A commercial whole blood polymerase chain reaction assay failed to diagnose histoplasmosis in cats confirmed by cytology or urine antigen detection.

OBJECTIVE: To determine the sensitivity and specificity of a commercial whole blood real-time PCR assay (RT-PCR) for the diagnosis of histoplasmosis when compared to direct organism identification and/or urine antigen quantification by enzyme immunoassay (UA-EIA). A secondary objective was to compare the sensitivity and specificity of RT-PCR to anti-Histoplasma immunoglobulin G antibody detection by enzyme immunoassay (IgG-EIA) and IgG-EIA to UA-EIA. ANIMALS: Cats presented to the Kansas State University Veterinary Health Center from February through September of 2023 in which histoplasmosis was diagnosed or suspected. METHODS: From February through September of 2023, cats were tested by RT-PCR, IgG-EIA, and UA-EIA if histoplasmosis was diagnosed cytologically or was a differential diagnosis for the presenting clinical signs. Cats were excluded if all 3 tests were not submitted or if the diagnosis of histoplasmosis could not be excluded despite a negative UA-EIA result. Cats with cytologically or histologically confirmed histoplasmosis were designated as proven histoplasmosis cases, and cats with a positive UA-EIA result without cytological or histological confirmation were designated as probable histoplasmosis cases. RESULTS: 10 cats were diagnosed with either proven (n = 6) or probable (4) histoplasmosis, and 10 cats were considered true negatives. Whole blood RT-PCR results were negative in all 20 cats (sensitivity, 0%; 95% CI, 0% to 30.85%). The IgG-EIA was 90% sensitive (95% CI, 55.50% to 99.75%) and 70% specific (95% CI, 34.75% to 93.33%). The UA-EIA results were positive in all cats with proven histoplasmosis. CLINICAL RELEVANCE: This commercial RT-PCR is insensitive when used on whole blood collected in EDTA and should not be used to diagnose feline histoplasmosis. Further studies are required to determine whether alternate RT-PCR protocols for EDTA-collected whole blood could be useful for diagnosing histoplasmosis in cats.

Serum C-reactive protein and haptoglobin decrease in the first three months of treatment and relative change in haptoglobin predict remission in dogs with pulmonary coccidioidomycosis.

OBJECTIVE: To evaluate temporal changes in serum C-reactive protein (CRP) and haptoglobin (Hp) concentrations in dogs with pulmonary coccidioidomycosis and assess their utility to detect remission. METHODS: 31 client-owned dogs with newly diagnosed pulmonary coccidioidomycosis from October 2020 to February 2021 were included in a retrospective cohort study that utilized archived serum. Serum was originally obtained at diagnosis and once every 3 months after antifungal administration until either remission or 12 months. Time points were designated as baseline (T0), 3 months (T1), 6 months (T2), 9 months (T3), and 12 months (T4). Serum CRP and Hp were measured at a reference laboratory with ELISA assays. RESULTS: Median serum CRP and Hp concentrations decreased from T0 (CRP, 56 mg/L; Hp, 716.1 mg/dL) to T1 (CRP, 3.3 mg/L; Hp, 240.5 mg/dL); subsequent decreases were not significant. Eighteen (60%) and 16 (53%) of 30 dogs had normal serum CRP and Hp concentrations at T1, respectively. Absolute serum CRP (AUC, 0.58; 95% CI, 0.45 to 0.72) and Hp (AUC, 0.65; 95% CI, 0.52 to 0.78) were poor detectors of remission. However, the percentage change in Hp from T0 to T1 (AUC, 0.90; 95% CI, 0.74 to 1.0) was an excellent predictor of remission within 12 months. CONCLUSIONS: Serum CRP and Hp concentrations decrease in the first 3 months of antifungal treatment in dogs with pulmonary coccidioidomycosis, and the percentage change of Hp may help predict dogs that will achieve remission within 12 months of treatment. CLINICAL RELEVANCE: Serum CRP and Hp may be useful adjunctive biomarkers to monitor treatment response in dogs with pulmonary coccidioidomycosis.

