Journal of Veterinary Diagnostic Investigation最新文献

Two methods of measuring triacylglycerol (TG) in the blood are used in clinical laboratories. The glycerol-blanked TG analysis method is used primarily in Japan; the total glyceride measurement method is used in most countries, including the United States. The latter method includes free glycerol in the blood, which is known to be slightly higher in humans. However, the extent to which the 2 methods differ in companion animals is unknown. We used cryopreserved blood from dogs and cats that visited a secondary veterinary hospital to investigate the relationship between the data obtained using the 2 TG analysis methods. The median ratio (5th and 95th percentiles) of total glyceride measurement:glycerol-blanked TG measurement ratios was 1.24 (1.08 and 1.77) for dogs and 2.00 (1.44 and 3.66) for cats, with the total glycerol method clearly having higher values. The Passing-Bablok regression equation comparing the total glyceride method (y) and glycerol-blanked method (x) was y = 1.049x + 0.119 for dogs and y = 1.476x + 0.177 for cats. The estimated free glycerol value calculated from the difference between the 2 TG measurements was strongly correlated with the measured free glycerol value (dog, r = 0.7905; cat, r = 0.8708), indicating that free glycerol in the blood was the cause of the TG measurement discrepancy. Therefore, the TG concentrations obtained from total glyceride assays in dogs and cats may contain non-negligible levels of free glycerol.

The 1890s marked a significant milestone with the introduction of antibody-based agglutination and precipitation assays, revolutionizing the detection of bacterial pathogens in both animals and humans. This era also witnessed pivotal contributions to our understanding of humoral immunity, as researchers elucidated the structure and functions of antibody molecules, laying the groundwork for diagnostic applications. Among antibody isotypes, IgG is of paramount importance in diagnostic investigations given its definitive indication of infection or vaccination, coupled with its widespread presence and detectability across various specimen types, such as serum, colostrum, milk, oral fluids, urine, feces, and tissue exudate. Despite their resilience, immunoglobulins are susceptible to structural alterations induced by physicochemical and enzymatic processes, which can compromise the reliability of their detection. Here we review comprehensively the historical milestones, underlying mechanisms, and influencing factors (e.g., temperature, pH, storage) that shape the structural integrity and stability of IgG antibodies in aqueous solutions and various clinical specimens.

The ingestion of cotyledons or seeds of cocklebur (Xanthium strumarium) causes poisoning as a result of acute liver failure. Here we describe a spontaneous outbreak of X. strumarium toxicity in dairy cows in Uruguay. The outbreak occurred in the winter when the cows were fed sorghum silage contaminated with X. strumarium seeds. Clinical signs of depression, anorexia, paddling, opisthotonos, muscle tremors, sternal recumbency, and death were observed 2-12 h following ingestion. Of 160 Holstein cows, 30 (19%) animals were ill, and 6 (4%) died. At autopsy, the liver had a diffuse mottled appearance with intercalated red and yellow areas. Histologically, centrilobular hemorrhagic coagulative necrosis was found. The diagnosis of this natural outbreak of intoxication was based on the clinical signs observed, finding the fruits of X. strumarium in the silage, and the characteristic macroscopic and histologic lesions.

Viscoelastic testing methods, including thromboelastography (TEG) and rotational thromboelastometry, have an advantage over traditional tests of coagulation due to their ability to reflect in vivo hemostasis and predict need for transfusion of blood products more accurately. TEG in clinical settings is most often performed on citrated whole blood samples that are recalcified at the time of analysis, with or without the addition of an activator of coagulation. To date, superiority of the use of an activator in canine patients with abnormal hemostasis has not been demonstrated. We compared the use of tissue factor-activated (TF) TEG with citrated native (CN) TEG in dogs with suspected hemostatic abnormalities. Forty-five of 79 enrolled dogs with suspected abnormal hemostasis had an abnormal MA value. There was very high correlation between CN samples and TF-activated samples for alpha, K, MA, and R; there was a high correlation for LY30 and LY60. Categorical agreement for CN- and TF-activated TEG classification of hypercoagulable and hypocoagulable cases based on MA was good to very good, with 91% and 97% categorical agreement, respectively. No difference was found in the variance for any TEG variable between the 2 methods of analysis. For canine patients with suspected abnormal hemostasis, use of CN or TF-activated TEG appears acceptable. Monitoring of coagulation should be done with the same method; methods may not be used interchangeably.

