ORCID Profile
0000-0003-0681-1878
Current Organisation
University of California Davis
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Publisher: SAGE Publications
Date: 13-03-2023
DOI: 10.1177/10406387231161508
Abstract: Clostridial infections in goats have been associated frequently with enteric diseases or gas gangrene but very rarely with the reproductive system. We describe here 12 cases of fatal postpartum gangrenous metritis in does associated with infection by several clostridial species. Clinically, these cases were characterized by rapid onset of hyperthermia followed by death after kidding. On postmortem examination, the uteri appeared to be necrotic and were hemorrhagic and edematous. Microscopically, the uteri had diffuse coagulative necrosis, edema, hemorrhage, and fibrinous thrombi with intralesional gram-positive rods. Clostridium perfringens was isolated from 7 of 9 uterine s les cultured, and C. perfringens, C. septicum, C. novyi, or C. chauvoei were demonstrated by immunohistochemistry (IHC) in the 5 cases examined. IHC for Paeniclostridium sordellii was negative in all 5 cases. PCR performed on 3 of the C. perfringens isolates was positive for alpha toxin and perfringolysin, identifying these isolates as type A. Clostridial infection should be considered in cases of postpartum gangrenous metritis of does.
Publisher: SAGE Publications
Date: 02-06-2021
DOI: 10.1177/10406387211021480
Abstract: Squamous cell carcinoma (SCC), which is a neoplasm that usually arises from the integument, is reported uncommonly in pet birds. Only a few reports of SCCs in the alimentary tract of birds, including psittacines, have been published, and a detailed description of the pathology is not available in the literature. We present here 12 cases of alimentary SCC in psittacines. The average age of the birds was 22.2 y (range: 15–29 y), and affected species included 4 Amazon parrots ( Amazona sp.), 3 cockatiels ( Nymphicus hollandicus), 3 macaws ( Ara sp.), 1 conure ( Eupsittula sp.), and 1 Senegal parrot ( Poicephalus sp.). Frequent clinical complaints included regurgitation, dysphagia, dyspnea, lethargy, and/or weight loss. SCC primarily affected the oral cavity in 6 of 12 cases, the crop alone in 2 of 12 cases, the crop and esophagus in 1 of 12 cases, the proventriculus alone in 1 of 12 cases, and the crop, esophagus, and proventriculus in 2 of 12 cases. Histologically, alimentary SCCs were locally invasive and often resulted in mucosal ulceration. Although there were no metastases in any of our cases, poor clinical outcomes were frequent and associated most commonly with complete effacement of the alimentary segment and severe inflammation with opportunistic bacterial infection. Our review of the literature records commonly affected species, variability of gross presentations and clinical signs, plausible etiologies, and current diagnostic developments.
Publisher: SAGE Publications
Date: 15-10-2020
Abstract: Enterotoxemia caused by Clostridium perfringens type D is one of the most prevalent clostridial diseases of sheep. The lesions of the acute form of this disease, particularly the cerebral lesions, are well characterized however, detailed descriptions of the cardiac and pulmonary lesions are lacking. Here we describe cardiopulmonary lesions in experimental acute type D enterotoxemia in sheep and determine the role of epsilon toxin (ETX) in the development of these lesions. Four groups of 6 sheep were intraduodenally inoculated with either a wild-type C. perfringens type D strain its etx knockout mutant, which is unable to produce ETX the etx mutant complemented with the wild-type etx gene, which regains the ETX toxigenic ability or sterile culture medium as a control. All sheep were subjected to postmortem examination within 24 hours of inoculation. Lesion scores were compared between groups for pulmonary edema hydrothorax ascites hydropericardium endocardial, myocardial and epicardial hemorrhages microscopic lesions of acute myocardial degeneration and necrosis and myocardial, endocardial, and epicardial edema, hemorrhage, and inflammation. Only sheep inoculated with the wild-type and complemented ETX-toxigenic bacterial strains developed cardiopulmonary lesions, which were present in varying degrees of severity and proportions. These lesions were not present in sheep inoculated with the etx mutant or in the negative control. We conclude that severe acute cardiopulmonary lesions in sheep with experimental enterotoxemia are associated with the capacity of the strains to produce ETX. These changes are likely contributors to the clinical signs and even death of affected animals.
Publisher: SAGE Publications
Date: 25-08-2021
DOI: 10.1177/10406387211041098
Abstract: An outbreak of acute encephalopathy occurred in pregnant ewes and their newborn lambs associated with consumption of Talisia esculenta fruits and bark. Clinical signs in 5 adult pregnant ewes included drooling, bloat, tachypnea, depression, ataxia, body shaking, difficulty in rising, and recumbency. Three neonatal lambs born to some of those ewes had similar clinical signs. No significant gross abnormalities were observed on autopsy. Histologically, neuronal necrosis, axonal and dendritic swelling, and loss of Purkinje neurons were observed in the cerebellum. The observation of similar neurologic clinical signs and lesions in pregnant ewes and their neonatal lambs suggests that the toxic principle of T. esculenta crosses the placenta and reaches the fetus.
Publisher: SAGE Publications
Date: 28-08-2021
DOI: 10.1177/10406387211041091
Abstract: To determine if there were significant differences produced by 5 of the most prevalent causes of equine enterocolitis, we studied retrospectively the gross and microscopic pathology of 90 cases of enterocolitis submitted to the San Bernardino laboratory of the California Animal Health and Food Safety Laboratory. Included were cases caused by Clostridium perfringens type C (CP n = 20), Clostridioides difficile (CD n = 20), Paeniclostridium sordellii (PS n = 15), Salmonella enterica subspecies enterica serovar Typhimurium (ST n = 20), and NSAID intoxication (NS n = 15). Grossly, necrotizing hemorrhagic typhlocolitis was seen most frequently in cases of CD, ST, and NS disease. Cases of CP and PS had enteritis or colitis in similar percentages. Congestion, hemorrhage, and pleocellular inflammatory infiltrates followed by mucosal and submucosal necrosis were the main lesions found in horses with enteritis or colitis produced by any of the etiologic agents investigated. Severe lesions were more frequent in cases of CD and CP than in cases associated with any of the other 3 etiologies. Pseudomembranes were observed with similar prevalence in the small intestine and colon affected by all agents studied. Thrombosis of the lamina propria and/or submucosa was observed in ~50% of the cases of enteritis and colitis by all etiologies, except for PS, in which the majority of the cases had thrombosis. Gross and microscopic lesions of enterocolitis were not sufficiently specific for any of these etiologic agents to enable these enteritides to be distinguished by gross and/or histologic examination.
Publisher: SAGE Publications
Date: 17-12-2021
DOI: 10.1177/10406387211050049
Abstract: Bisphosphonates are potent anti-resorptive agents that have the potential to adversely affect bone healing in equine athletes, and normal bone adaption in young racehorses. A concern exists that bisphosphonate inhibition of normal bone metabolism could lead to increased bone fractures during high-intensity exercise. We found only a single report describing concentrations of tiludronate in the bone of horses, and no studies describing clodronate. Knowledge of the residence time in bone could allow for a better understanding of the long-term effects of these compounds. Our objectives were to develop a method for detection of bisphosphonates in bone and add to the limited information available regarding the disposition of these drugs in the bone of horses. Two horses received clodronate and 2 tiludronate disodium. Postmortem collection of bones and teeth occurred either 4 or 30 d post drug administration. Additionally, postmortem blood, synovial fluid, aqueous humor, and bone s les from racehorses with various histories of bisphosphonate administration were collected, and concentrations determined using the developed LC-MS/MS method. Bisphosphonates were detected in bones and teeth tested at 4 and 30 d. In a postmortem s le, clodronate was detected in bone from a horse with reported administration 18 mo prior clodronate was not detected in other s le types collected from this horse. Bisphosphonates reside in bone for extended periods of time, which could lead to potential long-term effects, increasing the potential for bone fractures in young and/or athletic horses.
