Katharine F. Lunn

Evaluation of the effects of hospital visit stress on physiologic parameters in the cat

Physiologic parameters such as blood pressure, rectal temperature, heart rate, and respiratory rate are an important part of the medical assessment of a patient. However, these factors can potentially be affected by stress. The purpose of this study was to compare physiologic parameter data gathered from cats in the home environment with those gathered in a veterinary hospital. Thirty healthy cats were evaluated both at home and at Colorado State Universitys Veterinary Medical Center. Doppler systolic blood pressure, temperature, heart rate, and respiratory rate were recorded, and the differences between the values obtained in the home and veterinary clinic environments were evaluated using the Wilcoxon sign rank test. A significant difference was found in blood pressure, heart rate, and respiratory rate between the home and veterinary hospital environments. This information may help practitioners recognize that physiologic abnormalities can sometimes be due to transportation or environmental stress rather than medical illness.

Detection and Quantification of Equine Herpesvirus-1 Viremia and Nasal Shedding by Real-Time Polymerase Chain Reaction

Equine herpesvirus-1 (EHV-1) infection is common in young horses throughout the world, resulting in respiratory disease, epidemic abortion, sporadic myelitis, or latent infections. To improve on conventional diagnostic tests for EHV-1, a real-time polymerase chain reaction (PCR) technique was developed, using primers and probes specific for the EHV-1 gB gene. Amplification efficiencies of 100% ± 5% were obtained for DNA isolated from a plasmid, infected peripheral blood mononuclear cells (PBMCs), and nasal secretions from infected ponies. The dynamic range of the assay was 8 log10 dilutions, and the lower limit of detection was 6 DNA copies. Fifteen ponies, seronegative for EHV-1, were experimentally infected with EHV-1, and nasal samples were used to quantify shedding of virus by both virus isolation and real-time PCR analysis. Virus isolation identified nasal shedding of EHV-1 in 12/15 ponies on a total of 25 days; real-time PCR detected viral shedding in 15/15 ponies on 75 days. Viremia was quantified using PBMC DNA, subsequent to challenge infection in 3 additional ponies. Viremia was identified in 1/3 ponies on a single day by virus isolation; real-time PCR detected viremia in 3/3 ponies on 17 days. When real-time PCR was used to analyze PBMC DNA from 11 latently infected ponies (documented by nested PCR), EHV-1 was not detected. We conclude that real-time PCR is a sensitive and quantitative test for EHV-1 nasal shedding and viremia and provides a valuable tool for EHV-1 surveillance, diagnosis of clinical disease, and investigation of vaccine efficacy.

Variability in Results of the Microscopic Agglutination Test in Dogs with Clinical Leptospirosis and Dogs Vaccinated against Leptospirosis

Background: The microscopic agglutination test (MAT) is commonly used for the diagnosis of canine leptospirosis. In dogs it is sometimes suggested that the serogroup with the highest MAT titer is the infecting serogroup; however, this is not true in humans with confirmed leptospirosis. We sought to investigate the value of MAT results in predicting the infecting serogroup by comparing results across several laboratories and within individual dogs over time. Objectives: To examine the variability in MAT results across different laboratories in dogs recently vaccinated against leptospirosis, and in dogs with clinical leptospirosis, and to investigate variability over time in MAT results in individual dogs with leptospirosis. Animals: Eighteen dogs from a research colony, 9 of which had been vaccinated against leptospirosis, and 17 dogs clinically diagnosed with leptospirosis. Methods: Serum samples were submitted to up to 5 veterinary diagnostic laboratories for MAT titers from each dog on at least 1 occasion. MAT results also were followed over time in 6 dogs diagnosed with leptospirosis. Results: MAT results were discordant across different laboratories in dogs recently vaccinated against leptospirosis and in dogs with clinical leptospirosis. MAT results varied over time in individual dogs with the disease. Conclusions and Clinical Importance: The MAT is a valuable test for the diagnosis of leptospirosis in dogs, but it is unlikely that test results can be used to predict the infecting serogroup. Laboratories offering the MAT should consider participation in a proficiency scheme.

Comparison of the Infectivity and Transmission of Contemporary Canine and Equine H3N8 Influenza Viruses in Dogs

Phylogenetic analyses indicate that canine influenza viruses (CIVs) (H3N8) evolved from contemporary equine influenza virus (EIV). Despite the genetic relatedness of EIV and CIV, recent evidence suggests that CIV is unable to infect, replicate, and spread among susceptible horses. To determine whether equine H3N8 viruses have equally lost the ability to infect, cause disease, and spread among dogs, we evaluated the infectivity and transmissibility of a recent Florida sublineage EIV isolate in dogs. Clinical signs, nasal virus shedding, and serological responses were monitored in dogs for 21 days after inoculation. Real-time reverse transcription-PCR and hemagglutination inhibition assays showed that both the viruses have maintained the ability to infect and replicate in dogs and result in seroconversion. Transmission of EIV from infected to sentinel dogs, however, was restricted. Furthermore, both CIV and EIV exhibited similar sialic acid-α2,3-gal receptor-binding preferences upon solid-phase binding assays. The results of the in vivo experiments reported here suggesting that dogs are susceptible to EIV and previous reports by members of our laboratory showing limited CIV infection in horses have been mirrored in CIV and EIV infections studies in primary canine and equine respiratory epithelial cells.

