Dissecting the potential role of hepatitis E virus ORF1 nonstructural gene in cross-species infection by using intergenotypic chimeric viruses

Hepatitis E virus (HEV) infects humans and more than a dozen other animal species. We previously showed that open reading frame 2 (ORF2) and ORF3 are apparently not involved in HEV cross-species infection, which infers that the ORF1 may contribute to host tropism. In this study, we utilize the genomic backbone of HEV-1 which only infects humans to construct a panel of intergenotypic chimeras in which the entire ORF1 gene or its functional domains were swapped with the corresponding regions from HEV-3 that infects both humans and pigs. We demonstrated that the chimeric HEVs were replication competent in human liver cells. Subsequently, we intrahepatically inoculated the RNA transcripts of chimeras into pigs to determine if the swapped ORF1 regions confer the chimeras' ability to infect pigs. We showed that there was no evidence of infectivity in pigs for any of the chimeras. We also investigated the role of human ribosome protein sequence S17, which expanded host range in cultured cells, in HEV cross-species infection. We demonstrated that S17 insertion in HEV ORF1 did not abolish HEV replication competency in vitro, but also did not expand HEV host tropism in vivo. The results highlight the complexity of the underlying mechanism of HEV cross-species infection.

Use of three-dimensional accelerometers to evaluate behavioral changes in cattle experimentally infected with bovine viral diarrhea virus

OBJECTIVE To assess the use of 3-D accelerometers to evaluate behavioral changes in cattle experimentally infected with a low-virulent strain of bovine viral diarrhea virus (BVDV). ANIMALS 20 beef steers (mean weight, 238 kg). PROCEDURES Calves were allocated to a BVDV (n = 10) or control (10) group. On day 0, calves in the BVDV group were inoculated with a low-virulent strain of BVDV (4 × 10(6) TCID50, intranasally), and calves in the control group were sham inoculated with BVDV-free medium (4 mL; intranasally). An accelerometer was affixed to the right hind limb of each calf on day -7 to record activity (lying, walking, and standing) continuously until 35 days after inoculation. Baseline was defined as days -7 to -1. Blood samples were collected at predetermined times for CBC, serum biochemical analysis, virus isolation, and determination of anti-BVDV antibody titers. RESULTS All calves in the BVDV group developed viremia and anti-BVDV antibodies but developed only subclinical or mild disease. Calves in the control group did not develop viremia or anti-BVDV antibodies. Mean time allocated to each activity did not differ significantly between the BVDV and control groups on any day except day 8, when calves in the BVDV group spent less time standing than the calves in the control group. Following inoculation, calves in both groups tended to spend more time lying and less time walking and standing than they did during baseline. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that behavioral data obtained by accelerometers could not distinguish calves subclinically infected with BVDV from healthy control calves. However, subtle changes in the behavior of the BVDV-infected calves were detected and warrant further investigation.

Longitudinal Analysis of the Intestinal Microbiota in the Obese Mangalica Pig Reveals Alterations in Bacteria and Bacteriophage Populations Associated With Changes in Body Composition and Diet

