitted by the same culicoides species as Bluetongue (BT) disease in even-toed ungulates. Horses normally get seriously sick, with a high case fatality rate. Equine Encephalosis is another, but less-known viral disease of equines, caused by viruses of the same genus as BT and AHS. Like BT of serotype 8 in 2006, both diseases could theoretically be introduced to Europe anytime and spread rapidly then. After the lessons learnt from the most recent bluetongue outbreaks in Europe, the regulations and AHS-contingency plans in force must be updated. All stakeholders must be aware of the risks and take own measures to prevent a possible emergence of the diseases, and be prepared in case of an outbreak.

Equine travellers to the Olympic Games in Hong Kong 2008: a review of worldwide challenges to equine health, with particular reference to vector-borne diseases.

The past 10-20 years have seen exponential growth in the volume of trade in horses and equine germplasm; and the extent of global horse movements has increased significantly in the last 4 years. In preparing for the transport of elite Olympic horses to Hong Kong in 2008, it will be very important to be as fully informed as possible of the disease situation in both the exporting and importing country, import and re-entry requirements, as well as having a vaccination strategy to protect against particular diseases. In this context the review describes the equine vector-borne disease situation in Europe, Asia, Africa and South America and provides estimates of the number of horse movements between these countries, as well as information on import requirements and vaccination strategies.

Patterns of animal diseases and their control.

Despite enormous progress in scientific knowledge and improvements in sanitary standards in livestock production, the world has recently been confronted with several animal disease epidemics which have caused significant economic losses. General awareness regarding unusual clinical signs and prompt reporting of disease is an important requirement in disease detection and control and needs to be promoted among farmers and veterinarians. Unexpected clinical syndromes are of increasing importance for public health. Syndromic surveillance has been shown to be a key element in detecting emerging diseases. Once detected and diagnosed, surveillance programmes constitute the first step towards determining the disease pattern with regard to time and space. This pattern of disease occurrence becomes the basis for selecting approaches for further disease investigation and for disease control.

Endoscopic scoring of mucus quantity and quality: observer and horse variance and relationship to inflammation, mucus viscoelasticity and volume.

REASONS FOR PERFORMING STUDY: Endoscopic scoring of airway mucus quantity and quality has not been critically assessed. OBJECTIVES: To evaluate mucus scores for 1) observer- and horse-related variance and 2) association with inflammation, mucus viscoelasticity and measured volume. METHODS: Variance of scoring within and between observers and over time within horses were determined for airway mucus accumulation, apparent viscosity, localisation and colour, and correlations of mucus accumulation scores with neutrophil ratios in secretions. The relationship of accumulation score to measured volumes of 'artificial mucus' was investigated. Correlations of mucus accumulation, apparent viscosity and colour scores with measured viscoelasticity were tested. Viscoelasticity was compared between tracheal secretion samples collected ventrally and dorsally. RESULTS: Mucus accumulation scoring showed excellent interobserver agreement and moderate horse-related variance, was related to measured volumes of 'artificial mucus', and correlated well with neutrophilic airway inflammation. Scores of mucus viscosity, colour and localisation showed high observer-related variance. Mucus accumulation, apparent viscosity and colour scores did not correlate with measured tracheal mucus viscoelasticity, but dorsally-localised mucus showed 2-fold higher measured viscoelasticity than ventrally-localised samples. CONCLUSIONS: Mucus accumulation scores are a reproducible measure of mucus volumes in the trachea. POTENTIAL RELEVANCE: Endoscopic scoring of mucus accumulation is a reliable clinical and research tool. In contrast, apparent viscosity, localisation and colour scores should be interpreted with caution.

Measurement of tidal breathing flow-volume loop indices in horses used for different sporting purposes with and without recurrent airway obstruction.

Tidal breathing flow-volume loop (TBFVL) indices in healthy horses and in horses suffering from mild and moderate to severe recurrent airway obstruction (RAO) were measured. In addition, the ability of these indices to differentiate healthy controls from horses with mild RAO by separating the horses according to their usage was investigated. The horses were assigned to three sporting categories: 1 Leisure horses; 2 Horses competing at events with a duration of more than five minutes (eventing, coaching and endurance); and 3 Horses competing at events with a duration of less than five minutes (dressage and show jumping). Flow-volume curves were recorded with an ultrasonic spirometer and TBFVL indices were calculated with specially dedicated software. The sporting usage of the horses had a significant effect on the differentiating ability of TBFVL indices in diagnosing different degrees of RAO. The index TIF50 differentiated control horses from horses with minor RAO in all sporting categories.

Differences in pulmonary functional indices derived from the single-breath diagram for CO2 (SBD-CO2) in horses related to age, sex and usage.