Evaluation of virus isolation, one-step real-time reverse transcription polymerase chain reaction assay, and two rapid influenza diagnostic tests for detecting canine Influenza A virus H3N8 shedding in dogs

Sustained transmission of canine Influenza A virus (CIV) H3N8 among U.S. dogs underscores the threat influenza continues to pose to canine health. Because rapid and accurate detection of infection is critical to the diagnosis and control of CIV, the 2 main objectives of the current study were to estimate and compare the sensitivities of CIV testing methods on canine swab samples and to evaluate the performance of Flu Detect™ (Synbiotics Corp., Kansas City, MO) for detecting CIV nasal shedding in high-risk shelter dogs. To address the first objective, nasal and pharyngeal swab samples were collected from 124 shelter and household dogs seen by Colorado State University Veterinary Teaching Hospital clinicians for canine infectious respiratory disease between April 2006 and March 2007 and tested for CIV shedding using virus isolation, the rapid influenza diagnostic test Directigen Flu A+B™ (BD Diagnostic Systems, Sparks, MD), and real-time reverse transcription polymerase chain reaction (RT-PCR). For the second objective, 1,372 dogs with unknown respiratory health status were sampled from 6 U.S. shelters from December 2009 to November 2010. Samples were tested for presence of CIV using real-time RT-PCR and Flu Detect. Using a stochastic latent class modeling approach, the median sensitivities of virus isolation, rapid influenza diagnostic test, and real-time RT-PCR were 72%, 65%, and 95%, respectively. The Flu Detect test performed poorly for detecting CIV nasal shedding compared to real-time RT-PCR. In conclusion, the real-time RT-PCR has the highest sensitivity for detecting virus nasal shedding and can be used as a rapid diagnostic test for CIV.

The Kidney in Critically Ill Small Animals

Critically ill animals may have preexisting renal disease or develop acute kidney injury as a consequence of their presenting complaint. Age, concurrent medical therapy, electrolyte and fluid imbalances, and exposure to potential nephrotoxicants are factors that predispose to acute kidney injury. Many risk factors are correctable or manageable, and these should be addressed whenever possible. Measurement of serum creatinine is insensitive for the detection of acute kidney injury, and clinicians should consider assessment of other parameters such as urine output, urinalysis, and urine chemistry results. A stepwise approach for management of acute kidney injury in small animal patients is outlined.

Unilateral improvement in glomerular filtration rate after permanent drainage of a perinephric pseudocyst in a cat.

A 12-year-old, 6 kg, castrated male Siamese-cross cat was referred for investigation of an abdominal mass. The cat was found to have a left perinephric pseudocyst (PNP), accompanied by azotemia, with a small right kidney detected on ultrasound. Glomerular filtration rate (GFR) was determined by renal scintigraphy and was found to be low, with the left kidney contributing 64% of the total GFR. Percutaneous ultrasound-guided drainage of the PNP did not improve the GFR, and fluid reaccumulated within a short period of time. Laparoscopic fenestration of the cyst capsule was performed to allow for permanent drainage. The PNP did not recur, renal values progressively improved, and 8 months after the capsulotomy the GFR of the left kidney had increased by 50%, while renal function remained static on the right side.

Use of a point-of-care urine drug test in a dog to assist in diagnosing barbiturate toxicosis secondary to ingestion of a euthanized carcass

OBJECTIVE To describe a case of barbiturate toxicosis in a dog secondary to ingestion of a previously buried euthanized goat carcass and to discuss the utility of urine drug testing in diagnosing barbiturate toxicosis. CASE SUMMARY A 6-year-old neutered male Border Collie was presented to a university veterinary teaching hospital for evaluation of ataxia and acute collapse. Past pertinent history included Addisons disease that had been managed for 1 year. A companion dog was seen 12 hours earlier chewing on the partially decomposed head of a goat that had been euthanized 47 days previously and buried on the owners property. The dog was laterally recumbent, unresponsive to stimuli, and hypothermic on physical examination. Initial blood work revealed hyponatremia and hyperkalemia, with a Na/K ratio of 18.5. The dog was volume resuscitated and received an injection of dexamethasone sodium phosphate due to a suspected Addisonian crisis. Despite this treatment, the dog remained laterally recumbent and unresponsive to stimuli. A urine drug screen was performed and was positive for barbiturates. A diagnosis of barbiturate toxicosis secondary to ingestion of a euthanized goat carcass was made. The dog was treated supportively over 12 hours with IV fluids and activated charcoal. The dog was able to walk 11 hours after presentation and was subsequently discharged from the hospital. NEW OR UNIQUE INFORMATION PROVIDED Urine drug testing is a fast, easy, and point-of-care test that may be useful in dogs to assist in the diagnosis of barbiturate intoxication. Proper disposal of euthanized animals is necessary to prevent toxicosis and possible death of companion animals and wildlife.