Salmonellosis in Equines 34

spread over a relatively large area - cracks in walls and stalls, on the surface of water buckets or automatic watering devices, and in bedding materials that may be spread by wind or careless foot traffic. Salmonellae can persist in the environment and soil can remain contaminated for over 300 days, and water for 9 months. Although it can be killed by desiccation (removal of water) and exposure to sunlight, Salmonella can survive in dried manure for up to 30 months. Freezing doesn’t kill the bacteria and it can survive over two years in infected ice cream!

BIOSECURITY PLAN

To prevent the introduction of Salmonella, it is important to have a biosecurity plan. Some method of isolating new arrivals and sick horses is important. New horses should be isolated for approximately two-tothree weeks and monitored for diarrhoea or signs of respiratory disease. Salmonella is very infective, and control measures require strict attention to sanitation. Foot baths, protective clothing, isolation, and proper disposal of faeces are basic when caring for infected or shedding horses. Personal hygiene is important because human infections can occur from exposure to this organism. Zoonoses are diseases that can be transmitted to humans from animals.. Salmonella can move between animals and humans. Thus, people can and do become infected with Salmonella from horses. Ingesting contaminated faeces causes Salmonella in people. Signs of Salmonella in humans vary from none to severe gastrointestinal disease and medical advice is essential. Practice good hygiene. Always wash your hands before eating and don’t touch objects with manure-contaminated hands. Understanding disease transmission and effective management practices are both essential in preventing equine diseases. Your veterinarian is the best source of advice because successful disease prevention includes an effective vaccine and a rigid management protocol that carefully evaluates and isolates new arrivals, prevents stress and overcrowding, recognises clinical symptoms, and deals with disease quickly. Preventive hygiene and the use of effective disinfectants are essential to the management program. Fortunately, the steps involved in control and prevention of Salmonella also are applicable to most other equine infectious diseases. The cost and work involved with isolation, disinfection and good management can more than pay for themselves in the long run of not having to deal with salmonellosis, rotavirus, and other diseases.

© Dr J H Stewart July 2022 All content provided in this editorial is for general use and information only and does not constitute advice or a veterinary opinion. It is not intended as specific medical advice or opinion and should not be relied on in place of consultation with your equine veterinarian.

ABOUT THE AUTHOR –Dr Jennifer Stewart

CEO BVSc BSc PhD Dip BEP Equine Veterinarian and Consultant Nutritionist Dr Jen Stewart has been an equine veterinarian for more than 40 years and an equine nutritionist for more than 10 years. Jen has been developing premium formulas for studs, trainers and feed companies in Australia and around the world and regularly consults to leading international studs and trainers in various countries. Jen has spent a fair bit of time researching and being involved in nutritional management of developmental orthopaedic diseases, colic, tying-up, laminitis, performance problems, post-surgery and other conditions. And is currently the only practicing equine veterinarian and clinical nutritionist in Australia. Jen’s promise is to continue to BRING SCIENCE TO YOUR FEED BIN

www.jenquine.com

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WHAT IS SALMONELLOSIS

Salmonellosis is caused by a bacteria that can affect foals, adult horses and humans too. The bacteria spread easily by horse-to-horse contact and by shared tools, water buckets, and contaminated boots and clothing on which bacteria can ‘hitch a ride’ to the next horse.

It affects primarily the gut and can cause debilitating, even deadly– diarrhoea. Symptoms in adult horses include diarrhoea, fever and lethargy in mature horses, however the signs in foals are more serious. Some horses do not show clinical signs, but they can carry the bacteria, and when stressed, they can shed it or become ill themselves.

There are more than 2200 distinct variations (‘serovars’) of salmonellae and all are considered possible pathogens that can cause disease in horses.

In Australia, Salmonella typhimurium is the most common cause of salmonellosis. It produces intestinal disease (such as diarrhoea) in horses, and other animals including dogs, cats, birds, humans and many other species. Cases are usually sporadic with an affected horse here or there, but may become an epidemic/outbreak depending on the severity or harmfulness of the organism, the level of exposure (how many bacteria gain entry to the body) and individual horse factors. Recently there have been outbreaks of Salmonella in horses in Australia.

Signs of illness in adult horses include fever; colic; shock; severe watery, foul-smelling diarrhoea that might contain blood; weakness and loss of appetite. Although it is one of the most common infectious causes of diarrhoea in adult horses, importantly, Salmonella can develop without diarrhoea. Complications of salmonellosis include laminitis, bacteremia (viable bacteria within the bloodstream) and septicemia (blood poisoning), renal (kidney) failure, blood clots, hepatitis (inflammation of the liver) and pneumonia.