An in vitro larval motility assay characterizes anthelmintic efficacy against Crenosoma vulpis, Angiostrongylus vasorum, and Aelurostrongylus abstrusus

OBJECTIVE

This study determined the in vitro efficacy of 6 common anthelmintics (eprinomectin, ivermectin, milbemycin oxime, moxidectin, selamectin, and fenbendazole) on motility (viability) of infectious third-stage larvae (L3) of Crenosoma vulpis, Angiostrongylus vasorum, and Aelurostrongylus abstrusus, which are important causes of canine and feline cardiopulmonary disease.

SAMPLES

First-stage larvae (L1) from C vulpis, An vasorum, and Ae abstrusus.

PROCEDURES

Naïve Limax maximus slugs were fed 1,000 to 2,000 L1 and held at 16 °C for at least 4 weeks to produce live L3. Approximately 50 to 100 L3/well were subsequently incubated in culture media alone or media containing 6 separate test anthelmintics at 4 concentrations, to bracket expected in vivo drug plasma levels in anthelmintic-treated dogs and cats. Drug effects on L3 motility (viability) were analyzed by multilevel logistic models, generating dose-response relationships. Experiments were completed 1-9/2019.

RESULTS

Drug concentration estimates corresponding to a 50% larval mortality rate identified that C vulpis was the most sensitive species to the anthelmintics tested. Ae abstrusus was most susceptible to moxidectin and selamectin, while An vasorum was insusceptible to all anthelmintics tested, except for selamectin at high drug concentrations.

CLINICAL RELEVANCE

The in vitro anthelmintic response to antiparasitic agents may guide and improve disease therapy and prevention. Considering the observed lack of efficacy against L3, monthly anthelmintic treatment for protection against An vasorum infection in dogs would primarily rely on the anthelmintic's adulticidal activity. Maximal preventive control for An vasorum would, therefore, require at least 1 treatment administered a minimum of 1 week after the end of the transmission season.

A Longitudinal Analysis of Equine Asthma Presentation and Response to Treatment Using Lung Function Testing and BAL Cytology Analysis in Combination with Owner Perception

(1) Background: Equine asthma (EA) is a pervasive and important cause of poor performance and respiratory morbidity in horses. Diagnosis of EA includes an owner complaint, clinical scoring, lung function testing, and cytological analysis of bronchoalveolar lavage (BAL) cytology. There is a paucity of information about the longitudinal course of the disease using these outcome assessments; thus, this study sought to describe and quantify, in horses with more than one visit to a specialty pulmonary clinic in New England, the type and range of clinical presentations with an eventual diagnosis of EA. It also aimed to develop and compare the outcomes of scoring systems for owner complaints and veterinary assessments, document and assess the diagnostic methods used, and evaluate the response of the horses to treatment and time. (2) Methods: This study was a retrospective, cross-sectional, STROBE-compliant observational analysis of equine patients who visited the Tufts Cummings Hospital for Large Animals (HLA) for evaluation of equine asthma (EA) from 1999-2023. The horses were categorized as having mild-moderate (mEA) or severe EA (sEA) using the ACVIM consensus statement guidelines. After excluding those with inadequate documentation or only one visit (n = 936), a total of 76 horses were included in the study. Of the 197 visits, 138 (70.0%) resulted in a diagnosis of mEA and 45 (22.8%) resulted in a diagnosis of sEA. Demographic information, owner complaints, clinical examination and scoring, lung function testing, BAL cytology, and recommendations for environmental remediation and pharmacologic treatment were recorded for all the visits. The data were analyzed for agreement between owner complaints (complaint score, CS) and clinical examination findings (examination score, ES), changes in CS and ES, lung function testing, and BAL cytology over time, with 197 visits recorded. (3) Results: A comparison between the CS and ES showed that the owners were more likely than veterinarians to detect cough, and a decrease in cough was the most common owner observation after treatment. The response to the histamine challenge, used to detect airway hyperreactivity, was significantly improved with treatment or time in the horses with mEA, whereas baseline lung function did not significantly change in mEA or sEA. (4) Conclusions: Owners can be astute observers of clinical signs, especially cough, in EA. Tests of airway hyperreactivity are more successful in detecting changes in mEA than are baseline lung function testing and assessment of BAL cytology.

Bronchoalveolar lavage hemosiderosis in lightly active or sedentary horses

BACKGROUND

Hemosiderophages in bronchoalveolar lavage fluid (BALF) are commonly ascribed to exercise-induced pulmonary hemorrhage (EIPH). Little information exists regarding the presence of these cells in horses that perform light or no work and that are referred for respiratory problems.

OBJECTIVES

Evaluate the presence of hemosiderophages in BALF of horses suspected of respiratory disease without history of or risk factors for EIPH and determine predictors of hemosiderophages in BALF in this population.

METHODS

Observational retrospective cross-sectional study using STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines. Bronchoalveolar lavage fluid cytology reports of 353 horses evaluated for respiratory disease between 2012 and 2022 at the Cummings School for Veterinary Medicine were reviewed retrospectively. Horses with a history or likelihood of having performed past strenuous exercise were removed, and the remaining 91 horses were divided into hemosiderin-positive (HSD-POS) and hemosiderin-negative groups based on Perls' Prussian blue staining. Potential predictors for the presence of hemosiderophages in BALF (history, clinical evaluation, baseline lung function, airway reactivity, BALF cytology, and hemosiderin score) were compared between the 2 groups, using univariate and multivariate analyses.

RESULTS

Horses with a diagnosis of severe equine asthma (sEA; odds ratio, 11.1; 95% confidence interval, 3.2-38.5; P < .001) were significantly more likely to be HSD-POS than horses with mild-to-moderate equine asthma.

CONCLUSIONS AND CLINICAL IMPORTANCE

Hemosiderophages were found in the BALF cytology in a subset of horses that perform light or no work and presented for respiratory signs; these cells were found more frequently in horses with sEA. The link between hemosiderophages and sEA highlights previously unstudied pathology associated with this common disease.

Clinical effects and pharmacokinetics of nebulized lidocaine in healthy horses

Background

Nebulized lidocaine appears promising as a novel corticosteroid-sparing therapeutic for equine asthma, but its safety and pharmacokinetic behavior have yet to be confirmed.

Objective

To describe the effect of nebulized lidocaine on upper airway sensitivity, lung mechanics, and lower respiratory cellular response of healthy horses, as well as delivery of lidocaine to lower airways, and its subsequent absorption, clearance, and duration of detectability.

Animals

Six healthy university- and client-owned horses with normal physical examination and serum amyloid A, and no history of respiratory disease within 6 months.

Methods

Prospective, descriptive study evaluating the immediate effects of 1 mg/kg 4% preservative-free lidocaine following nebulization with the Flexineb^®. Prior to and following nebulization, horses were assessed using upper airway endoscopy, bronchoalveolar lavage, and pulmonary function testing with esophageal balloon/pneumotachography and histamine bronchoprovocation. Additionally, blood and urine were collected at predetermined times following single-dose intravenous and nebulized lidocaine administration for pharmacokinetic analysis.

