Pseudomonas aeruginosa sepsis in an adult horse with enteric Salmonellosis

Objective: To report a case of enteric Salmonellosis and Pseudomonas aeruginosa bacteremia in an adult horse. Case summary: A 7‐year‐old mare presented for signs of acute abdominal pain. Exploratory laparotomy allowed surgical correction of right dorsal displacement of the large colon with a 180° volvulus at the cecocolic ligament. Postoperatively, the mare developed fevers, leukopenia, and diarrhea. Salmonella newport was cultured from the feces and P. aeruginosa from 2 consecutive blood cultures. The mare responded well to intensive medical therapy. New or unique information provided: Bacteremia associated with colitis is unusual in an adult horse, although the percentage of animals that may be bacteremic is unknown. The bacteria isolated, P. aeruginosa, a common pathogen of other sites in the horse, has not, to our knowledge, been previously reported as a cause of bacteremia and septicemia in an adult horse.     

Equine botulism: A clinical approach to diagnosis and management

Botulism is a syndrome of neuromuscular weakness caused by the toxins of Clostridium botulinum. Whilst it can affect most mammals, the horse appears to be one of the more susceptible species. Intoxication can occur via ingestion of preformed toxins in spoiled foodstuffs, ingestion of spores with colonisation in the intestinal tract or the contamination of wounds by C. botulinum. Food‐borne botulism is the most common worldwide, usually associated with spoiled roughage. Both individual cases and outbreaks have been reported, with generally a poor prognosis. Many affected horses succumb to recumbency and death/euthanasia shortly after onset of signs. Botulism should be considered a differential diagnosis for any horse displaying dysphagia or symmetrical neuromuscular weakness.     

Medial pterygoid myositis in a Thoroughbred gelding

This case report describes the investigation and treatment of an adult horse with purulent, malodorous exudate originating from a large intermandibular mass. Microbial culture of fluid aspirated from a draining tract yielded Peptostreptococcus and Prevotella species which are usually considered to originate from the oral cavity. Computed tomography (CT) was used to aid in the diagnosis and to allow careful presurgical planning, and the horse underwent successful debridement of the abscess cavity under general anaesthesia. Post-operatively, the horse developed trismus (reduced opening of the jaws) but repeat CT identified that the surgery site was healing appropriately. It was recommended to continue feeding the horse hay to act as physiotherapy and the masticatory action of the horse subsequently returned to normal.     

Listeria keratitis in a horse

Listeria monocytogenes is ubiquitous in the environment but is rarely reported as a cause of keratitis in animals. In this case, a mare was presented with epiphora and evidence of pain in the right eye. Listeria monocytogenes was isolated from a corneal lesion, and bacteria were also seen in the cytologic evaluation. This is the first reported case of ulcerative keratitis associated with L. monocytogenes in a horse.     

Intracranial medulloblastoma as the cause of progressive ataxia in a 6-month-old draft horse cross gelding

We describe the unique clinical presentation of a central nervous system neoplasm in a 6-month-old draft horse cross gelding. Based on the neurologic examination at admission, neurolocalization was most consistent with a mildly asymmetric cervical, multifocal, or diffuse myelopathy. Mild vestibular involvement also was considered, but no cranial nerve deficits were observed. The gelding was negative for Sarcocystis neurona or Neospora hughesi based on paired serum and cerebrospinal fluid (CSF) samples analyzed, with no evidence of cervical compression based on contrast myelography. The horse was euthanized because of progression of clinical signs. At necropsy, a mass was identified associated with the cerebellum, and histopathology was consistent with medulloblastoma, which has not been reported previously in the horse.     

