Comparison of a modified 2-step insulin response test performed with porcine zinc insulin and an oral glucose test to detect hyperinsulinemic Icelandic horses

Both, oral and intravenous (IV) testing protocols, are recommended and still used to detect insulin dysregulation (ID) in equids. However, IV tests mainly focus on peripheral insulin resistance (IR), while oral tests assess hyperinsulinemia (HI), which are different aspects of ID. The objective of this study was to describe if horses with HI also demonstrate IR and consequently can be detected by a modified 2-step insulin response test (2-step IRT) performed with a veterinary approved porcine zinc insulin (PZI). Twelve Icelandic horses were subjected to an OGT and 2-step IRT in a crossover study. Serum insulin concentrations during the OGT revealed that six horses were hyperinsulinemic (HI) while six were not (NON-HI). To describe the glucose response to IV injected PZI, the decline of plasma glucose concentration within the first 30 min was analyzed. Glucose reduction was similar in horses with and without HI during the 2-step IRT over time. Additionally, none of the horses reached a glucose reduction of ≥ 50% at 30 min. The results of the present study indicated that a comparable insulin mediated glucose uptake may be observed in horses with and without HI during a modified 2-step IRT. While six out of twelve horses were identified as HI by the OGT, all twelve horses were identified as IR by the modified 2-step IRT performed with PZI underlining the importance, but difficulty in choosing the right diagnostic tool in clinical settings to assess ID.

Untersuchung des akut kolikkranken Pferdes – klinische und forensische Aspekte

Der Artikel fasst praktische Hinweise und Informationen über das Management von Pferden mit akuten Koliksymptomen zusammen. Anamnese und Diagnostik sowie wichtige Aspekte der Forensik werden diskutiert. Die Anamneseerhebung erfolgt entsprechend dem Erkrankungsgrad des Patienten und umfasst in jedem Fall kolikassoziierte Informationen wie z. B. den Beginn der Koliksymptome, Verlauf und Schweregrad, letzten Kotabsatz und etwaige Vorbehandlungen. Auch der Umfang der klinischen Untersuchung wird an die Koliksymptomatik angepasst. Bei Pferden, die aufgrund hochgradiger Koliksymptome nur eingeschränkt zu untersuchen sind, werden zunächst nur die kardiovaskulären Parameter sowie die Körperinnentemperatur und das Verhalten beurteilt. Die Untersuchung mit einer Magensonde gehört grundsätzlich zur Untersuchung eines Kolikpatienten, um die Gefahr einer Magenruptur durch eine Magenüberladung abzuwenden. Auch der transrektalen Untersuchung kommt große Bedeutung bei der Kolikeruntersuchung zu. Sie sollte bei jedem Patienten durchgeführt werden, bei dem keine triftigen Gründe gegen diese Untersuchungsmethode sprechen. Die sorgfältige, klinische Untersuchung eines Pferdes mit akuter Kolik ermöglicht dem Tierarzt zusammen mit dem Vorbericht in den meisten Fällen eine Verdachtsdiagnose zu stellen und eine prognostische Einschätzung sowie die Entscheidung hinsichtlich einer konservativen oder chirurgischen Therapie zu treffen. Der Tierarzt steht bei jeder Untersuchung eines an akuter Kolik erkrankten Pferdes in der tierärztlichen Dokumentations- und Aufklärungspflicht. Gerade die schriftliche Dokumentation erhobener Befunde und durchgeführter Therapien, aber auch der tierärztlichen Beratung und Aufklärung, sollte zeitnah erfolgen. Dies erleichtert sowohl eine Weiterbehandlung des Patienten als auch die Beweislage im Fall eines möglicherweise resultierenden Rechtsstreits.