Publisher: SAGE Publications
Date: 12-05-2023
DOI: 10.1177/03009858231171669
Abstract: Type D enterotoxemia, caused by Clostridium perfringens epsilon toxin (ETX), is one of the most economically important clostridial diseases of sheep. Acute type D enterotoxemia is characterized by well-documented lesions in the nervous, cardiocirculatory, and pulmonary systems. However, discrepancies and confusion exist as to whether renal lesions are part of the spectrum of lesions of this condition, which is controversial considering that for many decades it has been colloquially referred to as “pulpy kidney disease.” Here, the authors assess renal changes in an experimental model of acute type D enterotoxemia in sheep and evaluate the possible role of ETX in their genesis. Four groups of 6 sheep each were intraduodenally inoculated with either a wild-type virulent C. perfringens type D strain, an etx knockout mutant unable to produce ETX, the etx mutant strain complemented with the wild-type etx gene that regains the ETX toxin production, or sterile culture medium (control group). All sheep were autopsied less than 24 hours after inoculation none of them developed gross lesions in the kidneys. Ten predefined histologic renal changes were scored in each sheep. The proportion of sheep with microscopic changes and their severity scores did not differ significantly between groups. Mild intratubular medullary hemorrhage was observed in only 2 of the 12 sheep inoculated with the wild-type or etx-complemented bacterial strains, but not in the 12 sheep of the other 2 groups. The authors conclude that no specific gross or histologic renal lesions are observed in sheep with experimental acute type D enterotoxemia.
Publisher: Wiley
Date: 23-07-2021
DOI: 10.1111/EVJ.13291
Abstract: Proximal sesamoid bone (PSB) fracture is the most common fatal injury in Thoroughbred (TB) racehorses in the United States. Epidemiological and pathological evidence indicates PSB fracture is likely the acute culmination of a chronic stress-related process. However, the aetiopathogenesis of PSB fracture is poorly understood. To characterise bone abnormalities that precede PSB fracture. Two retrospective case-control groups of PSBs from TB racehorses with, and without, unilateral biaxial PSB fracture. Proximal sesamoid bones were harvested post-mortem from TB racehorses subjected to euthanasia for unilateral biaxial PSB fracture (cases) or causes unrelated to PSB fracture (controls) while racing or training. The fractured medial PSB (FX-PSB) and contralateral intact medial PSB (CLI-PSB) from racehorses that sustained PSB fracture, and an intact medial PSB (CTRL-PSB) from racehorses that did not have a PSB fracture were collected as case and control specimens. Study 1 distributions of morphological features were compared among case and control groups using visual examination, photographs, radiographs and histology of whole PSBs and serial sagittal sections (10 FX-PSB, 10 CLI-PSB and 10 CTRL-PSB). Study 2 local bone volume fraction and mineral densities were compared among case and control PSBs using microcomputed tomography (9 FX-PSB, 9 CLI-PSB and 9 CTRL-PSB). A focal subchondral lesion characterised by colocalised focal discoloration, radiolucency, osteopenia, low tissue mineral density and a surrounding region of dense cancellous bone was identified in most case horses but not in controls. This subchondral lesion was found in a slightly abaxial mid-body location and was bilaterally present in most case horses. The post-mortem s les may not represent the spectrum of abnormalities that occur throughout the development of the subchondral lesion. Lateral PSBs were not examined, so their contribution to biaxial PSB fracture pathogenesis is unknown. Abaxial subchondral lesions are consistent with pre-existing injury and likely associated with PSB fracture.
Publisher: American Society for Microbiology
Date: 24-06-2020
Abstract: Clostridium perfringens type A strains produce toxins that are responsible for clostridial myonecrosis, also known as gas gangrene. Toxin production is regulated by an Agr-like quorum-sensing (QS) system that responds to changes in cell population density. In this study, we investigated the importance of this QS system in a mouse model of gas gangrene. Mice challenged with a C. perfringens strain with a nonfunctional regulatory system developed less severe changes in the injected skeletal muscle compared to animals receiving the wild-type strain. In addition, a synthetic peptide was able to decrease the effects of the QS in this disease model. These studies provide new understanding of the pathogenesis of gas gangrene and identified a potential therapeutic target to prevent the disease.
Publisher: MDPI AG
Date: 14-08-2021
DOI: 10.3390/V13081612
Abstract: Six foals with interstitial pneumonia of undetermined etiology from Southern California were analyzed by viral metagenomics. Spleen, lung, and colon content s les obtained during necropsy from each animal were pooled, and nucleic acids from virus-like particles enriched for deep sequencing. The recently described equine copiparvovirus named eqcopivirus, as well as three previously uncharacterized viruses, were identified. The complete ORFs genomes of two closely related protoparvoviruses, and of a bocaparvovirus, plus the partial genome of a picornavirus were assembled. The parvoviruses were classified as members of new ungulate protoparvovirus and bocaparvovirus species in the Parvoviridae family. The picornavirus was classified as a new species in the Salivirus genus of the Picornaviridae family. Spleen, lung, and colon content s les from each foal were then tested for these viral genomes by nested PCR and RT-PCR. When present, parvoviruses were detected in both feces and spleen. The picornavirus, protoparvovirus, and eqcopivirus genomes were detected in the lungs of one animal each. Three foals were co-infected with the picornavirus and either a protoparvovirus, bocaparvovirus, or eqcopivirus. Two other foals were infected with a protoparvovirus only. No viral infection was detected in one animal. The complete ORFs of the first equine protoparvoviruses and bocaparvovirus, the partial ORF of the third equine picornavirus, and their detection in tissues of foals with interstitial pneumonia are described here. Testing the involvement of these viruses in fatal interstitial pneumonia or other equine diseases will require larger epidemiological and/or inoculation studies.
Publisher: SAGE Publications
Date: 24-10-2019
Abstract: We investigated deaths in a group of feedlot steers in Argentina. The main findings in 3 steers autopsied were pulmonary congestion and edema, necrotizing myocarditis, pericarditis, suppurative leptomeningitis, and bronchopneumonia. Histophilus somni was detected by bacterial culture and immunohistochemistry in the hearts of the 3 animals. Partial sequences of the 16S rRNA gene of a H. somni isolate had 99% similarity with other H. somni sequences in GenBank. Most reports of H. somni septicemia in cattle originate from North America and western Europe. There is scant information about cardiac histophilosis in South America. A survey of diagnostic laboratory personnel in 7 South American countries documented various forms of bovine histophilosis in Argentina, Brazil, Uruguay, and Venezuela.
Publisher: Wiley
Date: 21-01-2019
DOI: 10.1002/VMS3.145
Publisher: Wiley
Date: 27-11-2021
DOI: 10.1111/EVJ.13375
Abstract: Tibial fractures cause ~3% of racehorse deaths. Pre-existing stress fractures have been associated with multiple racing and training fractures, but not complete tibial fractures. To describe racehorse tibial fractures and compare signalment and exercise histories of affected and control racehorses. Retrospective analysis of necropsy reports. Racehorses that had a complete tibial fracture (1990-2018) were retrospectively reviewed. Signalment and exercise histories of affected horses were compared to 1) racehorses that died because of non-tibial musculoskeletal injuries or 2) non-musculoskeletal cause and 3) age, sex, event-matched control racehorses. Tibial fracture prevalence was described relative to California racehorses that had at least one official work or race. Age, sex and limb distributions were compared between affected and control horses (Chi-square, Fisher's Exact test). Exercise history data were reduced to counts and rates of official high speed works, races and layups (periods without an official high speed work or race >60 days). Variables were compared among groups using matched logistic regression (P ≤ .05). Tibial fractures in 115 horses (97% unilateral 50% left, 47% right) occurred most commonly during training (68%) and in 2- to 3-year-old horses (73%). Fractures were predominantly comminuted (93%), diaphyseal (44%) and oblique (40%). Of 61 cases examined for callus, 64% had periosteal callus associated with fracture, most commonly in proximal (65%) and distal diaphyseal (27%) locations. Of 28 racehorses with known exercise history, 57% never raced and 36% had a layup. Affected horses had fewer official-timed works and events (official high speed works and races), number of active days and accumulated less distance in events and works (P < .05) than control horses. Retrospective review of necropsy reports by multiple pathologists over 28 years. Tibial fractures were associated with pre-existing stress fracture early in career. Most fractures were associated with proximolateral stress fractures.
Publisher: SAGE Publications
Date: 11-09-2021
DOI: 10.1177/10406387211044555
Abstract: Rattlesnake envenomation is an important cause of morbidity and mortality in humans and animals in the southwestern United States and elsewhere. Two Visayan warty pigs ( Sus cebifrons) from a regional zoo were submitted for autopsy after being found dead close to a southern Pacific rattlesnake ( Crotalus helleri) in their enclosure. Both pigs had severe regionally extensive cutaneous, subcutaneous, and muscle hemorrhage and edema with myonecrosis. Additionally, both pigs had lesions consistent with puncture wounds within the oral cavity, and one pig had a similar wound on a forelimb. The history, and gross and histologic findings, were consistent with envenomation by rattlesnake bite. There are few documented cases of snakebite envenomation in pigs, and it had been suggested that pigs may have some degree of resistance to envenomation. Our results indicate that warty pigs are susceptible to the action of rattlesnake venom.