Results

Upper airway sensitivity was unchanged following lidocaine nebulization, and no laryngospasm or excessive salivation was noted. Lidocaine nebulization (1 mg/kg) resulted in a mean epithelial lining fluid concentration of 9.63 ± 5.05 μg/mL, and a bioavailability of 29.7 ± 7.76%. Lidocaine concentrations were higher in epithelial lining fluid than in systemic circulation (C_max 149.23 ± 78.74 μg/L, C_ELF:C_maxplasma 64.4, range 26.5–136.8). Serum and urine lidocaine levels remained detectable for 24 and 48 h, respectively, following nebulization of a single dose. Baseline spirometry, lung resistance and dynamic compliance, remained normal following lidocaine nebulization, with resistance decreasing post-nebulization. Compared to the pre-nebulization group, two additional horses were hyperresponsive following lidocaine nebulization. There was a significant increase in mean airway responsiveness post-lidocaine nebulization, based on lung resistance, but not dynamic compliance. One horse had BAL cytology consistent with airway inflammation both before and after lidocaine treatment.

Conclusions

Nebulized lidocaine was not associated with adverse effects on upper airway sensitivity or BAL cytology. While baseline lung resistance was unchanged, increased airway reactivity to histamine bronchoprovocation in the absence of clinical signs was seen in some horses following nebulization. Further research is necessary to evaluate drug delivery, adverse events, and efficacy in asthmatic horses.

Single domain antibodies against enteric pathogen virulence factors are active as curli fiber fusions on probiotic E. coli Nissle 1917

Enteric microbial pathogens, including Escherichia coli, Shigella and Cryptosporidium species, take a particularly heavy toll in low-income countries and are highly associated with infant mortality. We describe here a means to display anti-infective agents on the surface of a probiotic bacterium. Because of their stability and versatility, VHHs, the variable domains of camelid heavy-chain-only antibodies, have potential as components of novel agents to treat or prevent enteric infectious disease. We isolated and characterized VHHs targeting several enteropathogenic E. coli (EPEC) virulence factors: flagellin (Fla), which is required for bacterial motility and promotes colonization; both intimin and the translocated intimin receptor (Tir), which together play key roles in attachment to enterocytes; and E. coli secreted protein A (EspA), an essential component of the type III secretion system (T3SS) that is required for virulence. Several VHHs that recognize Fla, intimin, or Tir blocked function in vitro. The probiotic strain E. coli Nissle 1917 (EcN) produces on the bacterial surface curli fibers, which are the major proteinaceous component of E. coli biofilms. A subset of Fla-, intimin-, or Tir-binding VHHs, as well as VHHs that recognize either a T3SS of another important bacterial pathogen (Shigella flexneri), a soluble bacterial toxin (Shiga toxin or Clostridioides difficile toxin TcdA), or a major surface antigen of an important eukaryotic pathogen (Cryptosporidium parvum) were fused to CsgA, the major curli fiber subunit. Scanning electron micrographs indicated CsgA-VHH fusions were assembled into curli fibers on the EcN surface, and Congo Red binding indicated that these recombinant curli fibers were produced at high levels. Ectopic production of these VHHs conferred on EcN the cognate binding activity and, in the case of anti-Shiga toxin, was neutralizing. Taken together, these results demonstrate the potential of the curli-based pathogen sequestration strategy described herein and contribute to the development of novel VHH-based gut therapeutics.

The association between fecal microbiota, age and endoparasitism in adult alpacas

Endoparasitism is a major cause of morbidity and mortality in alpacas (Lama pacos), with growing emergence of anthelmintic resistance. The purpose of the study was to correlate nematode worm burden and selected host phenotypic characteristics, such as age and weight, with the composition of the intestinal microbiota of adult alpacas. Fecal samples were collected per rectum from 102 healthy adult (2.1-11.2 years) alpacas at 3 separate timepoints (pre- and post-treatment with 8.8 mg/kg oral Levamisole HCL, and 4.6 months later) at a single farm. The profile of the fecal bacterial microbiota was characterized using 16S amplicon sequencing. Serial clinical exams and fecal egg counts were compared using related-samples analyses. The fecal microbiota of identically managed, healthy alpacas was characterized by a high level of temporal stability, as both α and β-diversity significantly correlated between sampling timepoints. Pairwise β-diversity between samples collected at each timepoint was low, ranging from 0.16-0.21 UniFrac distance units. The intensity of strongylid nematode infection (including Haemonchus, Ostertagia, Trichostrongylus) was only significantly correlated with microbiota composition in samples collected 14 days after treatment with levamisole. Analysis of similarity revealed no clustering of microbiota from anthelmintic responders or non-responders. Alpaca age explained the largest proportion of fecal microbiota variation and was the only consistently significant predictor of fecal microbiota taxonomic composition, by impacting the ratio of relative Bacteroidetes and Firmicutes abundance. Firmicutes, mostly Clostridiales, was the most abundant taxon across all collections.

A CONSORT-guided, randomized, double-blind, controlled pilot clinical trial of inhaled lidocaine for the treatment of equine asthma

There are limited options for treatment of the common disease, equine asthma. The aim of this study was to estimate the feasibility and potential efficacy of using nebulized lidocaine for treating equine asthma, while at the same time treating a separate cohort of asthmatic horses with inhaled budesonide. Nineteen horses with a history consistent with equine asthma were recruited from our referral population for a double-blind, randomized, controlled pilot clinical trial using Consolidated Standards of Reporting Trials (CONSORT) guidelines. After screening, 16 horses met the inclusion criteria for equine asthma and 13 horses actually completed the study. Horses were treated by their owners at home for 14 d before returning to our hospital for follow-up assessment. Interventions consisted of nebulization q12h for 14 d with 1.0 mg/kg body weight (BW) of lidocaine or corticosteroid treatment (nebulized budesonide 1 μg/kg, q12h). Clinical and tracheal mucus score, pulmonary function testing, and respiratory secretion cytology were assessed after 2 weeks of treatment to determine the outcome. Both lidocaine and budesonide cohorts had significant decreases (P < 0.05) in clinical score; the lidocaine cohort showed a significant decrease in bronchoalveolar lavage (BAL) neutrophil percentage and tracheal mucus score. Neither treatment resulted in significant changes in lung function parameters. No adverse events occurred. Lidocaine may be an effective and safe treatment for equine asthma in horses that cannot tolerate treatment with corticosteroids.

Assessment of the impact of age and of blood-derived inflammatory markers in horses with colitis

OBJECTIVES

To determine the impact of age on survival in horses with colitis and to elucidate whether a lower type-1/type-2 cytokine ratio or an exaggerated inflammatory state contribute to reduced survival in aged horses.