[Fulminant sepsis after Capnocytophaga canimorsus infection]

Capnocytophaga canimorsus is a Gram-negative bacterium present in the oral cavities of cats and dogs. It is known for its capability to cause life-threatening sepsis following a dog bite, especially in immunocompromised patients. We report the case of a 67-year-old man who suffered from septic shock and multiorgan failure presumably following contamination of a pre-existing minor skin lesion by canine saliva. The purpose of this report is to raise awareness of Capnocytophaga canimorsus among physicians when faced with a patient presenting with fulminant septic shock and Gram-negative bacteremia, who has been exposed to dogs.

Comparison of three different methods for the quantification of equine insulin

Background

Exact analysis of equine insulin in blood samples is the key element for assessing insulin resistance or insulin dysregulation in horses. However, previous studies indicated marked differences in insulin concentrations obtained from sample analyses with different immunoassays. Most assays used in veterinary medicine are originally designed for use in human diagnostics and are based on antibodies directed against human insulin, although amino acid sequences between equine and human insulin differ. Species-specific assays are being used more frequently and seem to provide advantages compared to human-specific assays. The aim of this study was to compare three immunoassays, one porcine-specific insulin enzyme-linked immunosorbent assay (ELISA), advertised to be specific for equine insulin, one porcine-specific insulin radioimmunoassay (RIA) and one human-specific insulin chemiluminescence immunoassay (CLIA), all three widely used in veterinary laboratories for the analysis of equine insulin. Furthermore, we tested their clinical applicability in assessing insulin resistance and dysregulation by analysis of basal blood and blood samples obtained during a dynamic diagnostic stimulation test (OGT) with elevated insulin concentrations.

Results

Insulin values obtained from the ELISA, RIA and CLIA, investigated for analyses of basal blood samples differed significantly between all three assays. Analyses of samples obtained during dynamic diagnostic stimulation testing with consecutively higher insulin concentrations revealed significantly (p < 0.001) lower insulin concentrations supplied by the CLIA compared to the ELISA. However, values measured by ELISA were intermediate and not different to those measured by RIA. Calculated recovery upon dilution, as a marker for assay accuracy in diluted samples, was 98 ± 4 % for ELISA, 160 ± 41 % for RIA and 101 ± 11 % for CLIA.

Conclusions

Our results indicate that insulin concentrations of one sample measured by different methods vary greatly and should be interpreted carefully. Consideration of the immunoassay method and reliable assay-specific reference ranges are of particular importance especially in clinical cases where small changes in insulin levels can cause false classification in terms of insulin sensitivity of horses and ponies.

In vitro anticancer activity of Betulinic acid and derivatives thereof on equine melanoma cell lines from grey horses and in vivo safety assessment of the compound NVX-207 in two horses

Betulinic acid, a pentacyclic triterpene, and its derivatives are promising compounds for cancer treatment in humans. Melanoma is not only a problem for humans but also for grey horses as they have a high potential of developing melanoma lesions coupled to the mutation causing their phenotype. Current chemotherapeutic treatment carries the risk of adverse health effects for the horse owner or the treating veterinarian by exposure to antineoplastic compounds. Most treatments have low prospects for systemic tumor regression. Thus, a new therapy is needed. In this in vitro study, Betulinic acid and its two derivatives B10 and NVX-207, both with an improved water solubility compared to Betulinic acid, were tested on two equine melanoma cell lines (MelDuWi and MellJess/HoMelZh) and human melanoma (A375) cell line. We could demonstrate that all three compounds especially NVX-207 show high cytotoxicity on both equine melanoma cell lines. The treatment with these compounds lead to externalization of phosphatidylserines on the cell membrane (AnnexinV-staining), DNA-fragmentation (cell cycle analysis) and activation of initiator and effector caspases (Caspase assays). Our results indicate that the apoptosis is induced in the equine melanoma cells by all three compounds. Furthermore, we succeed in encapsulating the most active compound NVX-207 in 2-Hydroxyprolyl-β-cyclodextrine without a loss of its activity. This formulation can be used as a promising antitumor agent for treating grey horse melanoma. In a first tolerability evaluation in vivo the formulation was administered every one week for 19 consecutive weeks and well tolerated in two adult melanoma affected horses.

