Experimental infection of cats with Cryptosporidium felis.

OBJECTIVES: The aims of this study were to experimentally inoculate cats with Cryptosporidium felis oocysts and compare fecal detection by fluorescent antibody assay (FA) and quantitative PCR (qPCR), and document clinical signs associated with infection. METHODS: Cryptosporidium felis oocysts were concentrated from the feces of a naturally infected cat and orally inoculated into six cats that tested negative for C felis by an FA and fecal flotation (FF). Cats were observed daily for the presence of clinical signs consistent with infection. Fecal samples from all cats on days 0 and 9, and one sample per cat (days 18-21), were evaluated by all assays. On day 31, two cats negative for C felis by FF and FA were administered methylprednisolone acetate and all assays were repeated on days 34, 36 and 38. Samples from all cats were tested by FF and FA on days 41, 43, 45 and 48. RESULTS: A total of 41 samples were tested, 25 of which were compared by FA and qPCR. Cryptosporidium felis was detected in 2/25 (8%) and in 19/25 (76%) samples by FA and by qPCR, respectively; the other 16 samples were tested by FF and FA. None of the cats was positive for C felis by FF or FA in samples collected on days 0, 9 or 18-21. One, five and six samples tested positive by qPCR on days 0, 9 and 18-21, respectively. The cats administered methylprednisolone acetate tested positive for C felis by FA on day 36 and by qPCR on days 31, 34, 36 and 38. None of the cats showed clinical signs of disease. CONCLUSIONS AND RELEVANCE: Clinical signs were not recognized in any of the cats for the duration of the study. FA was insensitive compared with qPCR for detecting cats with subclinical C felis infection.

Coagulation status, fibrinolysis, and platelet dynamics in dogs with chronic inflammatory enteropathy.

BACKGROUND: Coagulation status is poorly understood in dogs with chronic inflammatory enteropathy (CIE). Fibrinolytic activity and platelet dynamics have not been evaluated in CIE dogs. OBJECTIVES: To assess coagulation status and fibrinolysis in normoalbuminemic CIE dogs (CIE-N) and CIE dogs with protein-losing enteropathy (CIE-PLE) compared to healthy controls (HC). To evaluate thromboelastography (TEG) variable differences between groups and for correlations with clinicopathologic data. To report platelet dynamics in CIE dogs. ANIMALS: Twenty-five client-owned dogs with CIE (n = 16 CIE-N; n = 9 CIE-PLE); 14 HC beagle dogs. METHODS: All dogs had tissue factor + tissue plasminogen activator TEG. Nine of 25 CIE dogs had whole blood impedance platelet aggregometry. The TEG variables and coagulation data were compared between all CIE vs HC dogs, CIE-N dogs vs HC, and CIE-PLE dogs vs HC. Clinicopathologic and coagulation data were available for CIE dogs and assessed for correlation to TEG variables. RESULTS: Dogs with CIE had higher maximum amplitude (MA; P < .001), longer clot lysis times (CLTs; P < .001), lower % lysis after 30 minutes (LY30; P < .001), and % lysis after 60 minutes (LY60; P < .001) compared to HC, suggesting hypercoagulability and hypofibrinolysis. When separated out, both CIE-N and CIE-PLE dogs had higher MA, longer CLT, and lower LY30 and LY60 compared to HC. Serum albumin and 25-hydroxyvitamin D (25[OH]D) concentrations, and plasma antithrombin and fibrinogen concentrations moderately correlated with MA. CONCLUSIONS AND CLINICAL IMPORTANCE: Normoalbuminemic and hypoalbuminemic CIE dogs were considered hypercoagulable based on TEG compared to HC. Some CIE dogs displayed hypofibrinolytic phenotypes on TEG.

Experimental infection of cats with Cystoisospora felis.