Publisher: MDPI AG
Date: 20-06-2022
DOI: 10.3390/ANI12121590
Abstract: Yellow lamb disease is an infrequent disease in sheep for which there is scant literature, and that has been reported in the US, Australia, New Zealand, South Africa and Europe, although anecdotal evidence indicates that it may have also been diagnosed in South America. The disease is produced by some strains of Clostridium perfringens type A that produce unusually high levels of alpha- toxin. Because C. perfringens type A is ubiquitous and is found in the intestine of most clinically healthy sheep, diagnosis of yellow lamb disease is challenging and requires quantitating the amount of this microorganism present in feces and/or intestinal content. Clinically, yellow lamb disease is characterized by depression, anemia, icterus and hemoglobinuria. Occasionally, sudden death may occur. Gross findings include generalized icterus, red urine in the bladder, enlarged, pale, and friable spleen, enlarged liver with an acinar pattern, and dark, swollen kidneys. Microscopically, yellow lamb disease is characterized by centrilobular necrosis of the liver, hemoglobinuria-associated acute tubular injury, splenic congestion, pulmonary congestion and edema. Although there are no vaccines specifically designed to prevent yellow lamb disease, several vaccines against the different types of C. perfringens may afford at least some level of protection against yellow lamb disease.
Publisher: SAGE Publications
Date: 06-05-2022
DOI: 10.1177/10406387221094272
Abstract: Several plants that contain indolizidine alkaloids, including swainsonine, are toxic to livestock, causing dysfunctional lysosomes and storage disease. Swainsonine induces a neurovisceral disease, known as locoism, in sheep, goats, and cattle, which occurs in several parts of the world, including, but not limited to, the western United States, China, and parts of Australia. In South America, locoism has been described in the Andean region of Argentina affecting sheep, cattle, and llamas. Intoxication by consumption of Astragalus punae was suspected in 4 llamas in Jujuy Province, northwestern Argentina. The grazing area contained abundant specimens of A. punae. The clinical course was ~15 d, and included moderate ataxia, incoordination of hindlimbs, and progressive loss of body condition. Microscopically, fine cytoplasmic microvacuolation was observed in the proximal convoluted renal tubules. Ultrastructurally, these changes consisted of severely dilated lysosomes. Swainsonine was detected in stem and leaf s les of A. punae at a concentration of 0.06%. Based on clinical history and signs, histologic and ultrastructural changes, and plant analysis, a diagnosis of swainsonine toxicosis caused by consumption of A. punae was made, which has not been reported previously, to our knowledge.
Publisher: SAGE Publications
Date: 14-10-2020
Abstract: Two horses that consumed well water with high fluoride content exhibited clinical signs of chronic dental and skeletal fluoride toxicosis and were later euthanized and autopsied. Both horses had degenerative disease of multiple joints and multiple dental defects. Elevated fluoride concentrations were found in bone and tooth s les of both horses, well water, and feed. Microscopically, abnormalities were noted in bone and tooth s les, and consisted mostly of foci of cement necrosis and hypercementosis. Horses exhibiting bilateral, highly symmetrical dental and/or skeletal lesions, with chronic lameness, should be evaluated for the possible presence of fluoride toxicosis.
Publisher: SAGE Publications
Date: 14-07-2022
DOI: 10.1177/10406387221109899
Abstract: Concurrent Clostridium piliforme and canine distemper virus (CDV) infection was diagnosed in 2 canine littermates and 1 gray fox kit from Texas, USA. In all 3 animals, intracytoplasmic, filamentous bacteria, consistent with C. piliforme, were present along the margins of foci of hepatic necrosis. Additional histologic findings included intracytoplasmic and intranuclear inclusion bodies in bile duct and bronchial epithelial cells of the fox kit, and mild intestinal necrosis in 1 puppy. PCR assays confirmed the presence of C. piliforme in all 3 animals, CDV in both puppies, and canine parvovirus in 1 puppy. Fluorescent antibody testing confirmed the presence of CDV in the fox kit. Concurrent canine distemper and Tyzzer disease in canine littermates and the gray fox has not been reported previously, to our knowledge.
Publisher: SAGE Publications
Date: 27-05-2021
DOI: 10.1177/10406387211018289
Abstract: The most prevalent causes of death in racehorses are musculoskeletal injuries, causing ~83% of deaths within the racing industry in California and elsewhere. The vast majority of these injuries have preexisting lesions that predispose to fatal injury. A 4-y-old Thoroughbred colt suffered an acute suspensory apparatus failure, including biaxial proximal sesamoid bone fractures of the right front fetlock, causing loss of support of the fetlock joint and consequent fall with fractures of the cervical and sacral spine. Cervical fracture caused spinal cord damage that resulted in sudden death. A preexisting lesion in the medial proximal sesamoid bone likely predisposed to complete fracture of this bone and fetlock breakdown. Interestingly, a comparable osteopenic lesion was present in the intact medial proximal sesamoid bone of the left forelimb, which is consistent with bilateral repetitive overuse injury in racehorses. The morphologic features of the cervical and sacral spine fractures were compatible with acute injury no evidence of preexisting lesions was seen. Most likely, these acute vertebral fractures occurred as a result of the horse falling. This case emphasizes the importance of performing a detailed autopsy in horses that suffer an appendicular musculoskeletal injury, particularly in fatal cases when the horse dies following a leg injury.
Publisher: SAGE Publications
Date: 21-02-2020
Abstract: Gas gangrene is a necrotizing infection of subcutaneous tissue and muscle that affects mainly ruminants and horses, but also other domestic and wild mammals. Clostridium chauvoei, C. septicum, C. novyi type A, C. perfringens type A, and C. sordellii are the etiologic agents of this disease, acting singly or in combination. Although a presumptive diagnosis of gas gangrene can be established based on clinical history, clinical signs, and gross and microscopic changes, identification of the clostridia involved is required for confirmatory diagnosis. Gross and microscopic lesions are, however, highly suggestive of the disease. Although the disease has a worldwide distribution and can cause significant economic losses, the literature is limited mostly to case reports. Thus, we have reviewed the current knowledge of gas gangrene in mammals.
Publisher: SAGE Publications
Date: 14-05-2020
Abstract: Eight duikers, representing 3 different species cohoused in a single zoological collection, died in a 10-month period. Black, red-flanked, and yellow-backed duikers were affected, appearing clinically with a combination of anorexia, diarrhea, ataxia, tremors, and/or stupor, followed by death within 72 hours of onset of clinical signs. Consistent gross findings were pulmonary ecchymoses (8/8), generalized lymphadenomegaly (6/8), ascites (5/8), and pleural effusion (4/8). Dense lymphocyte infiltrates and arteritis affected numerous tissues in most animals. Ibex-associated malignant catarrhal fever (MCF) viral DNA was detected in all cases by polymerase chain reaction and in situ hybridization. Identical ibex-MCF virus sequence was detected in spleen of a clinically healthy ibex ( Capra ibex) housed in a separate enclosure 35 meters away from the duikers.
Publisher: SAGE Publications
Date: 13-02-2020
Abstract: Enteric disease in horses may be caused by a variety of microorganisms, including several clostridial species. Paeniclostridium sordellii (previously Clostridium sordellii) has been frequently associated with gas gangrene in humans and several animal species, including horses. However, its role in enteric diseases of animals has not been fully determined. We describe herein 7 cases of enteric disease in horses associated with P. sordellii infection. Grossly, the small and/or large intestines were necrotic, hemorrhagic, and edematous. Microscopically, there was severe mucosal necrosis and hemorrhage of the small and/or large intestine of all horses. P. sordellii was isolated and/or demonstrated by immunohistochemistry and/or PCR in the intestine of all horses. All other known causes of enteric disease in horses were ruled out in these 7 cases. P. sordellii should be considered among the differential diagnoses in cases of enteric disease in horses.
Publisher: SAGE Publications
Date: 10-08-2022
DOI: 10.1177/10406387221118039
Abstract: Epiploic foramen entrapment (EFE) is a common cause of small intestinal colic in horses and may lead to intestinal strangulation. Strangulating intestinal obstruction impairs the gastrointestinal outflow and can lead to secondary gastric rupture and endotoxemia. Clostridioides difficile can cause enterotyphlocolitis with colic in horses of all ages, and the process is commonly referred to as C. difficile–associated disease (CDAD). Here we report the results of the postmortem examination of a 7-y-old Thoroughbred racehorse with concurrent CDAD, EFE, and gastric rupture that was euthanized following a history of colic over several days. A segment of distal jejunum and proximal ileum had passed through the epiploic foramen, and the intestinal wall was thickened and dark-red. The remaining small intestinal loops were distended and filled with blood-tinged contents. Peritonitis had resulted from escape of gastric contents into the abdominal cavity through a tear in the major curvature of the stomach. Histologically, the incarcerated segment had acute transmural hemorrhage with congestion and mucosal necrosis neutrophilic infiltrates with fibrin thrombi were in the mucosa of the non-incarcerated small intestinal segments. C. difficile toxins were detected in the small intestinal contents, and C. difficile was isolated from the small intestine, colon, and cecum.