DESIGN

Part 1: Retrospective cohort analysis. Part 2: Analytic observational study.

ANIMALS

Part 1: One hundred twenty-four adult horses with colitis. Part 2: Twenty-nine adult horses with new diarrhea onset while hospitalized.

MEASUREMENTS AND MAIN RESULTS

Part 1: Patient signalment, select clinicopathological data, diagnoses, treatment, hospitalization length, and invoice were compared between survivors (n = 101) and nonsurvivors (n = 23). Only age and plasma transfusion retained statistical significance in the final multivariate outcome model, with 8.5 times lower odds of survival in transfused horses (95% confidence interval [CI], 2.6-27.2%). Additionally, the likelihood of nonsurvival increased by 11.8% (95% CI, 4-20.2%) for every year the horse aged (P = 0.002). Similarly, geriatric horses (≥20 years) were 15.2 times more likely to die than young-adults (2-12 years, P = 0.03), independent of financial investment, documented comorbidities, and duration of hospitalization. Part 2: Select cytokine analyses were performed on serum collected from hospitalized horses within 1 hour of diarrhea onset (T0) and 6 hours later. At T0, all recorded clinicopathological variables were comparable between geriatric and young-adult horses, suggesting a similar degree of systemic illness. The median concentration of type-2 cytokines interleukin-4 and interleukin-10, and type-1 cytokine interferon-γ did not differ between age groups. Inflammatory cytokines interleukin-6 and tumor necrosis factor-α were significantly higher in geriatric compared to young-adult horses at both sampling time points.

CONCLUSIONS

Outcome of colitis was less favorable in aging horses and patients receiving a plasma transfusion. Although an exaggerated inflammatory state, based on increased interleukin-6 and tumor necrosis factor-α concentrations, in geriatric horses may contribute to reduced survival, a lower type-1/type-2 cytokines ratio was not identified in our geriatric population.

Comparative evaluation of clinical findings and prognostic outcome parameters in hospitalized, critically ill neonatal foals and crias

OBJECTIVE

Species-related differences in the prevalence, manifestation, and outcome of neonatal illness may impact management practices of neonatal intensive care. The study aimed to elucidate similarities between disease manifestations and mortality risks of critically ill (CI) neonatal crias and foals admitted to the same referral center.

DESIGN

A comparative, retrospective cohort evaluation of two species (camelid and equine).

SETTING

The study was conducted in a University hospital.

ANIMALS

Two hundred and forty-six CI neonatal crias (January 1999 to May 2016) and 356 neonatal foals (February 2001 to May 2016) under 4-week-old were admitted to a university hospital.

INTERVENTION

All data are presented descriptively and compared between groups using univariate and multivariate analyses.

MEASUREMENTS AND MAIN RESULTS

Female crias (142/246, 57.7%) were significantly overrepresented in comparison to fillies (132/352, 37.5%). Congenital defects and transfer failure of passive immunity were more often observed in neonatal crias, while colic, diarrhea, patent urachus, septic arthritis, and omphalitis were significantly more common in CI foals. Overall survival to discharge (excluding fatal congenital defects) was comparable between crias (174/224; 77.8%) and foals (287/347, 82.1%), while crias (26/48; 54.2%) were more likely than foals (21/60; 35%) to die naturally than undergo euthanasia. Lower respiratory disease and indications for oxygen or IV glucose support increased mortality in the multivariate outcome models of both species. Species-specific adaptations of pediatric diagnostic criteria for sepsis were significantly associated with mortality in the multivariate analysis of patients with complete hematological datasets. However, the diagnosis of systemic inflammatory response syndrome (SIRS) did not retain statistical significance as an independent outcome predictor.

CONCLUSIONS

Lower respiratory disease and oxygen or glucose dysregulation increased mortality irrespective of species. However, despite species-specific differences in disease prevalence, the success of intensive care management was comparable.

Comparison of Flowmetric Plethysmography and Forced Oscillatory Mechanics to Measure Airway Hyperresponsiveness in Horses

Airway hyperresponsiveness (AHR) is linked to airway inflammation and is considered a key manifestation of mild/moderate equine asthma (EA). The study purpose was to determine whether two modalities of non-invasive lung function testing (FOM-forced oscillatory mechanics vs. FP-flowmetric plethysmography) establish the same clinical diagnosis of AHR in horses, using histamine bronchoprovocation. Nineteen horses (3-25 years, 335-650 kg) with clinical signs suggestive of mild/moderate equine asthma were enrolled. FOM and FP testing was performed in each horse on two consecutive days, using a randomized cross-over design. AHR was defined by the histamine dose needed to double FOM baseline resistance, or to achieve a 35% increase in FP delta flow. Bronchoalveolar lavage fluid (BALF) was subsequently collected and stained with modified Wright's and toluidine blue stains. Binary statistical tests (related samples T-test, Mann-Whitney U, Chi-square analyses) were performed to compare study groups, with P < 0.05 considered significant. Abnormal BALF cytology confirmed EA in 14/19 (73.7%) horses. Both FOM and FP revealed AHR in 7/14 (50%) of these EA horses. An additional 4/19 (21.1%) horses showed AHR based on FP but not FOM, including two horses with normal BALF cytology. A diagnosis of AHR was more often associated with FP than FOM (P = 0.013), although the prevalence of AHR was significantly higher in EA vs. non-EA horses, regardless of testing methodology. The phase angle between thoracic and abdominal components of breathing did not differ between test groups. In conclusion, FP diagnosed AHR more frequently than did FOM, including horses with no other diagnostic evidence of EA. Without further evaluation, these two testing modalities of AHR cannot be used interchangeably.

Assessment of clinical and microbiota responses to fecal microbial transplantation in adult horses with diarrhea

BACKGROUND AND AIMS

Fecal microbial transplantation (FMT) is empirically implemented in horses with colitis to facilitate resolution of diarrhea. The purpose of this study was to assess FMT as a clinical treatment and modulator of fecal microbiota in hospitalized horses with colitis.

METHODS

A total of 22 horses with moderate to severe diarrhea, consistent with a diagnosis of colitis, were enrolled at two referral hospitals (L1: n = 12; L2: n = 10). FMT was performed in all 12 patients on 3 consecutive days at L1, while treatment at L2 consisted of standard care without FMT. Manure was collected once daily for 4 days from the rectum in all colitis horses, prior to FMT for horses at L1, and from each manure sample used for FMT. Fecal samples from 10 clinically healthy control horses housed at L2, and 30 healthy horses located at 5 barns in regional proximity to L1 were also obtained to characterize the regional healthy equine microbiome. All fecal microbiota were analyzed using 16S amplicon sequencing.

