Use of serologic tests to predict resistance to Canine distemper virus-induced disease in vaccinated dogs.

The objective of the current study was to determine whether detection of Canine distemper virus (CDV)-specific serum antibodies correlates with resistance to challenge with virulent virus. Virus neutralization (VN) assay results were compared with resistance to viral challenge in 2 unvaccinated Beagle puppies, 9 unvaccinated Beagle dogs (4.4-7.2 years of age), and 9 vaccinated Beagle dogs (3.7-4.7 years of age). Eight of 9 (89%) unvaccinated adult dogs exhibited clinical signs after virus challenge, and 1 (13%) dog died. As compared to adult dogs, the 2 unvaccinated puppies developed more severe clinical signs and either died or were euthanized after challenge. In contrast, no clinical signs were detected after challenge of the 9 adult vaccinated dogs with post-vaccination intervals of up to 4.4 years. In vaccinated dogs, the positive and negative predictive values of VN assay results for resistance to challenge were 100% and 0%, respectively. Results indicate that dogs vaccinated with modified live CDV can be protected from challenge for ≤4.4 years postvaccination and that detection of virus-specific antibodies is predictive of whether dogs are resistant to challenge with virulent virus. Results also indicate that CDV infection in unvaccinated dogs results in age-dependent morbidity and mortality. Knowledge of age-dependent morbidity and mortality, duration of vaccine-induced immunity, and the positive and negative predictive values of detection of virus-specific serum antibodies are useful in development of rational booster vaccination intervals for the prevention of CDV-mediated disease in adult dogs.

The Golden Retriever Lifetime Study: establishing an observational cohort study with translational relevance for human health.

The Golden Retriever Lifetime Study (GRLS) is the first prospective longitudinal study attempted in veterinary medicine to identify the major dietary, genetic and environmental risk factors for cancer and other important diseases in dogs. The GRLS is an observational study that will follow a cohort of 3000 purebred Golden Retrievers throughout their lives via annual online questionnaires from the dog owner and annual physical examinations and collection of biological samples by the primary care veterinarian. The field of comparative medicine investigating naturally occurring disorders in pets is specifically relevant to the many diseases that have a genetic basis for disease in both animals and humans, including cancer, blindness, metabolic and behavioural disorders and some neurodegenerative disorders. The opportunity for the GRLS to provide high-quality data for translational comparative medical initiatives in several disease categories is great. In particular, the opportunity to develop a lifetime dataset of lifestyle and activity, environmental exposure and diet history combined with simultaneous annual biological sample sets and detailed health outcomes will provide disease incidence data for this cohort of geographically dispersed dogs and associations with a wide variety of potential risk factors. The GRLS will provide a lifetime historical context, repeated biological sample sets and outcomes necessary to interrogate complex associations between genes and environmental influences and cancer.

Comparison of urine dipstick, sulfosalicylic acid, urine protein-to-creatinine ratio, and species-specific ELISA methods for detection of albumin in urine samples of cats and dogs.

OBJECTIVE: To evaluate the use of dipstick, sulfosalicylic acid (SSA), and urine protein-to-creatinine ratio (UP:C) methods for use in detection of canine and feline albuminuria. DESIGN: Evaluation study. SAMPLE POPULATION: 599 canine and 347 feline urine samples. PROCEDURES: Urine was analyzed by use of dipstick, SSA, and UP:C methods; results were compared with those for a species-specific ELISA to determine sensitivity, specificity, positive predictive value (PPV), negative predictive value, and positive and negative likelihood ratios. RESULTS: Positive results for dipstick and SSA tests (trace reaction or greater) in canine urine had moderate specificity (dipstick, 81.2%; SSA, 73.3%) and poor PPV (dipstick, 34.0%; SSA, 41.8%). Values improved when stronger positive results (>or= 2+) for the dipstick and SSA tests were compared with ELISA results (specificity, 98.9% and 99.0% for the urine dipstick and SSA tests, respectively; PPV, 90.7% and 90.2% for the dipstick and SSA tests, respectively). Data obtained for cats revealed poor specificity (dipstick, 11.0%; SSA, 25.4%) and PPV (dipstick, 55.6%; SSA, 46.9%). Values improved slightly when stronger positive test results (>or= 2+) were used (specificity, 80.0% and 94.2% for the dipstick and SSA tests, respectively; PPV, 63.5% and 65.2% for the dipstick and SSA tests, respectively). The UP:C had high specificity for albuminuria in dogs and cats (99.7% and 99.2%, respectively) but low sensitivity (28.7% and 2.0%, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Caution should be used when interpreting a positive test result of a dipstick or SSA test for canine or feline albuminuria.