Publisher: Hindawi Limited
Date: 16-09-2022
DOI: 10.1111/TBED.14315
Abstract: Rabbit haemorrhagic disease virus type 2 (RHDV2) causes a severe systemic disease with hepatic necrosis. Differently from classic RHDV, which affects only European rabbits (Oryctolagus cuniculus), RHDV2 can affect many leporid species, including hares (Lepus spp.) and cottontail rabbits (Sylvilagus spp.). RHDV2 emerged in Europe in 2010 and spread worldwide. During the last 5 years, there have been multiple outbreaks in North America since the first known event in 2016 in Quebec, Canada, including several detections in British Columbia, Canada, between 2018 and 2019, Washington State and Ohio, USA, in 2018 and 2019, and New York, USA, in 2020. However, the most widespread outbreak commenced in March 2020 in the southwestern USA and Mexico. In California, RHDV2 spread widely across several southern counties between 2020 and 2021, and the aim of this study was to report and characterize these early events of viral incursion and circulation within the state. Domestic and wild lagomorphs (n = 81) collected between August 2020 and February 2021 in California with a suspicion of RHDV2 infection were tested by reverse transcription quantitative real-time PCR on the liver, and histology and immunohistochemistry for pan-lagovirus were performed on liver sections. In addition, whole genome sequencing from 12 cases was performed. During this period, 33/81 lagomorphs including 24/59 domestic rabbits (O. cuniculus), 3/16 desert cottontail rabbits (Sylvilagus audubonii), and 6/6 black-tailed jackrabbits (Lepus californicus) tested positive. All RHDV2-positive animals had hepatic necrosis typical of pathogenic lagovirus infection, and the antigen was detected in sections from in iduals of the three species. The 12 California sequences were closely related (98.9%-99.95%) to each other, and also very similar (99.0%-99.4%) to sequences obtained in other southwestern states during the 2020-2021 outbreak however, they were less similar to strains obtained in New York in 2020 (96.7%-96.9%) and Quebec in 2016 (92.4%-92.6%), suggesting that those events could be related to different viral incursions. The California sequences were more similar (98.6%-98.7%) to a strain collected in British Columbia in 2018, which suggests that that event could have been related to the 2020 outbreak in the southwestern USA.
Publisher: MDPI AG
Date: 12-08-2022
DOI: 10.3390/IJMS23169050
Abstract: Clostridium perfringens type D epsilon toxin (ETX) produces severe, and frequently fatal, neurologic disease in ruminant livestock. The disorder is of worldwide distribution and, although vaccination has reduced its prevalence, ETX still causes substantial economic loss in livestock enterprises. The toxin is produced in the intestine as a relatively inactive prototoxin, which is subsequently fully enzymatically activated to ETX. When changed conditions in the intestinal milieu, particularly starch overload, favor rapid proliferation of this clostridial bacterium, large amounts of ETX can be elaborated. When sufficient toxin is absorbed from the intestine into the systemic circulation and reaches the brain, two neurologic syndromes can develop from this enterotoxemia. If the brain is exposed to large amounts of ETX, the lesions are fundamentally vasculocentric. The neurotoxin binds to microvascular endothelial receptors and other brain cells, the resulting damage causing increased vascular permeability and extravasation of plasma protein and abundant fluid into the brain parenchyma. While plasma protein, particularly albumin, pools largely perivascularly, the vasogenic edema becomes widely distributed in the brain, leading to a marked rise in intracranial pressure, coma, sometimes cerebellar herniation, and, eventually, often death. When smaller quantities of ETX are absorbed into the bloodstream, or livestock are partially immune, a more protracted clinical course ensues. The resulting brain injury is characterized by bilaterally symmetrical necrotic foci in certain selectively vulnerable neuroanatomic sites, termed focal symmetrical encephalomalacia. ETX has also been internationally listed as a potential bioterrorism agent. Although there are no confirmed human cases of ETX intoxication, the relatively wide species susceptibility to this toxin and its high toxicity mean it is likely that human populations would also be vulnerable to its neurotoxic actions. While the pathogenesis of ETX toxicity in the brain is incompletely understood, the putative mechanisms involved in neural lesion development are discussed.
Publisher: SAGE Publications
Date: 04-10-2019
Abstract: Gas gangrene occurs in several animal species and is caused by one or more clostridial species. In horses, the disease is most often caused by Clostridium perfringens type A. Although Clostridium sordellii has been associated with gas gangrene in ruminants and humans, cases of the disease associated with this microorganism have not been described in horses, to our knowledge. We report herein 8 cases of gas gangrene caused by C. sordellii in horses. These cases were characterized by myonecrosis and cellulitis, associated with systemic changes suggestive of toxic shock. The diagnosis was confirmed by gross and microscopic changes combined with anaerobic culture, fluorescent antibody test, immunohistochemistry, and/or PCR. The predisposing factor in these cases was an injection or a traumatic skin injury. C. sordellii should be considered as a possible etiologic agent in cases of gas gangrene in horses.
Publisher: SAGE Publications
Date: 10-11-2022
DOI: 10.1177/10406387221136568
Abstract: Four Indian ringneck parakeets (
Publisher: SAGE Publications
Date: 18-11-2022
DOI: 10.1177/10406387221130024
Abstract: Gastrointestinal disorders are among the most common disease processes in captive elephants. Colic is a frequent clinical presentation and may have several infectious and noninfectious causes. Ingestion of sand has been reported in elephants living in enclosures with loose sandy soils. Similar to the situation in horses, sand ingestion can cause intestinal impaction and colic in elephants. Here we describe a case of colonic sand impaction with cecal rupture and peritonitis in an African savanna elephant from a zoologic collection that died after several days of colic. On autopsy, abundant, gritty, sandy material was found within a segment of colon immediately aboral to the cecum. There was a full-thickness tear in the cecal wall, free intestinal contents within the abdominal cavity, and peritonitis. To our knowledge, the postmortem examination of an elephant with sand impaction and cecal rupture has not been reported previously this condition should be included among the differential diagnoses in elephants with colic. We review the reports of noninfectious causes of gastrointestinal disease in elephants, which include cases of small intestinal and colonic torsion and of intestinal obstruction by fecal boluses.
Publisher: SAGE Publications
Date: 10-02-2023
DOI: 10.1177/10406387231154554
Abstract: Clostridium piliforme, the agent of Tyzzer disease, has traditionally not been considered a major pathogen of cats. We queried the database of the Pathology Service of the Veterinary Medical Teaching Hospital, University of California–Davis, for kittens -mo-old autopsied between 2000–2021 that had colitis, hepatitis, and/or myocarditis 37 cases met the search criteria. Sections of colon, liver, and heart from these 37 cats were stained with modified Steiner 19 of 37 (51%) cases had intraepithelial, Steiner-positive rods compatible with C. piliforme in at least one organ, confirming Tyzzer disease. The affected age range was 7–42 d (median: 17.5 d). Eighteen were orphaned kittens. Colitis was the major lesion (18 of 19) followed by random hepatitis (11 of 19). Perianal dermatitis with intraepithelial stacked rods was seen in 2 of 19. Myocarditis was not evident in any of the cases. A PCR assay for C. piliforme on 10 selected cases using formalin-fixed, paraffin-embedded (FFPE) blocks was positive or suspected in colon (5 of 10), liver (5 of 10), and heart (1 of 10). The modified Steiner stain was more sensitive in the detection of bacteria than PCR on FFPE s les. Fifteen kittens had comorbidities. A weakened immune state caused by maternal, environmental, infectious, and/or nutritional causes is speculated to have contributed to disease onset. We found that Tyzzer disease is more common than previously believed in orphaned kittens and should be considered in kittens with colitis and/or hepatitis.
Publisher: American Society for Microbiology
Date: 15-10-2021
DOI: 10.1128/IAI.00256-21
Abstract: Clostridium perfringens type F strains causing nonfoodborne human gastrointestinal diseases (NFD) typically produce NanI sialidase as their major secreted sialidase. Type F NFDs can persist for several weeks, indicating their pathogenesis involves intestinal colonization, including vegetative cell growth and adherence, with subsequent sporulation that fosters enterotoxin production and release. We previously reported that NanI contributes to type F NFD strain adherence and growth using Caco-2 cells.
