Equine coronavirus (ECoV), a recently described enteric virus, belongs to the genus Betacoronavirus within the family Coronaviridae. It has been reported to cause lethargy, anorexia, fever, changes in faecal consistency and colic in adult horses. There have been publications of ECoV-related outbreaks in the United States, Japan and Europe. ECoV was first detected in Austria in 2013, although the role of ECoV in outbreaks of febrile diseases in the Austrian horse population has not yet been assessed. Here we report clinical signs and results of molecular biological investigations of eight Austrian ECoV outbreaks between 2018 and 2020. Overall, 298 horses were involved, of which 18 % were presented with clinical signs. Of the 54 clinically affected horses 52 % showed fever, 50 % had diminished faecal consistency and 28 % suffered from colic. Nine horses needed intensive care in an equine hospital and two fatalities were reported. Faecal samples of 219 in-contact horses were screened for ECoV-specific nucleic acids by RT-qPCR, with 41 % giving a positive result. Sequencing and phylogenetic analysis showed that the identified ECoV strains are most closely related to Irish strains and that different viruses have circulated in Austria in the past years.

Equine recurrent uveitis (ERU) is an inflammation of all ports of the uvea. Following new investigations it is mediated by a leptospiral infection of the inner eye with an immunologically mediated reaction to the infectious agents. Pars-plana-vitrectomy is documented as a successful treatment of ERU. Fruhouf et al. (1998) conducted only single-port vitrectomies with one scleral port, while Winterberg and Gerhards (1997) describe both single-port and modified double-port vitrectomies. A total of 56 vitrectomies were performed using the double-port method on 53 horses at the Equine Clinic of the University of Veterinary Medicine Hannover, Foundation, from January, 1999, until March, 2004. Of the 50 eyes included in a long-term follow-up study, 47 (94%) had no recurrence. This result confirms that ERU can be successfully treated by vitrectomy. In our study 14% of the eyes with no recurrence developed blindness due to retinal detachment and progressive cataract. There had been obvious damage to these eyes before surgery, so its purpose was to relieve pain and prevent recurrence. As these goals were achieved, the surgery is to be considered a success.

The stimulation of endogenous, non-antigen-related defense mechanisms by pox- and parapoxvirus-based immunomodulators opens up new possibilities for the control of infectious diseases in domestic animals. Several in vitro and in vivo studies, as well as controlled clinical trials and studies under field conditions in the literature, have shown the efficacy in target animals such as cattle, pigs, dogs, cats, and horses. Prophylactic and metaphylactic treatments with immunomodulators significantly reduced the incidence of infections in stressful situations (e.g. crowding, transport) or in immunodeficient animals such as newborn foals. Beneficial effects are even observed when an immunomodulator is applied for the additional treatment of manifest infectious diseases, e.g. equine herpesvirus infection.

From 1995 to 2002 investigations of renal function have been performed in 456 horses (44% female, 56% male). Therefore parameters were determined in blood or plasma (PI-): packed cell volume, hemoglobin, leukocytes, plasma protein,creatine kinase (CK), aspartate amino transaminase (ASAT), glutamat dehydrogenase (GLDH), creatinine (Creat, enzymatic PAP-method), sodium (No), potassium (K), calcium (Ca) and phosphate (P). In urine (U-) spezific gravity, Creat, No, K, Ca, P and GGT were measured. Proteine, glucose pH and contents of blood were determined with urine test strip, leukocytes were estimated microscopically. In case of glucosuria and of U-pH <6.5 glucose and L-lactate were measured in urine and plasma by enzymatic methods additionally. 130 horses showed no dysfunction of kidney or other organs. 59 horses had enzymatic characteristics of myopathies and/or hepatopathies. Renal dysfunction in 231 animals were differentiated in groups: Reduction of filtration (n=56; PI-Creat >140 mumol/l), disturbance of tubular reabsorption (n=70; U-specific gravity <1,020 kg/l) and tubular necrosis (n=26; U-GGT/Creat >1 0 U/mmol). Acute renal failure (n=7) und renal insufficiency (subacute, n=79) were characterized by combination of glomerular and tubular dysfunctions. Acute and progressive nephropathies are caused predominantly by hoemodynamic failure (shock) associated with enterotoxaemia (colic, diarrhea) or lactacidosis (myopathy). Nephrotoxic agents like gentamycine, phenylbutazone, mycotoxins or vitamin D may also causes renal failure or insufficiency. Hypercalcaemia and increased Ca-excretion in horses associated with renal dysfunction (n=32) may be responded by high mineral intake.

