Use of ultrasonographic and nuclear imaging to diagnose scrotal hernia in a dog

Ultrasonography and nuclear imaging were used in the diagnosis of scrotal hernia in a dog. Both techniques were useful as aids in the differential diagnosis of scrotal enlargement. Nuclear imaging was useful in ruling out testicular torsion; ultrasonography revealed a normal-appearing testis amid fluid and portions of omentum.     

Use of a fast test to detect rotavirus in feces

The commercially available immunoassay "OnSite Rotavirus" was used for the detection of animal rotaviruses in 113 faecal samples. The sensitivity of the test was 88% and the specificity 96% compared with reference methods (EIA, EM). This test would detect approximately 4.4 x 10(6) to 1.8 x 10(7) virus particles per ml. The presence of virus could be demonstrated in fresh faecal samples from cattle, horses and pigs within a few minutes. The rotaviruses of group A were identified independently of the virus serotype. Further results and additional problems of using this test kit are described.     

Use of a Giemsa stain to detect changes in acrosomes of frozen ram spermatozoa.

Acrosomal structures of ram spermatozoa were prominently stained when air dried smears of diluted semen were fixed for 15 minutes in buffered formal saline and stained for 90 minutes in a 6 per cent (v/v) buffered solution of Giemsa stain. Progressive disruption of the acrosomes was demonstrated during chilling and deep-freezing of the spermatozoa, and the degree of damage was systematically scored. A rapid and repeatable estimate of the state of the acrosomes in a sample could be made from the mean score of 20 spermatozoa examined per slide.     

Use of a public telephone hotline to detect urban plague cases

Current methods for vector‐borne disease surveillance are limited by time and cost. To avoid human infections from emerging zoonotic diseases, it is important that the United States develop cost‐effective surveillance systems for these diseases. This study examines the methodology used in the surveillance of a plague epizootic involving tree squirrels (Sciurus niger) in Denver Colorado, during the summer of 2007. A call‐in centre for the public to report dead squirrels was used to direct animal carcass sampling. Staff used these reports to collect squirrel carcasses for the analysis of Yersinia pestis infection. This sampling protocol was analysed at the census tract level using Poisson regression to determine the relationship between higher call volumes in a census tract and the risk of a carcass in that tract testing positive for plague. Over‐sampling owing to call volume‐directed collection was accounted for by including the number of animals collected as the denominator in the model. The risk of finding an additional plague‐positive animal increased as the call volume per census tract increased. The risk in the census tracts with >3 calls a month was significantly higher than that with three or less calls in a month. For tracts with 4–5 calls, the relative risk (RR) of an additional plague‐positive carcass was 10.08 (95% CI 5.46–18.61); for tracts with 6–8 calls, the RR = 5.20 (2.93–9.20); for tracts with 9–11 calls, the RR = 12.80 (5.85–28.03) and tracts with >11 calls had RR = 35.41 (18.60–67.40). Overall, the call‐in centre directed sampling increased the probability of locating plague‐infected carcasses in the known Denver epizootic. Further studies are needed to determine the effectiveness of this methodology at monitoring large‐scale zoonotic disease occurrence in the absence of a recognized epizootic.     

Use of polymerase chain reaction to detect latent channel catfish virus.

Polymerase chain reaction was used to detect an economically important herpesvirus, channel catfish virus (CCV). A segment of the viral DNA was sequenced and oligonucleotide primers were produced from that sequence. After the primers were tested for the possibility of hybridization to catfish DNA, they were used to prime the polymerase chain reaction, using pure CCV DNA, CCV DNA added to catfish DNA, and DNA from catfish infected and not infected with CCV. In all cases, the method proved to be simple and sensitive in its detection by CCV DNA. When catfish DNA was present, less than 0.1 pg of CCV DNA was detectable. Channel catfish virus DNA in a latent carrier of CCV was readily detectable.     

Use of a polymerase chain reaction assay to detect infection with Eperythrozoon wenyoni in cattle.

OBJECTIVE: To determine whether a polymerase chain reaction (PCR) assay could be used to detect Eperythrozoon wenyoni in the blood of cattle. DESIGN: Prospective study. ANIMALS: 95 cattle from various herds in Alabama and Georgia and 96 bulls enrolled in Auburn University's Alabama Beef Cattle Improvement Association Bull Test program. PROCEDURE: Blood samples were collected by means of venipuncture of the median caudal vein and submitted for a CBC and PCR assay. Blood smears were made immediately after blood collection and examined by means of light microscopy. RESULTS: Three of 95 cattle from herds in Alabama and Georgia and 5 of 96 bulls enrolled in the Bull Test program had positive PCR assay results. Organisms were seen in blood smears from only 5 of these 8 animals. Organisms were not seen in blood smears from any animals for which results of the PCR assay were negative. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a PCR assay may be an effective method for detecting E wenyoni infection in cattle and that the PCR assay may be a more sensitive test than evaluation of blood smears.     

