Swine Dysentery has long been recognised as a major disease of pigs throughout the world and can be seen in all types of pig keeping operations. The causative bacterium is identified\u00a0as\u00a0Brachyspira hyodysenteriae, but previously known as\u00a0Treponema\u00a0and\u00a0Serpulina hyodysenteriae.\u00a0Dysentery, as a pathological condition, is typified by bloody diarrhoea and in its original form this is how the disease presented in pigs.\u00a0 However,\u00a0Brachyspira hyodysenteriae\u00a0is not the only cause of bloody diarrhoea in the pig, but conversely it is now recognised that not all strains of\u00a0Brachyspira hyodysenteriae\u00a0cause classic signs of Swine Dysentery.<\/p>\n
Clinical Presentation<\/p>\n
The typical pig affected with swine dysentery will appear dull, depressed and inappetant with sunken (or slab) sides to its abdomen.\u00a0Dehydration is common.\u00a0 The faeces will range from soft to almost water, containing blood, mucous and in severe cases necrotic gut lining.\u00a0 It will give off a distinctive and unpleasant smell.\u00a0 The disease runs over a number of days, with initially raised rectal temperatures up to 41\u00b0C (106\u00b0F) but this will fall over a few days.\u00a0 Death can result early on or later and may itself be the result of dehydration\/salt poisoning.<\/p>\n
As a group disease, signs will spread steadily within and between pens over a number of days – rather than explosively.\u00a0 Untreated and uncontrolled, the disease will persist within dynamic production systems for prolonged periods of time, if not permanently, whereas in fixed populations survivors that fully recover\u00a0 will throw off infection over time and the disease can eventually burn itself out.<\/p>\n
In a na\u00efve population, the disease can occur in all age groups of pigs – as young as 2-3 weeks of age and in adults.\u00a0 However, it is most typically a disease of the growing pig above 12 weeks of age and in chronically infected herds disease is often restricted to this age group.<\/p>\n
Diet can have dramatic effects on the severity of the disease and some studies have shown that even in the face of severe challenge, pigs fed on cooked white rice show little sign. Swine Dysentery is a disease of the large intestine (colon) and this suggests that digestibility of the diet can affect the growth of the organism in the gut and the damage it subsequently does – the better the diet is digested in the small intestine, the less substrate will pass down the gut on which the organism will thrive. Diets with high levels of non-starch polysaccharides tend to induce more scour (with or without SD) as do pelleted diets compared to meal feeding.<\/p>\n
Individual pigs that survive infection can range from fully recovered to chronically stunted with permanent diarrhoea.\u00a0 In recent years, ‘milder’ strains of\u00a0Brachyspira hyodysenteriae\u00a0have been recognised which present more as a low grade, cow-pat like, grower scour than as frank dysentery.\u00a0However, these strains appear to have the ability to ‘drift’ within a population, causing variable levels of disease.<\/p>\n
Diagnosis<\/p>\n
Swine dysentery should be suspected in any situation where spreading scour is seen particularly in growing pigs, and certainly where there is any sign of blood or mucous in the scour.<\/p>\n
Post mortem examination of affected pigs- either freshly dead by natural causes of the disease or by euthanasia – will show signs typical of swine dysentery within the spiral colon – oedema within the gut wall with congestion with swollen lymph nodes.<\/p>\n
The inside lining of the large intestine (colon) will be inflamed, necrotic, blood streaked and with foul smelling material adhered to the surface.\u00a0 In milder cases the colon may only appear mildly congested and inflamed with watery grey contents. Of course, in the smaller populations where mortality does not occur, there is understandably a reluctance to sacrifice pigs for diagnostic purposes and if animals do not justify euthanasia on welfare grounds the diagnosis will be based on clinical signs supported by examination of faecal samples<\/p>\n
The organism can be demonstrated in faeces, gut contents and mucosal scrapings by PCR tests, which have largely superseded a range of other laboratory tests.\u00a0 It is possible to see spiral organisms under the microscope in wet smears prepared from typically affected gut lining.<\/p>\n
Other diseases that can mimic swine dysentery in the growing pig include Salmonella, Swine Fever, severe Spirochaetal diarrhoea (Brachyspira pilosicoli\u00a0infection) and Trichuris suis infection (particularly a risk in outside conditions of prolonged occupation and contamination) whereas the less specific growers scours can arise as a result of dietary indigestion, chilling and infection with a wide range of organisms that include B. pilosicoli, Yersinia, E.coli, Salmonella and Lawsonia.\u00a0 Secondary invasion of the colon by\u00a0Balantidium coli\u00a0– a commensal gut parasite – can produce signs of blood and mucous making diagnosis complex.<\/p>\n
Treatment
\nTiamulin and Lincomycin can be effective treatments given by injection or in water, and both of these products along with Valnemulin and Tylvalocin are available as in-feed products, which can be used at different levels, under veterinary direction, to effect treatment.\u00a0 As with any systemic disease, treatment of the sick pig by injection is essential and in the smaller populations may be the technique of choice for all pigs. However, there is an increasing concern that resistance to all of these antibiotics is increasing, potentially making treatment and control extremely challenging.\u00a0 Lincomycin had previously declined in efficacy following extensive use and the development of resistant strains but there has been some evidence that Brachyspira susceptibility has returned and may be effective where resistance to the pluromutilins (tiamulin & valnemulin) has occurred.<\/p>\n","protected":false},"excerpt":{"rendered":"
Swine Dysentery has long been recognised as a major disease of pigs throughout the world […]<\/p>\n","protected":false},"author":1,"featured_media":5251,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"footnotes":""},"categories":[20],"tags":[],"class_list":["post-5250","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pigs"],"_links":{"self":[{"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/posts\/5250","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/comments?post=5250"}],"version-history":[{"count":0,"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/posts\/5250\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/media\/5251"}],"wp:attachment":[{"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/media?parent=5250"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/categories?post=5250"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jaguzafarm.com\/support\/wp-json\/wp\/v2\/tags?post=5250"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}