Due to its immunomodulatory potential, the intestinal microbiota has been implicated as a contributing factor in the development of the meta-inflammatory state that drives obesity-associated insulin resistance and type 2 diabetes. A better understanding of this link would facilitate the development of targeted treatments and therapies to treat the metabolic complications of obesity. To this end, we validated and utilized a novel swine model of obesity, the Mangalica pig, to characterize changes in the gut microbiota during the development of an obese phenotype, and in response to dietary differences. In the first study, we characterized the metabolic phenotype and gut microbiota in lean and obese adult Mangalica pigs. Obese or lean groups were created by allowing either ad libitum (obese) or restricted (lean) access to a standard diet for 54 weeks. Mature obese pigs were significantly heavier and exhibited 170% greater subcutaneous adipose tissue mass, with no differences in muscle mass compared to their lean counterparts. Obese pigs displayed impaired glucose tolerance and hyperinsulinemia following oral glucose challenge, indicating that a metabolic phenotype also manifested with changes in body composition. Consistent with observations in human obesity, the gut microbiota of obese pigs displayed altered bacterial composition. In the second study, we characterized the longitudinal changes in the gut microbiota in response to diet and aging in growing Mangalica pigs that were either limit fed a standard diet, allowed ad libitum access to a standard diet, or allowed ad libitum access to a high fat-supplemented diet over an 18-week period. As expected, weight gain was highest in pigs fed the high fat diet compared to ad libitum and limit fed groups. Furthermore, the ad libitum and high fat groups displayed significantly greater adiposity consistent with the development of obesity relative to the limit fed pigs. The intestinal microbiota was generally resilient to differences in dietary intake (limit fed vs ad libitum), though changes in the microbiota of pigs fed the high fat diet mirrored changes observed in mature obese pigs during the first study. This is consistent with the link observed between the microbiota and adiposity. In contrast to intestinal bacterial populations, bacteriophage populations within the gut microbiota responded rapidly to differences in diet, with significant compositional changes in bacteriophage genera observed between the dietary treatment groups as pigs aged. These studies are the first to describe the development of the intestinal microbiota in the Mangalica pig, and are the first to provide evidence that changes in body composition and dietary conditions are associated with changes in the microbiome of this novel porcine model of obesity.

Double-outlet right ventricle with an intact interventricular septum and concurrent hypoplastic left ventricle in a calf

A 3-day-old Hereford heifer calf presented for evaluation of lethargy and dyspnea, with persistent hypoxia despite supplemental oxygen therapy. A grade III/VI right apical systolic murmur was noted during cardiac auscultation. Echocardiography revealed a double-outlet right ventricle with an intact interventricular septum and concurrent hypoplastic left ventricle and tricuspid valve dysplasia. Post-mortem examination revealed additional congenital anomalies of ductus arteriosus, patent foramen ovale, and persistent left cranial vena cava. This report illustrates the use of echocardiographic images to diagnose a double-outlet right ventricle with an intact interventricular septum and a hypoplastic left ventricle in a calf.

Prognostic indicators of outcome in nonambulatory beef cattle presented to 2 referral hospitals: A retrospective study of 63 cases

BACKGROUND

Down cow syndrome is commonly described in dairy cattle. The diagnosis and treatment of nonambulatory cattle is challenging and prognostic indicators of this condition in beef cattle have not been determined.

OBJECTIVES

Evaluate records of beef cattle (≥2 years of age) presented to 2 referral hospitals for inability to stand and identify prognostic indicators for survival to discharge.

ANIMALS

Sixty-three adult beef cattle treated for inability to stand at 2 referral hospitals.

METHODS

Medical records of 63 beef cattle presented for inability to stand between January 2010 and December 2022 were retrospectively analyzed. Continuous and categorical variables were included in univariate and multivariate regression models to evaluate their association with outcome.

RESULTS

Of 63 animals included in the study, 19% (12/63) were discharged, and the remaining 81% (n = 51) either died (11.1%) or were euthanized (69.8%). The odds of being discharged increased with each additional day of hospitalization (odds ratio [OR], 2.66; 95% confidence interval [CI], 1.39-6.89) and with each additional flotation therapy session (OR, 2.108; 95% CI, 1.209-4.219). Down beef cattle with a diagnosis of calving peripheral nerve paralysis and capable of walking out the tank after the first flotation session were 6.66 (95% CI, 1.58-35.51) and 30 (95% CI, 4.4-614.98) times more likely to be discharged compared with cattle that had other diagnoses and those that were unable to walk out the tank, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Treatment of nonambulatory beef cattle carries a poor prognosis. Practitioners can use information from our study as a guide for treatment or euthanasia decisions of nonambulatory beef cattle.

Small ruminant reproductive loss investigation: a retrospective analysis and recommendations for optimizing diagnostic outcomes

Objective

We present a retrospective evaluation of small ruminant reproductive loss investigations performed at the Iowa State University Veterinary Diagnostic Laboratory (ISUVDL) with comprehensive characterization of submission components, etiologies of reproductive losses, and assessment of factors contributing to diagnostic success.