RESULTS AND CONCLUSIONS

As expected, healthy horses at both locations showed a greater α-diversity and lower β-diversity compared to horses with colitis. The fecal microbiome of healthy horses clustered by location, with L1 horses showing a higher prevalence of Kiritimatiellaeota. Improved manure consistency (lower diarrhea score) was associated with a greater α-diversity in horses with colitis at both locations (L1: r = -0.385, P = 0.006; L2: r = -0.479, P = 0.002). Fecal transplant recipients demonstrated a greater overall reduction in diarrhea score (median: 4±3 grades), compared to untreated horses (median: 1.5±3 grades, P = 0.021), with a higher incidence in day-over-day improvement in diarrhea (22/36 (61%) vs. 10/28 (36%) instances, P = 0.011). When comparing microbiota of diseased horses at study conclusion to that of healthy controls, FMT-treated horses showed a lower mean UniFrac distance (0.53±0.27) than untreated horses (0.62±0.26, P<0.001), indicating greater normalization of the microbiome in FMT-treated patients.

Camelid VHH Antibodies that Neutralize Botulinum Neurotoxin Serotype E Intoxication or Protease Function

Botulinum neurotoxin (BoNT) serotype E is one of three serotypes that cause the preponderance of human botulism cases and is a Tier 1 Select Agent. BoNT/E is unusual among BoNT serotypes for its rapid onset and short duration of intoxication. Here we report two large panels of unique, unrelated camelid single-domain antibodies (VHHs) that were selected for their ability to bind to BoNT/E holotoxin and/or to the BoNT/E light chain protease domain (LC/E). The 19 VHHs which bind to BoNT/E were characterized for their subunit specificity and 8 VHHs displayed the ability to neutralize BoNT/E intoxication of neurons. Heterodimer antitoxins consisting of two BoNT/E-neutralizing VHHs, including one heterodimer designed using structural information for simultaneous binding, were shown to protect mice against co-administered toxin challenges of up to 500 MIPLD₅₀. The 22 unique VHHs which bind to LC/E were characterized for their binding properties and 9 displayed the ability to inhibit LC/E protease activity. Surprisingly, VHHs selected on plastic-coated LC/E were virtually unable to recognize soluble or captured LC/E while VHHs selected on captured LC/E were poorly able to recognize LC/E coated to a plastic surface. This panel of anti-LC/E VHHs offer insight into BoNT/E function, and some may have value as components of therapeutic antidotes that reverse paralysis following BoNT/E exposures.

The fecal microbiota of healthy donor horses and geriatric recipients undergoing fecal microbial transplantation for the treatment of diarrhea

BACKGROUND AND AIMS

Fecal microbial transplantation (FMT), a treatment for certain gastrointestinal conditions associated with dysbiosis in people, is also empirically employed in horses with colitis. This study used microbiota high-throughput sequencing to compare the fecal microbial profile of healthy horses to that of geriatric microbial transplant recipients experiencing diarrhea and tested whether FMT restores microbiota diversity.

METHODS

To evaluate the effect of environment and donor characteristics on the intestinal microbiota, fecal samples were collected per rectum from 15 healthy young-adult (2-12 years) and 15 geriatric (≥20 years) horses. Additionally, FMT was performed for 3 consecutive days in 5 geriatric horses with diarrhea using feces from the same healthy donor. Fecal samples were collected from both donor and recipient prior to each FMT and from recipients 24 hours following the last FMT. The profile of the fecal bacterial microbiota was compared using 16S amplicon sequencing.

RESULTS AND CONCLUSIONS

In contrast to diet and farm location, age did not significantly affect the healthy equine fecal microbiota, indicating that both healthy geriatric and young-adult horses may serve as FMT donors. The fecal microbiota of horses with diarrhea was significantly more variable in terms of β-diversity than that of healthy horses. An inverse correlation between diarrhea score and relative abundance of Verrucomicrobia was identified in surviving FMT recipients. At study completion, the fecal microbiota of horses which responded to FMT had a higher α-diversity than prior to treatment and was phylogenetically more similar to that of the donor.

Association between inflammatory airway disease of horses and exposure to respiratory viruses: a case control study

Background: Inflammatory airway disease (IAD) in horses, similar to asthma in humans, is a common cause of chronic poor respiratory health and exercise intolerance due to airway inflammation and exaggerated airway constrictive responses. Human rhinovirus is an important trigger for the development of asthma; a similar role for viral respiratory disease in equine IAD has not been established yet. Methods: In a case–control study, horses with IAD (n = 24) were compared to control animals from comparable stabling environments (n = 14). Horses were classified using pulmonary function testing and bronchoalveolar lavage. PCR for equine rhinitis virus A and B (ERAV, ERBV), influenza virus (EIV), and herpesviruses 2, 4, and 5 (EHV-2, EHV-4, EHV-5) was performed on nasal swab, buffy coat from whole blood, and cells from BAL fluid (BALF), and serology were performed. Categorical variables were compared between IAD and control using Fisher’s exact test; continuous variables were compared with an independent t-test. For all analyses, a value of P <0.05 was considered significant. Results: There was a significant association between diagnosis of IAD and history of cough (P = 0.001) and exercise intolerance (P = 0.003) but not between nasal discharge and IAD. Horses with IAD were significantly more likely to have a positive titer to ERAV (68 %) vs. control horses (32 %). Horses with IAD had higher log-transformed titers to ERAV than did controls (2.28 ± 0.18 v.1.50 ± 0.25, P = 0.038). There was a significant association between nasal shedding (positive PCR) of EHV-2 and diagnosis of IAD (P = 0.002). Conclusions: IAD remains a persistent problem in the equine population and has strong similarities to the human disease, asthma, for which viral infection is an important trigger. The association between viral respiratory infection and development or exacerbation of IAD in this study suggests that viral infection may contribute to IAD susceptibility; there is, therefore, merit in further investigation into the relationship between respiratory virus exposure and development of IAD.

Metagenomic Next-Generation Sequencing Reveal Presence of a Novel Ungulate Bocaparvovirus in Alpacas

Viruses belonging to the genus Bocaparvovirus(BoV) are a genetically diverse group of DNA viruses known to cause respiratory, enteric, and neurological diseases in animals, including humans. An intestinal sample from an alpaca (Vicugnapacos) herd with reoccurring diarrhea and respiratory disease was submitted for next-generation sequencing, revealing the presence of a BoV strain. The alpaca BoV strain (AlBoV) had a 58.58% whole genome nucleotide percent identity to a camel BoV from Dubai, belonging to a tentative ungulate BoV 8 species (UBoV8). Recombination events were lacking with other UBoV strains. The AlBoV genome was comprised of the NS1, NP1, and VP1 proteins. The NS1 protein had the highest amino acid percent identity range (57.89-67.85%) to the members of UBoV8, which was below the 85% cut-off set by the International Committee on Taxonomy of Viruses. The low NS1 amino acid identity suggests that AlBoV is a tentative new species. The whole genome, NS1, NP1, and VP1 phylogenetic trees illustrated distinct branching of AlBoV, sharing a common ancestor with UBoV8. Walker loop and Phospholipase A2 (PLA2) motifs that are vital for virus infectivity were identified in NS1 and VP1 proteins, respectively. Our study reports a novel BoV strain in an alpaca intestinal sample and highlights the need for additional BoV research.

