Resident forum abstractsEVALUATION OF THROMBOELASTOGRAPHY (TEG) IN NORMAL CATS

Objective: To establish normal parameters of thromboelastography (TEG) in healthy adult cats. Background: Thromboelastography (TEG) is an in vitro test of coagulation that has been shown to be useful in humans, dogs and select species to identify and quantify alterations of hemostasis (e.g., hypercoagulable and hypocoagulable states). It has also been demonstrated to be useful in monitoring effects of anticoagulant therapies. This test has not been evaluated in cats. Methods: Blood was collected from 25 clinically normal cats by venipuncture using a 21 gauge×3 1/2 inch butterfly catheter and syringe for medial saphenous or jugular venipuncture. A single 1.8 mL sample in 3.8% Sodium Citrate (9:1) was collected from each cat. Recalcified whole blood was analyzed 30 minutes following collection with the TEG® 5000 analyzer (Haemoscope, Niles, IL). Analysis temperature was 37.6°C. TEG parameters recorded included: R‐value (represents initial fibrin formation), K (time from R to standard fixed measure of clot firmness which represents contributions of platelets and fibrinogen), maximum amplitude (MA; represents absolute clot strength), and alpha angle (α; the slope of TEG tracing which represents rate of clot formation). The coagulation index (CI) was derived from the formula generated for humans to provide an overall assessment of whether the sample was hyper‐ or hypocoagulable. Results: Values for the 25 normal cat samples are reported as mean ±2 standard deviations. R=2.97; 1.23–4.72; K=1.54, 0.38–2.71; α=70.70, 57.76–83.65; MA=58.50, 45.26–71.74 and CI=2.27, 0.07–4.46. Compared to historical information obtained on normal dogs, cats have significantly shorter R and K and larger α, MA and CI. Conclusions: TEG does have reproducible performance when used to evaluate coagulation status in normal cats. Compared to dogs, normal cats favor a hypercoagulable state. Species‐specific normal values are necessary for interpretation of TEG results. This test bears potential value for use in future experimental and clinical work to investigate hemostasis in cats receiving anticoagulant therapies or in cats suffering from diseases such as cardiomyopathy which are thought to be associated with altered coagulation status.     

Transient diabetes mellitus in a neonatal Thoroughbred foal

Objective – To describe the clinical presentation, treatment, and outcome of a neonatal foal diagnosed with transient Type 1 diabetes mellitus. Case Summary – A 3‐day‐old Thoroughbred foal presented with a 24‐hour history of diarrhea and depression. Coronavirus particles were observed in the feces via electron microscopy. During hospitalization the foal developed hyperglycemia concomitantly with low insulin concentration and an adequate response to exogenous insulin therapy supported a diagnosis of Type 1 diabetes mellitus. The foal required SC insulin for 26 days, but developed complications associated with insulin therapy that resolved with appropriate care. On follow up assessment the foal was found to be a healthy euglycemic animal with normal insulin concentration at 11 months of age. New or Unique Information Provided – To our knowledge this is the first report of Type 1 diabetes in this age group and the first report of transient neonatal diabetes mellitus in horses. Type 1 diabetes mellitus should be considered a differential diagnosis for hyperglycemia in equine neonates and that it can be transient and managed successfully.     

Common variable immunodeficiency in a horse with chronic peritonitis

This report describes the clinical progression of a Quarter Horse filly with common variable immunodeficiency (CVID). Equine CVID is a primary immunodeficiency in which affected animals are unable to mount an appropriate antibody response and suffer recurrent bacterial infections. The filly in this report had a history of chronic respiratory tract infections but presented for assessment of poor weight gain and was diagnosed with Actinobacillus equuli peritonitis.     

LINEAR OSTEOCHONDROMATOSIS IN A CAT

A domestic shorthair cat was presented with quadriparesis and lumbar hyperesthesia that progressed over 4 months. There were linear and amorphous radiopaque masses throughout the soft tissue surrounding the long bones, vertebral bodies, ribs, pelvis, and scapula. The diagnosis of osteochondromatosis was confirmed by histopathology. Unlike previously reported patients with osteochondromatosis, most of the calcified masses in this cat were not connected to the periosteum; some were linear and were arranged parallel to the long bones involved.     

Severe acute rhabdomyolysis associated with Streptococcus equi infection in four horses

Four Quarter Horses (9 months to 7 years of age) with submandibular lymphadenopathy and firm muscles (palpation of which elicited signs of pain) were evaluated; in general, the horses had a stiff gait, and 3 horses became recumbent. Streptococcus equi was cultured from aspirates of lymph nodes or samples of purulent material collected from the auditory tube diverticula. Once the horses were recumbent, their condition deteriorated rapidly despite aggressive antimicrobial and antiinflammatory treatment, necessitating euthanasia within 24 to 48 hours. One horse did not become recumbent and recovered completely. Among the 4 horses, common clinicopathologic findings included neutrophilia, hyperfibrinogenemia, and high serum activities of creatine kinase and aspartate aminotransferase. Necropsies of the 3 euthanatized horses revealed large, pale areas most prominent in the semimembranosus, semitendinosus, sublumbar, and gluteal muscles that were characterized histologically by severe acute myonecrosis and macrophage infiltration of necrotic myofibers. Streptococcus equi was identified in sections of affected muscle by use of immunofluorescent stains for Lancefield group C carbohydrate and S. equi M protein. In the 4 horses of this report, acute severe rhabdomyolysis without clinical evidence of muscle atrophy or infarction was associated with S. equi infection; rhabdomyolysis was attributed to either an inflammatory cascade resembling streptococcal toxic shock or potentially direct toxic effects of S. equi within muscle tissue.     