Salmonella enterica subsp. arizonae-associated abortion in a mare

Abortion in mares can be a financially devastating event to horse owners and the equine industry. In this case report, we describe the gross, histopathological and microbiological findings associated with an abortion caused by Salmonella enterica subsp. arizonae, which should be considered in cases of abortion and metritis. Gross and histopathological evaluation of fetal and placental tissue were consistent with ascending septic placentitis resulting in fetal septicaemia. S. enterica subsp. arizonae was isolated from the placenta, lung and fetal gastric contents. Diagnosis was confirmed by MALDI-TOF MS. To our knowledge, this subspecies of S. enterica has not been previously reported as an isolate in a case of late-term equine abortion. A retrospective search of abortion cases at our institution was done, and no similar cases were identified for comparison. This case demonstrates S. enterica subsp. arizonae, although not previously reported as a cause of abortion in pregnant mares and uncommonly isolated from equids in the literature, may cause late-term abortions in susceptible animals. This pathogen should be considered in cases of abortion outbreaks on a farm and merits investigation of the carrier status of mares within a herd.     

Actinobacillus capsulatus peritonitis and chyloabdomen in a Warmblood gelding

Primary peritonitis in horses attributable to Actinobacillus equuli has been reported in Australia, New Zealand and North America. Published reports describe a rapid response to treatment with appropriate antimicrobial and supportive treatment and an excellent prognosis for survival. To our knowledge, this is the first reported case of Actinobacillus capsulatus in the horse. The case was complicated by the development of an idiopathic chylous abdominal effusion. The report highlights the importance of molecular methods in the correct identification of bacterial species. Prognosis for horses diagnosed with Actinobacillus peritonitis may be guarded given the atypical response to appropriate antimicrobial treatment in this case.     

Gastrointestinal stromal tumour and hypoglycemia in a Fjord pony: Case report

Background

Neoplasia may cause hypoglycemia in different species including the horse, but hypoglycemia has not previously been reported in the horse associated with gastrointestinal stromal tumours.

Case presentation

A case of a gastrointestinal stromal tumour in a Fjord pony with severe recurrent hypoglycemia is presented. The mechanism causing the hypoglycemia was not established.

Conclusion

This case indicates that a gastrointestinal stromal tumour may cause hypoglycemia also in the horse.     

Sequelae and complications of Streptococcus equi subspecies equi infections in the horse

Streptococcus equi ssp. equi infection in the horse, or strangles, commonly results in abscessation of the submandibular, submaxillary or retropharyngeal lymph nodes. Although this classical presentation of strangles is associated with a low mortality rate, complications and sequlae may worsen the prognosis and increase mortality rates. This article reviews sequelae and complictions of S. equi ssp. equi infection in the horse, including guttural pouch empyema, bastard strangles and immune mediated diseases such as purpura haemorrhagica, myopathies and myocarditis.     

Whole-genome sequence analysis reveals candidate genomic footprints and genes associated with reproductive traits in Thoroughbred horse

The primary objective of most horse breeding operations was to maximize reproductive efficiency and minimize the cost of producing live foals. Here, we compared individual horses from the Thoroughbred population (n = 17), known as a horse breed with poor reproductive performance, with other six horse populations (n = 28), to detect genomic signatures of positive selection underlying of reproductive traits. A number of protein-coding genes with significant (p-value <.01) higher F_ST values (616 genes) and a lower value for nucleotide diversity (π) (310 genes) were identified. The results of our study revealed some candidate genes such as IGFBP2, IGFBP5, GDF9, BRINP3 and GRID1 are possibly associated with functions influencing reproductive traits. These genes may have been under selection due to their essential roles in reproduction performance in horses. The candidate selected genes identified in this work should be of great interest for future research into genetic architecture of traits relevant to horse breeding programmes.     

Genotype distribution and allele frequencies of the genes associated with body composition and locomotion traits in Myanmar native horses

Myanmar native horses are small horses used mainly for drafting carts or carriages in rural areas and packing loads in mountainy areas. In the present study, we investigated genotype distributions and allele frequencies of the LCORL/NCAPG, MSTN and DMRT3 genes, which are associated with body composition and locomotion traits of horses, in seven local populations of Myanmar native horses. The genotyping result of LCORL/NCAPG showed that allele frequencies of C allele associated with higher withers height ranged from 0.08 to 0.27, and 0.13 in average. For MSTN, allele frequencies of C allele associated with higher proportion of Type 2B muscular fiber ranged from 0.05 to 0.23, and 0.09 in average. For DMRT3, allele frequencies of A allele associated with ambling gait ranged from 0 to 0.04, and 0.01 in average. The presences of the minor alleles of these genes at low frequencies suggest a possibility that these horse populations have not been under strong selection pressure for particular locomotion traits and body composition. Our findings of the presence of these minor alleles in Southeast Asian native horses are also informative for considering the origins of these minor alleles associated with body composition and locomotion traits in horse populations.     