Retrospective evaluation of clinical outcome after chemotherapy for lymphoma in 15 equids (1991-2017)

BACKGROUND

Prognosis associated with lymphoma in horses is poorly characterized, and treatment is often palliative. Long-term outcome after chemotherapy for horses with lymphoma is not well documented.

OBJECTIVE

To report long-term outcome of horses with lymphoma treated with chemotherapy.

ANIMALS

Fifteen equids.

METHODS

Retrospective case series. Medical record search and call for cases on the ACVIM listserv for horses treated with chemotherapy for lymphoma.

RESULTS

Fifteen cases with adequate data were identified. Complete remission was achieved in 5 horses (33.3%), partial response was achieved in 9 equids (60%), and stable disease was achieved in 1 horse. Overall response rate was 93.3% (14/15). Overall median survival time was 8 months (range, 1-46 months). Nine horses experienced a total of 14 adverse effects attributable to chemotherapy. Adverse effects were graded according to the Veterinary Cooperative Oncology Group common terminology criteria for adverse events grading system (grade 1 alopecia, n = 2; grade 1 neutropenia, n = 2; grade 1 lymphopenia, n = 3; grade 1 lethargy, n = 1; grade 2 neurotoxicity, n = 1; grade 2 colic, n = 1; grade 1 hypersensitivity, n = 1; grade 2 hypersensitivity, n = 2; grade 5 hypersensitivity, n = 1). Higher grade adverse effects most commonly were associated with doxorubicin administration (n = 4), including 1 horse that died 18 hours post-administration.

CONCLUSIONS AND CLINICAL IMPORTANCE

Chemotherapy can be used successfully for treatment of horses with lymphoma. Adverse effects, most commonly mild, occurred in approximately two-thirds of treated horses.

The effect of inhaled heliox on peak flow rates in normal and brachycephalic dogs

BACKGROUND

Heliox, a mixture of helium and oxygen, alleviates airway obstruction in people and improves air flow, and its use has been proposed in dogs. Brachycephalic dogs have naturally occurring airway obstruction where heliox might be a useful therapeutic option.

OBJECTIVE

The purposes of this study were to (1) determine the impact of breathing heliox on peak inspiratory and expiratory flows (PIF/PEF) in healthy dogs and (2) determine if brachycephalic dogs and mesocephalic dogs have similar responses to inhaled heliox.

ANIMALS

Eleven healthy dogs: 5 mesocephalic and 6 brachycephalic dogs.

METHODS

A prospective study. Tidal breathing flow-volume loops were recorded when dogs were breathing room air (nitrogen-oxygen) and heliox. Peak inspiratory and expiratory flow rates were recorded and the subjective shape of loops assessed. Peak inspiratory and expiratory flows pre- and post-heliox were compared using a Mann-Whitney Rank sum test with a P-value of <.05 considered significant.

RESULTS

In inhaled heliox, PIF and PEF were evaluated by tidal breathing flow-volume loops. In mesocephalic dogs, PIF increased from a median of 820 mL/s (range, 494-1010 mL/s) to 1386 mL/s; P = .02; and for PEF from 688 mL/s to 1793 mL/s (P = .04), whereas in brachycephalic dogs, the median PIF increased from 282 mL/s to 694 mL/s; P = .01 and the median PEF increased from 212 mL/s to 517 mL/sec; P = .03. Brachycephalic dogs showed normalization of loop shapes.

CONCLUSIONS AND CLINICAL IMPORTANCE

Heliox improves flow rate and appears to improve flow patterns in brachycephalic dogs.

Pharmacokinetics of intravenous gentamicin in healthy young-adult compared to aged alpacas

The study objective was to evaluate the effects of age on aminoglycoside pharmacokinetics in eight young-adult (<4 years) and eight aged (≥14 years) healthy alpacas, receiving a single 6.6 mg/kg intravenous gentamicin injection. Heparinized plasma samples were obtained at designated time points following drug administration and frozen at -80°C until assayed by a validated immunoassay (QMS^® ). Compartmental and noncompartmental analyses of gentamicin plasma concentrations versus time were performed using WinNonlin (v6.4) software. Baseline physical and hematological parameters were not significantly different between young and old animals with the exception of sex. Data were best fitted to a two-compartment pharmacokinetic model. The peak drug concentration at 30 min after dosing (23.8 ± 2.1 vs. 26.1 ± 2 μg/ml, p = .043) and area under the curve (70.4 ± 10.5 vs. 90.4 ± 17.6 μg hr/ml, p = .015) were significantly lower in young-adult compared to aged alpacas. Accordingly, young alpacas had a significantly greater systemic clearance than older animals (95.5 ± 14.4 and 75.6 ± 16.1 ml hr^-1 kg^-1 ; p = .018), respectively). In conclusion, a single 6.6 mg/kg intravenous gentamicin injection achieves target blood concentrations of >10 times the MIC of gentamicin-susceptible pathogens with MIC levels ≤2 μg/ml, in both young-adult and geriatric alpacas. However, the observed reduction in gentamicin clearance in aged alpacas may increase their risk for gentamicin-related adverse drug reactions.

Operator-based variability of equine thromboelastography

OBJECTIVE

To determine the extent of intraoperator (between duplicate samples) and interoperator (between different operators) variability in equine thromboelastography (TEG).

DESIGN

Kaolin-activated TEG was performed in duplicate by operator-pair A/B or A/C (2 groups of 10 horses) using discrete setups, within 30-45 minutes of vacuum-assisted blood collection. Recorded TEG variables included clot initiation time (R), clot formation time (K), rate of clot formation (α), clot strength (MA), and viscoelastic/shear strength (G). Operators independently determined the clinical coagulation status for each sample. Intra- and interoperator variabilities were reported as coefficients of variation (CV), using descriptive statistics and paired samples t-test or Wilcoxon matched pair signed-rank test (P < 0.05 considered significant).

ANIMALS

Twenty hospitalized adult horses with no clinical evidence of systemic inflammation.

MEASUREMENTS AND MAIN RESULTS

Mean intraoperator CVs ranged from 2.6 to 14% (operator A), 2.8 to 13% (operator B) and 1.2 to 18% (operator C). Both intra- and interoperator variabilities were lowest for MA (1.2-3.2%) and G (2.9-7.3%), and highest for K (13-23%). Mean CVs for all TEG parameters were lower when comparing intra- to interoperator variation. Seventy percent of horses had at least 1 TEG variable (out of 4 replicates) outside the established reference intervals. Assessment of coagulation status was conserved between operators in 9/10 and 8/10 horses for A/B and A/C, respectively, with comparable agreement between operator A/B (к = 0.73) and A/C (к = 0.74).