Publisher: SAGE Publications
Date: 04-2020
Abstract: Lysosomal storage diseases are inherited and acquired disorders characterized by dysfunctional lysosomes. Intracytoplasmic accumulation of undegraded substrates leads to impaired cellular function and death. Several plant species are toxic to livestock because of the presence of indolizidine alkaloids, including swainsonine, which cause a storage disease. Swainsonine-induced nervous disease (i.e., locoism) of sheep and cattle is well recognized in several parts of the world, particularly in the western United States and in parts of Australia. Spontaneous intoxication by Astragalus garbancillo var. garbancillo was suspected in a group of 70 llamas ( Lama glama) in Jujuy Province, northwestern Argentina. The animals grazed an area dominated by stands of A. garbancillo var. garbancillo. Clinical signs were staggering, ataxia, hypermetria, and progressive weight loss. The clinical course in in idual animals was ~50 d. The main microscopic changes were Purkinje cell degeneration, necrosis, and loss, associated with intracytoplasmic vacuolation, meganeurite formation, and Wallerian degeneration. Specific positive labeling for ubiquitin was observed in axonal spheroids. Composite leaf and stem s les of A. garbancillo var. garbancillo analyzed by high-performance liquid chromatography contained 0.03% swainsonine. Based on the microscopic lesions, clinical history, and plant analysis, a diagnosis was made of storage disease caused by consumption of swainsonine-containing A. garbancillo var. garbancillo.
Publisher: SAGE Publications
Date: 10-01-2022
DOI: 10.1177/10406387211065044
Abstract: Phlegmonous gastritis was diagnosed in 2 yearling fillies that were presented with a 1-wk history of fever, lethargy, and hypoproteinemia, associated with a previous diagnosis of equine proliferative enteropathy based on clinical signs and PCR assay detection of Lawsonia intracellularis in fecal s les. Abdominal ultrasound revealed enlargement of the stomach and expansion of its submucosal layer with hypoechoic fluid, as well as thickened hypomotile small intestinal segments. Given the poor prognosis and poor response to treatment, both horses were euthanized, one on the day of presentation and the other after 3 wk of intensive medical management including a combination of antimicrobials, analgesics, and intravenous colloids. At autopsy, acute mural gastritis characterized by severe submucosal edema with suppurative inflammation (i.e., phlegmonous gastritis) and necroulcerative enteritis compatible with the necrotizing form of equine proliferative enteropathy were identified in both horses. The gastric inflammation was associated with thrombosis and mixed bacterial populations, including Clostridium perfringens, that were confined to the submucosa without evidence of mucosal involvement toxin genes compatible with C. perfringens type C were identified in one case. Human phlegmonous gastritis is an uncommon, often-fatal pyogenic infection that is often associated with mucosal injury, bacteremia, or immunocompromise. Our finding of this unusual gastric lesion in 2 horses with similar signalment, clinical disease, and spectrum of postmortem lesions suggests a similar etiopathogenesis that possibly involves local, regional, or distant hematogenous origin, and should be considered a potential complication of gastrointestinal mucosal compromise in horses.
Publisher: Public Library of Science (PLoS)
Date: 08-11-2019
Publisher: MDPI AG
Date: 15-02-2021
DOI: 10.3390/ANI11020501
Abstract: The different ovine production and breeding systems share the cornerstone of keeping a good body condition to ensure adequate productivity. Several infectious and parasitic disorders have detrimental effects on weight gains and may lead to emaciation. Flock health management procedures are aimed to prevent such conditions. Nutritional management is equally important to guarantee adequate body condition. Persistent bouts of low ruminal pH due to excess concentrate in the diet may lead to subacute ruminal acidosis. Pre-stomach motility disorders may also lead to ill-thrift and emaciation. An adequate mineral supplementation is key to prevent the effects of copper, selenium, and other micronutrients deprivation, which may include, among others, loss of condition. This review elaborates on the clinico-pathologic, diagnostic, and therapeutic aspects of some of these conditions, and highlights the necessity of considering them as contributors to states of wasting in sheep flocks.
Publisher: SAGE Publications
Date: 23-07-2021
DOI: 10.1177/10406387211031944
Abstract: Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cells were counted in 5 random 17,600-µm 2 areas of villus lamina propria of the duodenum, jejunum, and ileum, and deep lamina propria of the duodenum, jejunum, ileum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon. Other features investigated in the same intestinal segments included villus height and width (small intestine), presence of ciliated protozoa, Paneth cells number, subcryptal leukocyte layers (number of leukocyte layers between the bottom of the crypts and the muscularis mucosae), and submucosal leukocytes. Lymphocytes were the most numerous cells in all segments analyzed, followed by plasma cells, eosinophils, macrophages, and neutrophils. Eosinophil numbers were significantly higher in both lamina propria and submucosa of the large intestine than in the small intestine. The duodenum had shorter and thinner villi than either jejunum or ileum. The data provided from our study will be useful for diagnosticians examining inflammatory processes in the intestinal tract of horses.
Publisher: SAGE Publications
Date: 28-06-2023
DOI: 10.1177/10406387231182106
Abstract: Although bovine respiratory syncytial virus (BRSV) infection has been reported in cattle in Argentina, it has not been associated with pneumonia in Argentina. We report here 5 cases of bovine pneumonia associated with BRSV. Autopsies were performed on 35 beef cattle with gross and/or microscopic lesions of pneumonia from 3 commercial feedlots. Lung s les in 5 of 35 animals were BRSV-positive by reverse-transcription nested PCR. The lungs of 2 of these 5 animals were coinfected with Mannheimia haemolytica, and 1 with bovine viral diarrhea virus 1. Microscopically, the lungs of 3 of the 5 BRSV PCR–positive animals had fibrinosuppurative bronchopneumonia, with or without pleuritis 2 of the 5 had interstitial pneumonia. We conclude that BRSV is part of the bovine respiratory disease complex in Argentina.
Publisher: MDPI AG
Date: 17-04-2023
Abstract: Blackleg is a common cause of death in cattle, mostly caused by the bacterium Clostridium chauvoei. Cardiac lesions were traditionally considered uncommon in cases of blackleg in cattle until a 2018 study reported otherwise. This study was aimed at determining the prevalence of cardiac disease among cattle that died of blackleg in Tennessee, USA. The outcome of this study would reinforce the importance of assessing cardiac lesions in suspected cases of blackleg in cattle. The University of Tennessee Veterinary Medical Center database searched for cattle with a confirmed diagnosis of blackleg necropsied between 2004 and 2018. Of the 120 necropsy reports, 37 had a diagnosis of blackleg. Histology slides of skeletal muscle (26/37) and the heart (26/37) were reviewed to confirm the presence of supportive lesions. Of the 37 cases of blackleg identified, 26 animals (70.3%) had cardiac lesions, including 4 (10.8%) that had only cardiac involvement without skeletal muscle lesions. Specifically, (5.4% 2/37) had only necrotizing myocarditis (13.5% 5/37) had only fibrinous or fibrinosuppurative pericarditis, epicarditis, or endocarditis (51.4% 19/26) had a combination of myocarditis and pericarditis, epicarditis, or endocarditis and (29.7% 11/37) had no lesions. Furthermore, of the 26 cases with cardiac lesions, 24 cases had gross lesions, while 2 cases were identified only by microscopic examination. This indicates that gross examination alone is insufficient to identify cardiac involvement in blackleg cases in cattle. Contrary to traditional perceptions, cardiac lesions in cases of bovine blackleg could be as high as 70% and are most often associated with skeletal muscle lesions. The prevalence of cardiac lesions in cases of blackleg in cattle may be higher when the heart is examined microscopically than if it is only evaluated grossly. Pathologists should specifically evaluate the heart for lesions in suspected cases of blackleg in cattle and utilize microscopic examination when gross lesions are absent.
