coli have been demonstrated in the duodenal juice of these dogs, and these may also play a role in the development of this condition. Predisposing conditions usually cannot be identified, although it remains important to rule out causes of intestinal stasis, such as neoplasia and intussusception. Serum IgA levels in these dogs have been variable. We have documented SIBO by culture of duodenal juice in over half of dogs with chronic intestinal disease dogs of many breeds are affected, although there is a predominance of German Shepherd Dogs. SIBO may also develop secondary to exocrine pancreatic insufficiency, and has been reported in asymptomatic laboratory Beagles. A naturally developing enteropathy associated with SIBO was first described in German Shepherd Dogs, and it has been postulated that this is related to an apparent relative deficiency of IgA in this breed. In dogs, there is rarely evidence for stasis, and the cause of SIBO is often unknown. Small intestinal dysmotility, as evidenced by reduced migrating motor complex activity, is probably responsible for the prevalence of SIBO in elderly human patients. In people, SIBO is usually associated with intestinal stasis (blind loop syndrome).

SIBO may develop if the normal host defence mechanisms, such as gastric acid secretion, intestinal peristalsis, the ileocaecal valve, intestinal immunoglobulin secretion, and mucus barrier are impaired. Clinical signs are variable and some animals may only exhibit weight loss, while others may have intermittent vomiting or signs suggestive of mild colitis. It typically presents in young animals as chronic intermittent small bowel diarrhoea, which may be accompanied by loss of body weight or failure to gain weight. However, this does not apply to all cases since it is not always associated with diarrhoea indeed, weight loss alone can be the only presenting sign.Īccumulated data on clinical cases indicate that SIBO should be considered an important emerging syndrome that may occur in many breeds of dog. There have been suggestions that it be renamed antibiotic-responsive diarrhoea (ARD) until more is known about its aetiopathogenesis. This condition in the dog has been controversial because of difficulties in defining its aetiology and pathogenesis. However, in recent years it has been described as a common finding in dogs with chronic small intestinal disease, either as a cause or a consequence of their disease. SIBO in the dog has been infrequently reported, probably because of the difficulty in establishing the diagnosis, and initial descriptions were limited to its occurrence in German Shepherd Dogs. In dogs with SIBO there are not only increased numbers of intraluminal bacteria, but the composition of the flora also changes to a predominantly anaerobic one, resembling that of the colon. coli, enterococci and lactobacilli, and that obligate anaerobic species are rare. However, it is generally accepted that species normally present in the proximal small intestine of dogs include E. Although recent reviews have questioned the accuracy of this upper limit of normal, some of the reported variation may reflect inclusion of dogs not from household environments rather than pet dogs. It is classically stated that in normal household pet dogs no more than 10 4 to 10 5 bacteria per mL of juice are present in the lumen of the upper small intestine. The definition of what is considered an abnormal number of bacteria in the dog is still under discussion.

The proximal small intestine normally contains few bacteria.In small intestinal bacterial overgrowth (SIBO) there is proliferation of abnormal numbers of bacteria in the lumen of the upper small intestine.

Books & VINcyclopedia of Diseases (Formerly Associate).

VINcyclopedia of Diseases (Formerly Associate).

Bacterial overgrowth