Mycobacterium ulcerans infections in two horses in south-eastern Australia

Two horses were diagnosed as having Mycobacterium ulcerans infections. The first was a 21-year-old Quarterhorse-cross mare living in Mallacoota (a coastal town near the border of New South Wales and Victoria, Australia) that presented with lichenification, hair-loss and oedema on a fetlock, which subsequently ulcerated, as well as a non-healing ulcer on the wither. The second horse was a 32 year-old Standardbred gelding from Nicholson, near Bairnsdale, Victoria, that had an ulcerated lesion on its caudal thigh. Histologically, there were characteristic changes seen with M. ulcerans infections in other species, including extensive necrosis without associated granulomatous inflammation. The organisms were seen in Ziehl-Neelsen-stained smears or sections of the lesions from both horses and were isolated in culture from the first horse. A definitive diagnosis was provided by real-time polymerase chain reaction targeting the M. ulcerans-specific insertion sequence, IS2404. Delayed identification of the infectious agent in the first case led to the use of suboptimal antimicrobial therapy, resulting in failure to control the infection and the horse was subsequently euthanased. The second horse was successfully treated following surgical debulking of the centre of the lesion and one session of aggressive cryosurgery. Mycobacterium ulcerans should be considered in the differential diagnosis of unexplained lichenification with oedematous and ulcerated skin lesions in horses living in regions where this organism is endemic.     

Septic peritonitis in a Percheron mare associated with Clostridium haemolyticum

This report describes an 11‐year‐old Percheron mare that presented with signs of colic and was ultimately diagnosed with bacterial peritonitis of unknown origin. Bacterial culture of a peritoneal fluid sample isolated 2 Clostridial species, one of which was strongly suspected to be Clostridium haemolyticum. The horse was markedly hypoalbuminaemic at presentation, leading to the development of low oncotic pressure and ventral oedema. The mare was administered a low molecular weight/low molar substitution hydroxyethyl starch solution in conjunction with other therapies that resulted in marked improvement of clinical signs. The purpose of this report is to describe the clinical findings associated with equine peritonitis associated with C. haemolyticum, a rarely identified pathogen in the horse. Secondly, this report serves to describe the beneficial effects of tetrastarch administration in a clinical case with severe hypoalbuminaemia and ventral oedema.     

Electrocardiographic anomalies in the racehorse

Extract

The veterinarian is often asked to examine the heart of the horse when its performance is below the standard that its owner knows — or hopes — that it should be. The usual complaint is that the horse has become deficient in stamina — it races well up to a point in the race, but when the gap comes and the jockey or driver tries to urge the horse through it, he finds that the gap is going faster than the horse and by the time he gets to the post there is nothing behind him but the ambulance. The clinician is usually under some pressure to provide a diagnosis and it is tempting to point to a prolonged PR interval or dropped beat. Of the 20 years I spent in practice, a good deal of my time was devoted to investigating horses with reduced exercise capacity and I must admit that the heart was only rarely involved. Perhaps this is not surprising since racehorses are not exposed to factors that cause heart disease in other species — e.g., high cholesterol-producing diets, persistent emotional tension, high circulating androgen levels, degenerative aging changes, genetic predisposition — horses are selected to eliminate this — and insufficient exercise.     