Histoplasmosis in domestic cats: new minimally invasive diagnostic techniques.

OBJECTIVES: The aim of the present study was to evaluate minimally invasive diagnostic techniques, such as the semi-quantitative indirect IgG antibody enzyme immunoassay (EIA) using blood serum and the urinary lateral flow assay (LFA), for the detection of Histoplasma capsulatum in cats with histoplasmosis. METHODS: Eight client-owned domestic cats diagnosed with histoplasmosis were selected based on cytological, histopathological, mycological, molecular or antigenic techniques. The blood serum of these animals was tested in a semi-quantitative indirect IgG antibody EIA for the detection of H capsulatum. Urine samples were tested for H capsulatum antigen using LFA. RESULTS: Five cats were seropositive on IgG EIA (5/8, with diagnostic sensitivity equal to 62.5%; 95% confidence interval [CI] 24.5-91.5) and five cats were positive on H capsulatum antigen LFA (5/7, with diagnostic sensitivity equal to 71.4%; 95% CI 29.0-96.3). The combined diagnostic sensitivity when interpreted in parallel was 87.5% (7/8, 95% CI 47.3-99.7). The specificity for the anti-Histoplasma IgG EIA was 100% (95% CI 71.5-100) and for the H capsulatum antigen LFA it was also 100% (95% CI 71.5-100). CONCLUSIONS AND RELEVANCE: The semi-quantitative indirect IgG antibody EIA for the detection of H capsulatum in blood serum and the urinary LFA for the detection of the same agent emerge as new minimally invasive diagnostic techniques that can assist in the approach to disseminated and pulmonary feline histoplasmosis, especially when both techniques are considered together.

ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats.

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

Tracing histoplasmosis genomic epidemiology and species occurrence across the USA.

ABSTRACTHistoplasmosis is an endemic mycosis in North America frequently reported along the Ohio and Mississippi River Valleys, although autochthonous cases occur in non-endemic areas. In the United States, the disease is provoked by two genetically distinct clades of Histoplasma capsulatum sensu lato, Histoplasma mississippiense (Nam1) and H. ohiense (Nam2). To bridge the molecular epidemiological gap, we genotyped 93 Histoplasma isolates (62 novel genomes) including clinical, environmental, and veterinarian samples from a broader geographical range by whole-genome sequencing, followed by evolutionary and species niche modelling analyses. We show that histoplasmosis is caused by two major lineages, H. ohiense and H. mississippiense; with sporadic cases caused by H. suramericanum in California and Texas. While H. ohiense is prevalent in eastern states, H. mississipiense was found to be prevalent in the central and western portions of the United States, but also geographically overlapping in some areas suggesting that these species might co-occur. Species Niche Modelling revealed that H. ohiense thrives in places with warmer and drier conditions, while H. mississippiense is endemic to areas with cooler temperatures and more precipitation. In addition, we predicted multiple areas of secondary contact zones where the two species co-occur, potentially facilitating gene exchange and hybridization. This study provides the most comprehensive understanding of the genomic epidemiology of histoplasmosis in the USA and lays a blueprint for the study of invasive fungal diseases.

A single injection of high-concentration buprenorphine significantly reduces food and water intake as well as fecal and urine production in New Zealand White rabbits (Oryctolagus cuniculus).

OBJECTIVE: To evaluate selected gastrointestinal side effects of high-concentration buprenorphine (HCB) in healthy rabbits. ANIMALS: 10 healthy New Zealand White rabbits ranging in body weight between 3.0 and 3.8 kg. METHODS: Eight, 6-month-old, New Zealand White rabbits received a single injection of HCB SC (0.24 mg/kg). The rabbits were previously randomized to receive SC and oral saline as a control. Two rabbits received saline for the purpose of blinding the outcome assessors. Food and water consumption, fecal and urine production, and fecal pellet number were recorded for all rabbits before HCB administration and the 3 days postinjection. RESULTS: A clinically and statistically significant decrease in food and water consumption was observed in rabbits receiving an injection of HCB, compared to rabbits receiving saline. In the 24 hours after injection, HCB-treated rabbits consumed a median of 17 g of food (range, 0 to 82 g), while saline-treated rabbits consumed 122 g of food (31 to 181 g). Rabbits receiving HCB injections also produced significantly less feces both in terms of pellet numbers and overall quantity, along with decreased urine production. CLINICAL RELEVANCE: A single administration of HCB has a clinically significant impact on multiple physiological functions in healthy rabbits. Administration of this drug could potentially worsen clinical signs of anorexia and decrease defecation in healthy rabbits. The effects of HCB on diseased or painful rabbits are not yet known.