Use of ELISA to detect toxigenic Pasteurella multocida in atrophic rhinitis in swine.

The use of an enzyme-linked immunosorbent assay (ELISA) as a means of detecting dermonecrotoxin-producing strains of Pasteurella multocida was investigated. The assay was evaluated as a means to identify toxigenic P. multocida isolates recovered from nasal secretions of swine with atrophic rhinitis. The sensitivity and specificity of the ELISA for detecting dermonecrotoxin-producing P. multocida strains were compared to those of mouse-inoculation and cytotoxicity assays. The ELISA was highly sensitive and more specific than animal inoculation or tissue culture assay and is thus a more effective method for screening swine herds for the presence of toxigenic strains of P. multocida. The ELISA is a rapid, effective, economical way to identify toxigenic P. multocida isolates.     

Use of a polymerase chain reaction assay to detect bovine leukosis virus in dairy cattle

OBJECTIVE: To evaluate the use of a polymerase chain reaction (PCR) assay in detecting bovine leukosis virus (BLV) in adult dairy cows. DESIGN: Prospective study. ANIMALS: 223 adult dairy cows. PROCEDURE: Cows were tested for BLV status by use of an ELISA and a PCR assay. Sensitivity, specificity, predictive values of positive and negative tests, and the percentage of cows correctly classified by PCR assay were calculated. Ninety-five percent confidence intervals were calculated for sensitivity and specificity. RESULTS: Sensitivity and specificity were 0.672 and 1.00, respectively. Prevalence of BLV in this herd was 0.807. Predictive value of a positive test was 1.00, and predictive value of a negative test was 0.421. The percentage of cows correctly classified by PCR assay was 73.5%. CONCLUSIONS AND CLINICAL RELEVANCE: A positive PCR assay result provided definitive evidence that a cow was infected with BLV. Sensitivity and negative predictive value for PCR assay were low. Consequently, PCR assay alone is unreliable for routine detection of BLV in herds with high prevalence of the disease.     

Use of breath hydrogen testing to detect experimentally induced disaccharide malabsorption in healthy adult dogs.

OBJECTIVE: To develop a noninvasive method to detect disaccharide malabsorption in dogs by measuring hydrogen concentration ([H2]) in exhaled breath before and after experimentally induced disaccharide malabsorption. ANIMALS: 8 healthy mixed-breed dogs. PROCEDURE: [H2] was measured every 30 minutes for 8 hours after administration of disaccharide solutions (lactose, 0.5 g/kg of body weight; lactose, 1.0 g/kg; sucrose, 2.0 g/kg; maltose, 1.5 g/kg; and lactose [0.5 g/kg] and sucrose [2.0 g/kg]) to determine reference ranges of [H2] for each solution, which were compared with [H2] in dogs with experimentally induced disaccharide malabsorption. To induce disaccharide malabsorption, dogs were given a mild overdose of lactose (1.5 g/kg) or a disaccharidase inhibitor. In the latter experiment, acarbose (10 mg/kg, PO) was given with the combination of lactose (0.5 g/kg) and sucrose (2 g/kg), and with maltose (1.5 g/kg). RESULTS: Overdosing with lactose resulted in [H2] persistently outside the reference range for lactose in 5 of 8 dogs. Acarbose administration resulted in [H2] persistently outside the reference range in 7 of 8 dogs that received a combination of sucrose and lactose but did not consistently affect [H2] after administration of maltose. CONCLUSIONS: Disaccharide malabsorption resulted in [H2] outside the reference ranges in most of the adult dogs studied, suggesting that the technique may be useful in detecting naturally occurring disaccharidase deficiency.     

Use of a monoclonal antibody to detect the F41 fimbrial adhesion of enterotoxigenic Escherichia coli

A monoclonal antibody that identifies a specific epitope on the F41 fimbrial adhesin was used in coagglutination and enzyme-linked immunosorbent assay (ELISA) tests, to identify successfully strains of Escherichia coli expressing the F41 adhesin. The antibody also bound to frozen sections of ileum from piglets infected with an F41 positive E coli demonstrating that the epitope is expressed in vivo.     

Use of variograms to detect critical spatial distances for the Knox's test

We aimed to find critical spatial distances (as an input quantity for the Knox's test) using geostatistical methods. The spatiotemporal data set included all individual-chamois cases of scabies observed in Styrian chamois populations in 137 of 2837 game preserves in Styria (a province in the south of Austria) over the time period between 1952 and 1998. Theoretical variogram models were fitted to empirical variograms, which were calculated for cycles of 5 years. The unit of analysis was the mean quadratic deviation between individual-chamois cases of scabies. The "range" (which represents the transition from the state in which spatial correlation exists to the state in which there is absence of spatial correlation) was used as an indicator for the critical spatial distance for the Knox's test. The critical distances for the 5-year cycles varied between 10.8 and 16.0 km. If the time of observation is not considered, the critical "overall" distance amounted to 13.5 km.     

