East Tennessee Clinical Research Inc.

Rockwood, TN, United States

East Tennessee Clinical Research Inc.

Rockwood, TN, United States
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Becskei C.,Zoetis Inc. | Reinemeyer C.,East Tennessee Clinical Research Inc. | King V.L.,Zoetis Inc. | Lin D.,Zoetis Inc. | And 2 more authors.
Veterinary Parasitology | Year: 2017

The efficacy of a new spot-on formulation of selamectin/sarolaner was evaluated against induced Otodectes cynotis infestations in cats in two randomized, blinded studies. Fourteen and 16 cats were randomly assigned to treatment groups in Studies 1 and 2, respectively. On Day 0, animals were either treated with placebo or with the spot-on formulation at the minimal dose of 6.0 mg selamectin and 1.0 mg sarolaner per kg bodyweight. Treatments were administered topically at the base of the neck. Presence of live mites was evaluated 14 days after treatment administration by otoscopic examination and total live mite counts (adults plus immature) were conducted on Day 30 by ear lavage. Efficacy was calculated based on the reduction of mean total live mite counts on Day 30 in the selamectin/sarolaner-treated group versus the placebo-treated group. There were no treatment-related adverse reactions during the studies, apart from one cat in each treatment group with alopecia at the administration site. In both studies combined, live mites were present on Day 14, in 14 out of 15 cats in the placebo-treated groups and in 2 out of 15 cats in the selamectin/sarolaner-treated groups. On Day 30, the arithmetic mean live mite counts were 576.9 and 875.8 in the placebo-treated groups and 5.8 and 4.7 in the selamectin/sarolaner-treated groups, in Studies 1 and 2, respectively. The live mite counts were significantly (P ≤ 0.0021) lower in the selamectin/sarolaner-treated groups compared to the placebo-treated groups with efficacies of 99.2% and 99.3%, in Studies 1 and 2 respectively. A single administration of a new spot-on formulation of selamectin/sarolaner at the minimum dose was safe and highly efficacious in the treatment of ear mite infestations in cats. © 2017 Zoetis Services LLC


McArthur M.J.,M2 VetSpeak Consulting | Reinemeyer C.R.,East Tennessee Clinical Research Inc.
Veterinary Parasitology | Year: 2014

Contemporary management of nematode parasitism in cattle relies heavily on a single class of drugs, the macrocyclic lactones (MLs). The potency and convenience of the MLs, along with the low cost of generic formulations, have largely supplanted the need for critical thinking about parasite control, and rote treatment has become the default 'strategy'. This approach to parasite control has exerted substantial pressure to select populations of nematodes that can survive recommended dosages of ML products. Although macrocyclic lactones have been available for over 30 years, putative ML resistance in U.S. cattle was not reported until fairly recently. This pattern begs the question, "Is this a new, emergent problem, or an old issue that is finally commanding some attention?". The implications of bovine anthelmintic resistance should stimulate a paradigm shift for U.S. cattle producers and their advisors. However, there are significant obstacles to changes in current thinking. It is anticipated that cattle producers will be extremely reluctant to abandon historical practices unless they can be convinced of the value of alternatives that are communicated through targeted education, practical demonstrations, economic analyses, and scientific evidence. Historically, the management advice of practitioners has not relied strongly on parasite epidemiology, and practitioners may not have the knowledge to implement evidence-based recommendations. Pharmaceutical companies could play a significant role in helping to shape and shift the thinking about sustainable use of anthelmintics. However, their primary responsibility is to stockholders, and they have strong economic incentives for maintaining the status quo.It is complicated and difficult to change attitudes and practices, and it will take more than logic or fear to shift the parasite control paradigm in the U.S. cattle industry. Achieving that goal will require collaboration among stakeholders, a consistent, straightforward and understandable message about resistance, and recommendations that are practical as well as effective. But if we hope to ultimately influence producers and their advisors, we need to be conscious of how individuals and groups change their minds. © 2013 Elsevier B.V.


Reinemeyer C.R.,East Tennessee Clinical Research Inc.
Veterinary Parasitology | Year: 2012

Since 2002, selected populations of Parascaris equorum in several countries have been reported to survive treatment with macrocyclic lactone (M/L) anthelmintics. Clinical treatment failures are characterized by negligible fecal egg count reduction, but M/L resistance has been confirmed in ascarids by controlled efficacy testing. Resistance was selected by current parasite control practices for foals, which often include exclusive and excessively frequent use of M/L dewormers, thereby minimizing refugia within the host and in the environment. Chemical control of M/L-resistant isolates can be accomplished with pyrimidine and/or benzimidazole anthelmintics, but a few M/L-resistant populations have recently exhibited resistance to pyrantel pamoate as well. Some specimens of Oxyuris equi regularly survive treatment with macrocyclic lactones, but it is uncertain whether this constitutes resistance or merely confirms the incomplete oxyuricidal efficacy of virtually all broad spectrum equine anthelmintics. Variations in other biological parameters of Oxyuris and Parascaris, specifically atypical infection of older hosts and shorter prepatent periods, have been reported anecdotally. These changes may represent genetic modifications that have evolved in parallel with resistance as a result of anthelmintic selection pressure. © 2011 Elsevier B.V.