CONCLUSIONS

TEG measurements of MA and G are more reproducible than assessment of K, within samples and between operators. The highest test variability was thus observed within the early phase of clot formation.

Comparison of indocyanine green and sodium fluorescein for anterior segment angiography of ophthalmically normal eyes of goats, sheep, and alpacas performed with a digital single-lens reflex camera adaptor

OBJECTIVE To compare results of anterior segment angiography of ophthalmically normal eyes of goats, sheep, and alpacas performed by use of indocyanine green (ICG) and sodium fluorescein (SF). ANIMALS 10 female goats (mean ± SD age, 6.8 ± 1.7 years), 10 female sheep (3.0 ± 2.2 years), and 10 alpacas (7 females and 3 males; 6.8 ± 3.8 years). PROCEDURES A catheter was aseptically placed into a jugular vein. Each animal was anesthetized and properly positioned, and 0.25% ICG was administered. Images were obtained by use of an adaptor system consisting of a modified digital single-lens reflex camera, camera adaptor, and camera lens. Images were obtained at a rate of 3 images/s for the 60 seconds immediately after ICG administration and then at 2, 3, 4, and 5 minutes after administration. Ten minutes later, 10% SF was administered IV and images were obtained in a similar manner. RESULTS Angiography with ICG provided visual examination of the arterial, capillary, and venous phases in all species. Visual examination of the iris vasculature by use of SF was performed in goats and sheep but was not possible in the alpacas because of iridal pigmentation. Extravasation of SF was a common finding in sheep and alpacas but not in goats. No adverse events were detected. CONCLUSIONS AND CLINICAL RELEVANCE Quality angiographic images of the anterior segment were obtainable after IV administration of ICG to goats, sheep, and alpacas. This may provide a useful imaging modality for ocular research in these animal species.

Association between inflammatory airway disease of horses and exposure to respiratory viruses: a case control study

Background

Inflammatory airway disease (IAD) in horses, similar to asthma in humans, is a common cause of chronic poor respiratory health and exercise intolerance due to airway inflammation and exaggerated airway constrictive responses. Human rhinovirus is an important trigger for the development of asthma; a similar role for viral respiratory disease in equine IAD has not been established yet.

Methods

In a case–control study, horses with IAD (n = 24) were compared to control animals from comparable stabling environments (n = 14). Horses were classified using pulmonary function testing and bronchoalveolar lavage. PCR for equine rhinitis virus A and B (ERAV, ERBV), influenza virus (EIV), and herpesviruses 2, 4, and 5 (EHV-2, EHV-4, EHV-5) was performed on nasal swab, buffy coat from whole blood, and cells from BAL fluid (BALF), and serology were performed. Categorical variables were compared between IAD and control using Fisher’s exact test; continuous variables were compared with an independent t-test. For all analyses, a value of P <0.05 was considered significant.

Results

There was a significant association between diagnosis of IAD and history of cough (P = 0.001) and exercise intolerance (P = 0.003) but not between nasal discharge and IAD. Horses with IAD were significantly more likely to have a positive titer to ERAV (68 %) vs. control horses (32 %). Horses with IAD had higher log-transformed titers to ERAV than did controls (2.28 ± 0.18 v.1.50 ± 0.25, P = 0.038). There was a significant association between nasal shedding (positive PCR) of EHV-2 and diagnosis of IAD (P = 0.002).

Conclusions

IAD remains a persistent problem in the equine population and has strong similarities to the human disease, asthma, for which viral infection is an important trigger. The association between viral respiratory infection and development or exacerbation of IAD in this study suggests that viral infection may contribute to IAD susceptibility; there is, therefore, merit in further investigation into the relationship between respiratory virus exposure and development of IAD.

Respiratory mechanics and results of cytologic examination of bronchoalveolar lavage fluid in healthy adult alpacas

OBJECTIVE

To evaluate respiratory mechanical function and bronchoalveolar lavage (BAL) cytologic results in healthy alpacas.

ANIMALS

16 client-owned adult alpacas.

PROCEDURES

Measurements of pulmonary function were performed, including functional residual capacity (FRC) via helium dilution, respiratory system resistance via forced oscillatory technique (FOT), and assessment of breathing pattern by use of respiratory inductive plethysmography (RIP) in standing and sternally recumbent alpacas. Bronchoalveolar lavage was performed orotracheally during short-term anesthesia.

RESULTS

Mean ± SD measurements of respiratory function were obtained in standing alpacas for FRC (3.19 ± 0.53 L), tidal volume (0.8 ± 0.13 L), and respiratory system resistance at 1 Hz (2.70 ± 0.88 cm H(2)O/L/s), 2 Hz (2.98 ± 0.70 cm H(2)O/L/s), 3 Hz (3.14 ± 0.77 cm H(2)O/L/s), 5 Hz (3.45 ± 0.91 cm H(2)O/L/s), and 7 Hz (3.84 ± 0.93 cm H(2)O/L/s). Mean phase angle, as a measurement of thoracoabdominal asynchrony, was 19.59 ± 10.06°, and mean difference between nasal and plethysmographic flow measurements was 0.18 ± 0.07 L/s. Tidal volume, peak inspiratory flow, and peak expiratory flow were significantly higher in sternally recumbent alpacas than in standing alpacas. Cytologic examination of BAL fluid revealed 58.52 ± 12.36% alveolar macrophages, 30.53 ± 13.78% lymphocytes, 10.95 ± 9.29% neutrophils, 0% mast cells, and several ciliated epithelial cells.

CONCLUSIONS AND CLINICAL RELEVANCE

Pulmonary function testing was tolerated well in nonsedated untrained alpacas. Bronchoalveolar lavage in alpacas yielded samples with adequate cellularity that had a greater abundance of neutrophils than has been reported in horses.

Association of admission L-lactate concentration in hospitalised equine neonates with presenting complaint, periparturient events, clinical diagnosis and outcome: a prospective multicentre study

REASONS FOR PERFORMING THE STUDY

Admission L-lactate concentration is a useful and commonly measured biomarker not previously prospectively evaluated in a large multicentre study of critically ill neonatal foals.

OBJECTIVES

To evaluate overall outcome and the association of survival and L-lactate concentration at admission ([LAC]ADMIT) by periparturient history, presenting complaint and clinicians' major diagnosis for ill neonatal foals.

METHODS

Thirteen university and private equine referral hospitals enrolled 643 foals over the 2008 foaling season. Case details, historical, clinical and clinicopathological data were entered into standardised spreadsheets then unified for analysis.

RESULTS

Overall survival was 79% (505/643). Risk of nonsurvival increased with each 1 mmol/l increase in [LAC]ADMIT (odds ratio 1.14, P < 0.001). Mean arterial pressure had a small (r2 = 19.1) but significant (P < 0.001) association with [LAC]ADMIT. Foals experiencing known dystocia or premature placental separation had increased [LAC]ADMIT (P < 0.001). Single umbilical problems (excluding uroperitoneum), meconium impaction only and failure of passive transfer of immunity only had 100% survival. Six clinicians' major diagnoses had increased odds of nonsurvival for each 1 mmol/l increase in [LAC]ADMIT: 'sepsis'; 'unspecified enterocolitis'; 'unspecified colic'; 'unspecified trauma'; 'immune related (not failure of passive transfer of immunity)' and 'respiratory only'.