Temporal tracheobronchial lymphadenopathy resolution is affected by initial severity and poorly correlated to serologic antibody testing in dogs with pulmonary coccidioidomycosis.

OBJECTIVE: To determine associations between antibody serologic tests and tracheobronchial lymphadenopathy (TBL) in dogs with pulmonary coccidioidomycosis and identify variables associated with time to resolution of TBL. ANIMALS: 32 client owned dogs with newly diagnosed pulmonary coccidioidomycosis from October 2020 to February 2021. METHODS: Prospective cohort study. Thoracic radiographs and anti-Coccidioides spp antibody serology were performed at baseline and once every 3 months until remission or for a maximum of 12 months. Radiographic tracheobronchial lymph node height, length, and area were measured and recorded as ratios via comparison with the length of the T4 vertebral body (LT4) and length of the manubrium. Severity of TBL was also subjectively categorized as mild, moderate, or severe. RESULTS: Tracheobronchial lymphadenopathy was identified in 81% (26/32; 95% CI, 64% to 93%) of dogs. There was no relevant association between TBL presence or severity and antibody serology results. Tracheobronchial lymphadenopathy resolved in 72% (n = 18) of dogs at the 3-month evaluation. The median time to resolution of TBL after initiation of fluconazole was 96 days (range, 72 to 386 days). Univariate analysis identified increasing TBL severity (hazard ratio, 0.40; 95% CI, 0.19 to 0.84; P = .02) and length:LT4 ratio (hazard ratio, 0.41; 95% CI, 0.20 to 0.82; P = .01) as variables associated with reduced probability of resolution of TBL. CLINICAL RELEVANCE: Antibody serologic test results are not clinically useful to predict TBL presence or severity in dogs with pulmonary coccidioidomycosis, and larger tracheobronchial lymph nodes are more likely to take longer to resolve. Resolution of TBL occurs in most dogs within 3 to 6 months after fluconazole administration.

Clinical utility of fungal culture and antifungal susceptibility in cats and dogs with histoplasmosis.

BACKGROUND: Culture can be used for diagnosis and antifungal susceptibility testing in animals with fungal infections. Limited information is available regarding the diagnostic performance of culture and the susceptibility patterns of Histoplasma spp. isolates. HYPOTHESIS/OBJECTIVES: Describe the clinical utility of culture and the susceptibility patterns of Histoplasma spp. isolates causing histoplasmosis in cats and dogs. ANIMALS: Seventy-one client-owned animals, including 33 cats and 19 dogs with proven or probable histoplasmosis. METHODS: Culture was attempted from tissue or fluid samples. Diagnostic performance of culture, cytopathology, and antigen detection were compared with final diagnosis. Susceptibility to antifungal agents was determined for a subset (11 from dogs, 9 from cats) of culture isolates. RESULTS: Culture had a diagnostic sensitivity of 17/33 (52%; 95% confidence interval [CI], 34%-69%) and 15/19 (79%; 95% CI, 61%-97%) and specificity of 6/6 (100%; 95% CI, 54%-100%) and 10/10 (100%; 95% CI, 69%-100%) in cats and dogs, respectively. Culture was not positive in any animal in which cytopathology and antigen testing were negative. Target drug exposure (area under the concentration curve [AUC]/minimum inhibitory concentration [MIC] >25) should be easily achieved for all isolates for itraconazole, voriconazole, or posaconazole. Five of 20 (25%) isolates had fluconazole MIC ≥32 µg/mL and achieving target drug exposure is unlikely. CONCLUSIONS AND CLINICAL IMPORTANCE: Fungal culture did not improve diagnostic sensitivity when used with cytopathology and antigen detection. Susceptibility testing might help identify isolates for which fluconazole is less likely to be effective.

