Fourteen dogs with known clinical hypersensitivity to soy and corn were maintained on a limited antigen duck and rice diet until cutaneous manifestations of pruritus were minimal (78 days). Sequential oral challenges with cornstarch, corn and soy were then performed. Subsequently, the dogs were fed a diet containing hydrolysed soy protein and cornstarch. Throughout the study period the dogs were examined for cutaneous manifestations of pruritus and, additionally, serum was collected for measurement of allergen-specific and total immunoglobulin (Ig)E concentrations. Intradermal testing with food antigens was performed prior to entry into the study and after 83 days. A statistically significant clinical improvement was measured between days 0 and 83. Significant pruritus was induced after oral challenge with cornstarch, corn and soy (P = 0.04, 0.002, 0.01, respectively) but not with the hydrolysed diet (P = 0.5). The positive predictive value of the skin test for soy and corn allergy was reduced after feeding a soy and corn free diet. Although increases in soy and corn-specific serum IgE concentrations were measured in individual dogs post challenge they were not statistically significant and could not be used to predict clinical hypersensitivity.

This study demonstrated that epicutaneous application of HDM slurry to MAB dogs results in elevations of HDM-specific IgE, localized and generalized pruritic dermatitis resembling spontaneous canine AD, and histologic changes typical of IgE-driven inflammation. We feel that these results suggest that epicutaneous exposure to allergen may play an important role during both the sensitization and the perpetuation of AD, and provide support for the use of a canine model in the investigation of the pathogenesis of AD.

SummaryImmunoglobulin E (IgE)-mediated late-phase reactions can be induced in atopic humans by intradermal injection of relevant allergens or anti-IgE antibodies. The histology of these reactions resembles that of naturally occurring atopic dermatitis. Strikingly similar responses can be induced in dogs, suggesting that a canine model could prove valuable for preclinical investigation of drugs targeting late-phase reactions. This study was designed to characterize the cellular, cytokine and chemokine responses after intradermal anti-IgE injection in untreated and prednisolone-treated dogs. Normal beagles were untreated or treated with prednisolone before intradermal injection of polyclonal rabbit anti-canine IgE or normal rabbit IgG. Biopsies were taken before injection and 6, 24 and 48 hr after injection. Samples were evaluated by histological and immunohistochemical staining, as well as by real-time quantitative polymerase chain reaction analysis. Dermal eosinophil and neutrophil numbers increased dramatically within 6 hr after injection of rabbit anti-canine IgE, and remained moderately elevated at 48 hr. The numbers of CD1c + and CD3 + mononuclear cells were also increased at 6 hr. The real-time quantitative polymerase chain reaction demonstrated marked increases in mRNA expression for interleukin-13 (IL-13), CCL2, CCL5 and CCL17. Levels of mRNA for IL-2, IL-4, IL-6 and IFN-c did not change within the limits of detection. Prednisolone administration suppressed the influx of neutrophils, eosinophils, CD1c + and CD3 + cells, as well as expression of IL-13, CCL2, CCL5 and CCL17. These data document the cytokine and chemokine responses to anti-IgE injection in canine skin, and they demonstrate the ability of the model to characterize the anti-inflammatory effects of a known therapeutic agent.

A 7-year-old castrated male Golden Retriever cross was evaluated because of intermittent blood-tinged diarrhea, severe weight loss, anorexia, and lethargy of 2 months' duration; the dog was unresponsive to antimicrobial and standard anthelmintic treatment. Results of fecal flotations for parasite ova were negative. Alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase activities and total protein and globulin conentrations were greater than reference ranges. Biopsy specimens were obtained during laparotomy and examination revealed multiple granulomatous lesions with helminth ova nidi in the intestine, pancreas, liver, and mesenteric lymph node. Saline solution direct smear and saline solution sedimentation of feces yielded trematode ova that were morphologically consistent with Heterobilharzia americana. Identification was confirmed when miracidia were hatched from these ova and produced characteristic cercariae from infected snails. An antigen capture ELISA, typically used for the diagnosis of schistosomiasis in humans, was performed, and schistosome circulating anodic antigen was detected. Treatment with 30 mg of praziquantel/kg (14 mg/lb) of body weight stopped ova shedding, removed detectable circulating antigens, and caused the dog's body weight and attitude to return to normal. Although this is the first report of canine heterobilharziasis in North Carolina, it suggests that heterobilharziasis is underdiagnosed in dogs that have contact with water frequented by raccoons. Inappropriate diagnostic procedures can foil accurate detection of this parasitic disease.

Summary Reasons for performing study: Possible anthelmintic resistance on a breeding farm where a rapid rotation anthelmintic programme had been implemented for 9 years was investigated. Cyathostomins resistant to fenbendazole and pyrantel were documented by faecal worm egg count reduction test (FWECRT). Objectives: To 1) manage small strongyle transmission in a herd of horses in which resistance to both pyrantel pamoate and fenbendazole was identified and thereby reduce the risk of clinical disease in the individual animal, 2) monitor the change in resistance patterns over time and 3) monitor the efficacy of ivermectin over the study period. Methods: Targeted ivermectin treatment of horses on the farm was instituted formature horses with faecal worm egg counts (FWEC) >200 eggs/g (epg) and for horses 100 epg. Results: Over a 30 month period, targeted ivermectin treatment achieved acceptable control in mares, as judged by FWEC, and improved control of patent cyathostome infection in consecutive foal crops. Egg reappearance time (ERT) after treatment with ivermectin was <8 weeks in mares and foals more frequently in the second year of the study than in the first year. Numbers of anthelmintic treatments were reduced by 77.6 and 53.3% in the mare and foal group, respectively. Conclusions: Targeted ivermect in treatment may be an economically viable method of managing multiple drug resistant cyathostominosis. Potential relevance: Use of ivermectin should be monitored closely for development of resistance.