Association of microalbuminuria and the urine albumin-to-creatinine ratio with systemic disease in cats.

OBJECTIVE: To determine the diagnostic usefulness of semiquantitative and quantitative microalbuminuria assays and urine albumin-to-creatinine (UAC) ratio for detecting disease in cats. DESIGN: Prospective study. ANIMALS: 441 cats evaluated at a veterinary teaching hospital. PROCEDURES: Urine samples from cats for which a complete medical record was available were included. Urine dipstick results, urine protein-to-creatinine ratios (cutoffs, 0.1 and 0.4), semiquantitative and quantitative microalbuminuria assay results (cutoff, 1 mg/dL), and UAC ratio values (cutoffs, 100 and 200 mg/g) were determined. Clinical diagnoses determined within 3 months of enrollment were recorded. Sensitivity and specificity were determined with disease status used as the standard. The influences of clinical diagnosis, sex, age, serum urea nitrogen and creatinine concentrations, blood pressure, bacterial urine culture results, rectal temperature, pyuria, hematuria, and bacteriuria were evaluated by means of logistic regression. RESULTS: Of 441 cats that were eligible for inclusion, 40 were healthy and 401 had > or = 1 disease. Results of logistic regression indicated that significant associations existed for age, presence of disease, presence of urinary tract disease, azotemia, hematuria, and pyuria and results of 1 or both of the microalbuminuria assays. CONCLUSIONS AND CLINICAL RELEVANCE: Microalbuminuria was associated with underlying disease. Sensitivity and specificity of the microalbuminuria assays for detection of systemic disease were superior to those of other tests. Microalbuminuria testing in conjunction with other screening procedures may increase identification of occult disease. A prospective study evaluating the predictive values of screening tests with and without microalbuminuria determination is needed to validate this recommendation.

Prevalence of DNA of Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum,' Anaplasma phagocytophilum, and species of Bartonella, Neorickettsia, and Ehrlichia in cats used as blood donors in the United States.

OBJECTIVE: To identify the prevalence of DNA of Mycoplasma haemofelis; 'Candidatus Mycoplasma haemominutum'; Anaplasma phagocytophilum; and species of Bartonella, Neorickettsia, and Ehrlichia in blood of cats used as blood donors in the United States. DESIGN: Prospective study. ANIMALS: 146 cats that were active blood donors. PROCEDURES: Environmental history was requested for each blood-donor cat from which a blood sample (mixed with EDTA) was available. Polymerase chain reaction assays capable of amplifying the DNA of the microorganisms of interest following DNA extraction from blood were performed. RESULTS: Overall, DNA of one or more of the infectious agents was detected in blood samples from 16 of 146 (11%) feline blood donors. Twenty-eight laboratory-reared cats housed in a teaching hospital had negative results for DNA of all organisms investigated. The DNA of at least 1 infectious agent was amplified from blood samples collected from 16 of 118 (13.6%) community-source cats; assay results were positive for 'Candidatus M haemominutum,' M haemofelis, or Bartonella henselae alone or in various combinations. Of the community-source cats allowed outdoors (n = 61) or with known flea exposure (44), DNA for a hemoplasma or B henselae was detected in 21.3% and 22.7%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: When community-source cats, cats allowed outdoors, or cats exposed to fleas are to be used as blood donors, they should be regularly assessed for infection with M haemofelis, 'Candidatus M haemominutum,' and Bartonella spp, and flea-control treatment should be regularly provided.

Evaluation of the association between microalbuminuria and the urine albumin-creatinine ratio and systemic disease in dogs.