Bowman D.D.,Cornell University | Reinemeyer C.R.,East Tennessee Clinical Research Inc. | Wiseman S.,Eli Lilly and Company | Snyder D.E.,Eli Lilly and Company
Veterinary Parasitology | Year: 2014

Ancylostoma caninum and Toxocara canis are two important zoonotic parasites of dogs. The primary objective of these studies were to confirm the oral effectiveness of milbemycin oxime (MO) and spinosad in dogs experimentally infected with immature (L4 and immature adult) stages of T. canis or A. caninum. Both trials were conducted as randomized, blinded, placebo-controlled dose confirmation studies. Treatments using the intended European commercial tablet formulation of Trifexis were administered in a timeframe relative to inoculation so that effectiveness could be assessed against specific immature stages of A. caninum or T. canis. In each study on Day 0, each of 32, 3-4 month old dogs were inoculated with 250 infective eggs of T. canis or 300 infective L3 of the hookworm, A. caninum. All dogs were weighed before their scheduled treatment, randomized to 1 of the 4 treatment groups in each study (8 dogs/group). All dogs were fed just prior to dosing. For T. canis, dogs were treated orally with an MO/spinosad tablet on Day 14 or Day 24. For A. caninum, dogs were treated orally with an MO/spinosad tablet on Day 7 or Day 11. Corresponding control groups in each study received a placebo tablet. Dogs were necropsied 5 or 6 days after their respective treatments. The digestive tract was removed and processed to recover, count, and identify all stages. The GM worm count for the MO/spinosad tablet on Day 14 (L4 T. canis) was 0.0, with efficacy calculated as 100%; however, only 3 of 8 control dogs had adequate infections. The GM worm count for the MO/spinosad tablet on Day 24 (immature adult stage) was 0.30; efficacy calculated at 96.15%. This is based on 5 of the 8 control dogs with adequate infections. In the two A. caninum studies, GM worm counts for the MO/spinosad tablets on Day 7 (L4 efficacy) was 2.37 and 0.8 with efficacy calculated as 98.92% and 99.25%, respectively. The GM count for the group treated with the MO/spinosad combination on Day 11 (immature adult) was 6.19 and 1.4; efficacy calculated at 97.77% and 98.58%, respectively. A minimum MO oral dose of 0.75. mg/kg was highly effective for the treatment of immature stages of T. canis and A. caninum infections in dogs. The ability to kill immature stages of these two parasites before they become patent will benefit dogs, their owners and family members due to reduced exposure to these potentially zoonotic parasites. © 2014 Elsevier B.V.


Onishi J.C.,Rutgers University | Park J.-W.,Rutgers University | Park J.-W.,Troy University | Prado J.,East Tennessee Clinical Research Inc. | And 5 more authors.
Veterinary Microbiology | Year: 2012

Carbohydrate overload models of equine acute laminitis are used to study the development of lameness. It is hypothesized that a diet-induced shift in cecal bacterial communities contributes to the development of the pro-inflammatory state that progresses to laminar failure. It is proposed that vasoactive amines, protease activators and endotoxin, all bacterial derived bioactive metabolites, play a role in disease development. Questions regarding the oral bioavailability of many of the bacterial derived bioactive metabolites remain. This study evaluates the possibility that a carbohydrate-induced overgrowth of potentially pathogenic cecal bacteria occurs and that bacterial translocation contributes toward the development of the pro-inflammatory state. Two groups of mixed-breed horses were used, those with laminitis induced by cornstarch (n=6) or oligofructan (n=6) and non-laminitic controls (n=8). Cecal fluid and tissue homogenates of extra-intestinal sites including the laminae were used to enumerate Gram-negative and -positive bacteria. Horses that developed Obel grade2 lameness, revealed a significant overgrowth of potentially pathogenic Gram-positive and Gram-negative intestinal bacteria within the cecal fluid. Although colonization of extra-intestinal sites with potentially pathogenic bacteria was not detected, results of this study indicate that cecal/colonic lymphadenopathy and eosinophilia develop in horses progressing to lameness. It is hypothesized that the pro-inflammatory state in carbohydrate overload models of equine acute laminitis is driven by an immune response to the rapid overgrowth of Gram-positive and Gram-negative cecal bacterial communities in the gut. Further equine research is indicated to study the immunological response, involving the lymphatic system that develops in the model. © 2012 Elsevier B.V.


