Barbara S. Horney

Babesia microti-like infections are prevalent in North American foxes

Babesia microti-like organisms have recently been identified as a cause of hemolytic anemia and azotemia in European dogs. A genetically and morphologically similar B. microti-like parasite has been identified in two foxes from North America. In order to assess the prevalence of this parasite in North American wild canids we screened blood samples from coyotes (Canis latrans) and red foxes (Vulpes vulpes) from eastern Canada and red foxes and gray foxes (Urocyon cinereoargenteus) from North Carolina, USA for the presence B. microti-like DNA by polymerase chain reaction. Thirty-nine percent (50/127) of the red fox samples, 26% (8/31) of the gray fox samples and none (0/12) from the coyote samples tested positive for the presence of B. microti-like DNA. Partial 18S ribosomal ribonucleic acid and beta-tubulin genes from the North American B. microti-like parasites of foxes were sequenced and samples from six domestic dogs from Spain that were infected with a B. microti-like parasite were analyzed for comparison. Partial 18S ribosomal ribonucleic acid and beta-tubulin gene sequences from the North American B. microti-like parasites of foxes were nearly identical to those previously reported from foxes as well as those from domestic dogs from Spain characterized in this study. Interestingly, partial beta-tubulin gene sequences characterized from the B. microti-like parasites of domestic dogs from Spain in this study were different from those previously reported from a Spanish domestic dog sample which is believed to be a pseudogene. The ability of the North American B. microti-like parasite to infect and induce disease in domestic dogs remains unknown. Further studies investigating the pathogenic potential of the North American B. microti-like parasite in domestic dogs are indicated.

Babesia (Theileria) annae in a red fox (Vulpes vulpes) from Prince Edward Island, Canada.

A 4–6-mo-old female red fox (Vulpes vulpes) was presented to the Atlantic Veterinary College (AVC) Teaching Hospital, Prince Edward Island, Canada. On presentation, the fox was weak and had pale mucous membranes. A complete blood count and a serum biochemistry profile were performed. Blood smear examination revealed low numbers of erythrocytes containing centrally to paracentrally located, single, rarely multiple, approximately 1×2 μm, oval to round organisms with morphology similar to Babesia microti. Polymerase chain reaction testing and DNA sequencing of the Babesia species 18S rRNA gene were performed on DNA extracted from whole blood. Results were positive for a Babesia microti–like parasite genetically identical to Babesia (Theileria) annae. The fox was euthanized due to poor prognosis for recovery. Necropsy examination revealed multifocal to locally extensive subacute nonsuppurative meningoencephalitis, an eosinophilic bronchopneumonia, a moderate diffuse vacuolar hepatopathy, and lesions associated with blunt trauma to the left abdominal region. This is the first reported case of a red fox in Canada infected with a piroplasm. It remains uncertain whether the presence of this hemoparasite in this fox was pathogenic or an incidental finding. The potential for competent vectors of Babesia species on Prince Edward Island, the potential for this Babesia microti–like parasite to infect other wild and domestic canids, and the significance of this parasite to the health of infected individuals are yet to be determined.

Evaluation of the Stress Response in Healthy Juvenile Rainbow Trout after Repetitive Intermittent Treatment with Chloramine-T or Formalin

Abstract Chloramine-T, a treatment chemical used in salmonid hatcheries, can cause significant growth deceleration as a result of inefficiency in feed conversion. A reasonable hypothesis proposes that the physiological mechanism involves the stress response, and two trials were designed to asses this. In the first trial, tanks of healthy juvenile rainbow trout Oncorhynchus mykiss were exposed to chloramine-T (10 mg/L) or formalin (200 mg/L) for 1 h once per week for four weeks. The effect of this treatment on the primary stress response was evaluated by measuring circulating cortisol levels with a radioimmunoassay technique. Blood cortisol levels were analyzed at 1, 24, and 96 h after each treatment and compared with preexposure baseline values and with values obtained from sham-treated fish. At 1 h, fish in all treatment categories had elevated cortisol levels compared with baseline values, but values in those fish treated with chemicals were no different from those that were sham treated. Cortisol level...