Immune response of healthy horses to DNA constructs formulated with a cationic lipid transfection reagent

Background

Deoxyribonucleic acid (DNA) vaccines are used for experimental immunotherapy of equine melanoma. The injection of complexed linear DNA encoding interleukin (IL)-12/IL-18 induced partial tumour remission in a clinical study including 27 grey horses. To date, the detailed mechanism of the anti-tumour effect of this treatment is unknown.

Results

In the present study, the clinical and cellular responses of 24 healthy horses were monitored over 72 h after simultaneous intradermal and intramuscular application of equine IL-12/IL-18 DNA (complexed with a transfection reagent) or comparative substances (transfection reagent only, nonsense DNA, nonsense DNA depleted of CG).

Although the strongest effect was observed in horses treated with expressing DNA, horses in all groups treated with DNA showed systemic responses. In these horses treated with DNA, rectal temperatures were elevated after treatment and serum amyloid A increased. Total leukocyte and neutrophil counts increased, while lymphocyte numbers decreased. The secretion of tumour necrosis factor alpha (TNFα) and interferon gamma (IFNγ) from peripheral mononuclear blood cells ex vivo increased after treatments with DNA, while IL-10 secretion decreased. Horses treated with DNA had significantly higher myeloid cell numbers and chemokine (C-X-C motif) ligand (CXCL)-10 expression in skin samples at the intradermal injection sites compared to horses treated with transfection reagent only, suggesting an inflammatory response to DNA treatment.

In horses treated with expressing DNA, however, local CXCL-10 expression was highest and immunohistochemistry revealed more intradermal IL-12-positive cells when compared to the other treatment groups.

In contrast to non-grey horses, grey horses showed fewer effects of DNA treatments on blood lymphocyte counts, TNFα secretion and myeloid cell infiltration in the dermis.

Conclusion

Treatment with complexed linear DNA constructs induced an inflammatory response independent of the coding sequence and of CG motif content. Expressing IL-12/IL-18 DNA locally induces expression of the downstream mediator CXCL-10.

The grey horses included appeared to display an attenuated immune response to DNA treatment, although grey horses bearing melanoma responded to this treatment with moderate tumour remission in a preceding study. Whether the different immunological reactivity compared to other horses may contributes to the melanoma susceptibility of grey horses remains to be elucidated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-015-0452-3) contains supplementary material, which is available to authorized users.

Influences of age and sex on leukocytes of healthy horses and their ex vivo cytokine release

Leukocytes and their functional capacities are used extensively as biomarkers in immunological research. Commonly employed indicators concerning leukocytes are as follows: number, composition in blood, response to discrete stimuli, cytokine release, and morphometric characteristics. In order to employ leukocytes as biomarkers for disease and therapeutic monitoring, physiological variations and influencing factors on the parameters measured have to be considered. The aim of this report was to describe the ranges of selected leukocyte parameters in a sample of healthy horses and to analyse whether age, sex, breed, and sampling time point (time of day) influence peripheral blood leukocyte composition, cell morphology and release of cytokines ex vivo. Flow cytometric comparative characterisation of cell size and complexity in 24 healthy horses revealed significant variance. Similarly, basal release of selected cytokines by blood mononuclear cells also showed high variability [TNFα (65-16,624pg/ml), IFNγ (4-80U/ml), IL-4 (0-5069pg/ml), IL-10 (49-1862pg/ml), and IL-17 (4-1244U/ml)]. Each animal's age influenced leukocyte composition, cell morphology and cytokine release (TNFα, IL-4, IL-10) ex vivo. Geldings showed smaller monocytes and higher spontaneous production of IL-10 when compared to the mares included. The stimulation to spontaneous release ratios of TNFα, IL-4 and IL-17 differed in Warmblood and Thoroughbred types. Sampling time influenced leukocyte composition and cell morphology. In summary, many animal factors - age being the dominant one - should be considered for studies involving the analysis of equine leukocytes. In addition, high inter-individual variances argue for individual baseline measurements.

