Equine coital exanthema and its potential economic implications for the equine industry

Equine coital exanthema (ECE) caused by equid herpesvirus 3 (EHV-3) is a contagious venereal disease characterised by the formation of painful papules, vesicles, pustules and ulcers on the external genitalia of both mares and stallions. EHV-3 is an alphaherpesvirus that is distinct from the other equine herpesviruses and endemic in most horse breeding populations worldwide. The negative impacts of ECE on equine breeding enterprises are the forced, temporary disruption of mating activities of mares and stallions, the additional care and supportive treatment that is required for affected horses, and the risk of virus spread by either fresh or frozen semen as well as by artificial insemination and embryo transfer. Because there are no effective surveillance systems to report ECE, its true prevalence and economic impact are difficult to assess and are probably underestimated. The purpose of this review is to describe the recent advances in understanding of EHV-3 infections and to consider the economic consequences of ECE within the current context of the equine industry.     

Equine influenza in the United Kingdom in 1998

In 1998, equine influenza was diagnosed by serology and nucleoprotein enzyme-linked immunosorbent assay as the cause of acute respiratory disease in vaccinated and unvaccinated horses in the UK. The signs were generally milder in vaccinated horses and completely susceptible animals showed the most severe signs, including pyrexia, inappetence, coughing, mucopurulent nasal discharge and secondary bacterial pneumonia. In a detailed investigation of an outbreak among 52 vaccinated thoroughbreds in a flat racing yard, more than 60 per cent of the horses seroconverted on the evidence of paired serum samples tested by single radial haemolysis (SRH). Preliminary sequencing and characterisation of an isolate from this outbreak indicated that it was an 'American-like' strain. In addition, in this outbreak there was a larger proportion of horses with preinfection SRH titres greater than 140 mm2 that subsequently seroconverted than in other recent outbreaks from which 'European-like' strains have been isolated. This result suggested that the cross-protectivity between circulating 'American-like' strains and the 'European-like' strains of A/equine-2 viruses present in current vaccines may be decreasing.     

Cases of equine coital exanthema in Denmark

A venereal disease usually designated equine coital exanthema (ECE) has been observed in horses all over the world. In a very few oases a virus, claimed to be the causative agent of the disease, has been isolated.     

英国兽药理事会批准的可用于马匹的兽药产品分析

为了探究英国兽药理事会(VMD)批准上市的马匹兽药产品情况,从VMD 2016年3月提供的产品信息数据库统计分析。结果显示,上市的可用于马匹的兽药产品占兽药总数的12%,而马匹专属产品占6%;1990年-2015年年均批准马匹用兽药产品约12个;持有上市总兽药以及马匹兽药数量最多的前3个企业依次为Norbrook laboratories Ltd,Zoetis UK Ltd和Intervet UK Ltd;批准产品中抗炎药、中枢神经系统药和抗寄生虫药比例最高;优势兽药活性成分中非甾体抗炎药美洛昔康、抗寄生虫药伊维菌素及其同吡喹酮复方和镇静剂甲苯噻嗪获批产品数名列前3位;从给药途径来看,注射给药产品占62%,而口服产品占27%,外用和吸入给药产品比例较低。以上统计结果说明国际兽药企业注重马匹用药在英国的审批和上市,从马匹用兽药优势品种和主要活性成分可以提示马匹用药热点,该统计结果为管理和制定同国际接轨的我国马匹用药标准提供参考。     

Equine hyperlipaemia in the United Kingdom: clinical features and blood biochemistry of 18 cases.

The background, clinical signs, blood biochemistry and management of 18 cases of equine hyperlipaemia are described. Eleven of the animals were Shetland ponies, four were Welsh mountain ponies or their crosses, one was a fell pony and two were riding ponies of mixed breeding. Their average age was nine years. Fourteen of the cases were mares, of which nine were in foal and two were lactating; the remainder were geldings. Underlying or concurrent diseases were identified in only six animals, but in one other animal the hyperlipaemia appeared to have been precipitated by stress, and in another by undernutrition to prevent laminitis. Twelve of the animals were considered obese. There was no age, seasonal, or geographic bias to the distribution of cases. Plasma triglyceride concentrations were increased by between five- and 80-fold, and ranged from 4.7 to 78.8 mmol/litre. There was biochemical evidence of hepatic damage in 17 cases, of renal insufficiency in 15, and pancreatic pathology in three cases. Four animals were euthanased without therapy. The others were treated with oral glucose solutions, which were supplemented with injections of insulin and heparin in four cases, and insulin alone in two cases. Eight of the treated animals died, to give an overall mortality of 67 per cent. The outcome of the treatment was unrelated to the degree of hypertriglyceridaemia, to the presence and severity of hepatic, renal or pancreatic pathology or to the therapeutic regimen.     

