Vetnews | Mei 2024 6 « BACK TO CONTENTS Clostridial diseases are well known and described in veterinary medicine and include tetanus, botulism, gangrene, “black leg,” lamb dysentery and necrotic enteritis in poultry, to name a few. CLOSTRIDIA HAVE SEVERAL FEATURES: • They are gram-positive. • They produce toxins. • They are anaerobic (they grow in the absence of oxygen). • They form spores (essentially armour) to withstand environmental change, including disinfectants that would kill more vulnerable bacteria. • Five biotypes (A, B, C, D and E) depending on what combination of four toxins it produces. • Dogs are almost exclusively infected with biotype A. This bacterium is often present in the intestine asymptomatically, and only when it starts to proliferate, will it produce spores and toxins. Causes for proliferation include stressors such as a diet change, allergic reactions, environmental disturbances such as staying in a hospital or a kennel. This overgrowth leads to production of spores and toxins which have severe e ects on the enterocytes (cells lining the gastrointestinal tract). TYPES OF DIARRHOEA: Acute – Self-limiting symptoms of diarrhoea lasting 5-7 days. Chronic – Recurrent symptoms occurring every 4-6 weeks (more common in older dogs). Haemorrhagic gastroenteritis – Sudden symptoms of profuse bloody diarrhoea and vomiting. Clostridium perfringens produce more than 16 toxins, of which Alpha, Epsilon, net E & net F are the ones involved in canines. In order to produce these toxins, sporulation must happen. The organism may have been innocuously living in the intestine for some time when something causes it to sporulate and produce toxins. These toxins ulcerate the intestinal lining, and the intestinal blood vessels become permeable, this leads to fluid being lost into the intestinal lumen, causing dehydration, an elevated haematocrit (red blood cells in relation to serum), and bleeding ulcers. CLOSTRIDIAL ENTEROTOXICOSIS IN DOGS Written by Dr. Elizna Boag.
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