Measurement of tissue lipid reserves in the American lobster (Homarus americanus): hemolymph metabolites as potential biomarkers of nutritional status

Evaluation of hepatopancreas (HP), pincher claw muscle (PCM), crusher claw muscle (CCM), and abdominal muscle (AM) lipid content in 86 recently caught, adult, male and female American lobsters, Homarus americanus, in the Northumberland Strait, PE, Canada, using the Folch method identified lipid as a significant metabolic reserve. The HP was the primary lipid reservoir in male and non-berried females. Among five moult categories (late inter-moult (mc-1), early pre-moult (mc-2), mid pre-moult (mc-3), late pre-moult (mc-4) and post-moult (mc-5)), devised for the study, the prominent trend observed was a post-moult depletion of lipid reserves in the HP, PCM, and AM. An increased lipid index (LIn) in both CCM and PCM at late pre-moult suggested a differential distribution to provide needed energy in the immediate post-moult foraging period. Hemolymph plasma concentrations of triglyceride (TG), cholesterol (CHOL), and total protein (TP) were highly correlated (TG > CHOL > TP) with HP lipid content in male lobsters only, with the highest values obtained for inter-moult animals. Use of all three parameters in multiple linear regression model improved fit from 0.6656 using TP alone to 0.8226. Hemolymph evaluation presents a non-lethal alternative to assess hepatopancreas lipid content in American lobsters when sex and moult stage are taken into account. These data emphasize the importance of timing and subject selection when using blood chemistry to aid in the monitoring of lobster populations, e.g., for predicting growth on an individual or population basis, response to changing environmental conditions and reproductive capacity.

Evaluation of platelet function in dogs with cardiac disease using the PFA-100 platelet function analyzer

BACKGROUND Cardiac disease has the potential to alter platelet function in dogs. Evaluation of platelet function using the PFA-100 analyzer in dogs of multiple breeds and with a broad range of cardiac conditions would help clarify the effect of cardiac disease on platelets. OBJECTIVES The objective of this study was to assess differences in closure time (CT) in dogs with cardiac disease associated with murmurs, when compared with that of healthy dogs. METHODS Thirty-nine dogs with cardiac murmurs and turbulent blood flow as determined echocardiographically were included in the study. The dogs represented 23 different breeds. Dogs with murmurs were further divided into those with atrioventricular valvular insufficiency (n=23) and subaortic stenosis (n=9). Fifty-eight clinically healthy dogs were used as controls. CTs were determined in duplicate on a PFA-100 analyzer using collagen/ADP cartridges. RESULTS Compared with CTs in the control group (mean+/-SD, 57.6+/-5.9 seconds; median, 56.5 seconds; reference interval, 48.0-77.0 seconds), dogs with valvular insufficiency (mean+/-SD, 81.9+/-26.3 seconds; median, 78.0 seconds; range, 52.5-187 seconds), subaortic stenosis (71.4+/-16.5 seconds; median, 66.0 seconds; range, 51.5-95.0 seconds), and all dogs with murmurs combined (79.6+/-24.1 seconds; median, 74.0 seconds; range, 48.0-187 seconds) had significantly prolonged CTs (P<.01). CONCLUSIONS The PFA-100 analyzer is useful in detecting platelet function defects in dogs with cardiac murmurs, most notably those caused by mitral and/or tricuspid valvular insufficiency or subaortic stenosis. The form of turbulent blood flow does not appear to be an important factor in platelet hypofunction in these forms of cardiac disease.

Measurement of Arginine Kinase Activity in Hemolymph of American Lobsters

Abstract The concentration of arginine kinase (AK) in the hemolymph of lobsters may aid in the identification of muscle diseases in these animals in the same way that creatine kinase activity in blood plasma does in mammalian species. Both manual and automated analysis methods were developed for measuring AK levels in the hemolymph of the American lobster Homarus americanus. A commercial reagent that is used to measure creatine kinase in human blood serum was modified by substituting phospho-L-arginine for creatine phosphate as the substrate to allow measurement of the AK enzyme. Stability of the enzyme in lobster hemolymph plasma was less than 3 h at room temperature (22°C), 6 h when refrigerated (2–5°C), and 24 h when frozen (−20°C). Comparisons were made between the manual and automated protocols using three lobster hemolymph plasma samples. The average recovery in the latter relative to the former was 103%. The automated assay was linear up to 1,940 U/L. Precision studies were conducted using the auto...

Clinical pathology of amphibians: a review

Amphibian declines and extinctions have worsened in the last 2 decades. Partly because one of the main causes of the declines is infectious disease, veterinary professionals have increasingly become involved in amphibian research, captive husbandry, and management. Health evaluation of amphibians, free-living or captive, can benefit from employing the tools of clinical pathology, something that is commonly used in veterinary medicine of other vertebrates. The present review compiles what is known of amphibian clinical pathology emphasizing knowledge that may assist with the interpretation of laboratory results, provides diagnostic recommendations for common amphibian diseases, and includes RIs for a few amphibian species estimated based on peer-reviewed studies. We hope to encourage the incorporation of clinical pathology in amphibian practice and research, and to highlight the importance of applying veterinary medicine principles in furthering our knowledge of amphibian pathophysiology.