Use of a flow-mediated vasodilation technique to assess endothelial function in dogs

OBJECTIVE: To develop and assess the reproducibility of a protocol to noninvasively test endothelial function in dogs on the basis of the flow-mediated vasodilation (FMD) procedure used in humans. ANIMALS: 5 healthy spayed female dogs. PROCEDURES: Luminal arterial diameter and blood flow velocity in the brachial and femoral arteries were measured with ultrasonography. The within-dog reproducibility of these ultrasonographic measurements was tested. An occlusion period of 1, 3, or 5 minutes with an inflatable cuff was used to create the FMD response. Measurements made at 15, 30, and 60 seconds following release of the occlusion were compared with measurements made immediately prior to each occlusion to assess the FMD response. RESULTS: Within-dog reproducibility of measurements revealed moderate to high correlations. Change from baseline in luminal arterial diameter was most substantial when measured at 30 seconds following release of occlusion, whereas blood flow velocity changes were maximal when measured at 15 seconds following release. The brachial imaging site provided a larger number of significant FMD responses than the femoral site. The 3-minute occlusion period provided equal or better responses than the 5-minute occlusion period. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic measurement of the FMD responses was a feasible and reproducible technique and significant changes from baseline were detected. The FMD responses in dogs were most substantial when performed at the brachial artery with blood flow velocity and luminal arterial diameter changes from baseline measured at 15 and 30 seconds, respectively, following release of a 3-minute occlusion period.     

Use of microsatellite markers to detect quantitative trait loci in Yorkshire pigs

To identify genetic markers associated with economic traits in pigs, 157 microsatellite markers were examined in Yorkshire pigs. Thirty eight female Yorkshire pigs were initially examined and six of them were selected as progenitors; half were more than 1.5 standard deviations (SD) above the mean for average daily gain (ADG) and backfat thickness (BFT), and the remaining half were more than 1.5 SD below the mean. These pigs were then mated to male Duroc pigs, and 200 F2 pig offspring were examined for the association of specific alleles with ADG and BFT. To confirm the specific markers identified in the initial analysis, associations of significant markers with economic traits were further examined in 228 additional performance-tested purebred pigs. Twenty-five microsatellite markers were significantly associated with either ADG or BFT, and among these, 17 were associated with both traits. The markers with the highest association to ADG were also associated with BFT. Our study reveals that specific markers could be used to predict economic significance, and confirms several quantitative trait loci (QTL) identified in previous studies. However, further analysis with more closely-spaced microsatellite markers is required to refine predictive values for economic traits and positions of QTL that are reliable for actual phenotypic prediction.     

Use of multiple antigen substrates to detect antinuclear antibody in canine sera

The presence of antinuclear antibody in serum has been used to serologically support the clinical diagnosis of systemic lupus erythematosus. Most often, diagnostic support is conferred if the titer is above a "cut-off" value determined by the particular laboratory. The precision estimates of these commonly used serological assays are high. The arithmetic and geometric precisions estimates of fluorescent antinuclear antibody (FANA) assays were determined utilizing sera from dogs with polysystemic signalment suggestive of SLE. A simple score assay was found to have improved precision over FANA endpoint titrations on Hep-2 or cryostat, rat liver substrates. In one case, the precision improved from an arithmetic coefficient of variation of 25.6% (HEp-2, endpoint dilution, FANA titers) or 19.7% (rat liver cryostat substrate FANA titers) to 15.5%. Geometric coefficients of variation followed similar trends. Further, the score values for dogs with SLE were considerably higher (mean = 3.28) than for clinically normal dogs (mean = 0.20). The score system was more precise than FANA endpoint titers and therefore may be useful for diagnostic purposes, especially when FANA titers are negative or low.     

Use of ultrasonography to detect pulmonary lesions in Thoroughbred foals in Argentina

Rhodococcus equi is an important cause of pulmonary disease in foals often related to economic losses and death. A study was performed on a Thoroughbred farm (Buenos Aires Province, Argentina) where this disease was enzootic causing 1–2% of foal deaths every year. One hundred foals were monitored by thoracic ultrasonography at ages 1–5 months to detect pulmonary lesions in order to initiate an early treatment. This strategy allowed reducing the number of foal deaths almost totally. In our experience, thoracic ultrasonography was proved to be very efficient in detection of early cases of pneumonia on a farm with high density of horses and intensive management.     

Metastasis of gastric adenocarcinoma to the abdominal wall following placement of a gastrostomy tube in a dog

Stoma site metastasis of gastric adenocarcinoma was documented 37 d after partial gastrectomy with gastrostomy tube placement, and 22 d after tube removal. The tube was placed through grossly normal tissue but histopathologic examination revealed neoplasia at the surgical margins and concurrent lymphatic metastasis. Stoma site metastases may be due to direct tumor seeding or hemolymphatic spread.