Journal of Veterinary Diagnostic Investigation最新文献

Here we describe 2 outbreaks of intoxication by Ricinus communis in cattle in Argentina. In outbreak 1, in 2010, 180 heifers were introduced to a paddock heavily invaded by R. communis. Thirty-two animals developed watery diarrhea, and 6 of them were drooling, and had constant chewing motions, blindness, incoordination, depression, and prostration. Four affected animals died 12-14 h after the onset of clinical signs; another died 4 d later. The surviving 27 animals were removed from the paddock and recovered. At autopsy, several organs were congested and hemorrhagic, and abundant pericarps, leaves, and seeds of R. communis were found in the rumen content. The main microscopic lesion was acute, diffuse, superficial necrotizing gastroenteritis, and intestinal congestion and hemorrhage. In outbreak 2, in 2013, severe neurologic signs were observed in 12 of 300 cows after being introduced into a corn paddock without grain production that had been severely invaded by R. communis. Affected animals were excited and had tremors, drooling, incoordination, and prostration. The herd was immediately transferred to another paddock, and all affected cows recovered without treatment. In outbreak 1, the clinical signs and lesions were characteristic of simultaneous poisoning by R. communis fruits, which contain ricin and cause mainly digestive signs and lesions, and by leaves and pericarps, which contain ricinine and cause nervous signs. In outbreak 2, clinical signs and the recovery of the animals suggest that the intoxication was caused by ricinine, which is present in the leaves of R. communis.

Acute interstitial pneumonia (AIP) has been a recognized bovine respiratory disease for many decades, yet the sporadic occurrences of AIP in feedlot cattle are poorly understood. We searched 3 databases (PubMed, CABI Direct Library, AGRICOLA) for primary literature on North American feedlot cattle, with a focus on interstitial pneumonia. We comprehensively reviewed reports of clinical signs, pathology findings, etiologies, risk factors, and treatments associated with AIP in feedlot cattle and identified gaps in knowledge. We included 19 peer-reviewed studies from 1976 to 2023. In 6 articles, the most common clinical signs for diagnosing AIP were severe dyspnea, increased expiratory effort, and grunting while breathing. In the 17 articles that provided detailed descriptions of the pathology and diagnostic features of AIP, consistent postmortem examination findings were interlobular edema and emphysema, a checkerboard appearance, and diffusely overinflated lung lobes. The most frequent histopathology findings were hyaline membranes, type II pneumocyte hyperplasia, and obliterative bronchiolitis. Although some potential etiologies, such as bovine respiratory syncytial virus (BRSV) and 3-methylindole (3MI), have been evaluated, no definitive cause has been identified consistently. Risk factors significantly associated with AIP in multiple studies included heifers, clinical onset at >45 days on feed (DOF), death at >78 DOF, and summer; the exact mechanisms remain unclear. The absence of standardized diagnostic criteria, along with a lack of research into potential effective prevention or treatment, underscore the need for further study to clarify the causes, diagnosis, and treatment of AIP in feedlot cattle.

In March and April 2024, an unusual morbidity event (UME) in the Texas Panhandle and eastern New Mexico was reported to the Texas A&M Veterinary Medical Diagnostic Laboratory. In total, 73 of 158 (46.2%) grade A dairy farms reported decreased milk production, reduced feed intake, and/or abnormal milk consistency. To identify potential etiologies, 22 affected operations submitted samples from 250 clinically affected cows and 9 operations submitted samples from 69 unaffected cows. Initial diagnostic efforts found no consistent causative factors between operations. Nine peridomestic birds and 10 domestic cats from affected premises tested positive for the highly pathogenic avian influenza virus (HPAIV) H5N1 subtype. On March 25, 2024, the United States Department of Agriculture confirmed HPAIV in unpasteurized milk from dairy cows in the region. Feces, serum, and whole blood from affected cows tested negative for H5N1 HPAIV. Milk from affected cows had 6.0 (95% CI [3.4, 10.8]) odds of being positive compared with unaffected cows. Our initial investigation ruled out many common pathogens allowing for the exploration of novel etiologies and facilitated testing of samples from affected premises through the National Animal Health Laboratory Network. When investigating an UME, clinical signs and histories from affected individuals should dictate sample and test selection; however, it is imperative that samples from unaffected individuals be submitted for comparison when determining a potential etiology.