Methods

Data from 354 small ruminant abortion submissions received at ISUVDL between January 1, 2019, and December 31, 2023, were evaluated for history completeness, sample inventory, gross and histologic lesions, culture yield, and molecular testing results. Univariate logistic regression models were employed to assess associations between achieving a definitive diagnosis and specific submission variables.

Results

A definitive etiology for pregnancy wastage was achieved in 50.3% of caprine and 64.6% of ovine submissions. Bacterial abortions represented the largest etiologic category, with Campylobacter jejuni accounting for the greatest share of bacterial infections (36.2% of bacterial abortions and 10.7% of all cases). Toxoplasma gondii was the single most frequently diagnosed abortifacient agent (15%), while fungal and viral abortions were rare (< 2%). Sampling and diagnostic completeness, with the inclusion of both fetus and placenta (OR, 2.61), and performance of histopathology, culture, and molecular screening in tandem (OR, 2.03) were found to have the greatest positive impact on diagnostic outcomes.

Conclusions

Diagnostic outcomes are optimized by complete sampling and testing, with priority placed on comprehensive molecular screening for pathogens that are highly significant for herd health.

Clinical Relevance

This retrospective provides an in-depth summary of small ruminant abortion case data from submissions received at ISUVDL and makes recommendations for improving diagnostic outcomes in reproductive loss investigations.

Sinonasal chondrosarcoma in a llama

A 14-y-old intact female llama (Lama glama) was presented for evaluation of a right maxillary swelling of 3-mo duration. Clinically, the animal had mild nasal discharge, abnormal retropulsion of the right eye, and moderate gingival disease. An incisional biopsy of the maxillary mass revealed pleomorphic and mitotically active neoplastic spindle-to-stellate cells organized in haphazard lacunae embedded in abundant chondroid matrix. Given the poor prognosis, euthanasia was elected. Postmortem examination and sectioning of the head exposed a large solid, white, firm mass that vastly expanded the right infraorbital region, extending to the maxilla, effacing the right nasal conchae and ipsilateral zygomatic bone. Collectively, postmortem dissection, cytology, and histopathology of the primary mass supported a diagnosis of sinonasal chondrosarcoma. To our knowledge, this entity had not been reported previously in this species and should be considered a differential for facial deformities in New World camelids.

Biosecurity Principles for Reproductive Diseases of Cattle

This article addresses infectious reproductive diseases in cattle, which can significantly impact production and profit on cattle operations. It highlights vital biosecurity practices aimed at minimizing the introduction of reproductive pathogens into breeding herds, including the importance of maintaining records, implementing a defined breeding season, culling nonproductive animals, quarantining and testing imported livestock, and the use of vaccines to maximize herd immunity. The article focuses on economically important reproductive pathogens of cattle from a biosecurity standpoint, focusing on mitigating the introduction and impact of reproductive diseases in cattle.

Onset and duration of action of escalating doses of atracurium in anesthetized healthy goats

OBJECTIVE

The aim of this study was to describe the onset and duration of action of escalating doses of atracurium in healthy, anesthetized goats.

STUDY DESIGN

Randomized, blinded, triple crossover study. Animals A total of eight (five males and three females) healthy goats weighing 42.7-123.5 kg and aged from 11 months to 8 years.

METHODS

Goats were anesthetized three times with propofol and anesthesia was maintained with isoflurane. One of three doses of atracurium was administered intravenously 30 minutes after induction: 0.25 mg kg-1 (AT25), 0.5 mg kg-1 (AT50) or 0.75 mg kg-1 (AT75). Acceleromyographic train-of-four ratio (TOFR) followed by train-of-four counts (TOFC) were recorded at 30 second intervals after atracurium administration to determine blockade onset (TOFC = 0). The TOFR followed by TOFC were recorded at 5 minute intervals until return to pre-atracurium baseline (TOFR = 1.0). Normally distributed data were analyzed with repeated measures anova and a Tukey multiple comparison test. Data not normally distributed were analyzed with a Friedman test and a Dunn's multiple comparison test.