Publisher: SAGE Publications
Date: 02-04-2021
DOI: 10.1177/10406387211006353
Abstract: An outbreak of rabbit hemorrhagic disease virus 2 (RHDV2)-associated disease occurred in the southwestern United States following its first detection in New Mexico in March 2020. The disease spread throughout several states and was diagnosed for the first time in California on May 11, 2020, in a black-tailed jackrabbit ( Lepus californicus). The following day, the California Department of Food and Agriculture (CDFA) issued an order banning the entrance into California of several lagomorph species and their products from any state in which the disease had been detected in the last 12 mo. RHDV2 is a threat to wild lagomorph species in California, including the endangered riparian brush rabbit ( Sylvilagus bachmani riparius). Therefore, the California Department of Fish and Wildlife (CDFW) started tracking any mortality event in wild lagomorph populations. As of August 9, 2020, RHDV2 had been detected in wild and domestic lagomorphs of several counties in southern California that were submitted to the California Animal Health and Food Safety laboratory system by the CDFA or the CDFW. These positive cases included 2 additional black-tailed jackrabbits and 3 desert cottontail rabbits ( Sylvilagus audubonii). In addition, the infection spilled over to domestic populations, whereby it was confirmed on July 10, 2020, in a domestic rabbit ( Oryctolagus cuniculus).
Publisher: SAGE Publications
Date: 10-03-2023
DOI: 10.1177/10406387231159371
Abstract: In animals, salmonellosis is seen typically as enteritis and/or septicemia. Subclinical infection also occurs, and outwardly healthy animals can serve as reservoirs of infection. Reports of salmonellosis in elephants are rare, limited to a few serovars, and the gross and microscopic lesions of enteric salmonellosis in this species have not been described in detail. We present here, in 2 elephants in managed care settings, cases of salmonellosis that resulted from infection by Salmonella enterica serovar Muenchen and S. enterica serovar Montevideo, serovars that have not been described previously as the cause of salmonellosis in elephants, to our knowledge. We also review the literature on salmonellosis in elephants. Animal A, an adult Asian elephant that was euthanized because of gastrointestinal hemorrhage, had multifocal, necrotizing, suppurative enterocolitis, and necrotizing gastritis. Animal B, an adult African elephant with chronic, recurrent colic, followed by death, had necrotizing typhlocolitis. The origin of infection was not determined in either case. The animals came from different facilities and did not have a common feed source. Previously reported cases of salmonellosis in elephants were caused by Salmonella Dublin, Salmonella Typhimurium, or Salmonella Enteritidis. The definitive diagnosis of salmonellosis is made based on compatible gross and microscopic lesions, coupled with the detection of Salmonella spp. in the affected tissues. Effective biosecurity should be adopted to minimize the risk of salmonellosis in elephants in managed care.
Publisher: SAGE Publications
Date: 20-01-2020
Abstract: Clostridium perfringens type D epsilon toxin (EXT) causes an important neurologic disorder of sheep, goats and, rarely, cattle. The disease can occur in peracute, acute, subacute, and chronic forms. High circulating levels of ETX produce vasculocentric brain lesions, in which microvascular endothelial injury results in diagnostically useful perivascular and intramural extravasations of plasma protein, especially in sheep, and less frequently in goats. With lower toxin doses, a more protracted clinical course tends to occur, particularly in sheep, leading to focal, bilaterally symmetrical, necrotic foci in certain brain regions. Although these morphologic features usually permit the diagnostic pathologist to make a definitive etiologic diagnosis, there are many aspects of the pathogenesis of these cerebral lesions that are not completely understood. ETX has also been shown to produce microvascular damage in the retina of rats, resulting in severe, diffuse vasogenic edema, similar to that found in brains exposed to this neurotoxin. The pathoclisis and vascular theories offer alternative explanations of the differential susceptibility of different brain regions to the same neurotoxic insult.
Publisher: SAGE Publications
Date: 21-03-2023
DOI: 10.1177/10406387231161053
Abstract: We characterized naturally occurring pigeon herpesvirus (PiHV Columbid alphaherpesvirus 1) infection in domestic pigeons in California. We retrieved and analyzed 62 pathology reports produced between 1991 and 2014 at the California Animal Health and Food Safety Laboratory System. In 56 of the cases, the diagnosis of PiHV infection was established based on histopathology, either alone (44 cases) or combined with virus isolation (VI 8), transmission electron microscopy (TEM 3), or PCR (1) in the remaining 6 cases, the diagnosis was established based on VI (5 cases) or TEM (1) alone. PiHV infection affected 1 system in 34, 2 in 16, and ≥3 systems in 6 cases data were not available for the remaining 6 cases. Most commonly affected was the digestive system (55 cases), followed by the respiratory tract (5) and lymphoid system (2). The liver (39 cases), crop (17), and esophagus (14) were the organs affected most commonly. Many affected cells often bore single eosinophilic intranuclear inclusion bodies. PiHV infection was a secondary diagnosis or incidental finding in 35 cases. Most (55) cases had 1 (21), or up to 4 (34), other concurrent infections the most common concurrent infections were pigeon circoviral infection (26), trichomonosis (24), aspergillosis (11), and colibacillosis (10).
Publisher: MDPI AG
Date: 18-01-2021
DOI: 10.3390/ANI11010229
Abstract: Infectious and parasitic agents have been frequently associated with debilitating and wasting conditions in sheep. The prevalence of these agents has probably undermined the role of toxic causes as contributors to such disorders. In addition, many of these intoxications frequently produce acute clinical disease with specific and characteristic lesions, thus a causal relationship with the toxic substance may be relatively easy to establish. However, persistent exposure to some of these organic or inorganic toxic substances may lead to emaciation, ill-thrift, and poor external aspect. The anti-nutritional factors and alkaloids of several plants, including pyrrolizidine alkaloids, among others, have also been associated with emaciation and/or poor general performance in sheep flocks. In this review, some of these disorders are discussed with an emphasis on clinical signs and lesions, relevant diagnostic aspects, and available therapeutic approaches. In most cases, demonstrating a history of exposure should be one of the most relevant aspects of the diagnostic approach, and removing the animals from the toxic source is the cornerstone of the majority of the treatment strategies.
Publisher: SAGE Publications
Date: 23-06-2021
DOI: 10.1177/10406387211025232
Abstract: Rickets is a metabolic bone disease associated with failure of endochondral ossification and impaired osteoid mineralization in growing animals. As a consequence, affected in iduals can develop gross and microscopic bone malformations. The most common causes of rickets in domestic species include vitamin D and phosphorus deficiency. Rickets has been described in multiple species however, comprehensive postmortem characterizations with confirmatory histopathology in equids have not been published. A 6-mo-old, Thoroughbred-cross foal was diagnosed with rickets based on gross autopsy findings and microscopic examination of the ribs and long bones. Grossly, all costochondral junctions of the ribs were enlarged with a “rachitic rosary” appearance, and there were multiple fracture calluses in the rib bodies. Epiphyses and metaphyses of the long bones appeared widened on sagittal section, and their physes were irregularly thickened. Histologically, there were poorly organized columns of hypertrophic chondrocytes within the physes of affected bones, islands of chondrocytes embedded within the primary and secondary spongiosa, and faintly eosinophilic seams of poorly mineralized osteoid within the bone trabeculae. Areas of focally increased osteoclastic activity were observed in some of the sections, perhaps pointing to a more complex metabolic bone disease in a growing animal. Low serum concentrations of calcium and 25-hydroxyvitamin D were detected in an antemortem s le. The pathogenesis of these imbalances was not definitively established, but lack of sunlight exposure, low concentration of vitamin D precursors in the diet (perhaps secondary to malnutrition), or both, were suspected a genetic basis cannot be ruled out.
Publisher: SAGE Publications
Date: 10-06-2019
Abstract: A cluster of 4 bovine abortions caused by Coxiella burnetii occurred in a dairy herd in Uruguay during a 2-mo period. Case 1 consisted of a placenta from an aborted cow cases 2–4 were fetuses and their placentas. Grossly, the placenta from one aborted cow had moderate, diffuse reddening of the cotyledons and loss of translucency of the intercotyledonary areas. No gross lesions were observed in the other 3 placentas. Microscopically, 2 of 4 placentas had fibrinonecrotizing placentitis with abundant intratrophoblastic gram-negative coccobacilli. C. burnetii was identified intralesionally by immunohistochemistry (IHC) in all 4 placentas, and by PCR and DNA sequencing in 3 placentas analyzed by these techniques. One fetus had mild neutrophilic alveolitis with multinucleate syncytial cells no gross or microscopic lesions were observed in the other 2 fetuses examined. The lungs of the 3 fetuses were negative for C. burnetii by IHC. Tests performed to investigate other possible causes of abortions in the 4 cases were negative. C. burnetii causes Q fever in humans and coxiellosis in animals. Clusters of abortions in cattle by C. burnetii have not been reported previously, to our knowledge this bacterium has been considered an opportunistic pathogen associated only with sporadic abortion in cattle. We present herein a cluster of 4 bovine abortions caused by C. burnetii in a dairy farm during a period of 2 mo and a review of the literature on C. burnetii infection in cattle.