Evaluation of the reactivity of commercially available monoclonal antibodies with equine cytokines

Research on equine cytokines is often performed by analyses of mRNA. For many equine cytokines an analysis on the actual protein level is limited by the availability of antibodies against the targeted cytokines. Generation of new antibodies is ongoing but time consuming. Thus, testing the reactivity of commercially available antibodies for cross-reactivity with equine cytokines is of particular interest. Fifteen monoclonal antibodies against IL-1β, IL-6, IL-8, IL-12, IL-18 and Granulocyte Macrophage Colony stimulating factor (GM-CSF) of different species were evaluated for reactivity with their corresponding equine cytokines. Dot Blot (DB) and Western Blot (WB) analyses were performed using recombinant equine cytokines as positive controls. Immunohistochemistry (IHC) was carried out on equine tissue and flow cytometry on equine PBMC as positive controls. As expected, three equine IL-1β antibodies detected equine IL-1β in DB, WB and IHC. For these, reactivity in IHC has not been described before. One of them was also found to be suitable for intracellular staining of equine PBMC and flow cytometric analysis. Two antibodies raised against ovine GM-CSF cross-reacted with equine GM-CSF in DB, WB and IHC. For these anti-GM-CSF mAbs this is the first experimental description of cross-reactivity with equine GM-CSF (one mAb was predicted to be cross-reactive in WB in the respective data sheet). The other clone additionally proved to be appropriate in flow cytometric analysis. Two mAbs targeting porcine IL-18 cross-reacted in IHC, but did not show specificity in the other applications. No reactivity was shown for the remaining five antibodies in DB, although cross-reactivity of two of the antibodies was described previously. The results obtained in this study can provide beneficial information for choosing of antibodies for immunological tests on equine cytokines.

[Examination of horses with acute colic - clinical pathology and diagnostic imaging]

The article summarizes the relevant clinical pathological assessment of horses with acute colic. A minimal laboratory evaluation should include the patient's haematocrit (or packed cell volume), total protein, and lactate concentration in the blood. Haematocrit and total protein provide an indication of the severity of dehydration (haematocrit < 0.45 l/l is evidence of no to mild dehydration whereas > 0.5 l/l points to a severe dehydration). The degree of dehydration is often associated with the severity of the colic. Additionally, the blood lactate concentration rises with increasing intestinal compromise with a concentration of > 4 mmol/l indicating a guarded prognosis. However, it is crucial to assess laboratory values only in the context of the clinical findings. If an abdominocentesis is performed, the leukocyte count and the protein and lactate concentrations offer valuable information regarding the type of colic, the severity of the lesion, further therapy, and prognosis of the colic. Reddish discolouration of peritoneal fluid may be a sign of a strangulating obstruction. Transcutaneous abdominal ultrasonography may provide a crucial insight into the colic cause and severity in a relatively short time, even for inexperienced examiners. In regards to small intestinal lesions, dilated small intestinal loops can often be imaged ultrasonographically before they can be palpated transrectally. The occurrence of free peritoneal fluid and dilated small intestine as well as the evaluation of the intestinal wall and the extent of the gastric wall, allow a better management of the acute colic patient. In ponies and foals, radiography as a further diagnostic imaging modality of the abdomen is of great value. It can help to visualise sand impactions, meconium impactions, or gastrointestinal atresia in the neonate.