PubMed | Eli Lilly and Company, Cornell University and East Tennessee Clinical Research Inc.
Type: Journal Article | Journal: Veterinary parasitology | Year: 2014

Ancylostoma caninum and Toxocara canis are two important zoonotic parasites of dogs. The primary objective of these studies were to confirm the oral effectiveness of milbemycin oxime (MO) and spinosad in dogs experimentally infected with immature (L4 and immature adult) stages of T. canis or A. caninum. Both trials were conducted as randomized, blinded, placebo-controlled dose confirmation studies. Treatments using the intended European commercial tablet formulation of Trifexis were administered in a timeframe relative to inoculation so that effectiveness could be assessed against specific immature stages of A. caninum or T. canis. In each study on Day 0, each of 32, 3-4 month old dogs were inoculated with 250 infective eggs of T. canis or 300 infective L3 of the hookworm, A. caninum. All dogs were weighed before their scheduled treatment, randomized to 1 of the 4 treatment groups in each study (8 dogs/group). All dogs were fed just prior to dosing. For T. canis, dogs were treated orally with an MO/spinosad tablet on Day 14 or Day 24. For A. caninum, dogs were treated orally with an MO/spinosad tablet on Day 7 or Day 11. Corresponding control groups in each study received a placebo tablet. Dogs were necropsied 5 or 6 days after their respective treatments. The digestive tract was removed and processed to recover, count, and identify all stages. The GM worm count for the MO/spinosad tablet on Day 14 (L4 T. canis) was 0.0, with efficacy calculated as 100%; however, only 3 of 8 control dogs had adequate infections. The GM worm count for the MO/spinosad tablet on Day 24 (immature adult stage) was 0.30; efficacy calculated at 96.15%. This is based on 5 of the 8 control dogs with adequate infections. In the two A. caninum studies, GM worm counts for the MO/spinosad tablets on Day 7 (L4 efficacy) was 2.37 and 0.8 with efficacy calculated as 98.92% and 99.25%, respectively. The GM count for the group treated with the MO/spinosad combination on Day 11 (immature adult) was 6.19 and 1.4; efficacy calculated at 97.77% and 98.58%, respectively. A minimum MO oral dose of 0.75 mg/kg was highly effective for the treatment of immature stages of T. canis and A. caninum infections in dogs. The ability to kill immature stages of these two parasites before they become patent will benefit dogs, their owners and family members due to reduced exposure to these potentially zoonotic parasites.


PubMed | Centenary College, RUCDR Infinite Biologics, Louisiana State University, Rutgers University and East Tennessee Clinical Research Inc.
Type: Journal Article | Journal: Veterinary microbiology | Year: 2014

In the equine carbohydrate overload model of acute laminitis, disease progression is associated with changes in bacteria found in the cecum. To date, research has focused on changes in specific Gram-positive bacteria in this portion of the intestinal tract. Metagenomic methods are now available making it possible to interrogate microbial communities using animal protocols that sufficiently power a study. In this study, the microbiota in cecal fluid collected from control, non-laminitic horses (n=8) and from horses with early-stage acute laminitis induced with either oligofructan (n=6) or cornstarch (n=6) were profiled. The microbiota were identified based on sequencing the V4 hypervariable region of the 16S rRNA gene. The results of the study show that the relative abundance of Lactobacillus sp. and Streptococcus sp. increased significantly (p<0.05) following OF and CS infusion. Other significant changes included an increase (p<0.05) in relative abundance of Veillonella sp. and Serratia sp., two potentially pathogenic, Gram-negative bacteria. Significant decreases in the relative abundance of presumptive normal flora were detected as well. Although changes in cecal microbiota described in this communication are from a pilot study, it is hypothesized that an overgrowth of pathogenic Gram-negative bacteria develops and contributes to enterocolitis, pyrexia and lameness in the carbohydrate overload model of acute laminitis.


