SummaryThe safety of veterinary vaccines is assessed in clinical trials in Europe. The assessment of the local tissue reaction to vaccination by magnetic resonance imaging (MRI) could reduce the number of animals needed because repeated examinations can be performed in the same animal over time. The present study compared the evaluation of local tissue reactions to vaccination using MRI in live pigs with histopathology of porcine tissue, the current gold standard in regulatory safety testing. Eight piglets each were administered one of two commercial vaccines into marked injection sites. All animals were sedated and scanned repeatedly by MRI using a contrast agent up to day 29 after vaccination. On day 29, the animals were euthanized and underwent a pathological examination. The MRI results were compared with the pathomorphological findings at the injection site by regression analysis. The MR images and the pathological examinations yielded matching results concerning the sizes of the affected tissue volumes or areas. The use of MRI for regulatory safety testing can reduce the number of animals needed to 8 per examination group. The volume of a local reaction and its progression over time can be evaluated and documented. If persistent lesions develop a final pathomorphological examination is needed to identify the kind and local distribution of the reaction.

SummarySafety testing of veterinary vaccines requires the use of a large number of animals to investigate possible local and systemic reactions. This includes, among others, the pathological examination of the injection site in frequent intervals. This examination requires a selected killing of animals in frequent intervals. To reduce the number of animals needed for this kind of safety testing, magnetic resonance imaging (MRI) was used to detect and quantify possible local reactions after vaccination in vivo. Sixty-four pigs were divided into four experimental groups (n = 16); two groups consisting of 12-week-old pigs and two of 6-month-old pigs at vaccination day. The pigs were vaccinated with four licensed products (each group receiving one vaccine) and examined up to 6 times using MRI during a period of 5 weeks. The MR images were evaluated semi-automatically, comparing the volumes of altered signal intensities on the vaccination side (VS) with the volumes of the signal intensities on the control side (CS). A paired t-test was used to identify significant differences (p < 0.05) between VS and CS. The results show that MRI allows a 3D-quantification of the extent of local reactions in vivo by scanning the same live animals at several time points after vaccination. MRI is a suitable alternative method for non-invasive safety testing of injectable medicines and can therefore be applied to reduce animal numbers used for safety testing purposes.

The aim of the study was to analyse interaction processes in equine-assisted therapy (EAT) sessions with ten female clients in the period of emerging adulthood with intellectual disability (ID). Heart rate (HR), heart rate variability and salivary cortisol levels have been analysed in humans and horses before, during and after a standardised therapy session as well as in a control condition. There was a trend of lower cortisol levels and higher variability and parasympathetic tone induced by horses. During challenge however, there was a significant lower HR in the horse condition. Significant correlations in heart rate between therapist, client and horse were found with stronger interaction with a familiar horse. Our findings suggest that EAT may effectively modulate stress in humans with ID. Our results further elucidate synchronisation patterns in HR highlighting the pivotal role of relationship quality and intensity as modulators of synchrony.

This study aimed at evaluating the local tissue reaction of an anti-GnRF product, which is used for the so called “immunocastration” in male pigs. A total of 34 pigs were injected two times (including a booster injection) with an anti-GnRF product. Injection was performed using the prescribed safety vaccinator. Injection sites were evaluated three times post injection using magnetic resonance imaging. Two examinations were performed after the first injection and one after the booster. The local tissue reaction was evaluated three-dimensionally by semi-automatic analyses, by linear measurements of injection depth and length, and by scoring the kind of tissue affected. Results showed a long-lasting reaction in affected muscle tissue. Therefore, needle length should be discussed, and an evaluation of the injection site after slaughter should be performed include behavioural scorings post injection to evaluate the impact on animal well-being and carcass quality.

ObjectivesVaccination is one of the most effective methods to keep up the health status in humans and in livestock. Therefore, farm animals are vaccinated several times during their lifetime. Although vaccines are being checked regarding their local reactogenicity, side effects occur frequently—especially in the case of the application of adjuvanted products. Many reports exist about local reactions in sheep. The present study aimed at testing MRI as a method to document injection site reactions three-dimensionally.DesignTwo groups of Merino lambs (n=16 each) were vaccinated subcutaneously into the left neck side. Two different, licensed inactivated vaccines were used. Both groups of lambs were anaesthetised and scanned using MRI at days 1, 3, 8, 15, 22 and 29 after vaccination.SettingThe study was performed on a commercial-like farm.ParticipantsThirty-two Merino lambs entered the experiment, 16 male and 16 female ones (one animal died at day 22 after vaccination). At first examination day they were approximately three months old.Primary and secondary outcome measuresVolume differences were measured between vaccination and control neck side to evaluate the time pattern of local tissue reactions.ResultsLocal tissue reactions were visible on the skin surface and also appeared in deeper tissue layers on MRI. These deeper reactions would not have been found without MRI or, alternatively, without sacrificing the animals. Some of these extensive local reactions lasted for more than 29 days.ConclusionsThe in vivo MRI results proved suitable to record local tissue reactions in terms of three-dimensional extent over a longer period of time in large farm animals without the need to sacrifice test animals. A three-dimensional MRI examination of the injection site during regulatory licensing studies offers an objective evaluation that could be used in a benefit-risk assessment of veterinary vaccines.Trial registration numberDistrict Government of Upper Bavaria:55.2-1-54-2532-2-13.