The results of our study identified a population of ERU cases with an active intraocular Leptospira infectious process in the Southern United States. The diagnosis of intraocular leptospirosis required ocular fluid sampling for PCR or culture. Twenty-one percent of ocular fluid samples were positive by culture and forty-five percent by PCR; no control horses were positive by either culture or PCR. These findings are in contrast to a recent study from the Southeastern US that showed no evidence of bacterial DNA by PCR and supports the conclusion that a regional variation in Leptospira infections exists. The most common culture isolate was the serovar pomona; additionally, we report the first cases of serovar grippotyphosa outside of Europe. Title Role of intraocular Leptospira infections in the pathogenesis of Equine Recurrent Uveitis in the Southern United States.Abstract: Equine Recurrent Uveitis (ERU) has been linked to leptospirosis in Europe, however regional differences exist in reports from the United States. The objective of this study was to investigate the role of intraocular leptospiral infections in horses with ERU in the Southern United States. Blood and ocular fluid samples were collected from horses with ERU as well as normal controls. Leptospira serology was performed using microscopic agglutination test (MAT). Aqueous and vitreous humor samples were obtained and submitted for aerobic and Leptospira culture, PCR and MAT. Twenty-one control horses (40 eyes) and 31 ERU horses (46 eyes) were available. Serology was available for 48/52 horses: 16/21 control and 23/27 affected horses were positive for at least one serovar; bratislava was the most common serovar identified. Bacillus sp. and Micrococcus sp. were cultured from one control eye; Streptococcus sp. (n=1) and Leptospira (n=6) from the eyes of 6 ERU horses. Leptospira isolates belonged to serogroup pomona (n=4) and grippotyphosa (n=2). PCR results were positive in 14/31 (45%) horses with ERU; no control horses were positive by PCR (p=0.0001). MAT was positive for 17/24 of ERU horses (71%) and 1/21 (4.7%) of normal horses (p<0.0001). Horses with ERU had a high prevalence of Leptospira infection based on PCR and MAT results from intraocular fluids compared to controls. The diagnosis of intraocular infections was not aided by serology and required specific, invasive sampling of ocular fluid. Leptospira infection should be considered as a cause of ERU in the Southern United States.

Abstract. AL amyloidosis is the most common type of systemic amyloidosis in humans, and it is frequently associated with multiple myeloma. But, AL amyloidosis is very rare in domestic animals. A 16-year-old Quarter horse gelding was diagnosed with systemic AL amyloidosis associated with multiple myeloma. Clinical problems were rapid weight loss, muscle atrophy, soft unformed stool, and ventral edema. Grossly, diffuse gastrointestinal hemorrhage, markedly thickened jejunal mucosa, and splenomegaly were present. Microscopically, diffuse severe amyloid deposits were present in the lamina propria of glandular stomach, duodenum, and jejunum. Much of the spleen and sternal bone marrow was replaced by neoplastic round cells, and multiple foci of amyloid were also present in the spleen and bone marrow. Electron microscopy revealed the neoplastic round cells to be of plasma cell origin, and the amyloid showed a strongly positive immunoreactivity with polyclonal anti-human immunoglobin lambda light-chain antisera. To our knowledge, this is the second report describing systemic AL amyloidosis in domestic animals-associated plasma cell neoplasia and the first associated with multiple myeloma, as is common in humans.

These results support further investigation of mTORC1/RPS6 signalling as a potential therapeutic target(s) in EMSAL. The Summary is available in Chinese - see Supporting Information.