RESULTS

For AT50 and AT75, 100% of goats achieved TOFC = 0 after atracurium administration. For AT25, however, 87.5% of goats achieved TOFC = 0 after atracurium administration. The onset time was shorter for AT75 [1.5 (0.5-1.5) minutes; median (range)] than for AT25 [2 (1-4) minutes] (p = 0.048). The duration of action [from onset time to complete reversal (TOFR = 1.0)] was significantly shorter for AT25 (52 ± 12 minutes, mean ± SD) than for AT50 (77 ± 18 minutes) (p < 0.001) and AT75 (85 ± 16 minutes) (p < 0.001). There was no significant difference in duration between AT50 and AT75 (p = 0.238).

CONCLUSIONS AND CLINICAL RELEVANCE

Doses of 0.5 and 0.75 mg kg-1 atracurium may produce complete neuromuscular blockade in healthy, anesthetized goats.

Risk factors associated with outcome in goats with encephalitic listeriosis: A retrospective study of 36 cases from 2008 to 2021

BACKGROUND

There exists a scarcity of information on risk factors associated with case outcomes in goats diagnosed with encephalitic listeriosis.

OBJECTIVE

Evaluate risk factors associated with outcomes in 36 cases of suspected encephalitic listeriosis in goats presented to a referral hospital.

ANIMALS

Thirty-six goats (26 does, 7 bucks, and 3 wethers) were presented to Auburn University Large Animal Teaching Hospital between 2008 and 2021 for treatment of neurologic disease diagnosed as encephalitic listeriosis based on any combination of clinical signs, cerebral spinal fluid (CSF) analysis, or postmortem examination.

METHODS

Retrospective study. Data were analyzed as binary and under a proportional odds model. The medical records were searched for presumptive encephalitic listeriosis in goats between 2008 and 2021. Data collected included signalment (sex, age, and breed), history, clinical signs, temperature, and ability to stand at presentation. Final diagnosis, CSF results, all treatments, outcomes, and results of necropsy were also collected for analysis.

RESULTS

Male goats were 14 (95% CI: 1.98-166.0) times more likely to be a non-survivor compared to females despite being presented with similar history, clinical signs, and treatments. Animals presented with circling or a history of circling were 6.24 (95% CI: 1.40-23.21) times more likely to be a survivor than a non-survivor. Other risk factors evaluated were not significantly associated with outcomes.

CONCLUSIONS AND CLINICAL IMPORTANCE

Few risk factors were associated with outcomes. Duration of clinical signs, antimicrobial or anti-inflammatory choices, or CSF results were not associated with outcome. Only sex and history or presence of circling were associated with case outcomes.

Successful resolution of a preputial prolapse in an alpaca using medical therapy

A 2-year-old intact male alpaca was presented for a post-breeding preputial prolapse of 5 days duration. The internal lamina of the prepuce was prolapsed approximately 6 cm and the exposed preputial epithelium was edematous and necrotic. Following 7 days of medical treatment, resolution of the preputial prolapse was achieved.

Biosecurity for Reproductive Disease Prevention in Sheep and Goats

Infectious reproductive diseases pose a significant economic threat to sheep and goat operations. Maintaining records, a defined breeding season, and recognizing deviations from normal are crucial to herd health programs. Signs of suboptimal fertility, such as repeat breeding, unexpected open females, and abnormal gestational distributions, warrant further investigation. Important causes of infectious abortion discussed include chlamydiosis (enzootic abortion), coxiellosis, campylobacteriosis, toxoplasmosis, and brucellosis. Given the potential zoonotic nature of abortion in small ruminants, producer education is imperative. Implementing the sound biosecurity practices is critical for reducing the introduction of reproductive pathogens and enhancing the overall health of flocks and herds.

Pregnancy Toxemia Therapeutic Options

This review covers the treatment options for pregnancy toxemia in small ruminants. Clinical assessment and detection of underlying metabolic and electrolyte derangements direct resuscitation efforts and provide prognostic indications. Treatment programs are dependent on producer goals and case specifics. Options include oral glucogenic precursors (eg, propylene glycol, glycerol), intravenous glucose solutions, insulin, and other supportive care measures. Induction of parturition or C-section is often carried out to minimize ongoing energy deficits, with variable survival rates. Prolonging gestation to maximize fetal viability often requires intensive care in a hospital setting and carries significant risk to both dam and offspring.

