Presumptive Nocardia spp. infection in a dog treated with cyclosporin and ketoconazole

Abstract

CASE HISTORY: A dog that had received 8 months of cyclosporin and ketoconazole therapy for treatment of atopic dermatitis subsequently developed severe neurological disease, that failed to respond to treatment with trimethoprim-sulphadiazine and clindamycin.

HISTOPATHOLOGICAL FINDINGS: Histopathological examination of the pulmonary parenchyma and spinal cord revealed loose aggregates of Gram-positive, partially acid-fast, fine, beaded, filamentous bacteria, most consistent with Nocardia spp.

DIAGNOSIS: A presumptive diagnosis was made of disseminated nocardiosis of the spinal cord and lungs.

CLINICAL RELEVANCE: Nocardia spp. is an opportunistic actinomycete that may cause disseminated disease, particularly in immunocompromised animals. Cyclosporin is used in veterinary medicine to control immune-mediated and allergic disorders, with few reported adverse side effects. This case gives further evidence that involvement of the spinal cord in nocardiosis of the central nervous system (CNS) carries a poor prognosis, and opportunistic infection by Nocardia spp. may be a potential complication of immunosuppressive cyclosporin therapy in the dog.     

A retrospective survey of riders' opinions of the use of saddle pads in horses

Horse riders have used layers between saddles and their horse's back since ancient times. Despite the apparent common usage of such layers, most research regarding pressures under horses' saddles seems to have been conducted without such layers present. An online survey of equestrian riders was conducted to quantify the use of such layers and how the layers behaved during use. This produced 1,011 responses from participants in 16 equestrian activities. More than 98% of respondents reported they used some form of layer between their horse's back and the saddle. Differences in layer usage were associated with the respondent's preferred riding discipline and the wither type of their horse. Compensation for perceived saddle fit problems was commonly cited as a reason for using layers. Although horse comfort was nominated by 87.5% of respondents as a reason for using a layer between saddle and the horse's back, many respondents (45%) reported using more than 1 layer. This often resulted in layers thicker than 1 cm, which paradoxically could compromise horse welfare. Half of the respondents reported that the layer between the saddle and the horse's back slipped during riding. Although some significant risk factors for this slippage were identified, they are deemed not to be definitive because of similar factors being identified by the group who did not report layer slippage. These results suggest that incorrect usage of layer between saddles and horses' backs can sabotage good saddle design and compromise equine welfare. Future research on the layers used between the saddles and horses' back is warranted. The question of whether using thicker layers can create greater pressure under saddles or improve rider–horse communication also needs to be investigated.     

Gamna‐Gandy bodies: a case of mistaken identity in the spleen of a cat

A 4‐year‐old, female spayed Domestic Shorthair cat was presented for a 2‐day history of lethargy, anorexia, and vomiting. Diagnostic assessments revealed a severe, regenerative anemia and the presence of a solitary, 3 × 4 cm splenic mass. Cytologic examination of fine‐needle aspirates of the splenic mass showed sheets of pleomorphic histiocytic cells with numerous intracellular and extracellular, negatively staining to deeply basophilic, branching structures. These structures were typically of thin uniform thickness with random angled branching that formed geometrical shapes and fragments, occasionally with sharpened ends and a crystalline appearance. Septal‐like divisions were irregularly spaced along some of the linear branches. The cytology was interpreted as a probable histiocytic inflammatory response to the unidentified foreign material with histiocytic sarcoma as a differential diagnosis. Histopathologic evaluation of the splenic mass resulted in a diagnosis of histiocytic sarcoma. The branching material stained positively for both iron and calcium, indicating that the material was compatible with Gamna‐Gandy bodies present secondary to tumor‐associated hemorrhage and the formation of calcium–iron complexes.     