BACKGROUND: Cystoisospora felis is a common parasite of cats and is diagnosed by fecal flotation, but false-negative results can be common. HYPOTHESIS/OBJECTIVES: To experimentally inoculate cats with C. felis oocysts, to compare fecal flotation and polymerase chain reaction (PCR) results, and to describe any clinical signs consistent with infection. ANIMALS: Six cats. METHODS: Cystoisospora felis oocysts were identified morphologically from feces of a naturally infected kitten with diarrhea, sporulated oocysts (5000) were inoculated to 6 cats that were negative for fecal parasites by fecal flotation and by a fluorescent antibody assay (FA) for Giardia spp. and Cryptosporidium spp. Cats were observed daily for the presence of clinical signs consistent with infection. Fecal samples were evaluated by fecal flotation and FA up to 3 times per week post inoculation (PI) to Day 27. Thirty-six samples collected before inoculation and from Days 8, 10, 13, 15, and 20 PI were assayed using an internal transcribed spacer 1 (ITS1) PCR that amplifies DNA of C. felis. RESULTS: All cats were negative for C. felis by both assays before inoculation. All cats shed C. felis oocysts by Day 10 PI, oocysts were not detected by fecal flotation after Day 15 PI. Cystoisospora felis DNA was amplified from 24/36 (66.6%) fecal samples from 6/6 (100%) of the cats. Oocysts were not detected by fecal flotation in 4 of the samples that were positive for C. felis DNA by PCR. Clinical signs were not recognized in any of the study cats. CONCLUSIONS AND CLINICAL IMPORTANCE: Fecal flotation is a convenient assay for detection of C. felis but could occasionally give false-negative results when compared to this ITS1 PCR.

Comparison of clinical, clinicopathologic, and histologic variables in dogs with chronic inflammatory enteropathy and low or normal serum 25-hydroxycholecalciferol concentrations.

BACKGROUND: The cause of low serum vitamin D concentrations in dogs with chronic inflammatory enteropathy (CIE) is not well understood. OBJECTIVE: Improve understanding of pathogenesis of low serum vitamin D concentrations in dogs with CIE by comparing several clinical, clinicopathologic, and histologic variables between CIE dogs with low and normal serum 25-hydroxyvitamin D concentrations (25[OH]D). ANIMALS: Fifteen dogs with CIE and low serum 25[OH]D concentrations; 15 dogs with CIE and normal serum 25(OH)D concentrations. METHODS: Prospective cohort study. Clinical and clinicopathologic variables were compared between groups. Correlations between serum 25(OH)D concentration and histopathologic variables were assessed. RESULTS: Dogs with CIE and low serum 25(OH)D concentrations had higher canine chronic enteropathy clinical activity index scores (P = .003), lower serum α-tocopherol (P < .001), cholesterol (P < .001), and albumin (P < .001) concentrations and higher serum C-reactive protein (P = .004) concentrations compared to CIE dogs with normal serum 25(OH)D concentrations. Serum concentrations of vitamin D-binding protein (VDBP) were not different between groups (P = .91). Duodenal morphologic and inflammatory histopathological scores (P = .002 and P = .004, respectively) and total histopathological scores in duodenum and combined duodenum and ileum negatively correlated with serum 25(OH)D concentration. CONCLUSIONS AND CLINICAL IMPORTANCE: The pathogenesis of low serum vitamin D concentrations in dogs with CIE is likely multifactorial. Fat malabsorption deserves further study in dogs with low serum vitamin D concentration and CIE. Loss of VDBP does not appear to be an important cause of low serum vitamin D concentration in dogs with CIE.

Humoral immune responses against gut bacteria in dogs with inflammatory bowel disease.