Cardiovascular changes associated with intravenous administration of fumonisin B1 in horses

OBJECTIVE: To determine whether cardiovascular dysfunction is evident in horses with leukoencephalomalacia experimentally induced by administration of fumonisin B1. ANIMALS: 11 healthy horses of various breeds (body weight, 252 to 367 kg). PROCEDURE: Horses were randomly assigned to 3 groups and administered fumonisin B1 daily. Horses received IV injections of 0 (control horses; n = 4), 0.01 (3), or 0.20 mg (4) of fumonisin B1/kg for 7 to 28 days. Horses were examined daily for evidence of neurologic disease. When neurologic signs consistent with leukoencephalomalacia were evident, horses were anesthetized, and catheters were inserted for evaluation of the cardiovascular system. After recovery from anesthesia, hemodynamic measurements were obtained. RESULTS: Fumonisin-treated horses with clinical signs of neurologic disease had evidence of cardiovascular dysfunction manifested as decreases in heart rate, cardiac output, right ventricular contractility (assessed by measuring the maximal rate of change of right ventricular pressure), coccygeal artery pulse pressure, and pH and base excess in venous blood as well as increases in systemic vascular resistance, compared with values for control horses. Fumonisin-treated horses with and without clinical signs of neurologic disease also had higher serum and right ventricular sphinganine and sphingosine concentrations than control horses. CONCLUSIONS AND CLINICAL RELEVANCE: An association was detected among fumonisin-induced neurologic disease, increased serum and myocardial sphinganine and sphingosine concentrations, and decreased cardiovascular function in horses. Fumonisin-induced decreases in cardiovascular function may contribute to the pathophysiologic development of leukoencephalomalacia in horses.     

Technical note: using calcium carbonate as an osmolar control treatment for acid-base studies in horses

The efficacy of using calcium carbonate as an osmolar control treatment for acid-base studies in horses receiving alkalizing compounds was evaluated. Six mares were nasogastrically intubated with isomolar quantities of sodium or calcium as sodium bicarbonate or calcium carbonate or with water during three treatment periods. Doses of the carbonic acid salts were 500 mg/kg sodium bicarbonate mixed with 4 L of distilled water (positive control) and 595 mg/kg calcium carbonate mixed with 2 L of distilled water to yield isoosmolar treatments. Four liters of distilled water served as the negative control. Jugular venous blood samples were drawn before intubation and at hourly intervals for 6 h after intubation. The serum electrolytes Na+ and K+, blood pH, and HCO3- were determined. The sodium bicarbonate treatment increased blood pH and HCO3- (P < 0.01) above both the water and CaCO3 treatments. No differences (P > 0.05) were found between the water and CaCO3 treatments. These data indicate that calcium carbonate may serve as a suitable osmolar control treatment for studying the effects of treatments that affect acid-base status of horses.     

Seroprevalence of Coxiella burnetii antibodies in wild deer populations in eastern Australia

Coxiella burnetii causes significant reproduction losses in livestock and the disease Q fever in humans. Transmission of C. burnetii is facilitated by the stability of the bacterium in the environment and the susceptibility of a variety of host species to infection. Consequently, inter-species transmission occurs frequently through either direct or indirect contact. Wildlife may represent reservoirs of C. burnetii and could therefore be a source of infection for domestic animals. Understanding the prevalence of C. burnetii infections at the wildlife-livestock interface is important for disease control. This study aimed to investigate the extent of C. burnetii exposure in wild deer in eastern Australia. Serum samples were obtained from 413 wild deer from seven regions in four eastern Australian states from 2017 to 2020. Antibodies were detected using a commercial Q fever antibody kit validated for ruminants. Seroprevalence of C. burnetii antibodies in deer was determined and true prevalence estimated, for each region. The overall seroprevalence of C. burnetii antibodies in wild deer was 3.4% (14 seropositive of 413 deer sampled) with true prevalence estimated to be 4.3% (95% credible interval: 0.6%, 10.9%). Seropositive deer were identified only in Queensland (7/108 seropositive) and northern New South Wales (7/120 seropositive). This geospatial distribution is consistent with seropositivity in other animal species and indicative of the level of C. burnetii in the environment. The low seroprevalence suggests that wild deer are unlikely to be a major reservoir species for C. burnetii in eastern Australia but may still be implicated in inter-species transmission cycles.     

Ubiquity of biological ice nucleators in snowfall

Despite the integral role of ice nucleators (IN) in atmospheric processes leading to precipitation, their sources and distributions have not been well established. We examined IN in snowfall from mid- and high-latitude locations and found that the most active were biological in origin. Of the IN larger than 0.2 micrometer that were active at temperatures warmer than -7 degrees C, 69 to 100% were biological, and a substantial fraction were bacteria. Our results indicate that the biosphere is a source of highly active IN and suggest that these biological particles may affect the precipitation cycle and/or their own precipitation during atmospheric transport.