Canine cutaneous neosporosis in Brazil

The clinical signs of infection in dogs with Neospora caninum are usually associated with neurological disorders and are seen in young dogs. In this brief case report we observed multifocal ulcerative and exudative skin nodules on the neck and pelvic limbs of a 10‐year‐old cocker spaniel dog. Infection with N. caninum was diagnosed on the basis of cytology and examination of skin tissues by PCR. The dog initially responded to treatment with clindamycin and then relapsed; the dog died. Infection with N. caninum may have been due in part to immune suppression due to hyperadrenocorticism; which either allowed for the development of a primary infection or reactivation of a latent infection by N. caninum with the occurrence of skin lesions.     

Distribution of the mutant allele of the DMRT3 gene associated with ambling gaits in Japanese native horse populations

There are currently eight native horse populations in Japan, namely, Hokkaido, Kiso, Noma, Taishu, Misaki, Tokara, Miyako, and Yonaguni horses. Since locomotion traits, including gaitedness, are important for riding and packing horses, the genetic properties associated with these traits could be informative for understanding the characteristics and history of these horses. In this study, we investigated the distribution of the mutant allele of DMRT3 gene (DMRT3:p.Ser301Ter) associated with ambling gaits in the Japanese native horse. We also examined haplotypes of SNPs in the 83‐kb region including DMRT3 gene by genotyping four SNPs in this region. The results revealed the presence of DMRT3:p.Ser301Ter in the Hokkaido and Yonaguni populations at allele frequencies of 0.18 and 0.02, respectively, and the observed haplotype associated with DMRT3:p.Ser301Ter was estimated as the most common haplotype in the horses in the world. Since DMRT3:p.Ser301Ter has been hypothesized to spread across Eurasian continent from Medieval England after 850 to 900 CE, our findings of the presence of DMRT3:p.Ser301Ter with the common haplotype in the Japanese native horses will provide a new insight into the history of the Japanese native horse, such as considerable level of gene flow from Eurasian continent after 850 to 900 CE.     

Successful surgical management of eosinophilic granuloma on the urethral process of a gelding associated with Habronema spp. infection

Habronemiasis, otherwise known as summer sores, is a parasitic disease of horses, donkeys and other equids, commonly encountered in subtropical and tropical regions. It occurs as a result of nematode infestation of the skin and typically manifests as ulcerative granulating lesions or masses. Habronema muscae, Habronema microstoma and Draschia megastoma are the usual invaders, usually transmitted by house flies, face flies and stable flies. In this case report, an eosinophilic granuloma on the urethral process of a 15-year-old gelding is presented, followed by successful surgical excision without further medical treatment. To the authors’ knowledge, equine eosinophilic granuloma on the urethral process associated with habronemiasis has not previously been documented in southern Europe and should be considered as a potential differential diagnosis for penile masses.     

Ante mortem diagnosis of necrotising emphysematous oesophagitis and gastritis in a horse

The case reported here describes a rare presentation of necrotising, emphysematous oesophagitis and gastritis in a horse presenting for signs of anorexia, dysphagia and ptyalism. Radiography of the retropharyngeal region revealed intramural gas within the cranial oesophagus. Further diagnostic evaluation supported an ante mortem diagnosis of emphysematous oesophagitis with concurrent septic pleuritis and peritonitis. Post mortem findings confirmed an emphysematous, necrotising oesophagitis and gastritis with a Clostridium sp. transmural infection. To our knowledge, this case describes the first recorded ante mortem diagnosis of emphysematous oesophagitis with concurrent gastritis in the horse.     

The distribution pattern of Halicephalobus gingivalis in a horse is suggestive of a haematogenous spread of the nematode

The majority of Halicephalobus gingivalis-infections in horses have been fatal and are usually not diagnosed before necropsy. Therefore, knowledge about the nematode and the pathogenesis of infection in horses is limited. This has resulted in an on-going discussion about the port of entry and subsequent dissemination of H. gingivalis within the host. The present case of H. gingivalis-infection in a horse was diagnosed ante mortem. Post mortem findings, the distribution pattern of H. gingivalis nematodes in the brain, a high prevalence of inflammation in close relation to blood vessels, and the presence of the nematode in multiple organs with a disseminated pattern of distribution strongly suggested a haematogenous spread of the nematode in the horse.