Untersuchung des akut kolikkranken Pferdes – labordiagnostische und bildgebende Verfahren

Der Artikel gibt eine Übersicht über die für die Untersuchung des akut kolikkranken Pferdes relevanten labordiagnostischen Untersuchungsparameter in Blut und Bauchhöhlenpunktat. Als minimale Datenbasis werden Hämatokrit und Gesamteiweißkonzentra tion empfohlen. Sie können einen Hinweis auf den Dehydratationsgrad liefern (Hämatokrit < 0,45 l/l als Anzeichen einer maximal geringgradigen und > 0,5 l/l als Hinweis auf eine hochgradige Dehydratation). Der Grad der Dehydratation geht häufig mit dem Schweregrad der Kolik einher. Wertvolle Hinweise auf einen minderdurchbluteten Darm kann die Blutlaktatkonzentration geben, wobei ein Wert von > 4 mmol/l auf eine ungünstige Prognose hinweist. Zu beachten ist, dass die Laborparameter immer in Kombination mit den Befunden der klinischen Untersuchung beurteilt werden. Gerade die Verlaufsuntersuchung des klinischen Zustands und dieser Laborparameter ist für die Beurteilung des Krankheitsgeschehens und dessen Entwicklung äußerst wertvoll. Bei erfolgter Abdominozentese können die Bestimmung von Zellzahl, Proteinund Laktatkonzentration wertvolle Hinweise zu Art der Kolik, Therapie und Prognose liefern. Eine Rotfärbung des Bauchhöhlenpunktats stellt ein Indiz für eine Strangulation des Darms dar (hämorrhagische Infarzierung). Auch durch die transkutane Sonographie des Abdomens lassen sich in kurzer Zeit wertvolle Informationen zur Ursache der Kolik und deren Schweregrad gewinnen. Bei einem Dünndarmileus stellt sich häufig bereits vor der transrektalen Palpation von Dünndarmanteilen dilatierter Dünndarm sonographisch im ventralen Flankenbereich dar. Das Vorliegen freier Flüssigkeit im Peritonealraum, das Auffinden dilatierter Dünndarmanteile, die Beurteilung der Darmwanddicke und die Ausdehnung der Magengrenzen können Anhaltspunkte für das weitere Management akut kranker Kolikpatienten liefern. Besonders bei Ponys und Fohlen eignet sich auch die röntgenologische Untersuchung zur weiterführenden Dia gnostik. Sie kann beispielsweise zur Darstellung von Sandobstipationen, Mekoniumobstipationen sowie gastrointestinalen Atresien beim Neonaten herangezogen werden.

In vivo induction of interferon gamma expression in grey horses with metastatic melanoma resulting from direct injection of plasmid DNA coding for equine interleukin 12

Whole blood pharmacokinetics of intratumourally injected naked plasmid DNA coding for equine Interleukin 12 (IL-12) was assessed as a means of in vivo gene transfer in the treatment of melanoma in grey horses. The expression of induced interferon gamma (IFN-g) was evaluated in order to determine the pharmacodynamic properties of in vivo gene transduction. Seven grey horses bearing melanoma were injected intratumourally with 250 µg naked plasmid DNA coding for IL-12. Peripheral blood and biopsies from the injection site were taken at 13 time points until day 14 post injection (p.i.). Samples were analysed using quantitative real-time PCR. Plasmid DNA was quantified in blood samples and mRNA expression for IFN-g in tissue samples. Plasmid DNA showed fast elimination kinetics with more than 99 % of the plasmid disappearing within 36 hours. IFN-g expression increased quickly after IL-12 plasmid injection, but varied between individual horses. Intratumoural injection of plasmid DNA is a feasible method for inducing transgene expression in vivo. Biological activity of the transgene IL-12 was confirmed by measuring expression of IFN-g.