Perianesthetic death (PAD) is an uncommon yet devastating outcome in veterinary medicine, with incidence rates consistently higher than those reported in human anesthesia. In our scoping review, we summarize the current literature on PAD in dogs and cats and discuss definitions, risk factors, species-specific challenges, and the role of postmortem examinations. Although advances in veterinary anesthesia have occurred, inconsistencies in PAD definitions and follow-up periods have limited the ability to compare PAD incidence over time. Risk factors consistently associated with PAD include high American Society of Anesthesiologists physical status classification, age and weight extremes, species-specific traits, and procedural urgency. PAD risk is consistently higher in cats than dogs. Most studies rely on identifying clinical risk factors, with limited use of postmortem examination. When autopsies are used, they can reveal undiagnosed lesions that may have contributed to the animal's death. However, many PAD autopsy cases yield no identifiable lesions, complicating determination of cause of death. Additionally, the lack of standardized submission forms and autopsy protocols further hampers consistency in case evaluation. We highlight the need for a multidisciplinary, standardized approach to the investigation of PAD cases. Future prospective studies should incorporate structured autopsy protocols and anesthesiologist reviews to improve diagnostic yield, with the goal of improving patient safety in veterinary anesthesia.

A wild, male American crow (Corvus brachyrhynchos) nestling found dead in a pond in San Diego, CA, USA, was submitted for postmortem examination. Autopsy revealed that the chick was markedly underweight for the presumed age with no grossly appreciable fat stores. The primary histologic finding was lymphocytic vasculitis throughout the cerebrum and optic tectum, with lymphohistiocytic meningoencephalitis. The areas of inflammation were consistently associated with myriad, argyrophilic, curved bacilli with a characteristic "seagull" morphology. Additional significant findings included severe unilateral heterophilic and lymphohistiocytic pectoral myositis, with similar intralesional bacilli, and evidence of sepsis based on pancarditis, multifocal random hepatitis, and bilateral orchitis. Using conventional PCR and third-generation sequencing, the bacteria in the brain were identified as most closely related to Campylobacter molothri, a recently described species of Campylobacter. Our finding of a novel pathogen inducing encephalitis and sepsis in a wild bird highlights the utility of advanced molecular techniques in diagnostic pathology.

Investigations of wildlife diseases and mortality events can sometimes lead to inconclusive results because of limitations in testing combined with an ever-increasing number of emerging viruses. The use of tools such as unbiased metagenomic next-generation sequencing (mNGS) can facilitate the identification of causative agents when conventional investigation methods fail. We performed a retrospective mNGS analysis on RNA isolated from postmortem samples collected during a mortality event in free-ranging, wild black vultures (Coragyps atratus) that occurred in eastern Pennsylvania and western New Jersey in 2020. We describe the discovery and identification of a novel species of bandavirus (family Phenuiviridae) in case specimens from this die-off, as well as some of the associated pathology findings. The Bandavirus genus comprises tickborne viral species that have been reported across 5 continents. These viruses have been implicated in outbreaks in a variety of mammalian hosts, including humans, and in avian species, making them important potential sources of zoonotic spillover events. Genomic and phylogenetic analyses of the bandavirus that we detected indicate that its closest relative is Hunter Island virus, a bandavirus previously implicated in albatross mortality events off the coast of Tasmania, Australia. Follow-up PCR testing of samples from 16 additional vultures from the same cohort indicate that this new bandavirus was the likely cause of death.