OBJECTIVE: To evaluate semiquantitative and quantitative assays for microalbuminuria and determination of the urine albumin-creatinine (UAC) ratio in detection of systemic disease in dogs without overt proteinuria. DESIGN: Prospective study. ANIMALS: 408 dogs. PROCEDURES: Urine samples that had been obtained from dogs for which a complete medical record was available and in which results of a dipstick test for urine protein were negative were evaluated. Urine protein-creatinine ratios (cutoff values, 0.5 and 0.1), semiquantitative and quantitative microalbuminuria values (cutoff value, 1 mg/dL), and UAC ratios (cutoff values, 100 and 200 mg/g) were determined. Clinical diagnoses rendered within 3 months of enrollment in the study were recorded. Sensitivity and specificity were determined with disease status serving as the standard. Associations with clinical diagnosis, sex, age, BUN and serum creatinine concentrations, blood pressure, results of bacterial culture of urine, temperature, pyuria, hematuria, and bacteriuria were evaluated by use of logistic regression analysis. RESULTS: 48 dogs were healthy, and 360 had at least 1 disease. Significant associations were detected between age, presence of disease, presence of neoplastic disease, BUN and serum creatinine concentrations, and hematuria and results of 1 or both of the microalbuminuria assays. CONCLUSIONS AND CLINICAL RELEVANCE: Microalbuminuria was associated with underlying disease. The sensitivity and specificity of the semiquantitative microalbuminuria test for detection of systemic disease were superior to those of other tests. Microalbuminuria testing in conjunction with other screening procedures may increase diagnosis of subclinical disease, but a prospective study in which the predictive values of screening tests are evaluated, with and without microalbuminuria determination, is needed.

Interstitial nephritis in cats inoculated with Crandell Rees feline kidney cell lysates.

Parenteral administration of Crandell Rees feline kidney (CRFK) cell lysates or feline herpesvirus 1, calicivirus, and panleukopenia virus-containing vaccines (FVRCP) grown on CRFK cells induces antibodies against CRFK cells. These antibodies also react with feline renal cell extracts. The purpose of this study was to determine whether interstitial nephritis would be detected in cats that were immunologically sensitized with CRFK lysates, boosted with CRFK lysates, and then biopsied 2 weeks after the booster. Cats (2 per group) were immunologically sensitized against CRFK lysates by administering 10 microg, 50 microg, or 50 microg plus alum 13 times (12 times in the first 50 weeks) over 2 years. Two cats were inoculated three times, 4 weeks apart with an FVRCP vaccine for intranasal administration as kittens, boosted 50 and 102 weeks later, and then renal biopsies taken 2 weeks after the last booster. Neither of the cats vaccinated with the FVRCP for intranasal administration had detectable renal inflammation. One cat in each of the three CRFK lysate sensitization groups had lymphocytic-plasmacytic interstitial nephritis.

Prevalence of Bartonella species, haemoplasma species, Ehrlichia species, Anaplasma phagocytophilum, and Neorickettsia risticii DNA in the blood of cats and their fleas in the United States.

Ctenocephalides felis were killed and collected from 92 cats in Alabama, Maryland, and Texas. The fleas and blood from the corresponding cat were digested and assessed in polymerase chain reaction assays that amplify DNA of Ehrlichia species, Anaplasma phagocytophilum, Neorickettsia risticii, Mycoplasma haemofelis, 'Candidatus M haemominutum' and Bartonella species. DNA consistent with B henselae, B clarridgeiae, M haemofelis, or 'Candidatus M haemominutum' was commonly amplified from cats (60.9%) and their fleas (65.2%). Results of this study support the recommendation to maintain flea control on cats in endemic areas.

Investigation of the induction of antibodies against Crandell-Rees feline kidney cell lysates and feline renal cell lysates after parenteral administration of vaccines against feline viral rhinotracheitis, calicivirus, and panleukopenia in cats.