[Examination of horses with acute colic: clinical and legal aspects]

The article provides hands-on advice and scientific background information regarding the management of the equine acute colic patient. It summarizes essential information on the patient's history, clinical examination, and legal aspects. The scope of the history is based on the clinical appearance of the patient. In horses with violent and barely controllable signs of pain, it is limited to colic-associated information such as onset, course and severity of colic signs, and the last time of defecation, as well as prior therapeutic intervention. In these patients, the clinical examination is focussed primarily on the assessment of cardiovascular parameters, rectal temperature, and the patient's behaviour. The nasogastric intubation is an essential part of the examination of a horse with colic to prevent a gastric rupture due to gastric distension. Transrectal palpation is equally important and should always be performed unless there are important reasons to object to this procedure. In most cases, a thorough patient history and clinical examination of an acute colic patient allows the examining veterinarian to make a tentative diagnosis and a prognostic evaluation. This helps with the decision to start a conservative or a surgical therapy. Due to the existing obligatory documentation requirement and the duty to inform patient owners, it is of utmost importance to promptly document one's findings, therapeutic measures, consultations, and information of the patient owner in written form. This supports further therapy and it can also be of relevance in a potentially resulting lawsuit.

Electrophysiological characterization of electrolyte and nutrient transport across the small intestine in horses

The aim of this study was to characterize the transport mechanisms of electrolytes and nutrients across the jejunum of nine healthy horses electrophysiologically. The stripped mucosa was mounted in Ussing chambers and tissue conductances (G(t)) and short circuit currents (I(sc)) were continuously monitored. After blocking the sodium and potassium channels with amiloride, tetraethylammonium chloride (TEA) and barium, chloride secretion was stimulated by carbachol and forskolin. Subsequently, chloride channels were inhibited by 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid, 5-nitro-2-(3-phenylpropylamino)benzoic acid, CFTR(inh)-172, N-(2-naphtalenyl)-(3.5-dibromo-2.4-dihydroxyphenyl)methylene glycine hydrazide (GlyH-101) and glibenclamide and their dose-response effect was investigated. The response to glucose, l-alanine and glycyl-l-glutamine was determined at two different mucosal pH values (pH 7.4 and 5.4 respectively). Mean basal I(sc) was -0.47 +/- 0.31 microEq/cm(2)h and mean G(t) was 22.17 +/- 1.78 mS/cm(2). Amiloride and TEA did not alter the baseline I(sc). Barium, carbachol and forskolin significantly increased I(sc). Irrespective of the dose, none of the chloride inhibitors changed I(sc). All nutrients induced a significant increase in I(sc) with the increase being significantly higher at pH 7.4 than at pH 5.4. In conclusion, there is evidence that chloride secretion in horses may be different from respective transport mechanisms in other species. The glucose absorption is suggestive of a sodium-dependent glucose cotransporter 1. However, a decrease in luminal pH did not stimulate current response to peptides as shown for other mammals.

Necrosis of the nasal conchae in 12 horses

Twelve horses with a history of a unilateral malodorous nasal discharge were examined clinically, endoscopically and radiographically. The head of one of the horses was examined by computed tomography. Tissue samples were taken for microbiology from four of the horses and for histology from three. The conchal necrosis was unilateral in 11 of the horses and bilateral in the other, and no particular concha was affected more than the others. The affected tissue was removed transendoscopically with a polypectomy snare while the horses were sedated and standing. Mild disinfectants were used locally in six of the horses. After the removal of all the necrotic tissue, the affected concha healed without any complications in all 12 horses.