Although pulmonary function tests have been used to evaluate horses with clinically normal lungs and those with recurrent airway obstruction (RAO), comprehensive studies of equine respiratory function, considering factors such as sex, age and usage are not available. Studies on the influence of these factors on pulmonary function in healthy horses are required for interpretation of measurements made in those with respiratory disease. The study was performed with 63 warmblood horses and the status of their pulmonary health was evaluated by clinical examination. The functional aspect of pulmonary health was assessed by indices derived from the single-breath diagram for CO2 (SBD-CO2). Differences in pulmonary functional indices between the sexes, age groups and usage groups adjusted for pulmonary health were analysed with hierarchical linear models. It was shown that the effects on pulmonary function of age, sex and usage of a horse were significant and have to be considered when establishing the true pulmonary functional status of a horse suffering from RAO. The multivariate statistical model used included the covariates age, sex and sporting discipline of the horses and accounted for the complex, non-linear interactions between the different covariates.

Relationship between clinical signs and pulmonary function estimated by the single breath diagram for CO(2) (SBD-CO(2)) in horses with chronic obstructive pulmonary disease.

The pulmonary health of 66 horses was assessed by a clinical examination and simple supplementary diagnostic methods. Single breath diagrams for CO(2) (SBD-CO(2)) and derived lung function indices were used to determine pulmonary function. The clinical signs in different groups were related to the results of the lung function indices derived from the SBD-CO(2). In horses with moderate to severe chronic obstructive pulmonary disease (COPD), a significant relationship was found between the respiratory frequency and the ratio of Bohr's dead space to the tidal volume (VD(Bohr)/VT), and between the physiological dead space/tidal volume ratio (VD(phys)/VT) and the ratio of the alveolar dead space to the alveolar tidal volume (VD(alv)/VT(alv)), but no significant associations were found between the arterial oxygen tension (P(a)O(2)) and lung function indices derived from the SBD-CO(2). The occurrence of cough, the viscosity of tracheobronchial mucus and the amount of polynuclear neutrophils in tracheobronchial aspirates were significantly related to the expiratory tidal volume (VT), the total expired volume of CO(2) (VCO(2)), VD(Bohr)/VT, VD(phys)/VT and VD(alv)/VT(alv). We conclude that abnormal findings in these clinical parameters indicate a measurable ventilation and perfusion (V(A)/Q) mismatch which is reflected by increases in dead space, VD(Bohr)/VT and VD(phys)/VT as well as VD(alv)/VT(alv).

Validity of pulmonary function indices derived from the volumetric capnogram in horses with recurrent airway obstruction (RAO).

The objective of this study was to determine the accuracy with which pulmonary function indices derived from the volumetric capnogram can diagnose different degrees of recurrent airway obstruction (RAO) in 63 warmblood horses. The sensitivity, specificity, the area under the receiver operating curve (AUC), optimal cut-off values and predictive values of the indices were calculated. The results obtained have shown that there is no single index characterised by specificity and sensitivity to differentiate with an accuracy of >90 per cent between the different degrees of RAO compared to the clinical examination. The indices A(1)/A(2) and VD(alv)/ VT(alv) (AUC=0.55 and 0.53) appeared to have the highest relative sensitivity and specificity to differentiate between healthy horses and horses suffering from subclinical or minor RAO and the indices VD(phys)/ VT and VD(Bohr)/ VT between horses suffering from subclinical or minor RAO and horses with moderate to severe RAO (AUC=0.71 and 0.70). We do not consider it acceptable to use cut off values optimised for both maximal sensitivity and specificity, because a great number of horses would have been inappropriately classified.

The variability and repeatability of indices derived from the single-breath diagram for CO2 in horses with chronic obstructive pulmonary disease and the effect of lobelin hydrochloride on these indices.

Several indices of ventilatory heterogeneity can be identified from the volumetric capnogram and its graphic presentation, the single-breath diagram for CO2 (SBD-CO2). Physiologically based indices of pulmonary function (VTE, VCO2, FACO2, VDBohr% VDBohr%, VD/VTE, A1/A2) were calculated for healthy horses (group I, n = 5) and for horses with subclinical (group II, n = 7) or clinically manifest chronic obstructive pulmonary disease (COPD) (group III, n = 8) during tidal breathing and after medication with lobelin hydrochloride (Lobelin). We investigated the variability and repeatability of the lung function indices in healthy horses and in those with COPD both during tidal breathing and after administration of Lobelin, a centrally acting respiratory stimulant. In particular, we were interested in whether the discriminating ability of SBD-CO2-derived lung function indices would be increased between different patient groups after administration of Lobelin compared to those for the resting values. Of the indices studied, VTE, FACO, VDBohr% and A1/A2 appeared to be those with good to excellent repeatability in discriminating healthy horses from those with COPD. Stimulating respiration with Lobelin gave no advantage in the repeatability of the lung function indices or in differentiating between horses with different degrees of COPD.