CONCLUSIONS AND POTENTIAL RELEVANCE

Survival of critically ill foals is good but varies with peripartum history, presenting complaint and clinicians' major diagnosis. L-lactate concentration at admission proves its utility as a valuable prognostic biomarker in neonatal foals and its utility appears to vary with peripartum history and clinicians' major diagnosis.

Systemic Distribution of Viral Antigen in Alpacas Persistently Infected With Bovine Pestivirus

Recently, confirmed occurrences of persistent bovine viral diarrhea virus (BVDV) infection in North American alpacas have raised concerns about the role of persistently infected (PI) alpacas in transmission of virus among herds, yet only limited pathological descriptions of persistent infections in alpacas have been reported. The objective of this study was to characterize BVDV antigen distribution in 10 PI alpacas of varying age and to compare viral antigen distribution and localization in tissues of PI alpacas with 5 PI calves of varying age. Ocular dysplasia was evident in 1 PI alpaca, constituting the first reported congenital ocular lesion in PI alpacas. Viral antigen was widely distributed in alpaca tissues and was prominent in neurons, endothelial cells, and vascular tunica media myocytes but had limited distribution in lymphoid tissues and moderate distribution in epithelium of several organ systems of alpacas. Macrophages in the alpaca gastrointestinal system submucosa and lymph node medullary sinuses often had prominent labeling. In addition, only 1 alpaca had antigen labeling in the bone marrow in contrast to PI cattle. Labeled cells in calf tissues were more widely distributed, occurring prominently in lymphoid and epithelial tissues. Common features of the 2 host species were widespread antigen labeling and absence of lymphoid depletion.

Florfenicol pharmacokinetics in healthy adult alpacas after subcutaneous and intramuscular injection

A single dose of florfenicol (Nuflor(®)) was administered to eight healthy adult alpacas at 20 mg/kg intramuscular (i.m.) and 40 mg/kg subcutaneous (s.c.) using a randomized, cross-over design, and 28-day washout period. Subsequently, 40 mg/kg florfenicol was injected s.c. every other day for 10 doses to evaluate long-term effects. Maximum plasma florfenicol concentrations (C(max), measured via high-performance liquid chromatography) were achieved rapidly, leading to a higher C(max) of 4.31±3.03 μg/mL following administration of 20 mg/kg i.m. than 40 mg/kg s.c. (C(max): 1.95±0.94 μg/mL). Multiple s.c. dosing at 48 h intervals achieved a C(max) of 4.48±1.28 μg/mL at steady state. The area under the curve and terminal elimination half-lives were 51.83±11.72 μg/mL·h and 17.59±11.69 h after single 2 mg/kg i.m. dose, as well as 99.78±23.58 μg/mL·h and 99.67±59.89 h following 40 mg/kg injection of florfenicol s.c., respectively. Florfenicol decreased the following hematological parameters after repeated administration between weeks 0 and 3: total protein (6.38 vs. 5.61 g/dL, P<0.0001), globulin (2.76 vs. 2.16 g/dL, P<0.0003), albumin (3.61 vs. 3.48 g/dL, P=0.0038), white blood cell count (11.89 vs. 9.66×10(3)/μL, P<0.044), and hematocrit (27.25 vs. 24.88%, P<0.0349). Significant clinical illness was observed in one alpaca. The lowest effective dose of florfenicol should thus be used in alpacas and limited to treatment of highly susceptible pathogens.

Long-term clinicopathological characteristics of alpacas naturally infected with bovine viral diarrhea virus type Ib

BACKGROUND

Substantial bovine viral diarrhea virus (BVDV)-related production losses in North American alpaca herds have been associated with BVDV type Ib infection.

OBJECTIVES

To classify and differentiate the long-term clinicopathological characteristics of BVDV type Ib infection of alpaca crias, after natural virus exposure. We hypothesized that persistently infected (PI) alpacas specifically demonstrate growth retardation, clinicopathological evidence of opportunistic infections, and early mortality.

ANIMALS

Thirty-five crias naturally exposed to BVDV (18 acute, 3 chronic, 14 PIs), and 19 healthy cohort controls of 5 northeastern alpaca farms were prospectively evaluated over 2 years (September 2005-September 2008).

METHODS

Observational cohort-control study.

RESULTS

Chronically (viremia >3 weeks) and PI crias demonstrated significantly lower birth weights, decreased growth rates, anemia, and monocytosis compared with control animals. Common clinical problems of PI alpacas included chronic wasting, diarrhea, and respiratory disease. Median survival of PI alpacas that died was 177 days (interquartile range, 555) with a case fatality rate of 50% within 6 months of life. Transplacental infection was confirmed in 82% (9/11) of pregnant females on 1 farm, resulting in the birth of 7 PI crias (7/10 deliveries; 1 animal was aborted). Mean gestation at the beginning and end of BVDV exposure was 64 and 114 days, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Natural BVDV type 1b infection during early pregnancy resulted in a high incidence of PI offspring. Although PI alpacas may have distinct clinical characteristics, verification of persistent viremia in the absence of endogenous, neutralizing antibodies is essential to differentiate persistent from chronic infection.

Retrospective evaluation of parenteral nutrition in alpacas: 22 cases (2002-2008)

BACKGROUND

Parenteral nutrition is an important method of nutritional support in hospitalized animals, but minimal information has been published on its use in camelids.

HYPOTHESIS/OBJECTIVES

The purpose of this study was to characterize the use of total parenteral nutrition (TPN) in alpacas, evaluate the formulations used, and determine potential complications.

ANIMALS

Twenty-two alpacas hospitalized at the Tufts Cummings School for Veterinary Medicine (site 1: n = 8) and the Ohio State University Veterinary Teaching Hospital (site 2: n = 14).

METHODS

A retrospective analysis of all alpacas that received TPN between 2002 and 2008 was performed to assess clinical indications, clinical and clinicopathologic data, and outcome.

RESULTS

The most common underlying diseases in animals receiving TPN were gastrointestinal dysfunction (n = 16), hepatic disease (n = 2), and neoplasia (n = 2). Several metabolic abnormalities were identified in animals (n = 20/22) before TPN was initiated, including lipemia (n = 12/22), hyperglycemia (11/22), and hypokalemia (n = 11/22). Median age was significantly lower for site 1 cases (0.1 years; range, 0.01-11.0) compared with those from site 2 (4.9 years; range, 0.1-13.7; P = .03). Animals at site 2 also had a longer duration of hospitalization (P = .01) and TPN administration (P = .004), as well as higher survival rate (P < .02). Twenty-one of 22 alpacas developed at least 1 complication during TPN administration. Metabolic complications were most prevalent (n = 21/22) and included hyperglycemia (n = 8/21), lipemia (n = 7/21), hypokalemia (n = 3/21), and refeeding syndrome (n = 3/21).