Stenosis of the nosolocrimal duct was diagnosed in two horses by clinical examination and computed tomography, In an argentinian polo pony mare, dacryocystitis and stenosis of the duct was associated with depression fracture and sequestration of the frontal, nasal and lacrimal bone including the fosso socci locrimalis. In a Quarter horse gelding, a head shaking syndrome was observed for eight months, In this horse, clinical examination revealed epiphora caused by stenosis of the middle part of the nasolocrimol duct without signs of external trauma. In both horses, external canaliculosinuostomy was performed under general anesthesia to create an anastomosis between the Carnaliculi lacrimales and the caudal part of the maxillary sinus. Complete healing and abscence of epiphora was the result in the polo pony following surgery. In the second horse immediate interruption of the headshaking and essential reduction of epiphora was observed after the surgical correction, Computed tomography was judged to be a diagnostic tool of high sensitivity and specifity in the diagnosis of diseases of the nosolacrimal duct. Canaliculosinuosfomy was found to be effective for surgical treatment of stenosis of the nosolacrimal duct.

Over a six year period, 83 fools that where referred to the clinic because of colic underwent explorative abdominal surgery. Indication for an explorative laparotomy was based on the results of clinical examination, laboratory evaluation, abdominal radiography and peritoneal fluid analysation following abdominocentesis. Severe or persisting abdominal pain in combination with abdominal distension were predominant reasons for explorative surgery as well as radiographically visualized distension of small intestine or abnormal laboratory findings.Intraoperative findings included small intestinal ileus (n=41), large intestinal lesions (n=25), uroperitoneum (n=8) and others (n=9) like perforated gastric ulcer, peritonitis or ovarian torsion. Of the 83 foals subjected to abdominal surgery 49 (59%) could be released from the clinic in a good general condition without further signs of colic. 21 foals had to be euthanized during surgery because of a poor prognosis. Therefore there was a survival rate of 79% in those foals that were allowed to recover from surgery.With one exception all foals in which uroperitoneum was diagnosed were discharged fom the clinic. In the contrast to this prognosis for fools with small intestinal strangulation was judged to be poor due to the common intraoperative finding of severe damage in large sections of the small intestine and a survival rate of 46%. In foals with large intestinal lesions, a survival rate of 80% was found.

Polysaccharide storage myopathy (PSSM) is characterized by abnormal polysaccharides and increased glycogen storage in the musculature of affected horses, which are predisposed for recurrent exercise-induced myopathies. A familial predisposition for PSSM has been reported in American Quarter Horses (AQH) and related breeds. Two AQH and a Swiss Warmblood were presented to us for recurrent rhabdomyolysis and one Haflinger for severe exercise intolerance. The signalment, clinical examination, and serumactivity valves of CK, ASAT and LDH before and after an exercise test lead to the tentive diagnosis of PSSM, which was confirmed by the histopathological evaluation of muscle biopsies. Increased muscle glycogen and pathognomonic, PAS-positive amylase-resistent polysaccharides were present in all the cases. Our report illustrates that PSSM must be included in the differential diagnosis of exercise induced recurrent myopathies in AQH as well as in horses of other breeds in Europe.

In 29 horses showing keratitis or keratoconjunctivitis and 21 horses with no ocular disease ocular swabs were taken from both eyes, the nasal mucosa and the tracheobronchial secretion. Peripheral blood leukocytes were also isolated. All these samples were examined by means of nested PCR in order to detect EHV-2 genome. These investigations were carried out twice over a course of three to four weeks. Compared to horses without ocular disease horses with keratitis and keratokonjunctivitis showed a significantly higher rate of detected EHV-2 genome in ocular swabs as well as in swabs from the nasal mucosa and tracheobronchial secretion. No specific clinical picture corresponding to the the detection of EHV-2 could be determined. The suggested pathognomonical picture of a herpes keratitis, described as a keratitis punctata, was seen in one case only. In addition to the virological investigations by means of PCR, serological examinations were carried out. Titers of antibodies against EHV-2 were observed in all horses. No significant difference in the distribution of antibody titers was found between the group of horses showing keratitis and keratokonjunctivitis and the horses with no ocular disease. Therefore the detection of EHV-2 genome by means of PCR appeared to be a faster and more sensitive method, in order to detect a possible viral involvement in equine keratitis.