Statistical shape analysis of volumetric capnograms: evaluation of a new approach for the assessment of pulmonary function in horses with chronic obstructive pulmonary disease.

The shape of the volumetric capnogram is modified by airway obstruction, and the evaluation of this deformation could allow an indirect measurement of bronchial patency. The study included 35 horses; five horses without evidence of pulmonary disease (group I) and 30 horses suffering from different degrees of chronic obstructive pulmonary disease (COPD) (groups II-IV). Data of recorded CO2 and volume curves were off-line plotted and statistically analysed using regression analysis. Analyses were performed separately for fractions 25-95% (VTE25-95), 25-50% (VTE25-50) and 50-95% (VTE50-95) of expiratory tidal volume. For VTE25-95 estimates of linear and quadratic regression parameters were significantly different between groups. For VTE25-50 linear terms were significant in all clinical groups and decreased considerably from group I to group IV. Linear and quadratic terms for VTE50-95 were significant in all clinical groups and increased with the severity of COPD. The difference of total expiratory CO2 volume was significant between all groups. Statistical analysis of the volumetric capnogram is a precise method for description of shape deformities of the single breath diagram for CO2 (SBD-CO2) in horses with COPD and global models including phase II and III of the SBD-CO2 are helpful in the detection of pulmonary function impairment. However, although the model of the statistical shape analysis of the SBD-CO2 is precise, it may not necessarily be a useful test to discriminate horses with minor, moderate and severe COPD for clinical use.

Ultrasound-spirometry and capnography in horses: analysis of measurement reliability.

Ultrasound-spirometry and capnography and the evaluation of corresponding 'single-breath diagrams for CO2' (SBD-CO2) is a relatively new, non-invasive method for assessing pulmonary function in horses. The relative variation and the reliability of observations within measurement sessions were calculated for expiratory tidal volume, for expired CO2 volume (%) and for the phase II and phase III slopes of the SBD-CO2 in horses without pulmonary disease and in horses suffering from differing degrees of chronic obstructive pulmonary disease. The coefficient of variation of expiratory tidal volume ranged from 0.23 to 0.32 and that of the expiratory CO2 volume from 0.19 to 0.43. The reliability of the measurements can be considered as good for expiratory tidal volume, and as excellent for expiratory CO2. Clinical status had little influence on the descriptive parameters or on the sample statistics of the expiratory tidal volume and expiratory CO2. The slopes of the SBD-CO2 curves had high variation and only moderate to good reliability. Clinical status had a considerable influence on the variation in the slopes of phase II.

Comparison of the clearance of 99mTechnetium-DTPA from the lung and lung function indices derived from the single breath diagram for carbon dioxide in horses with chronic obstructive pulmonary disease.

The elimination of carbon dioxide from the lung can be used to monitor ventilation and perfusion, and 99mtechnetium-diethylenetriaminepentaacetate (99mTc-DTPA) clearance is a highly sensitive index of alveolar epithelial integrity, which is a presupposition for effective gas exchange. The aim of this study was to determine whether a correlation exists between indices of lung function derived from the single breath diagram for CO2, and 99mTc-DTPA clearance in horses with chronic obstructive pulmonary disease. The rate of 99mTc-DTPA elimination was negatively and substantially correlated with the dead space according to Bohr's formula, and the physiological and alveolar dead space. Strong and significant correlations existed between the three dead space indices and the alveolar fraction of CO2, and the ratio A1/A2 as an index of alveolar efficiency. The associations found were dependent on the clinical status of health and the mode of calculation of 99mTc-DTPA alveolar clearance.

Detection of the ADP-ribosyltransferase toxin gene (cdtA) and its activity in Clostridium difficile isolates from Equidae.

Clostridium difficile is an antibiotic-associated emerging pathogen of humans and animals. Thus far three toxins of C. difficile have been described: an enterotoxin (ToxA), a cytotoxin (ToxB) and an ADP-ribosyltransferase (CDT). In the present work we describe the first isolation of CDT producing C. difficile from Equidae with gastro-intestinal disease. Out of 17 C. difficile strains isolated from Equidae, 11 were positive for the genes tcdA and tcdB encoding ToxA and ToxB. In addition four of these 11 isolates were positive for the cdtA gene encoding the catalytic subunit of the ADP-ribosyltransferase CDT. Interestingly none of the isolates derived from canines (41 isolates) and felines (4 isolates) harboured the cdtA gene. In C. difficile field isolates which contained the cdtA gene, ADP-ribosyltransferase activity could also be detected in culture supernatants indicating expression and secretion of CDT. All strains were associated with intestinal disorders, but no association was found for the occurrence of toxins with a specific clinical diagnosis.