Evaluation of an enzyme immunoassay and immunodiffusion for detection of anti-Histoplasma antibodies in serum from cats and dogs.

BACKGROUND: Histoplasma antigen and anti-Histoplasma antibody detection are used to support the diagnosis of histoplasmosis. There is a paucity of published data on antibody assays. OBJECTIVES: Our primary hypothesis was that anti-Histoplasma immunoglobulin G (IgG) antibody detection using enzyme immunoassay (EIA) will be more sensitive as compared to immunodiffusion (ID). ANIMALS: Thirty-seven cats and 22 dogs with proven or probable histoplasmosis; 157 negative control animals. METHODS: Residual stored sera were tested for anti-Histoplasma antibodies using EIA and ID. Results of urine antigen EIA were reviewed retrospectively. Diagnostic sensitivity was calculated for all three assays and compared between immunoglobulin G (IgG) EIA and ID. The diagnostic sensitivity of urine antigen EIA and IgG EIA, interpreted in parallel, was reported. RESULTS: Sensitivity of IgG EIA was 30/37 (81.1%; 95% confidence interval [CI], 68.5%-93.4%) in cats and 17/22 (77.3%; 95% CI, 59.8%-94.8%) in dogs. Diagnostic sensitivity of ID was 0/37 (0%; 95% CI, 0%-9.5%) in cats and 3/22 (13.6%; 95% CI, 0%-28.0%) in dogs. Immunoglobulin G EIA was positive in all animals (2 cats and 2 dogs) with histoplasmosis but without detectable antigen in urine. Diagnostic specificity of IgG EIA was 18/19 (94.7%; 95% CI, 74.0%-99.9%) in cats and 128/138 (92.8%; 95% CI, 87.1%-96.5%) in dogs. CONCLUSION AND CLINICAL IMPORTANCE: Antibody detection by EIA can be used to support the diagnosis of histoplasmosis in cats and dogs. Immunodiffusion has an unacceptably low diagnostic sensitivity and is not recommended.

Evaluation of serum 25-hydroxyvitamin D, C-reactive protein, and haptoglobin as biomarkers in dogs newly diagnosed with histoplasmosis.

BACKGROUND: Serum 25-hydroxyvitamin (OH)D, C-reactive protein (CRP), and haptoglobin are useful biomarkers in various infectious diseases and inflammatory disorders in dogs, but their utility in histoplasmosis is unknown. OBJECTIVE: Determine if serum 25(OH)D, CRP, and haptoglobin concentrations are different in dogs with histoplasmosis compared to healthy controls and whether serum globulin, albumin, CRP, or haptoglobin are associated with 25(OH)D concentration. ANIMALS: Twenty-two client-owned dogs (histoplasmosis, n = 12; controls, n = 10). METHODS: Prospective case-control study. Dogs with histoplasmosis were categorized as pulmonary, disseminated, or gastrointestinal (GI) tract. Serum 25(OH)D was measured using modified high-performance liquid chromatography (HPLC). Serum CRP and haptoglobin were measured with ELISA assays. RESULTS: Dogs with histoplasmosis were grouped as disseminated (n = 8) and GI tract (n = 4). No dogs had pulmonary tract involvement alone. Dogs with histoplasmosis (median, interquartile range [IQR]; 11.6 ng/mL, 16.8) had lower serum 25(OH)D concentrations than controls (35.7 ng/mL, 17.6; P < .001). Serum CRP and haptoglobin concentrations were higher in dogs with histoplasmosis (CRP: median, IQR; 63.5 mg/L, 37.1 and haptoglobin: 459.7 mg/dL, 419.6) than controls (CRP: 1.9 mg/L, 2; P < .001 and haptoglobin: 85.5 mg/dL, 106.7; P = .003). Serum 25(OH)D concentration was positively associated with fold change in serum albumin concentration (ρ = 0.77; P < .001), and negatively associated with fold change in serum globulin (ρ = -0.61; P = .003) and CRP concentrations (ρ = -0.56; P = .01). CONCLUSION AND CLINICAL IMPORTANCE: Assay of serum 25(OH)D, CRP, and haptoglobin could have clinical value in dogs with histoplasmosis.