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OBJECTIVE To investigate risk factors for the development of pasture- and endocrinopathy-associated laminitis (PEAL) in horses and ponies in North America. DESIGN Case-control study. ANIMALS 199 horses with incident cases of PEAL and 351 horses from 2 control populations (healthy horses [n = 198] and horses with lameness not caused by laminitis [153]) that were evaluated in North America between January 2012 and December 2015 by veterinarian members of the American Association of Equine Practitioners. PROCEDURES North American members of the American Association of Equine Practitioners were contacted to participate in the study, and participating veterinarians provided historical data on incident cases of PEAL, each matched with a healthy control and a lameness control. Conditional logistic regression analysis was used to compare data on PEAL-affected horses with data on horses from each set of controls. RESULTS Horses with an obese body condition (ie, body condition score ≥ 7), generalized or regional adiposity (alone or in combination), preexisting endocrinopathy, or recent (within 30 days) glucocorticoid administration had increased odds of developing PEAL, compared with horses that did not have these findings. CONCLUSIONS AND CLINICAL RELEVANCE The present study identified several risk factors for PEAL that may assist not only in managing and preventing this form of laminitis, but also in guiding future research into its pathogenesis.

Summary Reasons for performing study: Abdominal insufflation is performed routinely during laparoscopy in horses to improve visualisation and facilitate instrument and visceral manipulations during surgery. It has been shown that high‐pressure pneumoperitoneum with carbon dioxide (CO2) has deleterious cardiopulmonary effects in dorsally recumbent, mechanically ventilated, halothane‐anaesthetised horses. There is no information on the effects of CO2 pneumoperitoneum on cardiopulmonary function and haematology, plasma chemistry and peritoneal fluid (PF) variables in standing sedated horses during laparoscopic surgery. Objectives: To determine the effects of high pressure CO2 pneumoperitoneum in standing sedated horses on cardiopulmonary function, blood gas, haematology, plasma chemistry and PF variables. Methods: Six healthy, mature horses were sedated with an i.v. bolus of detomidine (0.02 mg/kg bwt) and butorphanol (0.02 mg/kg bwt) and instrumented to determine the changes in cardiopulmonary function, haematology, serum chemistry and PF values during and after pneumoperitoneum with CO2 to 15 mmHg pressure for standing laparoscopy. Each horse was assigned at random to either a standing left flank exploratory laparoscopy (LFL) with CO2 pneumoperitoneum or sham procedure (SLFL) without insufflation, and instrumented for measurement of cardiopulmonary variables. Each horse underwent a second procedure in crossover fashion one month later so that all 6 horses had both an LFL and SLFL performed. Cardiopulmonary variables and blood gas analyses were obtained 5 mins after sedation and every 15 mins during 60 mins baseline (BL), insufflation (15 mmHg) and desufflation. Haematology, serum chemistry analysis and PF analysis were performed at BL, insufflation and desufflation, and 24 h after the conclusion of each procedure. Results: Significant decreases in heart rate, cardiac output and cardiac index and significant increases in mean right atrial pressure, systemic vascular resistance and pulmonary vascular resistance were recorded immediately after and during sedation in both groups of horses. Pneumoperitoneum with CO2 at 15 mmHg had no significant effect on cardiopulmonary function during surgery. There were no significant differences in blood gas, haematology or plasma chemistry values within or between groups at any time interval during the study. There was a significant increase in the PF total nucleated cell count 24 h following LFL compared to baseline values for LFL or SLFL at 24 h. There were no differences in PF protein concentrations within or between groups at any time interval. Conclusions: Pneumoperitoneum with CO2 during standing laparoscopy in healthy horses does not cause adverse alterations in cardiopulmonary, haematology or plasma chemistry variables, but does induce a mild inflammatory response within the peritoneal cavity. Potential relevance: High pressure (15 mmHg) pneumoperitoneum in standing sedated mature horses for laparoscopic surgery can be performed safely without any short‐term or cumul...

The large number of apoptotic basal layer cells detected in the lamellar tissue of horses with acute naturally acquired laminitis suggests that apoptosis may be important in the development of acute laminitis. The role of the large number of TUNEL-positive keratinocytes detected in the interface of primary and secondary epidermal laminae of horses with acute laminitis remains to be elucidated.

SummaryReasons for performing study: One of the causes of equine laminitis is hyperinsulinaemia, which may be associated with endothelial dysfunction and insulin resistance of vessels. Hypothesis and objectives: Insulin resistance can be induced in palmar digital vessels by continued exposure to insulin in vitro. The objective was to evaluate this in vitro model for future studies.