In this issue - April 2014

Abstract

In Australia, the emergence of Hendra virus as a zoonotic disease, coupled with the 2007 equine influenza (EI) outbreak, raised awareness of biosecurity and methods to prevent the spread of infectious diseases. The response to EI required coordination of government and industry. Private veterinarians were not formally included in the emergency animal disease response arrangements, but were essential for the diagnosis treatment and subsequent eradication of the disease. The first paper in the April issue assesses the level of biosecurity training undertaken by Australian equine veterinarians before and after the EI outbreak, and their opinions about the management of the outbreak.1 The authors surveyed conference attendees at the Bain Fallon meeting of Equine Veterinarians Australia. As only 23.5% of those completed the questionnaire, and they were more likely to be middle-aged and practice owners, the results may not be widely applicable. Recently graduated veterinarians had received more biosecurity training at veterinary schools than had the older attendees. Most thought that there was a low likelihood of spreading infectious diseases from one client's horse to another (84%) and more than half thought that hand-washing/wearing gloves was very effective in preventing disease spread. One-quarter had some reservations about the practicality of performing general biosecurity practices in everyday working life, particularly the younger ones. Respondents were mainly satisfied with the EI outbreak response, but had mixed opinions about the control measures and communications used. A second equine study studied a population of ponies in a drought-affected area near Gatton in Queensland. The study population included 208 ponies that were recruited using an internet database of pony studs and trainers.2 Hyperinsulinaemia is a good indication of underlying metabolic disease and is associated with development of laminitis. In total, 27% of the ponies were hyperinsulinaemic, which was shown to be associated with increasing age, supplementary feeding and metabolic disturbances. This has implications for strategies to reduce the risk of laminitis in this population, although more studies are needed to assess its relevance to individually kept family ponies. Perennial ryegrass toxicosis is caused by ingestion of lolitrem B and ergovaline from fungal-infected perennial ryegrass. Presenting signs are variable throughout the flock and include alterations in normal behavioural, staggers, ill thrift and scours, and range in severity from mild to death. Large-scale sheep losses occasionally occur in Australia, in contrast to other perennial ryegrass toxicosis risk zones such as North America and New Zealand. The authors of this study studied a mild an outbreak of toxicosis in Victoria, which affected large numbers of animals but limited mortalities.3 The properties had a long history of outbreaks and sheep were generally improving at the time of sampling. In addition, there were low temperatures and abundant green feed and the levels of lolitrem B and ergovaline were lower than usually reported. This raises the question of whether other factors could have been involved in this case. The authors speculate that changes in hydration status may be a contributory aetiological factor in years in which high numbers of deaths are associated outbreaks. Further samples are needed from sheep in years when losses are extensive. Metaphyseal osteopathy, or hypertrophic osteodystrophy, is a bone disease in young dogs. It causes painful swelling of the metaphyseal region of the long bones and is usually associated with large breeds, although there are individual case reports in smaller dogs. Three Australian Kelpie puppies that were from different litters from the same breeding pair4 presented separately with dullness, depression and shifting lameness. Metaphyseal osteopathy was diagnosed and the paper shows the pathognomonic radiographic appearance of the metaphyseal region of the long bones. The diagnosis was confirmed on histopathology in one patient, showing the characteristic eosinophilic band of necrotic material parallel to the growth plate. The authors report that these cases were similar to those seen in the Weimaraner breed. Leishmania infantum causes human visceral leishmaniosis, a severe debilitating disease that causes an estimated 59,000 deaths annually, and canine leishmaniosis (CL), which causes severe and potentially fatal disease in dogs. Australia is considered to be free of zoonotic leishmaniosis. A retrospective case series of five imported dogs diagnosed with CL between 2000 and 2011 describes the clinical, clinicopathological and serological data, and reviews the biosecurity implications for Australia.5 The authors stress the importance of obtaining a travel history, as some dogs that were imported prior to 2006 may develop clinical signs of this disease. They also note that there is a possible risk of zoonotic leishmaniosis to become established within Australia under certain circumstances. A case report describes an unusual complication of a routine arthroscopic procedure to treat a fragmentation of the medial portion of the coronoid process in a young Labrador Retriever.6 The authors report that the tip of the arthroscopic curette broke off during the procedure and describe the attempts to retrieve it. They finally left it in situ, and the dog made an uneventful recovery and. At 6 months afterward, radiography showed that the tip had not migrated from its original position. The authors give recommendations for what to do in such circumstances. An investigation in poultry aimed to determine if there was a relationship between the production of eggs with poor internal quality, as measured by Haugh units, and the detection of infectious bronchitis virus (IBV) in Australian layer flocks.7 Cloacal swabs were collected from 20 chickens from each flock approximately every 6 weeks. IBV was detected from most of the flocks, but infection was primarily subclinical and was usually the A-vaccine-related field strain, even in flocks where the vaccine was not used. Potential risk factors for the production of eggs with poor Haugh units included detection of IBV in a flock, farm type and flock size. The authors recommend further investigation into the pathogenicity and risks of vaccine-related field strains.