Clinical utility of an immunoglobulin A-based serological panel for the diagnosis of chronic enteropathy in dogs.

BACKGROUND: A panel of IgA-based serologic assays might aid in the diagnosis of chronic enteropathy (CE) in dogs, a syndrome encompassing conditions such as food-responsive enteropathy, immunosuppressant-responsive enteropathy, and inflammatory bowel disease (also referred to as chronic inflammatory enteropathy). However, it is unclear whether these biomarkers discriminate between CE and other types of primary intestinal disorders. OBJECTIVES: To evaluate a diagnostic panel that measures serum concentrations of IgA directed against OmpC (ACA), canine calprotectin (ACNA), and gliadin-derived peptides (AGA) in dogs with well-characterized intestinal diseases. ANIMALS: Fifty-five dogs with primary intestinal disease. METHODS: Serum ACA, ACNA, and AGA concentrations were measured in 30 dogs with CE and 25 dogs with other intestinal diseases (non-CE population), including histoplasmosis, parasitism, E. coli-associated granulomatous colitis, and lymphoma. Serum IgA concentrations were compared among populations, and sensitivities and specificities were calculated using laboratory-provided cut-points. RESULTS: Twenty-six of 30 (87%) CE dogs and 21 of 25 (84%) non-CE dogs had abnormal concentrations (intermediate or high) of at least 2 markers; these proportions were not significantly different (P = .99). A serum ACA concentration ≥15 EU/mL was 86.7% (95% confidence interval [CI], 69.3%-96.2%) sensitive and 24.0% (95% CI, 9.4%-45.1%) specific for CE diagnosis. High AGA concentrations were observed in 16 of 25 (64%) non-CE dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: The evaluated serologic markers were poorly specific for CE diagnosis, which raises concerns that their use in clinical practice might lead to misdiagnoses and delayed or even detrimental treatments in dogs with non-CE intestinal diseases.

In vitro effect of hydroxyethyl starch on coagulation in dogs as assessed by dynamic viscoelastic coagulometry.

OBJECTIVE: To evaluate the effect of 6% hydroxyethyl starch (HES) 670/0.75 and 6% HES 130/0.4 dilution of canine whole blood on coagulation using dynamic viscoelastic coagulometry (DVC). ANIMALS: 56 healthy adult dogs. PROCEDURES: 2 blood samples were obtained from each dog and randomized to 1 of 7 groups-undiluted or 2 dilutions (1:3 or 1:10) of 3 different fluids: saline (0.9% NaCl) solution, 6% HES 670/0.75, or 6% HES 130/0.4. Dilutions were calculated to simulate approximately a 10- or 30-mL/kg body weight IV bolus of each fluid. DVC was performed on each sample. Coagulation parameters compared between groups included clot rate (CR), platelet function (PF), and activated clotting time. RESULTS: Dilution with saline solution did not significantly affect coagulation, while dilution with HES 670/0.75 and HES 130/0.4 caused a dose-dependent significant decrease in CR (1:3 HES 670/0.75, P = 0.007; 1:10 HES 670/0.75, P = 0.002; 1:3 HES130/0.4, P < 0.0001; and 1:10 HES 130/0.4, P = 0.0003) and PF (1:3 HES 670/0.75, P < 0.0001; 1:10 HES 670/0.75, P < 0.0001; 1:3 HES130/0.4, P < 0.0001; and 1:10 HES 130/0.4, P = 0.0015). CLINICAL RELEVANCE: Dilution of canine blood with HES 670/0.75 and HES 130/0.4, at clinically relevant doses (10 and 30 mL/kg), led to significant hypocoagulability beyond dilutional effect. This was, in part, due to impaired PF, which was significantly greater with HES 670/0.75. Further research using DVC to assess the effects of HES on coagulation in dogs, ideally with clinical conditions warranting HES administration, is needed.