Exploratory application of a cannulation model in recently weaned pigs to monitor longitudinal changes in the enteric microbiome across varied porcine reproductive and respiratory syndrome virus (PRRSV) infection statuses

Introduction

The enteric microbiome and its possible modulation to improve feed conversion or vaccine efficacy is gaining more attention in pigs. Weaning pigs from their dam, along with many routine procedures, is stressful. A better understanding of the impact of this process on the microbiome may be important for improving pig production. The objective of this study was to develop a weaner pig cannulation model, thus allowing ileum content collection from the same pig over time for 16S rRNA sequencing under different porcine reproductive and respiratory syndrome virus (PRRSV) infection statuses.

Methods

A total of 15 3-week-old pigs underwent abdominal surgery and were fitted with an ileum cannula, with ileum contents collected over time. In this pilot study, treatment groups included a NEG-CONTROL group (no vaccination, no PRRSV challenge), a POS-CONTROL group (no vaccination, challenged with PRRSV), a VAC-PRRSV group (vaccinated, challenged with PRRSV), a VAC-PRO-PRRSV group (vaccinated, supplemented with a probiotic, challenged with PRRSV), and a VAC-ANTI-PRRSV group (vaccinated, administered an antibiotic, challenged with PRRSV). We assessed the microbiome over time and measured anti-PRRSV serum antibodies, PRRSV load in serum and nasal samples, and the severity of lung lesions.

Results

Vaccination was protective against PRRSV challenge, irrespective of other treatments. All vaccinated pigs mounted an immune response to PRRSV within 1 week after vaccination. A discernible impact of treatment on the diversity, structure, and taxonomic abundance of the enteric microbiome among the groups was not observed. Instead, significant influences on the ileum microbiome were observed in relation to time and treatment.

Discussion

The cannulation model described in this pilot study has the potential to be useful in studying the impact of weaning, vaccination, disease challenge, and antimicrobial administration on the enteric microbiome and its impact on pig health and production. Remarkably, despite the cannulation procedures, all vaccinated pigs exhibited robust immune responses and remained protected against PRRSV challenge, as evidenced by the development of anti-PRRSV serum antibodies and viral shedding data.

Acute renal failure in 2 adult llamas after exposure to Oak trees (Quercus spp.)

Two adult llamas (Lama glama) previously exposed to oak trees (Quercus spp.) were presented with a history of depression and anorexia. Clinicopathological abnormalities included severe gastroenteritis, acute renal failure, and increased liver enzymes. This is believed to be the first report of oak toxicosis in South American camelids.

Similar performance between modified retrobulbar and ultrasound-guided Peterson nerve blocks using computed tomography in bovine cadavers

Objective

Description and performance of an ultrasound-guided Peterson (UP) block technique were compared to those of a conventional modified retrobulbar (RB) nerve block in bovine cadaver heads by use of CT.

Methods

This was an original descriptive study using 10 normal orbits from 5 bovid cadavers between April 17 and 23, 2024. Standardized techniques for the modified RB and UP blocks were utilized, with each technique randomly performed on either orbit of each head. Blocks were performed with 9-cm, 18-gauge spinal needles and iopamidol as a contrast solution. Ultrasound guidance involved the use of a 12-MHz linear transducer, and subsequent imaging of contrast distribution was performed with a GE Lightspeed 16-slice CT scanner.

Results

Contrast deposition within the intraconal space was observed in 5 of 5 RB blocks and 5 of 5 UP blocks. No extraconal contrast deposition was observed in either block technique. Extension of contrast in close association with the optic nerve to the level of orbital foramen was observed in 5 of 5 RB orbits and 5 of 5 UP orbits. Extension of the contrast to the level of the foramen orbitorotundum was seen in 5 of 5 RB orbits and 3 of 5 UP orbits. Correct needle placement was observed in 5 of 5 UP orbits and confirmed on CT images.

Conclusions

The RB and UP blocks performed similarly, demonstrating similar intraconal distribution of contrast medium and no inadvertent distribution to unintended anatomical locations.

Clinical Relevance

The performance of the ultrasound-guided technique in live cattle and ability to successfully achieve adequate blockade need further study.