OBJECTIVE: To determine whether administration of Crandell-Rees feline kidney (CRFK) cell lysates or vaccines against feline viral rhinotracheitis, calicivirus, and panleukopenia (FVRCP vaccines) that likely contain CRFK cell proteins induces antibodies against CRFK cell or feline renal cell (FRC) lysates in cats. ANIMALS: 14 eight-week-old cats. PROCEDURE: Before and after the study, renal biopsy specimens were obtained from each cat for histologic evaluation. Each of 4 FVRCP vaccines was administered to 2 cats at weeks 0, 3, 6, and 50. Between weeks 0 and 50, another 3 pairs of cats received 11 CRFK cell lysate inoculations SC (10, 50, or 50 microg mixed with alum). Clinicopathologic evaluations and ELISAs to detect serum antibodies against CRFK cell or FRC lysates were performed at intervals. RESULTS: Cats had no antibodies against CRFK cell or FRC lysates initially. All cats administered CRFK cell lysate had detectable antibodies against CRFK cell or FRC lysates on multiple occasions. Of 6 cats vaccinated parenterally, 5 had detectable antibodies against CRFK cell lysate at least once, but all 6 had detectable antibodies against FRC lysate on multiple occasions. Cats administered an intranasal-intraocular vaccine did not develop detectable antibodies against either lysate. Important clinicopathologic or histologic abnormalities were not detected during the study. CONCLUSIONS AND CLINICAL RELEVANCE: Parenteral administration of vaccines containing viruses likely grown on CRFK cells induced antibodies against CRFK cell and FRC lysates in cats. Hypersensitization with CRFK cell proteins did not result in renal disease in cats during the 56-week study.

Molecular and serologic evidence of Anaplasma phagocytophilum infection in cats in North America.

Anaplasma phagocytophilum DNA was detected in blood of clinically ill cats from Massachusetts (n = 4) and Connecticut (1) by use of polymerase chain reaction assay and DNA sequencing. All 5 cats were allowed outdoors, and Ixodes scapularis were found on 3 cats. Clinical signs of fever, anorexia, and lethargy resolved quickly after treatment with doxycycline or tetracycline. Serum samples from each cat reacted with A. phagocytophilum morulae via an indirect fluorescent antibody assay; positive antibody titers persisted even after 21 to 30 days of treatment with tetracycline. To the authors' knowledge, this is the first report of A. phagocytophilum infection of domestic cats in North America. Results suggest that infection with the organism may be associated with clinical illness in some cats.

Effects of urinary tract inflammation and sample blood contamination on urine albumin and total protein concentrations in canine urine samples.

BACKGROUND: Urinary tract inflammation and hemorrhage are believed to be common causes of proteinuria in dogs based on results of studies that measured total urine protein concentration. A method to quantify urine albumin (UAlb) concentration in dogs recently has become available; however, the effect of inflammation on albuminuria is unknown. OBJECTIVES: The goals of this study were to determine the effects of urinary tract inflammation, as indicated by pyuria and sample blood contamination, on UAlb concentration and on urine protein:creatinine (UPC) ratio in dogs. METHODS: Urine samples were obtained from dogs with pyuria that were presented to a veterinary teaching hospital or were part of a laboratory colony. To mimic the effects of hematuria, canine whole blood was added to a microscopically normal canine urine sample that had baseline albumin and total protein concentrations below the limits of detection. UAlb concentration was measured using a canine albumin-specific competitive ELISA. UPC ratio was determined using routine methods. RESULTS: Of 70 samples with pyuria, 67% had negligible UAlb concentrations and 81% had normal UPC ratios. UAlb concentration but not UPC ratio was significantly higher (P < 0.05) in samples with concurrent hematuria or bacteriuria. When whole blood was added to normal urine, UAlb concentration did not exceed 1 mg/dL until the sample became visibly pink; the UPC did not exceed 0.4 at any dilution. CONCLUSIONS: Many dogs with pyuria do not have albuminuria or proteinuria; however, albuminuria may be more likely in dogs with pyuria and concurrent hematuria or bacteriuria. Hematuria may not cause an increase in UAlb concentration until it becomes macroscopic and even then may not increase the UPC ratio.

The effects of exercise on urinary albumin excretion in dogs.