Inflammatory bowel disease (IBD) in dogs is associated with clinical signs of intestinal dysfunction, as well as abnormal lymphocytic and myeloid cell infiltrates in the small and/or large intestine. Thus, in many respects IBD in dogs resembles IBD in humans. However, the factors that trigger intestinal inflammation in dogs with IBD are not well understood and have been variously attributed to immune responses against dietary antigens or intestinal antigens. Previous studies in humans with IBD have documented increased production of IgG and IgA antibodies specific to intestinal bacteria, and this abnormal immune response has been linked to disease pathogenesis. Therefore, we investigated the humoral immune response against gut bacteria in dogs with IBD, using flow cytometry to quantitate IgG and IgA binding. Studies were also done to investigate the source of these antibodies (locally produced versus systemic production) and whether greater antibody binding to bacteria is associated with increased inflammatory responses. We found that dogs with IBD had significantly higher percentages and overall amounts of IgG bound to their intestinal bacteria compared to healthy dogs. Similarly, significantly higher percentages of bacteria were IgA+ bacteria were also found in dogs with IBD. Serum antibody recognition of gut bacteria was not different between healthy dogs and dogs with IBD, suggesting that anti-bacterial antibodies were primarily produced locally in the gut rather than systemically. Importantly, bacteria in the Actinobacteria phylum and in particular the genus Collinsella had significantly greater levels of antibody binding in dogs with IBD. Based on these findings, we concluded that antibody binding to commensal gut bacteria was significantly increased in dogs with IBD, that particular phyla were preferential targets for gut antibodies, and that anti-bacterial antibody responses may play an important role in regulating gut inflammation.

Lymphatic endothelial cell immunohistochemical markers for evaluation of the intestinal lymphatic vasculature in dogs with chronic inflammatory enteropathy.

BACKGROUND: Lymphatic endothelial cell (LEC) immunohistochemical markers have identified intestinal lymphatic vasculature abnormalities in humans with inflammatory bowel disease, but have not been used to evaluate intestinal lymphatic vasculature in a group of dogs with chronic inflammatory enteropathy (CIE). OBJECTIVES: To utilize LEC markers to identify and measure intestinal lymphatic vasculature in endoscopic biopsy samples of CIE dogs. To evaluate whether measured lymphatic vasculature variables correlate with serum albumin concentrations. ANIMALS: Twenty-four dogs with CIE; n = 13, serum albumin concentration <2.5 g/dL (CIE-protein-losing enteropathy [PLE]), n = 11, serum albumin concentration ≥2.5 g/dL (CIE-N). METHODS: Prospective study. Lymphatic endothelial cell immunolabeling with Prox-1 and LYVE-1 performed on endoscopic biopsy samples from 24 dogs with CIE. Duodenal and ileal villous lacteal width (VLW) and proprial mucosal lacteal width (MLW) were determined for each case and analyzed for correlation with serum albumin concentration. Lacteal dilatation scores using routine H&E histopathology were assessed for correlation with immunohistochemistry (IHC)-calculated VLW and MLW. RESULTS: Lower serum albumin concentrations were correlated with increased VLW (rho = -.4644; P = .02) and MLW (rho = -.6514; P < .001) in the ileum. Lymphatic endothelial cell IHC identified presumptive proprial mucosal lymphangiectasia in some dogs that was not recognized with routine H&E staining. Lacteal dilatation scores were correlated with VLW in duodenum (rho = .4634; P = .02) and ileum (rho = .5292; P = .008), but did not correlate with MLW. CONCLUSIONS AND CLINICAL IMPORTANCE: Lymphatic endothelial cell immunolabeling identified presumptive proprial mucosal lymphangiectasia in CIE dogs, particularly in the ileum of hypoalbuminemic dogs. Routine evaluation of villous lacteals likely underestimates abnormalities of the lymphatic vasculature in dogs with CIE.

Bilious Vomiting Syndrome in Dogs: Retrospective Study of 20 Cases (2002-2012).