Kurz- und Langzeitprognose von Dünndarmkolikern nach Kolikoperation

Ziel der vorliegenden Arbeit war, die Prognose von Pferden nach chirurgisch therapierter Dünndarmkolik mithilfe von Kurz- und Langzeitüberlebensraten hinsichtlich ihres Zusammenhangs mit präoperativ und intraoperativ ermittelten Befunden zu untersuchen. Material und Methoden: Es erfolgte eine retrospektive Auswertung der Krankenakten von Pferden, die wegen Kolik laparotomiert wurden und eine pathologische Veränderung im Dünndarm aufwiesen. Der prä- und postoperative Verlauf der 233 die Aufstehphase überlebenden Patienten wurde hinsichtlich präoperativer Parameter bei Klinikeintritt (Rektaltemperatur, Herzfrequenz, Atemfrequenz, Hämatokrit, Plasmaproteingehalt, Kolikdauer bis Klinikeintritt, Kolikverlauf, Verhalten bei Klinikeintritt, Maulschleimhautfarbe, kapilläre Rückfüllzeit, Bauchhöhlenpunktat) und intraoperativer Befunde (bestehende Veränderungen der Darmfarbe, Dünndarmresektion, Resektatlänge, Kolikursache) ausgewertet. Ferner erfolgte eine Auswertung des postoperativen Krankheitsverlaufes bis zur Entlassung aus der Klinik sowie ein und 5 Jahre danach. Ergebnisse: Die Überlebensrate aller Patienten betrug bei Entlassung aus der Klinik 81%, nach einem Jahr 66% und nach 5 Jahren 35%. Präoperativ erhobene Befunde mit Einfluss auf die 1-Jahres-Überlebenswahrscheinlichkeit waren der Kolikverlauf vor Klinikeintritt und der Hämatokrit bei der Erstuntersuchung. Kolikursachen mit Dünndarmstrangulation resultierten in einer schlechteren Kurzzeitprognose (80%) als Kolikursachen ohne Dünndarmstrangulation (90%). Dagegen war die Durchführung einer Dünndarmresektion im Vergleich zu einer Kolikoperation ohne Dünndarmresektion nicht mit einer schlechteren Prognose assoziiert. Schlussfolgerung und klinische Relevanz: Aus den Ergebnissen wird abgeleitet, dass sich eine Dünndarmresektion weder auf die Kurzzeitüberlebensrate noch die Langzeitüberlebensrate auswirkt.

Botulismus bei einem 3 Monate alten Fohlen

Gegenstand und Ziel: Darstellung der Symptome, des klinischen Verlaufs sowie der labordiagnostischen Befunde bei einem Fohlen mit Botulismus. Material und Methoden: Ein 3 Monate altes Friesenpferdfohlen wurde mit seit 12 Stunden andauerndem unkoordiniertem Gang, vermehrtem Liegen und Husten vorgestellt und einer klinischen Allgemeinuntersuchung und speziellen Untersuchung unterzogen. Ergebnisse: Bei der klinischen Untersuchung war das Fohlen aufmerksam, zeigte eine reduzierte Darmmotorik und einen generalisiert reduzierten Muskeltonus. Neben deutlich verzögerten Haltungs- und Stellreaktionen war die Hautsensibilität deutlich reduziert. Bei bestehender Ptosis und Mydriasis fand sich beidseits ein geringgradig verzögerter Pupillarreflex. Der Zungentonus war hochgradig reduziert und die Zunge wurde nach seitlichem Herausziehen aus dem Maul nicht wieder zurückgezogen. Ein Schluckreflex konnte nicht ausgelöst werden. Aufgrund der erhobenen Befunde wurde die Verdachtsdiagnose eines Botulismus gestellt und das Fohlen wegen der Schwere der Symptomatik euthanasiert. In der am lebenden Fohlen entnommenen Kotprobe konnte im Labor freies Botulinum-Neurotoxin der Gruppen C und D nachgewiesen werden. Schlussfolgerung: Bei schlaffer Lähmung der Skelettmuskulatur, Zungenlähmung und Schluckstörungen bei gleichzeitig ungetrübtem Bewusstsein sollte nach Ausschluss anderer differenzialdiagnostisch infrage kommender Erkrankungen eine Intoxikation mit Botulinumtoxin in Betracht gezogen werden. Klinische Relevanz: Die Botulinumintoxikation stellt beim Pferd wie beim Menschen und anderen Tierspezies eine lebensbedrohliche Erkrankung dar. Aufgrund der fehlenden pathognomonischen Symptome ist die Diagnosestellung schwierig und basiert zunächst auf einer eingehenden Anamnese und klinischen Untersuchung.