Preliminary evaluation of a gel tube agglutination major cross-match method in dogs

BACKGROUND A major cross-match gel tube test is available for use in dogs yet has not been clinically evaluated. OBJECTIVES This study compared cross-match results obtained using the gel tube and the standard tube methods for canine samples. METHODS Study 1 included 107 canine sample donor-recipient pairings cross-match tested with the RapidVet-H method gel tube test and compared results with the standard tube method. Additionally, 120 pairings using pooled sera containing anti-canine erythrocyte antibody at various concentrations were tested with leftover blood from a hospital population to assess sensitivity and specificity of the gel tube method in comparison with the standard method. RESULTS The gel tube method had a good relative specificity of 96.1% in detecting lack of agglutination (compatibility) compared to the standard tube method. Agreement between the 2 methods was moderate. Nine of 107 pairings showed agglutination/incompatibility on either test, too few to allow reliable calculation of relative sensitivity. Fifty percent of the gel tube method results were difficult to interpret due to sample spreading in the reaction and/or negative control tubes. CONCLUSIONS The RapidVet-H method agreed with the standard cross-match method on compatible samples, but detected incompatibility in some sample pairs that were compatible with the standard method. Evaluation using larger numbers of incompatible pairings is needed to assess diagnostic utility. The gel tube method results were difficult to categorize due to sample spreading. Weak agglutination reactions or other factors such as centrifuge model may be responsible.

Comparison of white and red blood cell estimates in urine sediment with hemocytometer and automated counts in dogs and cats

BACKGROUND Therapeutic decisions regarding urinalysis are commonly based on the presence of white and red blood cells. Traditionally, numbers per high-power field are estimated using wet-mount microscopic examination. This technique is not standardized and counts are likely prone to inaccuracy. In addition, differentiation of leukocyte types is not possible. OBJECTIVES The aims of this study were to (1) compare WBC and RBC estimates using wet-mount examination with counts obtained using a hemocytometer, (2) assess if a hematology automated analyzer (Sysmex ST-2000iV/XT) provides reliable WBC and RBC counts in urine comparable to hemocytometer counts, and (3) evaluate air-dried Wright-Giemsa-stained urine drop sediment preparations for the determination of differential leukocyte counts. METHODS WBC and RBC counts were obtained by performing wet-mount estimates, manual hemocytometer counts, and Sysmex automated counts on 219 canine and feline urine samples. Results were correlated using Spearman rank correlation. Air-dried Wright-Giemsa stained sediment drop preparations (n = 215) were examined for differential counts of leukocytes. RESULTS A low but significant association was found between WBC estimates on wet-mount examination and hemocytometer counts (rho = 0.37, P < .01). There was a high and significant association when RBC counts were compared between wet-mount and hemocytometer evaluation (rho = 0.7, P < .01). There was very high and significant interassay correlation between Sysmex data from duplicate samples for what the analyzer classified as WBC (rho = 0.97, P < .01) and RBC (rho = 0.94, P < .01). Low correlations were found between the Sysmex RBC counts and both wet-mount estimates and hemocytometer RBC counts (rho = 0.43, P < .01 and rho = 0.39, P < .01, respectively). Cell preservation in the air-dried sediment preparations was so poor that differential counts could not be performed. CONCLUSION WBC and RBC estimates on wet-mount examination agreed with hemocytometer counts and are therefore considered adequate. The Sysmex ST-2000iV/XT did not provide reliable cell counts under the conditions used.

Culture Method Influences Degree of Growth Rate Reduction in Rainbow Trout Following Exposure to Hydrogen Peroxide

Abstract We used hydrogen peroxide to reproduce gill lesions typical of a broad assemblage of gill diseases encountered in aquaculture and examined the degree of growth rate depression that it caused. Additionally, we compared growth rates of gill-damaged fish when they were either kept separate from or cohabited with healthy untreated fish. In contrast to expectations, treated fish reared separately from controls exhibited a much more dramatic decline in growth rate (30% less than controls) compared with those reared with controls (13% less than controls). Although the effect was transient and persisted for only 2 weeks, it suggests that when considering the bioenergetic costs of disease and when designing studies to quantify the costs, the interaction of diseased fish and healthy fish needs to be considered.