Bilious vomiting syndrome (BVS) is a condition historically associated with early morning vomiting of bile, but it is otherwise poorly characterized. The vomiting is thought to result from a reflux of duodenal fluid into the gastric lumen causing mucosal irritation. Medical records from Colorado State University Veterinary Teaching Hospital (CSUVTH) were searched for "canine" and "bilious vomiting syndrome" between 2002 and 2012. Visual inspection confirmed a diagnosis of BVS during the case history. The diagnosis remained BVS for the duration of the dog's contact with the hospital in 17 cases. Therapy involved frequent feedings, late evening meals, gastric acid reducers, prokinetics, and gastroprotectants. Twelve dogs improved with therapy. Five dogs did not improve or were lost to follow-up. The diagnosis of BVS was supplanted in three cases with gastric adenocarcinoma, dietary indiscretion, and hepatopathy. The patient most likely given a diagnosis of BVS would be a young, mixed-breed, castrated male dog with a chronic history of vomiting bile. Response to therapy suggests abnormal gastrointestinal motility, local gastritis, gastric pH, or stimulation of the emetic center may be important factors in BVS. Dogs diagnosed with BVS rarely received a diagnostic evaluation sufficient to qualify it as a diagnosis of exclusion.

Evaluating Femoral-Sciatic Nerve Blocks, Epidural Analgesia, and No Use of Regional Analgesia in Dogs Undergoing Tibia-Plateau-Leveling-Osteotomy.

This is a retrospective study evaluating femoral-sciatic nerve blocks (FSBs), epidural analgesia, and non-regional analgesia (NRA) in dogs undergoing tibia-plateau-leveling-osteotomy surgery. Thirty-five records met the criteria for each of the FSB and epidural analgesia groups. Seventeen anesthesia records met the criteria for the NRA or control group. The parameters reported were: isoflurane vaporizer setting, rescue analgesia/anesthesia drugs received, heart rate, systolic blood pressure, and recovery quality (0-4, with 0 being poor and 4 being good). Rescue analgesia-anesthesia during surgery was performed with either fentanyl, ketamine, or propofol. A larger percentage of dogs in the NRA group required rescue analgesia during surgery. The FSB group had a higher recovery quality with median (95% confidence interval of four (±0.3) when compared to two (±0.8) in NRA (p < 0.01). No difference between groups was observed on any other parameter reported. As part of a multimodal analgesia approach for tibia-plateau-leveling-osteotomy surgery, the use of femoral and sciatic nerves blocks with bupivacaine appears to be an alternative technique to help with analgesia and anesthesia during surgery.

Field comparison of tolerance of a collar containing 10.0% imidacloprid/4.5% flumethrin (Seresto) and a placebo collar placed on cats.

OBJECTIVES: A collar containing 10.0% imidacloprid/4.5% flumethrin (Seresto; Bayer Animal Health) controls flea and tick infestations for 8 months and is effective in preventing transmission of Bartonella henselae and Cytauxzoon felis among cats. The purpose of this study was to compare tolerance of client-owned cats for the 10.0% imidacloprid/4.5% flumethrin collar or a physically identical placebo collar. METHODS: A total of 96 client-owned cats were enrolled in the study. Cats that were systemically ill, of hairless breed or declawed in all four limbs were excluded. Cats were randomized by household to wear a placebo collar for 14 days followed by the 10.0% imidacloprid/4.5% flumethrin collar for 14 days or the 10.0% imidacloprid/4.5% flumethrin collar for 28 days. Examinations by a veterinarian were performed on days 0, 14 and 28. Owners recorded daily systemic and local health observations. RESULTS: All but two cats, including one that entrapped the mandible in the collar and one that developed local pyodermatitis (10.0% imidacloprid/4.5% flumethrin collar), completed the 28 day study. The majority of the local lesions or licking associated with the collars occurred in the first 14 days, and licking (but not skin lesions) was more common in cats wearing the 10.0% imidacloprid/4.5% flumethrin collars. No local lesions were reported for placebo cats after switching to the 10.0% imidacloprid/4.5% flumethrin collar, and only one cat wearing the 10.0% imidacloprid/4.5% flumethrin collar had reports of licking after day 14. Housing status, single or multiple cat household, and whether a collar had been worn previously were not associated with side effects. CONCLUSIONS AND RELEVANCE: Adverse events detected for cats wearing 10.0% imidacloprid/4.5% flumethrin collars were similar to those for cats wearing placebo collars and to cats wearing identification collars in a separate study. The data suggest that most cats originally intolerant of collars become receptive over time.