Publisher: SAGE Publications
Date: 25-07-2022
DOI: 10.1177/10406387221114622
Abstract: Coccidioidomycosis is a fungal disease caused by Coccidioides immitis or Coccidioides posadasii. We searched the records of the California Animal Health and Food Safety Laboratory from 1990 through 2020 for cases of coccidioidomycosis in horses. The selection criteria for these cases were: 1) live-born horses submitted for autopsy, and 2) a diagnosis of coccidioidomycosis was established, regardless of cause of death. During that time, 19,054 horses were received, and 26 cases (0.14%) of coccidioidomycosis were diagnosed in horses, of which 19 (73%) cases had pneumonia and/or pleuritis with or without lesions in other organs, and 7 (27%) cases had lesions only in organs other than the lungs (nasal mucosa, spleen, thoracic lymph nodes, heart, pericardial sac, liver, kidney, mediastinum, and/or mesentery). Pneumonia was diagnosed as the cause of death in 1,838 (9.64%) of the horses received Coccidioides spp. was the cause of pneumonia in 19 (1.0%) of these animals. Horses have been reported to have low susceptibility to coccidioidomycosis, and the severity and chronicity of the disease can be variable. Lesions in our cases consisted of multifocal-to-coalescing pyogranulomas with intralesional fungal spherules. Coccidioidomycosis must be considered a differential diagnosis in cases of persistent cough, chronic weight loss, fever, and cases with a travel history to, or living in, a region considered endemic for coccidioidomycosis. Coccidioides spp. infection should also be considered when pyogranulomatous inflammation is found within lung, spleen, nasal mucosa, and lymph nodes of horses.
Publisher: SAGE Publications
Date: 30-08-2022
DOI: 10.1177/10406387221120816
Abstract: Blackleg is an infectious disease caused by Clostridium chauvoei. Cardiac blackleg has been reported in ruminants as an uncommon presentation of the disease its pathogenesis is not understood completely. We include here a literature review of cardiac blackleg and a description of 2 cases in 12–15-mo-old feedlot steers in Argentina. Fourteen of 1,190 steers died suddenly over a period of 10 d. Postmortem examinations were performed on 5 of these animals. Grossly, severe, diffuse, fibrinous pericarditis and pleuritis, multifocal necrohemorrhagic myocarditis, diffuse pulmonary congestion, mild splenomegaly, and moderate congestion of meningeal vessels were observed. No significant gross lesions were observed in the skeletal muscles of any animal. Histology was performed on 2 of the steers. The main microscopic features were necrotizing myocarditis with myriad intralesional gram-positive rods with subterminal spores plus fibrinosuppurative pericarditis and pleuritis. C. chauvoei was detected by immunohistochemistry and PCR in the myocardium of both animals. These findings confirm a diagnosis of cardiac blackleg in these 2 steers and presumptively in the other affected animals.
Publisher: SAGE Publications
Date: 26-07-2023
DOI: 10.1177/10406387231186190
Abstract: Four alpine goats developed diarrhea soon after the owner placed plant clippings believed to be yellow oleander ( Thevetia peruviana) into their pen on a suburban property near Palm Desert, CA, USA. A 1-y-old female goat died suddenly ~1 h after eating the plant clippings and was submitted to the San Bernardino Branch of the California Animal Health and Food Safety Laboratory System for postmortem examination. The main autopsy and histopathologic findings were myocardial hemorrhage and necrosis, consistent with cardiac glycoside intoxication. Rumen contents were analyzed by LC-MS/MS peruvoside, a cardiac glycoside, was detected, but oleandrin, the cardiac glycoside of common oleander ( Nerium oleander), was not. An LC–high-resolution MS (LC-HRMS) analysis revealed the presence of peruvoside and neriifolin in the rumen contents and in a tested plant fragment, indicating that the plant was a member of the Thevetia genus. A clipping from the plant fed to the goats and submitted by the owner was identified as yellow oleander, Thevetia peruviana (also known as Cascabela thevetia).
Publisher: SAGE Publications
Date: 24-02-2023
DOI: 10.1177/10406387231157711
Abstract: Four turkeys from a commercial flock with acutely elevated mortality levels were submitted for postmortem examination and diagnostic workup. No clinical signs had been observed before death. On gross examination, hemorrhage and necrosis were present throughout the intestinal tracts, and the spleens were markedly enlarged and speckled. Microscopically, numerous, large basophilic-to- hophilic intranuclear inclusion bodies were observed in mononuclear cells of the spleen and the lamina propria of the small intestine. In addition, there were lesions of diffuse villus blunting and necrosis of the small intestine, with large numbers of rod-shaped bacteria adhered to the epithelium and in the intestinal lumen. Hemorrhagic enteritis virus (HEV) infection was confirmed via PCR on the spleen. Clostridium perfringens was demonstrated in the small intestine by anaerobic culture and immunohistochemistry. The C. perfringens isolate was type F by PCR and, to our knowledge, necrotic enteritis in turkeys has not been described in association with C. perfringens type F infection.
Publisher: SAGE Publications
Date: 22-05-2023
DOI: 10.1177/10406387231176995
Abstract: Enterotoxemia caused by Clostridium perfringens type D usually affects sheep and goats ≥ 2-wk-old. The main clinical signs and lesions of the disease are produced by the epsilon toxin (ETX) elaborated by this microorganism. However, ETX is produced in the form of a mostly inactive prototoxin that requires protease cleavage for activation. It has traditionally been believed that younger animals are not affected by type D enterotoxemia given the low trypsin activity in the intestinal content associated with the trypsin-inhibitory action of colostrum. Two Nigerian dwarf goat kids, 2- and 3-d-old, with a history of acute diarrhea followed by death, were submitted for postmortem examination and diagnostic workup. Autopsy and histopathology revealed mesocolonic edema, necrosuppurative colitis, and protein-rich pulmonary edema. Alpha toxin and ETX were detected in intestinal content, and C. perfringens type D was isolated from the colon of both animals. The isolates encoded the gene for lambda toxin, a protease that has been shown previously to activate ETX in vitro. Type D enterotoxemia has not been reported previously in neonatal kids, to our knowledge, and we suggest that lambda toxin activated the ETX.
Publisher: SAGE Publications
Date: 06-02-2023
DOI: 10.1177/10406387231152788
Abstract: Reproductive failure represents an important cause of economic loss for the equine industry. We reviewed the cases of equine abortion and stillbirth submitted to the California Animal Health and Food Safety Laboratory System, University of California–Davis from 1990 to 2022. A total of 1,774 cases were reviewed. A confirmed cause of abortion was determined in 29.2% of the cases. Abortion or stillbirth was attributed to infectious agents in 18.7% of the cases, with Streptococcus spp., equine herpesvirus 1, and Leptospira spp. being the most prevalent. Noninfectious causes of abortion were established in 10.5% of the cases, with umbilical cord torsion being the most common. In 70.8% of the cases, a definitive cause of abortion could not be established. Our study demonstrated the difficulties in establishing an etiologic diagnosis, even when following a standard diagnostic work-up. New diagnostic approaches are needed to improve the likelihood of reaching a final diagnosis in cases of equine abortion and stillbirth.
Publisher: SAGE Publications
Date: 02-09-2022
DOI: 10.1177/10406387221123007
Abstract: An 18-y-old female tufted deer ( Elaphodus cephalophus) had a short history of chronic diarrhea, progressive weight loss, and hindlimb instability. Given the poor prognosis, the deer was euthanized and submitted for postmortem examination. The most significant gross finding was segmental and multinodular mural thickening of the proximal colon. On cut surface of the affected colonic segments, 0.5–2-cm diameter, intramural, multiloculated, cystic structures containing gray, translucent, gelatinous material elevated the edematous mucosa. Microscopically, the intramural cystic structures were filled with mucinous matrix admixed with foamy macrophages, and lined by discontinuous segments of well-differentiated columnar, pancytokeratin-positive epithelium with basilar nuclei. Multifocally, transition was observed from hyperplastic mucosal crypt epithelium to dysplastic or neoplastic columnar and flattened epithelium lining submucosal and serosal cysts. Cyst lumina were irregularly disrupted by polypoid ingrowths of collagenous tissue covered by attenuated epithelium. Based on these findings, we diagnosed a well-differentiated mucinous adenocarcinoma. Although intestinal adenocarcinomas have been described in humans and animals, they are considered uncommon in most domestic species, except for sheep, for which genetic and environmental factors appear to influence occurrence. Our report addresses the knowledge gap regarding intestinal adenocarcinomas affecting cervids and specifically the tufted deer, a less-studied, near-threatened Asian cervid.