In 2018, a new virus, named equine parvovirus-hepatitis (EqPV-H), was discovered in a biologic product that had been administered to horses that subsequently developed clinical signs of equine serum hepatitis (Theiler disease). Further correlation of the virus with the disease sparked federal requirements that all equine biologics be free of EqPV-H. The initial quantitative real-time PCR (qPCR) test for EqPV-H has proved to be sensitive to co-extracted PCR inhibitors in template nucleic acids, causing false-negative results. We investigated the use of digital PCR (dPCR) as a more robust test. Examination of 227 equine biologic product lots available for purchase both before and after regulatory implementation using both detection methods indicated that dPCR is a more reliable platform. Nevertheless, use of the qPCR method for product screening had reduced the fraction of serials with EqPV-H detected from 39.6% prior to regulation to 6.8% after regulatory implementation. Adoption of dPCR testing is an opportunity to further decrease the prevalence of EqPV-H in equine biologics.

We describe here a case of the sinus roundworm, Skrjabingylus chitwoodorum, found incidentally in a rabies-positive striped skunk (Mephitis mephitis) in Texas, USA. Skunks serve as a natural definitive host for this metastrongylid nematode in North America, in which infections result in observable damage to the host cranium, where adult parasites reside. Additionally, skunks are considered the primary reservoir of rabies in Texas. In November 2022, the animal was discovered in northern Texas displaying neurologic signs before euthanasia and submission to the Oklahoma Animal Disease Diagnostic Laboratory for rabies testing. Direct fluorescent antibody testing indicated that the animal was rabies-positive, and, upon tissue collection, numerous adult nematodes were recovered from the cranium and identified as S. chitwoodorum by morphology and amplification of the mitochondrial cytochrome c oxidase subunit I gene. Histologically, we found lymphohistiocytic meningitis in several loci and chronic sinusitis rostral to the cribriform plate. Due to behavioral abnormalities, we additionally tested for Toxoplasma gondii via PCR, but no parasite DNA was detected. Concurrent infection by S. chitwoodorum and rabies virus may contribute to neurologic signs in skunks.

We estimated the Leptospira seroprevalence in dogs, cats, and horses from Tennessee, USA, using the microscopic agglutination test (MAT) against 12 Leptospira serovars. We observed Leptospira seropositivity in 110 of 374 (29.4%) dogs, 21 of 170 (12.4%) cats, and 42 of 88 (47.7%) horses. The highest seroprevalence was observed for serovars Autumnalis (74.6%) in dogs, and Bratislava in cats (42.9%) and horses (95.2%). We found a significant level of potential cross-reactivity between multiple Leptospira serovars tested, with highest cross-reactivity to serovar Autumnalis in dogs. Leptospira seroprevalence was significantly higher in vaccinated dogs (45 of 98 [46%]) compared to unvaccinated dogs (14 of 86 [16%]; p < 0.001). A significant difference in seroprevalence was observed in vaccinated and unvaccinated dogs to all 4 serovars included in canine leptospiral vaccines (p < 0.001). We also evaluated the Leptospira testing results from our diagnostic laboratory submissions from 2021-2023; 103 of 252 (40%) canine serum samples were positive, with the highest positivity rate for serovar Autumnalis. On Leptospira real-time PCR, 35 of 325 (10.7%) urine samples and 15 of 257 (5.8%) blood samples were positive. The cross-reactivity between the Leptospira serovars used in the MAT and vaccination status should be considered when estimating seroprevalence.

Giardia duodenalis is a common parasite of the gastrointestinal tract of dogs, with an especially high prevalence in dogs <1-y-old. Methods for detecting G. duodenalis are point-of-care (POC) tests such as lateral-flow tests or fecal flotation. The Vetscan Imagyst (Zoetis) is a new POC device for the detection of G. duodenalis in fecal samples using zinc sulfate flotation, automated slide scanning, and image recognition with artificial intelligence. Vetscan results are the number of Giardia cysts per coverslip. We compared the performance of the Vetscan and another POC test (SNAP Giardia test; Idexx) with a direct immunofluorescence assay (IFA) performed in a specialized parasitology laboratory as the reference test. We included 164 dogs <19-mo-old. We used pooled fecal samples from 3 defecations gained within 2-3 d and tested the repeatability of the Vetscan by triplicate measurement. Compared to IFA, Vetscan had a diagnostic sensitivity of 88.4% and specificity of 98.1%; SNAP had a diagnostic sensitivity of 74.4% and specificity of 98.1%. A variation coefficient of 67.0% was determined for the Vetscan results. The performance of the Vetscan is acceptable for the qualitative evaluation of fecal samples (Giardia positive or negative), and the device can be used by untrained personnel. Given its high variation coefficient, we do not recommend the Vetscan for monitoring the number of cysts.