Isolation of equine coital exanthema virus (equine herpesvirus 3) from the nostril of a foal

The virus causing equine coital exanthema (equine herpesvirus 3) was isolated from a lesion on the nostril of a 2-month-old foal. One week after the mare had returned from a stallion station, vesicular lesions developed on her vulva. They were diagnosed clinically as coital exanthema, and 5 days later a lesion developed on the nostril of her foal. This case is an example of horse-to-horse transmission of coital exanthema virus without coitus. A laboratory diagnosis is necessary to differentiate viruses that cause vesicular lesions about the oral and nasal cavities of horses.     

Equine viral arteritis (EVA): A potential trapdoor for the practicing veterinary surgeon in the United Kingdom

Equine viral arteritis (EVA) is a notifiable disease in the UK with potentially serious consequences for horse owners and breeders. Legislation exists under ‘The Equine Viral Arteritis Order 1995’ to protect the UK from this contagious equine disease. The UK is at risk of introduction of EVA through importation of infected horses or semen. There is however much misunderstanding regarding the importance of EVA and occasionally misinterpretation, specifically on how to protect and manage stallions with vaccination. Issues with changing vaccine datasheet recommendations and vaccine availability have resulted in stallions being inappropriately vaccinated or vaccinations lapsing. This article is aimed at the practicing veterinary surgeon, to update them as to the current status of EVA vaccination and disease screening in horses in the UK and how to avoid some common pitfalls.     

Occurrence of equine coital exanthema in pastured draft horses and isolation of equine herpesvirus 3 from progenital lesions

During the period from 2001 to the following year, progenital diseases had been epidemic among the draft stallions and mares pastured together in Iwate Prefecture, the northeastern district of Japan. A stallion and 8 of 31 mares were affected in 2001, and 1 of 2 stallions and 10 of 36 mares in 2002. The clinical symptoms consisted of the formation of papules, pustules, ulcers and scabs on the progenital skin and mucosa in stallions and mares. In 2002, Equine herpesvirus 3 (EHV3) was isolated from 2 mares and the glycoprotein G gene of the virus detected from a stallion and 4 mares by polymerase chain reaction. Serum neutralizing tests showed that 12 of 38 horses, 10 clinically and 2 subclinically affected, changed to be positive for the EHV3 antibody. The results suggest that the horses were affected with equine coital exanthema (ECE) through coitus. Five mares with the antibody at the pre-pastured period may have been the possible origins of EHV3 infection in 2002, although the exact origin in 2001 remains unknown. The artificial insemination was performed for the prevention of ECE spreading through coitus on the pasture in 2003. There was no epidemic of the disease in 31 mares, although 3 mares with the antibody at the pre-pastured period showed the significant increase in the titers during the pastured period.     

Molecular pathogenesis of equine coital exanthema: temperature-sensitive function(s) in cells infected with equine herpesviruses

Preliminary experiments have revealed that several laboratory and wild-type strains of the equine herpesvirus (EHV) triad were temperature-sensitive for growth when assayed at 39 degrees C. The efficiencies of plating (EOP) observed were 10(-2) for both EHV 1 and 2, and 1 X 10(-6) for EHV 3. The EOPs were determined by plaque assays which compared titrations at 34 degrees C and 39 degrees C on equine fetal dermal fibroblast cells. Growth yield experiments, assayed at 34 degrees C, reflected those EOP's, but did not indicate any difference in yields when infected cultures were incubated at 34 degrees C and 37 degrees C. Temperature shift experiments with EHV 3-infected cultures revealed that a temperature-sensitive function(s) responsible for the reduction in titer appeared to be a late function(s). All strains examined appeared to incorporate H3-thymidine into viral-density DNA at the non-permissive temperature of 39 degrees C. Electron microscopy of EHV 3-infected cell cultures, incubated continuously at the non-permissive temperature and examined at 18 h after infection, revealed structures consistent with the accumulation of nucleocapsids within the nucleus. The evidence presented is consistent with the hypothesis that in equine dermal cells infected with a plaque-purified wild-type strain of EHV 3 (1118LP), a function needed for the egress of nucleocapsids from the nucleus is absent at 39 degrees C. The significance of these findings relative to the pathogenicity of the disease (equine coital exanthema) caused by this virus is discussed.     

Male tortoiseshell cats in the United Kingdom

A questionnaire concerning the coat colour and sex of cats being vaccinated or neutered was sent to 2585 veterinary practices; 393 (15.2 per cent) were returned and information was obtained about 9816 cats. Of 4598 males, 20 were recorded as tortoiseshell (0.43 per cent). The frequency of the orange gene was 19.7 per cent assuming that male tortoiseshell cats had two X chromosomes. The chromosome complement and/or gonadal histology of 14 male tortoiseshell cats is described. Cytogenetic analysis of 11 animals revealed six with a 38,XX/38,XY complement, two with 39,XXY, two with 38,XX, and one with a 38,XY complement.     

Keratomycosis in six horses in the United Kingdom

Six horses with keratomycosis were examined and three different clinical expressions of the disease were recognised. The diagnostic work-up and response to treatment is described.