Altered carcasses present a diagnostic challenge to veterinary pathologists. Autolysis and putrefaction may render organs unrecognizable, and scavenging by vertebrates and insects may remove organs entirely. Sampling for viral or bacterial testing is greatly hindered and determination of an infectious cause of death is nearly impossible. An outbreak of highly pathogenic avian influenza (HPAI) in California condors in the spring of 2023 offered an opportunity to explore the utility of blow fly larvae (maggots) as an alternative test sample. An 18-y-old male condor that died during the outbreak could not be accessed and sent for necropsy for ~16 d. At the time of retrieval, numerous third-instar fly larvae were associated with the body. HPAI A(H5N1) virus was detected in the spleen of the condor, with a Ct value of 15.7. A group of fly larvae collected from the bird at postmortem examination and stored frozen was also HPAI A(H5N1) virus-positive, with a Ct of 32. Blow fly larvae may be an acceptable alternative sample if ideal tissues are not available. Caution should be exercised in interpreting negative values, however, because the virus may be transient in larvae and other fly life stages.

Highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b virus was identified in 4 cull dairy cows condemned by the U.S. Department of Agriculture because of pneumonia with accompanying systemic changes. Histologic findings were bronchopneumonia in 3 cows and embolic pneumonia and nephritis in 1 cow. In addition to detection of HPAI A(H5N1) virus by reverse-transcription real-time PCR in various formalin-fixed, paraffin-embedded tissues, influenza A virus was detected by immunohistochemistry and in situ hybridization in the pulmonary respiratory epithelium of 2 of the cows with bronchopneumonia and in renal medullary tubules of the cow with nephritis. A PCR panel screening for common bovine respiratory pathogens in the cows with bronchopneumonia revealed variable coinfections with Histophilus somni, Pasteurella multocida, Mannheimia haemolytica, Mycoplasmopsis bovis, and bovine coronavirus. We describe the distribution of HPAI A(H5N1) virus in naturally infected cows while highlighting the need for research on the roles of coinfection and immune response in influenza viral replication.

We describe a 3-y-old Standard Poodle that was fed a raw elk-meat diet and developed anorexia, icterus, and markedly elevated liver enzyme activities. Histopathology of the pancreatic and liver biopsy specimens revealed lymphohistiocytic pancreatitis and hepatitis with intraepithelial protozoa. Histologically, Hammondia spp. are indistinguishable from Neospora caninum. Therefore, we employed PCR and amplicon sequencing to further investigate our case. Amplification and sequencing of the ITS1 marker matched 100% with Hammondia heydorni. Intrapancreatic involvement and the histopathologic features of hepatic and pancreatic H. heydorni infection have not been reported previously in dogs, to our knowledge. H. heydorni is a coccidian organism with an obligatory 2-host life cycle. The definitive hosts are dogs and coyotes; the intermediate hosts are mostly ruminants, including cervids. Ingesting tissue cysts within the skeletal muscle of the intermediate hosts leads to infection in the definitive hosts. H. heydorni has been considered clinically inconsequential; however, increasing reports note gastrointestinal and hepatic disease in dogs associated with this organism, and H. heydorni is considered an emerging pathogen in dogs. Infection in our case was associated with ingestion of raw cervid meat; cases of H. heydorni infection are invariably linked to ingestion of raw-meat diets.

An accessory tragus-a congenital malformation of part of the external ear-is an abnormal appendage developed from the first pharyngeal (or branchial) arch. In humans, an accessory tragus can be associated with other abnormalities as part of congenital malformative syndromes, most of which are transmitted in an autosomal dominant mode. Three cutaneous exophytic lesions were detected in the right preauricular region of a 2.5-y-old, castrated-male, European shorthair cat. Two of these lesions were submitted for histologic examination and were diagnosed as accessory tragi. They consisted of a vertical axis of loose collagenous tissue with hair follicles and sebaceous glands covered by a simple fold of epidermis. The epidermis was of normal thickness and slightly hyperpigmented. Only the pretragal lesion contained a central core of well-differentiated elastic cartilage. To our knowledge, accessory tragus has not been reported previously in cats and has been reported only once in veterinary medicine, in a dog with a solitary unilateral lesion. For pathologists, the diagnosis of this rare lesion may not be straightforward, especially if the cartilaginous core is absent or the location of the sample is unknown.