Publisher: SAGE Publications
Date: 31-03-2022
DOI: 10.1177/10406387221085584
Abstract: Evaluation of gastrointestinal (GI) biopsies is a multistep process that includes reviewing an appropriate history, determining s le quality, and evaluating histologic sections. Selected diagnostic parameters that, in combination with intestinal histopathology, can be useful to localize disease to the intestinal tract in the horse include hypoproteinemia and hypoalbuminemia, ultrasound evidence of increased thickness of the small intestinal wall, and alterations in glucose or D-xylose absorption tests. Biopsies may be acquired either endoscopically, or via laparoscopy or standing flank incisional approaches. GI sections should be evaluated using a systematic approach that includes both architectural changes and inflammatory cell infiltrates. Although strategies have been developed for assessment of GI biopsies from the dog and cat, a standardized approach to interpretation of the equine GI biopsy has yet to be developed. GI biopsies pose several challenges to the pathologist, especially for endoscopic biopsies in which the quality of the specimen and its orientation may vary greatly. Architectural changes are arguably the most critical changes to evaluate. In a horse with chronic GI inflammation, such as occurs in idiopathic inflammatory bowel disease (IBD), the cell types encountered frequently are macrophages, eosinophils, lymphocytes, and plasma cells. Increased numbers of these cell types are categorized loosely as mild, moderate, and severe. Specific forms of idiopathic IBD have been further classified by this infiltrate as granulomatous enteritis, eosinophilic enteritis, and lymphoplasmacytic enteritis there is limited information on microscopic changes with each. Unfortunately, microscopic GI lesions are usually nonspecific, and determination of etiology requires further investigation.
Publisher: SAGE Publications
Date: 11-11-2021
DOI: 10.1177/10406387211057469
Abstract: Enteritis, colitis, and enterocolitis are considered some of the most common causes of disease and death in horses. Determining the etiology of these conditions is challenging, among other reasons because different causes produce similar clinical signs and lesions, and also because some agents of colitis can be present in the intestine of normal animals. We review here the main bacterial and viral causes of enterocolitis of horses, including Salmonella spp., Clostridium perfringens type A NetF-positive, C. perfringens type C, Clostridioides difficile, Clostridium piliforme, Paeniclostridium sordellii, other clostridia, Rhodococcus equi, Neorickettsia risticii, Lawsonia intracellularis, equine rotavirus, and equine coronavirus. Diarrhea and colic are the hallmark clinical signs of colitis and enterocolitis, and the majority of these conditions are characterized by necrotizing changes in the mucosa of the small intestine, colon, cecum, or in a combination of these organs. The presumptive diagnosis is based on clinical, gross, and microscopic findings, and confirmed by detection of some of the agents and/or their toxins in the intestinal content or feces.
Publisher: SAGE Publications
Date: 06-12-2021
DOI: 10.1177/03009858211057222
Abstract: Since axonal injury (AI) is an important component of many veterinary neurologic disorders, we assessed the relative ability of a panel of antibodies (amyloid precursor protein, 3 subunits of neurofilament protein, protein gene product 9.5, ubiquitin, and synaptophysin) to detect axonal swellings or spheroids. Abundant axonal spheroids found in necrotic internal capsule foci produced in 4 sheep by chronic Clostridium perfringens type D epsilon neurotoxicity provided a model system in which to evaluate this important diagnostic tool. There was heterogeneous labeling of subsets of spheroids by the respective antibodies, suggesting that, in order to detect the complete spectrum of AI in diagnostic cases, a range of antibodies should be used, not only when spheroids are plentiful but also when they are few in number or incompletely developed. The application of insufficient markers in the latter cases can potentially lead to the contribution of AI to lesion pathogenesis being underappreciated.
Publisher: American Society for Microbiology
Date: 22-12-2021
Abstract: NanI is a sialidase produced by some Clostridium perfringens type F strains. Here, we found that NanI can significantly increase the action of C. perfringens enterotoxin (CPE), which is the main toxin responsible for severe human enteric disease caused by type F strains. This effect likely helps to explain why even some type F strains that produce small amounts of CPE are pathogenic.
Publisher: SAGE Publications
Date: 08-07-2021
DOI: 10.1177/10406387211031213
Abstract: Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD 24 of 25 cases occurred in foals d old the remaining foal was 90 d old. There were 12 males and 12 females no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and Hanoverian. Most of the cases (19 of 25) occurred in the spring. There were 9 cases of sudden death the remaining animals had diarrhea, fever, distended abdomen, depression, weakness, non-responsiveness, and/or recumbency. Gross findings included icterus, hepatomegaly with acinar pattern, serosal hemorrhages, pulmonary edema, and/or fluid content in small and large intestine. Microscopically, all foals had severe, multifocal, necrotizing hepatitis. Necrotizing lymphohistiocytic colitis was observed in 10 of 25 foals, and multifocal necrotizing myocarditis was found in 8 of 25. Gram-negative, Steiner-positive, intracytoplasmic filamentous bacteria were observed in hepatocytes, enterocytes, and myocardiocytes, respectively. PCR detected C. piliforme DNA in the liver (24 of 24), colon (20 of 24), and heart (5 of 25). Our results indicate that necrotic hepatitis is the hallmark of TD in horses the so-called triad of lesions is not a consistent characteristic of the disease in this species.
Publisher: SAGE Publications
Date: 12-03-2023
DOI: 10.1177/10406387231160771
Abstract: Free-living amoebae are rare causes of morbidity and mortality in humans and animals around the globe. Because the route of exposure and clinical progression of disease caused by different species of amoebae may vary in people and animals, determining the species of amoeba present is important. We describe here a fatal infection by the free-living amoeba Balamuthia mandrillaris in a Siberian tiger ( Panthera tigris altaica). The 17-y-old patient had a rapid clinical decline after a peracute onset of severe lethargy, dull mentation, and anorexia. Autopsy did not identify a cause of death. Histology revealed inflammation associated with amoebic trophozoites in the brain, lungs, and iris of one eye. These amoebae were confirmed to be B. mandrillaris based on a PCR assay and sequencing. Although there are subtle morphologic differences between cyst stages of Acanthamoeba spp., B. mandrillaris, and Naegleria fowleri when present and identified on routine staining, other modalities, including PCR, immunofluorescence, electron microscopy, and immunohistochemistry, are typically utilized to confirm the pathogen involved in these cases. We review the reports of balamuthosis in animals.
Publisher: American Society for Microbiology
Date: 26-10-2022
Abstract: Clostridium perfringens enterotoxin (CPE) causes lethal enterotoxemia when absorbed from the intestines into the bloodstream. Testing recombinant CPE (rCPE) or rCPE variants impaired for various specific steps in CPE action showed that full CPE-induced cytotoxicity causes rapid Caco-2 monolayer permeability alterations, as well as enterotoxemic lethality and rapid CPE absorption in mouse small intestinal loops.
Publisher: SAGE Publications
Date: 20-01-2019
Abstract: Enterotoxemia caused by Clostridium perfringens type D is an important disease of sheep and goats with a worldwide distribution. Cerebral microangiopathy is considered pathognomonic for ovine enterotoxemia and is seen in most cases of the disorder in sheep. However, these lesions are poorly described in goats. In this article, we describe the vasculocentric brain lesions in 44 cases of caprine spontaneous C. perfringens type D enterotoxemia. Only 1 goat had gross changes in the brain, which consisted of mild cerebellar coning. However, 8 of 44 (18%) cases showed microscopic brain lesions, characterized by intramural vascular proteinaceous edema, a novel and diagnostically significant finding. The precise location of the edema was better observed with periodic acid–Schiff, Gomori’s, and albumin stains. Glial fibrillary acidic protein and aquaporin 4 immunostaining revealed strong immunolabeling of astrocyte foot processes surrounding microvessels. The areas of the brain most frequently affected were the cerebral cortex, corpus striatum (basal ganglia), and cerebellar peduncles, and both arterioles and venules were involved. Most of the goats of this study showed lesions in the intestine (enteritis, colitis, and typhlitis), although pulmonary congestion and edema, hydrothorax, hydropericardium, and ascites were also described. Although the intramural edema described, for the first time, in these caprine cases is useful for the diagnosis of enterotoxemia when observed, its absence cannot exclude the disease.
Publisher: SAGE Publications
Date: 15-03-2022
Publisher: Springer Science and Business Media LLC
Date: 17-08-2021
No related grants have been discovered for Francisco Uzal.