Prevalence of ocular lesions in cats newly diagnosed with histoplasmosis: 55 cases (2015-2022).

OBJECTIVE: To describe the prevalence of ocular lesions in cats with newly diagnosed histoplasmosis. ANIMALS: 55 client-owned domestic cats. PROCEDURES: As part of this prospective case series, cats diagnosed with histoplasmosis between the years 2015 and 2020 underwent complete ophthalmic examinations by a board-certified veterinary ophthalmologist prior to the initiation of antifungal treatment. Histoplasmosis was diagnosed by consistent clinical findings and identification of Histoplasma yeast on pathology or by the use of a commercially available enzyme immunoassay to detect Histoplasma antigen in urine. RESULTS: Of the 55 cats, 45 (82%; 95% CI, 72% to 92%) had signs of active anterior, posterior, or panuveitis. The most common lesions were identified in the posterior portion of the globe and included chorioretinitis and partial retinal detachments (44/55 [80%; 95% CI, 69% to 90%] cats). CLINICAL RELEVANCE: Detailed ophthalmic examinations should be performed on all cats with diagnosed or suspected histoplasmosis, as ocular involvement and subsequent vision loss are common.

Invasive fungal rhinitis with adnexal involvement caused by Histoplasma capsulatum in a cat from a non-enzootic location.

CASE SUMMARY: This report describes a cat with a rare form of histoplasmosis: invasive rhinitis with adnexal involvement, mimicking disease more commonly caused by cryptococcosis or aspergillosis. This case is especially noteworthy as it was from an area where histoplasmosis is not enzootic. RELEVANCE AND NOVEL INFORMATION: Invasive fungal rhinitis causes significant morbidity in cats. Diagnostic investigation of more common pathogens includes detection of fungal antigen (Cryptococcus) or antifungal antibodies (Aspergillus). This case demonstrates that histoplasmosis can present as chronic nasal disease in cats. Histoplasma antigen testing provides a non-invasive diagnostic option. Moreover, this case serves as a reminder that histoplasmosis can affect cats anywhere, even in non-enzootic areas.

Evaluation of a novel monoclonal antibody-based enzyme immunoassay for detection of Histoplasma antigen in urine of dogs.

BACKGROUND: Commercially available, noninvasive testing options for histoplasmosis are limited outside of the United States. OBJECTIVES: To describe the diagnostic performance of a novel Histoplasma antigen enzyme immunoassay (IM EIA) for the diagnosis of histoplasmosis in dogs. ANIMALS: Twenty dogs with histoplasmosis, 79 dogs without histoplasmosis, and 11 unclassified dogs providing 202 urine samples. METHODS: This a prospective study using stored urine samples. Samples were analyzed with the IM EIA and with the commercially available Histoplasma antigen EIA (MV EIA). Dogs were classified based on final proven diagnosis and performance of the IM EIA was described and compared with the MiraVista enzyme immunoassay (MV EIA). RESULTS: The diagnostic sensitivity (DSe), specificity (DSp), and accuracy (DAc) of the IM EIA were 70% (51%-89%), 99% (97%-100%), and 93% (81%-100%), respectively. The DSe, DSp, and DAc for the MV EIA were 95% (85%-100%), 99% (97%-100%), and 98% (95%-100%), respectively. The area under the receiver operator characteristic curve was significantly smaller for IM EIA (0.87) as compared with MV EIA (0.97, P = .03). This was primarily due to 6 false negative IM EIA results, 4 from dogs with disease localized to the gastrointestinal tract. The MV EIA was positive in 5/6 of these dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: The IM EIA might be useful for the diagnosis of disseminated histoplasmosis in dogs, but clinical usefulness will be limited in dogs with histoplasmosis localized to the GI tract.

Clinical pharmacokinetics and outcomes of oral fluconazole therapy in dogs and cats with naturally occurring fungal disease.