The recovery phase is a crucial phase of equine anesthesia and the most difficult to control. Postanesthetic sedation is thought to be useful to prevent horses from hastened recovery with a great chances of lifethreatening trauma. In the following study 73 horses were given two different dosages of xylazine (0,1 mg/kg BW and 0,2 mg/kg BW, Rompun(R), Firma Bayer) after general anesthesia with halothane. A third group was given saline solution only. In all horses recovery phase was monitored. The different groups were compared for duration of general anesthesia depending on duration of recovery phase, numbers of attempts to arise and coordination of arising.Horses of group 1, sedated with a dosage of 0,2 mg/kg BW xylazine, showed significantly less attempts to arise and coordination was significantly better Horses without postanesthetic sedation (group 3) or with lower xylazine dosage (0,1 mg/kg BW) showed a high correlation between duration of anesthesia and number of attempts to arise or duration of recovery phase. In group 1 these correlations were lower. In all groups numbers of attempts to arise were higher with longer duration of anesthesia. But the higher the postanesthetic sedation was the less numbers of attempts to arise were needed. It was also found, that the indication for surgery was also influencing the recovery period of horses. Horses of group 1 after painful surgeries (ovarectomy) tried to arise faster and showed more attempts to arise than horses after less painful surgeries (vitrectomy).The results of this study show that higher dosages of xylazine (0,2 mg/kg BW) for postanesthetic sedation of horses lead to a quieter and better coordinated recovery phase.

The prevalence of EHV-2 in 27 horses with keratoconjunctivitis and 21 clinically healthy horses of different ages and stocks were analyzed. We demonstrated that EHV-2 was present in 12 keratoconjunctivitis cases as shown by nested PCR on ocular swabs. This is statistically more often than in the control group, where only two ocular swabs were EHV-2 positive. Cocultivation was successful on peripheral blood leukocytes of healthy and diseased horses but not on swabs. We isolated ten EHV-2 strains from diseased and nine from control horses, whereas 16 isolates showed different restriction enzyme patterns. The results of immunfluorescence and neutralization tests are predictory only in combination with the nested PCR data on ocular swabs. A successful antiviral treatment in nine out of 16 cases supports the aetiological role of EHV-2 in this ocular disease.

A seven-day-old Hannoveranian warmblooded filly was referred to the clinic with a history of acute colic. Clinical examination revealed severe abdominal pain but radiological investigation only demonstrated low grade intestinal distension. A ventral midline laparotomy was performed including total resection of the umbilicus because of patent urachus. Exploration of the abdomen revealed presence of all intestinal structures in typical anatomic position but torsion and haemorrhagic infarction of the left ovary. After ligation of the ovarian pedicle the left ovary was resected. Recovery from surgery was without complication and the filly was discharged from the clinic 11 days later. Histopathological examination of the ovary revealed an ovarian haematoma with an age of approximately seven days. The process might have happened due to trauma during partus. Adnexal torsion was suggested to result from such preexisting ovarian pathological change. Ovarian torsion should be considered in fillies presenting with acute abdominal pain in particular when intestinal or urinary tract abnormalities cannot be detected during surgical intervention.

Examination of renal function (Bickhardt et al. 1996) gives extensive information on renal disfunctions. This can be determined from a voided urine and a blood sample. Furthermore a transendoscopic, selective collection of urine from each ureter allows a differentiated assessment of the right and left kidney's function. Renal function of 38 patients of the clinic for horses were examined. Nine of them showed a deviation of the normal range. Four patients had acute renal diseases. In two cases there was a prerenal and in the other two an intrinsic acute renal dysfunction. The horses were in a severe bad general condition. Serum urea and creatinine levels were elevated. In two horses a serum electrolyte disturbance could be seen. In examination of renal function a reduction of renal creatinine clearance was obvious. In three cases an enormous elevation of tubular enzyme excretion (U-gamma GT/Crea) was found. Five of nine horses showed chronic nephropathies. Poor performance and weariness were the most dominating clinical findings. The horses showed elevated serum urea and creatinine levels and in two cases a hyperkaliaemia occurred. In examination of renal function a reduction of renal creatinine clearance and in one case an elevation of fractional lactate excretion could be found.

In autumn 1995 for the first time horses were taken to the clinic for horses in Hannover that showed symptoms of a muscular disease. not seen so far. None of the twelve patients survived this atypical myoglobinuria although extensive treatment was performed. At the same time other veterinarians reported on 103 cases. 99 of them died.Without exception all horses and ponies were not in training and kept on pasture just before the disease set on. In most of the cases more than one horse of a single pasture was affected. Different breeds, sexes and age groups were concerned.In the beginning all horses showed muscular tremor, stiffness and stagger. They were dull or apathetic. Heart rates and breathing frequencies were elevated. Appetite was maintained very long and only a few horses were painful. The rectal palpation revealed only a highly filled bladder. All patients showed a massive elevation of creatine kinase and myoglobinuria was characteristic. Treatment included infusion of isotonic solutions, analgesics, anti-inflammatory agents and doses of Vitamin E/selenium. Despite intensive medical care and treatment all horses came to recumbency within three days and finally died.In pathologic-anatomical examinations various muscle groups showed a marked, acute rhabdomyolysis of type I fibres. Up to this day laboratory diagnostics, clinical, pathologic-anatomical, histological and toxicological findings could not reveal the etiology of atypical myoglobinuria.