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Many regulatory agencies require that the efficacy of veterinary anthelmintic medications be evaluated by enumerating parasites in treated and untreated animals after necropsy. Current ethical considerations, i.e., the 3 Rs of research, call for the replacement of this method with less invasive techniques that would not require animal sacrifice. This study tested standard gastrointestinal endoscopy as an in vivo method of quantifying the intestinal hookworm, Ancylostoma caninum. Worm counts were compared with those from gold standard necropsy. Thirteen dogs inoculated with third-stage A. caninum larvae underwent endoscopy 4-6 weeks post-infection, just prior to necropsy. Two-thirds of the adult hookworms were located in the middle section of the small intestine that could not be reached for endoscopic examination. Not surprisingly, the total worm counts obtained by endoscopy did not correlate with those from necropsy (R(2)=0.05, p=0.464). One method to increase small intestinal access would be to use specialized balloon or spiral endoscopes developed for this purpose in human gastroenterology. Based on the results of this study, standard endoscopy alone is unsuitable for quantification of A. caninum in the small intestine. Parasites in more accessible sites, such as whipworms in the cecum and colon, might be more appropriate targets for endoscopic counting., (Copyright © 2013 Elsevier B.V. All rights reserved.)

This study included a total of 14 dogs with spontaneous esophageal spirocercosis. Historical and clinical evidence of esophageal dysphagia, detection of parasitic ova in fecal samples and endoscopic documentation of esophageal nodules were the inclusion criteria. The animals were randomly assigned into two groups: group A (n = 6 ) dogs received two intranodular injections of absolute ethanol (96%) via a through-the-endoscope injector, at weekly intervals; group B (n = 8) dogs were put on ivermectin (600 microg/kg BW, subcutaneously, twice, 14 days apart) and oral prednisolone (0.5mg/kg BW, every 12h, for a total of 3 weeks, tapering the dose accordingly). Clinical and fecal examination as well as endoscopy, were performed on admission and at 20, 60 and 180 days from the beginning of the treatment. One group A dog responded poorly and died of pyothorax during the trial and another developed esophagitis due to accidental intraluminal ethanol infusion, only to experience an uneventful recovery. At different times during the 6-month follow-up period, there was a complete disappearance of the clinical signs in 4/6 group A dogs. However, full nodular regression was achieved only in one dog, and parasitic ova were still found in the feces of 4/6 dogs. At the same period of time in five group B dogs still available for evaluation, resolution of the clinical signs and complete nodular regression were seen in four and five animals, respectively, while negative fecal results were obtained in all dogs (8/8) of the same group 2 months from the beginning of the treatment. No significant difference was found between the groups, regarding the resolution of clinical signs, though group B dogs demonstrated a significantly higher rate of regression of esophageal nodules as well as negative fecal results, compared to group A dogs. The combination of ivermectin and prednizolone may be considered an effective treatment in the symptomatic and evidently asymptomatic esophageal spirocercosis of the dog.

The nematode Spirocerca lupi is a parasite of dogs with beetles of several species serving as intermediate hosts. The medical records of 50 dogs diagnosed with spirocercosis at the Hebrew University Veterinary Teaching Hospital (HUVTH) in Israel during 1991-1999 were retrospectively reviewed and compared to a control group (n=100). There was a seven-fold increase in the annual number of dogs diagnosed with spirocercosis during these years while the hospital caseload increased by 80%, indicating an emerging outbreak of this infection. Dogs from the greater Tel Aviv area were at the highest risk of being diagnosed with spirocercosis with 74% of the cases originating from this region compared to only 17% of the controls. The disease appeared to have a primarily urban pattern of distribution with a significantly higher percentage (P=0.025) of dogs from cities versus rural areas, as compared to the control group. Sixty-two percent of the cases were diagnosed during the colder months of December through April. The median age of infected dogs was 5 years, with dogs 1 year old or younger at the lowest risk of being diagnosed with spirocercosis. Large breeds were at a higher risk of infection in comparison to small breeds and the Labrador Retriever was significantly over represented (P=0.027) in the study group compared to the control population. The most common signs were vomiting or regurgitation (60%), pyrexia (24%), weakness (22%), respiratory abnormalities (20%), anorexia (18%), melena (18%) and paraparesis (14%). A caudal esophageal mass was identified by radiography in 53% of the dogs and spondylitis of the thoracic vertebrae in 33%. Fecal flotation was positive for S. lupi eggs in 80% of the dogs, and endoscopy was found to be the most sensitive diagnostic procedure and allowed diagnosis in 100% of the examined dogs. Fifty-three percent of the dogs were anemic and creatine kinase (CK) activities were elevated in 54%. Necropsy of 14 dogs revealed esophageal or gastric granulomas in 13 dogs, and an esophageal osteosarcoma in a single animal. Aortic aneurysms were found in six (43%) dogs. Out of 24, 15 dogs (63%) for which follow-up information was available died or were euthanized within 1 month of admission. The case-fatality rate decreased toward the end of the study period when improved therapy with avermectins became available.