Comparison of 3 methods of onychectomy

The frequency of claw regrowth, bony remnants, and complications in cats that underwent forelimb onychectomy using laser, scalpel, or guillotine techniques were evaluated. Eighty-seven client-owned cats were recruited from 27 veterinary clinics in the Canadian Atlantic provinces. At least 1 year after onychectomy the cats underwent a physical examination, gait analysis, and radiographic evaluation by 1 of 2 authors. There was no significant difference in the frequency of claw regrowth among the 3 methods (P = 0.283). Significantly more cats had bony remnants following guillotine onychectomy (P < 0.001). Bony remnants were significantly associated with claw regrowth (P = 0.001). Cats that underwent laser onychectomy had significantly less post-operative complications (P = 0.023). The long-term outcome was not significantly different among the 3 methods. We conclude that leaving remnants of the third phalanx in situ is associated with an increased frequency of claw regrowth. Laser onychectomy may be preferred to reduce the risk of post-operative complications, bony remnants, and claw regrowth.     

Effects of supplemental feeding on gastrointestinal parasite infection in elk (Cervus elaphus): preliminary observations

The effects of management practices on the spread and impact of parasites and infectious diseases in wildlife and domestic animals are of increasing concern worldwide, particularly in cases where management of wild species can influence disease spill-over into domestic animals. In the Greater Yellowstone Ecosystem, USA, winter supplemental feeding of Rocky Mountain elk (Cervus elaphus) may enhance parasite and disease transmission by aggregating elk on feedgrounds. In this study, we tested the effect of supplemental feeding on gastrointestinal parasite infection in elk by comparing fecal egg/oocyst counts of fed and unfed elk. We collected fecal samples from fed and unfed elk at feedground and control sites from January to April 2006, and screened all samples for parasites. Six different parasite types were identified, and 48.7% of samples were infected with at least one parasite. Gastrointestinal (GI) nematodes (Nematoda: Strongylida), Trichuris spp., and coccidia were the most common parasites observed. For all three of these parasites, fecal egg/oocyst counts increased from January to April. Supplementally fed elk had significantly higher GI nematode egg counts than unfed elk in January and February, but significantly lower counts in April. These patterns suggest that supplemental feeding may both increase exposure and decrease susceptibility of elk to GI nematodes, resulting in differences in temporal patterns of egg shedding between fed and unfed elk.     

A multicenter evaluation of the effectiveness of Quest Gel (2% moxidectin) against parasites infecting equids

Controlled trials with a common protocol were conducted in Idaho, Illinois and Tennessee to evaluate anthelmintic effectiveness of Quest Gel (QG; 2% moxidectin) against lumenal parasites in horses. Candidate horses were required to have naturally acquired nematode infections, as confirmed by presence of strongylid eggs in feces. At each site, 24 equids were blocked on the basis of pretreatment strongyle fecal egg counts (EPG) and randomly assigned to treatments within blocks. Within each block of two animals, one received QG on Day 0 at a dosage of 0.4 mg moxidectin/kg b.w. and one was an untreated control. Body weights measured the day before treatment served as the basis for calculating treatment doses. Horses assigned to treatment with QG received the prescribed dose administered orally with the commercially packaged Sure Dial syringe. Horses were necropsied 12-14 days after treatment, and lumenal parasites and digesta were harvested separately from each of five organs, including the stomach, small intestine, cecum, ventral colon and dorsal colon. Parasites from stomachs and small intestines were identified to genus, species and stage. Micro- (i.e., < 1.5 cm) and macroparasites (i.e., > 1.5 cm) in aliquots from the cecum, ventral colon and dorsal colon were examined in aliquots of approximately 200 parasites until at least 600 parasites had been identified to genus, species and stage or until all parasites in the 5% aliquot were examined, whichever occurred first. Data were combined across sites and analyzed by mixed model analysis of variance to assess the fixed effect of treatment and random effects of site and block within site. Because QG does not contain a cestocide, efficacy of QG against tapeworms was not significant (P > 0.05). Based on geometric means, however, efficacy of QG was greater than 90% (P < 0.05) against 38 species and developmental stages of cyathostomes, strongyles, bots, larval pinworms and ascarids encountered in at least 6 of 36 control horses in the combined data set. None of the horses treated with moxidectin exhibited evidence of adverse effects. Study results demonstrate QG, administered to horses with naturally acquired endoparasite infections at a dosage of 0.4 mg moxidectin/kg b.w., was highly effective against a broad range of equine parasitic infections.