Persistent microalbuminuria has been shown to be an indicator of glomerular damage associated with early progressive renal disease in people and dogs. In people, transient or reversible microalbuminuria has been shown to occur with exercise. A semi-quantitative test to measure microalbuminuria in the dog recently has become available. The purpose of this study was to determine if mild-to-moderate exercise induced microalbuminuria in the dog. Twenty-six dogs were included in the study after undergoing tests to rule out hyperglycemia, urinary tract infection, azotemia, and a urine protein:creatinine ratio >1. Exercise consisted of 20 minutes of flat treadmill running. Urine samples were collected on 2 separate days before exercise, the morning of exercise, 3 hours postexercise, 7-9 hours postexercise, and each of the 2 mornings after exercise. For 24 of 26 dogs, this procedure was repeated after a minimum 7-day interval between exercise sessions. The canine E.R.D. (early renal disease)-Screen Urine Test (E.R.D.-Screen test) was used to determine semiquantitative urine albumin concentrations. Microalbuminuria-positive samples, as determined by the E.R.D.-Screen test, were further analyzed to determine quantitative albumin concentrations. Four (15%) dogs were microalbuminuria positive. In each of these dogs, microalbuminuria was present both before and after exercise with no quantitative increase in urine albumin concentration postexercise. Twenty-two (85%) dogs were microalbuminuria negative throughout the study and did not develop microalbuminuria at any time after exercise. On a 95% confidence interval, the proportion of dogs that might be expected to develop microalbuminuria after exercise is between 0 and 15%.

Detection of canine microalbuminuria using semiquantitative test strips designed for use with human urine.

BACKGROUND: Commercial testing for microalbuminuria in human urine is often performed with point-of-care semiquantitative test strips followed by quantitative testing when indicated. An ELISA that quantifies canine urine albumin concentration has been developed, but semiquantitative test strips for use in the dog are not available. OBJECTIVE: The purpose of this study was to prospectively determine the concordance of canine urine albumin concentrations measured by a commercial human test strip and by ELISA. METHODS: Urine samples were obtained from 67 dogs evaluated for a variety of clinical conditions. Dipstick urinalyses were performed on all samples; clinician discretion determined method of urine collection and performance of urine sediment examination and/or urine culture. Urine albumin concentration was determined using test strips (Clinitek Microalbumin, Bayer Corporation, Elkhart, Ind, USA), and results were compared with those obtained by ELISA. RESULTS: The Clinitek strips correctly determined albumin concentration in 42 of 67 (63%) urine samples tested. Concordance was lowest (48%) for dogs with microalbuminuria (10-300 microg/mL by ELISA). Clinitek strip sensitivity and specificity for correct identification of microalbuminuria were 48% and 75%, respectively. Concordance was lower in dogs with urinary tract infection or hematuria and in samples collected by catheterization. Sensitivity and specificity for correct identification of microalbuminuria after exclusion of dogs with urinary tract infection or hematuria were 59% and 83%, respectively. CONCLUSIONS: These results suggest that the Clinitek strips lack sufficient concordance with results obtained by ELISA to be a reliable screening for test microalbuminuria in the dog. A reliable semiquantitative point-of-care test for canine urine albumin concentrations below those detected by standard urine dipsticks is still needed.

Use of serologic tests to predict resistance to feline herpesvirus 1, feline calicivirus, and feline parvovirus infection in cats.

OBJECTIVE: To determine whether detection of virus-specific serum antibodies correlates with resistance to challenge with virulent feline herpesvirus 1 (FHV-1), feline calicivirus (FCV), and feline parvovirus (FPV) in cats and to determine percentages of client-owned cats with serum antibodies to FHV-1, FCV, and FPV. DESIGN: Prospective experimental study. ANIMALS: 72 laboratory-reared cats and 276 client-owned cats. PROCEDURES: Laboratory-reared cats were vaccinated against FHV-1, FCV, and FPV, using 1 of 3 commercial vaccines, or maintained as unvaccinated controls. Between 9 and 36 months after vaccination, cats were challenged with virulent virus. Recombinant-antigen ELISA for detection of FHV-1-, FCV-, and FPV-specific antibodies were developed, and results were compared with results of hemagglutination inhibition (FPV) and virus neutralization (FHV-1 and FCV) assays and with resistance to viral challenge. RESULTS: For vaccinated laboratory-reared cats, predictive values of positive results were 100% for the FPV and FCV ELISA and 90% for the FHV-1 ELISA. Results of the FHV-1, FCV, and FPV ELISA were positive for 195 (70.7%), 255 (92.4%), and 189 (68.5%), respectively, of the 276 client-owned cats. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for cats that have been vaccinated, detection of FHV-1-, FCV-, and FPV-specific antibodies is predictive of whether cats are susceptible to disease, regardless of vaccine type or vaccination interval. Because most client-owned cats had detectable serum antibodies suggestive of resistance to infection, use of arbitrary booster vaccination intervals is likely to lead to unnecessary vaccination of some cats.