Background Peritonitis in horses is historically associated with prolonged treatment regimens of broad-spectrum antimicrobials and a guarded prognosis for survival. The condition is most often seen as a secondary complication to traumatic injuries involving the abdominal cavity, rupture of bowel or abdominal surgery. However, cases of idiopathic peritonitis with no such underlying cause have been described. In Sweden idiopathic peritonitis is commonly identified and, in contrast to peritonitis secondary to traumatic incidents, affected horses appear to respond well to medical treatment. The objectives of this study were to describe clinical signs, laboratory findings, bacterial culture results, treatment regimens and survival rates for horses diagnosed with idiopathic peritonitis. Results Medical records were obtained from horses diagnosed with peritonitis without identifiable cause. Diagnosis was based on macroscopically abnormal peritoneal fluid, with an elevated nucleated cell count (> 10 × 10 9 cells/L) or total protein (> 25 g/L). A total of 130 horses were included, presenting with pyrexia (83%), lethargy (80%), anorexia (68%) and abdominal pain (51%). Microbial cultures were performed in 84% of the cases of which 41% were positive. The most commonly recovered bacteria were Actinobacillus spp., cultured from 21% of the submitted samples. All horses received antimicrobial therapy and many responded to treatment with penicillin alone. Survival until discharge was 94%. Conclusions Idiopathic peritonitis is a disease that should be considered in horses presented with fever, signs of colic and lethargy. Medical treatment of idiopathic peritonitis is often successful and in Sweden most cases appear to respond well to treatment with penicillin as the sole antimicrobial.

Background: Ingestion of sand can cause colic, diarrhoea and weight loss in horses, but these signs are unspecific and can have many other causes. The amount of sand that induces disease may vary between individuals. To avoid over-diagnosing, it is important to determine the amount of sand that can be found in horses without clinical signs of gastrointestinal disease. The aim of this study was to use previously suggested parameters for establishing a radiographic diagnosis of sand colic, and compare these findings between a sand colic group and a control group.

of Gram-positive, and 23/44 (43%) of Gram-negative bacteria were susceptible to trimethoprim-2 sulfonamide. Of 126 isolates, 33 (26%) were MDR; >1 isolate with MDR was cultured from 24/64 (38%) foals, and ≥2 isolates with MDR were recovered from 8/64 (13%) foals.CONCLUSIONS: Multi-drug resistance, including resistance to commonly used antimicrobials, was found in bacterial isolates from foals in New Zealand.CLINICAL RELEVANCE: The results of this study are of concern from a treatment perspective as they indicate a potential for antimicrobial treatment failure. For future surveillance of AMR and the creation of national guidelines, it is important to record more data on samples submitted for bacterial culture.

A standardbred gelding with a history of 10 days pyrexia and lethargy was referred to the Equine Hospital at the Swedish University of Agricultural Sciences in Uppsala, Sweden.The horse had tachypnea with increased respiratory effort and was in thin body condition. Laboratory findings included leukocytosis, hyperfibrinogenemia and hypoxemia. Thoracic radiographs showed signs of pneumonia with a multifocal nodular pattern, which in combination with lung biopsy findings indicated Equine Multinodular Pulmonary Fibrosis (EMPF). EMPF is a recently described disease in adult horses with clinical signs of fever, weight loss and respiratory problems. The pathological findings include loss of functional pulmonary parenchyma due to extensive nodular interstitial fibrosis which has been related to infection with the equine herpesvirus type 5 (EHV-5). In this case, lung biopsy and tracheal wash samples tested positive for both asinine herpesvirus type 5 (AHV-5) and EHV-5 using PCR assays. The horse failed to respond to treatment and was euthanized for humane reasons. Postmortem examination confirmed the diagnosis of EMPF. This case suggests that not only EHV-5 alone should be considered in association with the development of this disease.

BackgroundDecreased efficacy of antimicrobials and increased prevalence of multidrug resistance (MDR) is of concern worldwide.ObjectivesTo describe and analyze bacterial culture and antimicrobial susceptibilities from respiratory samples submitted from young horses (4 weeks to 3 years old).AnimalsSamples from 289 horses were submitted to a commercial laboratory.MethodsA retrospective database search of submissions made to a New Zealand veterinary laboratory between April 2004 and July 2014. The results of in vitro susceptibility testing by Kirby‐Bauer disc diffusion were described and tabulated for the major bacterial species isolated. Multiple correspondence analysis (MCA) was used to describe the clustering of MDR isolates and selected demographic variables.ResultsOverall, 774 bacterial isolates were cultured from 237 horses, the majority of these isolates were gram‐positive (67.6%; 95% CI 64.3–70.9%). Streptococcus spp. were the most common genus of bacteria isolated and were 40.1% (95% CI 36.6–43.5%) of the isolates cultured. Susceptibility of Streptococcus spp. to penicillin, gentamicin, and ceftiofur was >85%. Overall, gram‐negative susceptibility to ceftiofur, tetracycline, and TMPS was <75%. MDR was defined as resistance to 3 or more antimicrobials, and was found in 39.2% of horses (93/237; 95% CI 33.0–45.5%).Conclusions and clinical importanceCulture and susceptibility results have highlighted that MDR is an emerging problem for young horses in New Zealand (NZ), where a bacterial respiratory infection is suspected. This should be considered when prescribing antimicrobials, and emphasizes the need for submission of samples for culture and susceptibility.