This multi-institutional study was designed to determine the clinical pharmacokinetics of fluconazole and outcomes in client-owned dogs (n = 37) and cats (n = 35) with fungal disease. Fluconazole serum concentrations were measured. Pharmacokinetic analysis was limited to animals at steady state (≥72 hr of treatment). The mean (range) body weight in 31 dogs was 25.6 (2.8-58.2) kg and in 31 cats was 3.9 (2.4-6.1) kg included in pharmacokinetic analyses. The dose, average steady-state serum concentrations (CSS ), and oral clearance in dogs were 14.2 (4.5-21.3) mg/kg/d, 26.8 (3.8-61.5) µg/mL, and 0.63 ml min-1  kg-1 , respectively, and in cats were 18.6 (8.2-40.0) mg/kg/d, 32.1 (1.9-103.5) µg/mL, and 0.61 ml min-1  kg-1 , respectively. Random inter-animal pharmacokinetic variability was high in both species. Two dogs had near twofold increases in serum fluconazole when generic formulations were changed, suggesting lack of bioequivalence. Median CSS for dogs and cats achieving clinical remission was 19.4 and 35.8 µg/ml, respectively. Starting oral doses of 10 mg/kg q12h in dogs and 50-100 mg total daily dose in cats are recommended to achieve median CSS associated with clinical remission. Due to the large pharmacokinetic variability, individualized dose adjustments based on CSS (therapeutic drug monitoring) and treatment failure should be considered.

Dynamic viscoelastic coagulometry of blood obtained from healthy chickens.

OBJECTIVE: To assess feasibility of the use of a dynamic viscoelastic coagulometer on chicken blood and compare coagulation variables for fresh whole blood and sodium citrate-preserved whole blood as well as effects of 3 coagulation activators on blood from chickens. SAMPLE: Blood samples from 30 hens. PROCEDURES: Chickens were allowed to rest undisturbed for 1 hour. A blood sample was collected from an ulnar vein; 1.4 mL was analyzed immediately, and 1.8 mL was mixed with sodium citrate and subsequently recalcified and analyzed. A separate coagulation activator (glass beads, kaolin clay, or tissue factor) was in each of the 2 channels of the analyzer. Chickens were allowed a 1-hour rest period, and another blood sample was collected from the contralateral ulnar vein; it was processed in the same manner as for the first sample, except both channels of the analyzer contained the same coagulation activator. RESULTS: Compared with fresh samples, citrated samples had higher values for activated clotting time and platelet function and lower clotting rates. Intra-assay coefficients of variation of coagulation profiles for citrated samples were markedly greater than the limit of 10%, whereas values for fresh samples were close to or < 10%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that use of a dynamic viscoelastic coagulometer on chicken blood was feasible and that analysis of fresh whole blood from healthy chickens provided results with less variability than did analysis of citrated blood. Samples preserved with sodium citrate were associated with significant relative hypocoagulability, compared with results for fresh blood.

Novel canine anti-Coccidioides immunoglobulin G enzyme immunoassay aids in diagnosis of coccidioidomycosis in dogs.

The diagnosis of coccidioidomycosis (CM) in dogs is typically based on clinical presentation, serology, and (less frequently) spherule identification. Agar gel immunodiffusion (AGID) is the most commonly employed serological method, but AGID is slow (requiring up to a week for titer). A Coccidioides antigen enzyme immunoassay (EIA) is also available; however, sensitivity is low in CM dogs. An antibody EIA was developed to detect canine immunoglobulin G (IgG) reacting to Coccidioides antigens. Serum was evaluated from dogs with pathology proven CM and/or AGID positive CM, as well as dogs with histoplasmosis, blastomycosis, non-fungal infections, or healthy dogs. A standard curve was used to convert optical density (OD) values into EIA units (EU). Serum and urine samples from CM dogs were also tested in the antigen EIA. Sensitivity and specificity for IgG were 89.2% and 97.2%, respectively, upon evaluation of dogs with proven or probable CM and control dogs. Cross-reactivity was observed in 7.7% and in 6.4% of dogs with histoplasmosis or blastomycosis, respectively. The antigen EIA alone was insensitive (33.8%). Combined IgG and antigen testing increased sensitivity to 93.2%, as three dogs were IgG-negative but had detectable serum or urine antigen. In 22 dogs with proven CM, sensitivity was statistically similar for antibody EIA and AGID (86% and 73%; P = .487). The MiraVista® canine Coccidioides antibody IgG EIA may aid in the diagnosis of CM by improving turnaround time with comparable sensitivity to AGID. Serial or concurrent testing by antibody and antigen EIAs may be beneficial when screening dogs for CM.

