Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. V. Microscopic observations

Lungs from 19 Thoroughbred racehorses with a history of exercise-induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lungs examined. With two exceptions, these eosinophilic foci had a different distribution to the three lesions. In areas of severe bronchiolar changes and fibrosis, vascular lesions typical of hypertension were found occasionally. Transmission electron microscopy was used to confirm cell types seen by light microscopy and to examine arterioles for changes characteristic of neovascularisation. Areas of enlarged airspaces from the vascular injected right lungs were examined by scanning electron microscopy. The balance of fibrosis and destruction varied in these areas, but none were as extensive as those seen in chronic obstructive pulmonary disease. The authors hypothesise that bronchiolitis and related neovascularisation are essential components of the aetiology of EIPH.     

Costs and complications of equine castration: a UK practice-based study comparing 'standing nonsutured' and 'recumbent sutured' techniques

REASONS FOR PERFORMING STUDY: Clinicians are often asked to guide owners and trainers over the relative advantages and disadvantages of equine castration performed in either the standing horse with an open unsutured scrotal wound with healing by second intention, or a recumbent horse under general anaesthesia in aseptic conditions, with sutured scrotal skin allowing primary wound closure. OBJECTIVES: To identify types and frequency of complications following the 2 differing approaches, and to compare the financial cost associated with each procedure, based on practice charges. METHODS: Veterinary expenses of 217 horses castrated by a Newmarket equine veterinary practice over an 18-month period were analysed. Of these, Group 1 (n = 121) were castrated standing and nonsutured by one of 2 ambulatory clinicians and Group 2 (n = 96) castrated in recumbency, in aseptic equine hospital conditions. RESULTS: Group 1 had a complication prevalence of 22% with no mortalities, and Group 2 a significantly lower complication prevalence of 6% (P = 0.001) with a mortality rate of 1%. The financial cost of Group 1, without complications, was approximately one-third of the cost of uncomplicated Group 2. However, the cost of Group 1 with complications increased to approximately two-thirds of the cost of an uncomplicated Group 2 castration. CONCLUSIONS: Even though the complication prevalence for Group 1 castrations leaving an open scrotal wound was significantly higher than for a recumbent horse with a sutured scrotal wound in a hospital, the average cost of Group 1 was still less, even taking into account the additional follow-up costs associated with treating such complications. POTENTIAL RELEVANCE: This report provides a benchmark for the outcome of 2 methods of castration based on a database obtained from particular circumstances within the practice involved. Further studies are required to corroborate and take into account future development in surgical and anaesthetic techniques.     

Acute febrile neutrophilic vasculitis of the skin of young Shar-Pei dogs

Three young Shar-Pei dogs were presented for signs of an acute widespread dermatopathy associated with fever and malaise. Cutaneous lesions initially consisted of multifocal areas of skin discolouration (haemorrhagic papules, macules or plaques) or oedema, preferentially affecting the head and limbs. In some locations, pus-filled bullae were evident also. Cutaneous lesions exuded seropurulent liquid and, in time, usually progressed to full thickness necrosis and ulceration. Lesions were so widespread and severe that one of the dogs was euthanased because its owners could not afford the reconstructive surgery required to close the skin deficits left at the completion of otherwise successful therapy. Histological examination of representative biopsies showed neutrophilic dermatitis and vasculitis, which ultimately resulted in ischaemic necrosis of skin. Therapy with immunosuppressive doses of corticosteroids, and in one case cyclophosphamide, resulted in prompt amelioration of the underlying inflammatory process, although regions of skin deprived of their blood supply eventually became necrotic and sloughed. Healing occurred through granulation, contraction and epithelialisation. The physical findings in these three dogs were so similar that it is likely all suffered from the same breed-related syndrome, an immune-mediated vasculitis precipitated by some event, such as vaccination or an undetected infection. Whatever the inciting cause, it was most likely a one-off event, as the two surviving dogs were readily weaned off immunosuppressive medication without relapse.     

Endometrial hyperplasia and mineralization in zoo felids treated with melengestrol acetate contraceptives

Melengestrol acetate (MGA) contraceptives are widely used in zoo felids to regulate fertility and may have deleterious effects on endometrial health. To determine whether MGA exposure was associated with endometrial disease, the genital tracts of 212 zoo felids (99 MGA treated and 113 control) representing 23 species were evaluated. Adenomatous and cystic hyperplasia were prevalent in both MGA-treated (85%) and control (61%) groups, and the risk of developing these lesions increased with age. Treatment with MGA further increased the risk of developing advanced hyperplasia regardless of dose, and treatment for >72 months significantly elevated that risk, whereas parous animals had a lower risk. Endometrial polyps, fibrosis, adenomyosis, and hydrometra occurred in both MGA-treated and control animals. MGA treatment was associated with an increased risk of hydrometra and mineralization but not of adenomyosis, polyps, or fibrosis after adjusting for advanced hyperplasia. Acute or chronic endometritis were associated with advanced hyperplasia but not with MGA treatment. These results indicate that proliferative and inflammatory endometrial lesions are common spontaneous diseases in zoo cats, and MGA contraceptives increase the risk of some diseases. The association of MGA with endometrial lesions that could impair fertility should be considered when using this contraceptive in genetically valuable felids.     

Subcutaneous emphysema, pneumoperitoneum, and pneumoretroperitoneum after gastrostomy tube placement in a cat

A 17-year-old spayed female domestic shorthair cat developed subcutaneous emphysema, pneumoperitoneum, and pneumoretroperitoneum during endoscopic placement of a gastrostomy feeding tube after gastric insufflation and cannula insertion. The cat underwent exploratory laparotomy to investigate the possibility of gastric rupture but only a 2- to 3-mm defect was found in the gastric fundus at the site of cannula insertion. Pasteurella multocida and Enterobacter spp were cultured aerobically from the peritoneal cavity. The cat recovered without complications.     

Absolute monocyte counts as an aid to early diagnosis of equine herpesvirus 1 (EHV1) infection in Hong Kong thoroughbred horses

Two isolates of the abortion strain (subtype 1) of equine herpes virus 1 (EHV1) were recovered from nasopharyngeal swabs of 3 Thoroughbreds in training in Hong Kong taken during an outbreak of clinical respiratory disease. There are 2 subtypes of EHV1, the abortion (1) and respiratory strains (2) and serologically it is not possible to differentiate between the 2 due to antigen cross-reactivity.⁴Monocyte counts undertaken by the same experienced technologist on blood films made by a modification of the traditional ‘wedge’ smear taken from blood samples collected from 58 Thoroughbred horses during the outbreak revealed a significant correlation to EHV1 serum titres.This may allow for earlier identification of affected animals during an outbreak especially in situations where virus confirmation facilities are not readily available.     

The inability of a South African Babesia bovis vaccine strain to infect Boophilus microplus

A strain of Babesia bovis that had been attenuated by rapid syringe passage through a series of 23 splenectomized calves was unable to infect its vector Boophilus microplus. An attempt to transmit the attenuated Australian Babesia bigemina G strain with a South African strain of B. microplus was likewise unsuccessful. The epidemiological implication of these observations in terms of babesiosis control is discussed.