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.

Evaluation of Leptospira infection and exposure in free-roaming cat populations in northern California and southern Texas.

OBJECTIVES: Leptospirosis is a re-emergent zoonotic bacterial disease associated with renal and hepatic injury. In free-roaming cats in some regions, a high prevalence of Leptospira antibodies has been identified, and pathogenic leptospires have been detected in renal tissue, indicating that they may play a role in Leptospira epidemiology. The objective of this study was to determine the prevalence of Leptospira seroreactivity and urinary shedding of Leptospira DNA in free-roaming cats from northern California and southern Texas. A secondary objective was to compare the results of a point-of-care (POC) assay, designed to detect Leptospira antibodies, with the results of the microscopic agglutination test (MAT) when applied to serum samples from feral cats. METHODS: Specimens were obtained from free-roaming cats from northern California (n = 52; 2020) and southern Texas (n = 75; 2017). Leptospira quantitative PCR was performed on blood and urine specimens from Californian cats. Serum samples from Californian and Texan cats were subjected to MAT to categorize them as Leptospira antibody-positive or antibody-negative. The performance of the POC assay was assessed using the MAT as the gold standard. RESULTS: Leptospira DNA was not detected in the blood or urine of any cats tested. The results of the MAT were positive in 17.3% (n = 9) of Californian cats and 10.7% (n = 8) of Texan cats (P = 0.3). The median MAT titer was 1:100 (range 1:100-1:200) in Californian cats and 1:200 (range 1:100-1:800) in Texan cats. The POC assay was negative in all specimens. CONCLUSIONS AND RELEVANCE: Free-roaming cats in California and Texas are exposed to Leptospira species and may have the potential to act as sentinel hosts. No cats had evidence of current infection, as determined using PCR on blood and urine specimens. The POC test did not reliably detect anti-Leptospira antibodies in these cats. The role of cats in the maintenance or shedding of pathogenic leptospires requires further investigation.

Characterization of clinicopathologic and abdominal ultrasound findings in dogs with glucocorticoid deficient hypoadrenocorticism.

BACKGROUND: Clinical findings of glucocorticoid-deficient hypoadrenocorticism (GDH) can overlap with other diseases, presenting a diagnostic challenge. OBJECTIVES: Describe clinicopathologic and ultrasonographic features of dogs with GDH and those suspected of having GDH that had the disease ruled out. ANIMALS: Six hundred twenty-three dogs. METHODS: Records from dogs with suspected GDH between 2003 and 2018 were reviewed. Dogs with hyperkalemia or hyponatremia were excluded. Dogs were categorized as controls when the resting serum cortisol or post-ACTH cortisol concentration were > 2 µg/dL. Clinicopathologic and ultrasonographic features were compared between groups. The optimal cut-point, area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were calculated for individual features used to detect GDH. RESULTS: Dogs were categorized as GDH (n = 29) or controls (n = 594). Lymphocyte count (>1750 cells/L; sensitivity, 96.6%; 95% confidence interval [CI], 82.8%-99.8%; specificity, 60.3%; 95% CI, 56.3%-64.1%; AUC, 0.828; 95% CI, 0.762-0.894) and albumin/globulin ratio (<1.081; sensitivity, 86.2%; 95% CI, 69.4%-94.5%; specificity, 78.8%; 95% CI, 75.3%-81.9%; AUC, 0.886; 95% CI, 0.827-0.944) had the highest discriminatory power between groups. Left adrenal gland width <0.39 cm was 80% (95% CI, 58.4%-91.9%) sensitive and 82.4% (95% CI, 74.2-88.4) specific for GDH. Serum cobalamin concentrations and ultrasonographic abnormalities of the GI tract were not different between groups. CONCLUSION AND CLINICAL IMPORTANCE: No single variable could be used to confidently rule out GDH and obviate the need for cortisol testing in dogs with a clinical presentation consistent with GDH.

Use of machine-learning algorithms to aid in the early detection of leptospirosis in dogs.

Leptospirosis is a life-threatening, zoonotic disease with various clinical presentations, including renal injury, hepatic injury, pancreatitis, and pulmonary hemorrhage. With prompt recognition of the disease and treatment, 90% of infected dogs have a positive outcome. Therefore, rapid, early diagnosis of leptospirosis is crucial. Testing for Leptospira-specific serum antibodies using the microscopic agglutination test (MAT) lacks sensitivity early in the disease process, and diagnosis can take >2 wk because of the need to demonstrate a rise in titer. We applied machine-learning algorithms to clinical variables from the first day of hospitalization to create machine-learning prediction models (MLMs). The models incorporated patient signalment, clinicopathologic data (CBC, serum chemistry profile, and urinalysis = blood work [BW] model), with or without a MAT titer obtained at patient intake (=BW + MAT model). The models were trained with data from 91 dogs with confirmed leptospirosis and 322 dogs without leptospirosis. Once trained, the models were tested with a cohort of dogs not included in the model training (9 leptospirosis-positive and 44 leptospirosis-negative dogs), and performance was assessed. Both models predicted leptospirosis in the test set with 100% sensitivity (95% CI: 70.1-100%). Specificity was 90.9% (95% CI: 78.8-96.4%) and 93.2% (95% CI: 81.8-97.7%) for the BW and BW + MAT models, respectively. Our MLMs outperformed traditional acute serologic screening and can provide accurate early screening for the probable diagnosis of leptospirosis in dogs.

Sex Differences in Susceptibility to Coccidioidomycosis.

To assess sex-specific differences in coccidioidomycosis, a retrospective analysis of human patients, nonhuman primates, and veterinary patients (including the neutered status of the animal) was performed. We found higher rates of infection and severity in males. This observed increased infection risk suggests deeper biological underpinnings than solely occupational/exposure risks.

Closing the intention-behaviour gap for sunscreen use and sun protection behaviours.

OBJECTIVE: Two studies were conducted with the aim of closing the intention-behaviour gap for sunscreen use and sun protection behaviours by examining the influence of self-regulatory capacity on the prediction of sunscreen use (Study 1) and self-regulatory capacity and habit on sun protection behaviours (Study 2). DESIGN: Studies were conducted online. Participants completed questionnaires and cognitive measures and then reported behaviour one week later. MAIN OUTCOME MEASURES: Questionnaires measuring intention and cognitive tasks measuring self-regulatory capacity were administered to 209 university students. One week later, participants reported behaviour. In Study 2, questionnaires measuring intentions, and habit and cognitive tasks measuring self-regulatory capacity were administered to 178 university students who reported behaviour one week later. RESULTS: Intention accounted for 7.1% of variance in sunscreen use, no measures of self-regulation accounted for variance in behaviour or moderated the intention-behaviour gap (Study 1). Intention, self-regulatory capacity and habit accounted for 56.1% of variance in sun protection behaviours (Study 2). Intention, self-regulatory ability and habit predicted behaviour, while habit moderated the intention-behaviour gap. CONCLUSION: Interventions aimed at increasing sun protection behaviours should take into account level of intention, self-regulatory capacity and habit. Individuals may benefit from habit formation strategies and self-regulation training.