A monoclonal antibody-based urine Histoplasma antigen enzyme immunoassay (IMMY®) for the diagnosis of histoplasmosis in cats.

BACKGROUND: An in-house Histoplasma urine antigen test for cats might be desirable in certain situations. OBJECTIVE: To validate and compare the diagnostic performance of a monoclonal antibody-based IMMY urine Histoplasma antigen enzyme immunoassay (IMMY EIA) to the commercially available urine Histoplasma antigen enzyme immunoassay (MiraVista Diagnostics, MV EIA). ANIMALS: One hundred ninety-three urine samples from 105 client-owned and purpose-bred research cats. METHODS: Cats were classified as Histoplasma positive or negative based on diagnostic investigation. The IMMY EIA and MV EIA were performed on all urine samples. Correlation and agreement between the assays were determined. Diagnostic performance was determined and compared between assays. RESULTS: The IMMY EIA, with a 0.25 ng/mL diagnostic cutoff, provided a diagnostic sensitivity (DSe), diagnostic specificity (DSp), and diagnostic accuracy (DAc) of 89% (95% confidence interval [CI]; 73%-97%), 80% (67%-89%), and 83% (74%-90%), respectively. The IMMY EIA, with a 1.1 ng/mL diagnostic cutoff, provided a DSe, DSp, and DAc of 77% (95% CI 60%-90%), 97% (88%-100%), and 89% (81%-95%), respectively. The MV EIA provided a DSe, DSp, and DAc of 94% (95% CI 81%-99%), 97% (89%-100%), and 96% (90%-99%), respectively. Moderate overall agreement was found between MV EIA and IMMY EIA using the 0.25 ng/mL cut-off (к = 0.44; 95% CI 0.31-0.57) and the 1.1 ng/mL cut-off (к = 0.43, 95% CI, 0.31-0.56). CONCLUSIONS AND CLINICAL IMPORTANCE: The IMMY EIA might be useful as a diagnostic test for histoplasmosis in cats. Further modifications of the IMMY EIA are required to achieve the diagnostic performance of the MV EIA.

Feline histoplasmosis presenting with bone and joint involvement: clinical and diagnostic findings in 25 cats.

OBJECTIVES: The aim of this study was to describe clinical and diagnostic findings in cats with bone and joint disease associated with histoplasmosis. METHODS: Medical records from between 2011 and 2017 were reviewed. Inclusion criteria required: (1) diagnosis of histoplasmosis by cytology, histology, urine or serum Histoplasma antigen testing, or culture; and (2) lameness or joint effusion as a presenting complaint or physical examination finding. RESULTS: Twenty-five cases met the inclusion criteria. Four had incomplete records, but available data were included when applicable. Lameness was a presenting complaint in 17/21 cats and was the only complaint in 9/21 cats. Initial diagnosis was made by cytology in 22/25 cats and by culture, urine antigen and necropsy in one case each. Diagnostic cytology samples included synovial fluid (n = 13), lymph node (n = 5), skin (n = 2), lung (n = 1) and bone (n = 1). Two additional cases had synovial fluid examined but no organisms present. Inflammation was present in all synovial fluid samples examined. Biopsy was obtained in two cats and histologic diagnoses included osteomyelitis with no infectious organisms identified and severe lymphoplasmacytic synovitis suggestive of feline periosteal proliferative polyarthritis. Histoplasma urine antigen test was positive in 7/12 cats. CONCLUSIONS AND RELEVANCE: Inflammatory arthritis is common in cats with histoplasmosis, with lameness a common presenting complaint. Organisms are found in synovial fluid cytology in most cases. If not, appropriate additional diagnostics must be pursued.