CONCLUSIONS AND CLINICAL IMPORTANCE

TPN is a feasible method of nutritional support for alpacas when enteral feeding is not possible. Prospective studies are warranted to determine optimal TPN formulations for alpacas.

The effect of body position, sedation, and thoracic bandaging on functional residual capacity in healthy deep-chested dogs

The objective of this study was to determine the effect of body position, chest wrap, and sedation on functional residual capacity (FRC) in 6 healthy dogs. Functional residual capacity was determined by helium dilution (re-breathing) whilst in different clinically relevant conditions. These conditions included the standing (sternal) and lateral positions in unsedated dogs and then again both standing and lateral following chest bandaging, and sedation with acepromazine, IV and butorphanol, IV. The mean FRC at each measurement point was determined, as was the change in FRC (delta FRC) from one measurement point to another. Analysis of variance (ANOVA) with repeated measures with Fisher's LSD post hoc test was used to evaluate the effect of interventions. The differences in delta FRC were evaluated using a t-test or Wilcoxon rank-sum test. P < 0.05 was considered significant. The mean FRC at baseline, defined as standing, unsedated and unwrapped, was 75.3 +/- 23.8 mL/kg. Body position or sedation had the most profound effect on FRC with right lateral recumbency lowering FRC by a median of 20.4 mL/kg and sedation lowering FRC by a median of 19.8 mL/kg. Common clinical procedures and positioning result in lowered FRC in healthy deep-chested dogs. In critically ill or injured dogs, the iatrogenic loss of FRC through chest bandaging, sedation, or body position may be clinically relevant.

Prevalence of bovine viral diarrhea virus infections in alpacas in the United States

OBJECTIVE

To determine the prevalence of bovine viral diarrhea virus (BVDV)-infected alpaca herds in the United States and investigate factors associated with seropositive herd status and, subsequently, determine the proportion of animals within seropositive alpaca herds that are persistently infected (PI) carriers for BVDV, obtain information regarding previous herd exposure to BVDV, determine titers of anti-BVDV antibodies of dams, and ascertain whether individual seropositive crias had received supplemental colostrum at birth.

DESIGN

Prevalence study.

ANIMALS

63 alpaca herds with >or= 12 registered female alpacas.

PROCEDURES

250 alpaca breeders were randomly selected from 562 eligible herds listed in the Alpaca Owner and Breeders Association membership directory and mailed a voluntary participation request. Sixty-three alpaca breeders participated in the study. From each herd, blood samples from >or= 4 crias were tested for BVDV, BVDV RNA, and serum neutralizing antibodies against BVDV. A region of the genome of BVDV recovered from PI crias was sequenced to determine genetic homology.

RESULTS

Among the 63 herds, 16 (25.4%) had seropositive crias and 4 (6.3%) had PI crias. Infections in 3 of the 4 herds with PI crias were linked as evidence by the genetic homologies of viruses. In addition to PI crias, feeding supplemental colostrum was associated with herd seropositivity.

CONCLUSIONS AND CLINICAL RELEVANCE

Results confirmed the importance of BVDV infections in alpacas in the United States and highlighted the importance of determining the BVDV infection status of animals before they are commingled to limit exposure of herds to BVDV infection.

Association between cough and cytology of bronchoalveolar lavage fluid and pulmonary function in horses diagnosed with inflammatory airway disease

BACKGROUND

The objective of this study was to examine the relationship between chronic cough, pulmonary mechanical function, bronchial hyper-responsiveness, and peripheral airway inflammation in adult performance horses with nonseptic inflammatory airway disease (IAD).

HYPOTHESIS

We hypothesized that horses with a presenting complaint of cough have a higher percentage of inflammatory cells on bronchoalveolar lavage (BAL), greater airway obstruction, and airway hyper-responsiveness (AHR) than do horses without cough. ANIMALS/SAMPLE POPULATION: Adult performance horses (n = 137) referred for evaluation of signs of IAD including cough or exercise intolerance (university hospital patients) and BAL samples (n = 142) taken in first opinion practice.

METHODS

A descriptive, retrospective cohort analysis was performed to evaluate the association between chronic cough and pulmonary mechanical function, AHR, BAL cytology, patient signalment, and comorbid features (multivariable logistic regression).

RESULTS

Cough was significantly more prevalent in horses >7 years, and best characterized by a high BAL neutrophil count (>5%) and nasal discharge. Lung function mechanics, abnormal thoracic auscultation, and exercise intolerance did not retain statistical significance in the logistical regression analysis of cough. Although AHR was not related to neutrophilic airway inflammation (BAL neutrophils >5%), it was significantly associated with BAL mast cells >2%.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our data support that neutrophilic airway inflammation may potentiate cough without further changing respiratory mechanical function in IAD. In contrast, mast cell release increased AHR without affecting the incidence of cough. Cough may be used as an indicator of neutrophilic airway inflammation in the presence of low-grade nonseptic respiratory disease.

Eastern equine encephalitis in 9 South American camelids

BACKGROUND

Eastern equine encephalitis (EEE) virus is a mosquito-borne togavirus (alphavirus) that causes severe (often fatal) encephalitis in many mammalian species, but it has not been reported previously in South American camelids.

HYPOTHESIS

South American camelids can become naturally infected with EEE virus and show encephalitic signs similar to those observed in other affected species.

ANIMALS

Nine cases (8 alpacas and 1 llama, aged 3.5 weeks to 12 years) were identified; 4 of 9 were 510 weeks old. All cases were from the East Coast of the United States and presented in late summer and fall.

METHODS

A retrospective study was performed to include confirmed cases of EEE in camelids in North America before 2006.

RESULTS

Eight of nine (89%) camelids died or were euthanized in extremis, with the mean time to death of 2 days. Clinical signs were consistent with encephalitis and included fever, lethargy, ataxia, seizures, recumbency, torticollis, opisthotonus, and vestibular signs. No consistent hematologic abnormalities were identified, and cerebrospinal fluid contained an increased protein concentration in the single camelid analyzed. No successful therapy was identified. EEE was confirmed by alphavirus detection by using immunohistochemistry (IHC) and polymerase chain reaction (PCR) in the central nervous system (CNS) and by serology. Findings included polioencephalitis with lymphocytic perivascular cuffing; neutrophil infiltration; gliosis; neuron satellitosis; necrosis; and edema, with intracytoplasmic alphavirus within neurons and glial cells. No virus was detected in extraneural tissues.

CONCLUSIONS AND CLINICAL IMPORTANCE

In endemic areas, EEE should be considered a differential diagnosis for young and adult camelids with CNS disease. Brain histopathology with indirect IHC or PCR is diagnostic.