عدد المساهمات : 275 نقاط : 726 السٌّمعَة : 10 تاريخ التسجيل : 25/01/2010 العمر : 31 الموقع : l2vevet.ahlamontada.com
موضوع: III. Colibacillosis الجمعة أكتوبر 28, 2011 9:54 pm
III. Colibacillosis
A. Etiology:Escherichia coli is a gram-negative, lactose-fermenting, indole positive rod.
Rabbits are known to be affected by non-toxin producing, enteropathogenic E. coli (EPEC).
EPEC adhere to the intestinal mucosa through a 2-step process. First, a bacterial pilus first allows attachment of the bacterial cell to the enterocyte.
Second, a more intimate attachment through the eae pathogenicity island disrupts the cytoskeleton and destroys microvilli. A secretory diarrhea is induced by an unknown mechanism.
Receptors for EPEC attachment to the epithelial cells are not present in newborn rabbits. They first appear at 21 days and reach normal adult levels by 35 days. The stress of weaning and loss of passively acquired maternal antibody contribute to susceptibility at this time.
B. Clinical Signs: Rabbits have diarrhea, fever, anorexia, and may consume more water than usual.
C. Pathology:Fecal-stained perineal fur and fluid-filled intestinal contents with serosal vascular injection are seen.
Edema and pyogranulomatous cellularity of the lamina propria without mucosal ulceration are prominent histopathologic findings. Edema or hemorrhage can be seen in the submucosa.
Small bacterial rods (arrow) adhered to and effacing enterocyte margins are common in the ileum and cecum.
D. Treatment:
Fluid therapy and supportive care are indicated. The salicylates in Pepto bismol may be protective.
Chlorpromazine (1 to 10 mg/kg IM) may help decrease fluid loss from the the secretory diarrhea.