Andersen U.V.,Copenhagen University | Howe D.K.,University of Kentucky | Dangoudoubiyam S.,University of Kentucky | Toft N.,Copenhagen University | And 6 more authors.
Parasites and Vectors | Year: 2013

Background: Strongyle parasites are ubiquitous in grazing horses. Strongylus vulgaris, the most pathogenic of the large strongyles, is known for its extensive migration in the mesenteric arterial system. The lifecycle of S. vulgaris is characterised by a long prepatent period where the migrating larvae are virtually undetectable as there currently is no test available for diagnosing prepatent S. vulgaris infection. Presence of S. vulgaris larvae in the arterial system causes endarteritis and thrombosis with a risk of non-strangulating intestinal infarctions. Emergence of anthelmintic resistance among cyathostomins has led to recommendations of reduced treatment intensity by targeting horses that exceed a predetermined strongyle faecal egg count threshold. One study suggests an apparent increase in prevalence of S. vulgaris on farms where reduced anthelmintic treatment intensity has been implemented. These issues highlight the need for an accurate and reliable assay for diagnosing prepatent S. vulgaris infection. Methods. Immunoscreening of a larval S. vulgaris cDNA library using hyperimmune serum raised against S. vulgaris excretory/secretory antigens was performed to identify potential diagnostic antigens. Immunoreactive clones were sequenced, one potential antigen was characterised, expressed as a recombinant protein, initially evaluated by western blot (WB) analysis, the diagnostic potential of the IgG subclasses was evaluated by ELISA, and the diagnostic accuracy evaluated using serum from 102 horses with known S. vulgaris infection status. Results: The clone expressing the potential antigen encoded a S. vulgaris SXP/RAL2 homologue. The recombinant protein, rSvSXP, was shown to be a potential diagnostic antigen by WB analysis, and a target of serum IgGa, IgG(T) and total IgG in naturally infected horses, with IgG(T) antibodies being the most reliable indicator of S. vulgaris infection in horses. Evaluation of diagnostic accuracy of the ELISA resulted in a sensitivity of 73.3%, a specificity of 81.0%, a diagnostic odds ratio of 11.69; a positive likelihood ratio (LR) of 3.85 and a negative LR was 0.33. The area under the ROC curve was 0.820. Conclusion: IgG(T) antibodies to recombinant SvSXP show potential for use as an antigen for prepatent diagnosis of migrating stages of S. vulgaris with moderate to good diagnostic accuracy. © 2013 Andersen et al.; licensee BioMed Central Ltd.


PubMed | University of Kentucky, Copenhagen University and East Tennessee Clinical Research Inc.
Type: Journal Article | Journal: Veterinary immunology and immunopathology | Year: 2015

Encysted cyathostomin larvae are ubiquitous in grazing horses. Arrested development occurs in this population and can lead to an accumulation of encysted larvae. Large numbers of tissue larvae place the horse at risk for developing larval cyathostominosis. This disease complex is caused by mass emergence of these larvae and is characterized by a generalized acute typhlocolitis and manifests itself as a profuse protein-losing watery diarrhea with a reported case-fatality rate of about 50%. Two anthelmintic formulations have a label claim for larvicidal therapy of these encysted stages; moxidectin and a five-day regimen of fenbendazole. There is limited knowledge about inflammatory and immunologic reactions to larvicidal therapy. This study was designed to evaluate blood acute phase reactants as well as gene expression of pro-inflammatory cytokines, both locally in the large intestinal walls and systemically. Further, mucosal tissue samples were evaluated histopathologically as well as analyzed for gene expression of pro- and anti-inflammatory cytokines, cluster of differentiation (CD) cell surface proteins, and select transcription factors. Eighteen juvenile horses with naturally acquired cyathostomin infections were randomly assigned to three treatment groups; one group served as untreated controls (Group 1), one received a five-day regimen of fenbendazole (10mg/kg) (Group 2), and one group received moxidectin (0.4mg/kg) (Group 3). Horses were treated on day 0 and euthanatized on days 18-20. Serum and whole blood samples were collected on days 0, 5, and 18. All horses underwent necropsy with collection of tissue samples from the ventral colon and cecum. Acute phase reactants measured included serum amyloid A, iron and fibrinogen, and the cytokines evaluated included interferon , tumor necrosis factor , transforming growth factor (TGF)-, and interleukins 1, 4, 5, 6, and 10. Transcription factors evaluated were FoxP3, GATA3 and tBet, and CD markers included CD163, CD3z, CD4, CD40, and CD8b. Histopathology revealed an inflammatory reaction with higher levels of lymphocytes, T cells, B cells, eosinophils and fibrous tissue in the moxidectin-treated group compared to controls or horses treated with fenbendazole. No apparent systemic reactions were observed. Expression of IL-5 and TGF- in intestinal tissues was significantly lower in Group 3 compared to Group 1. This study revealed a subtle inflammatory reaction to moxidectin, which is unlikely to cause clinical issues.


PubMed | University of Kentucky, Copenhagen University and East Tennessee Clinical Research Inc.
Type: Journal Article | Journal: Veterinary parasitology | Year: 2014

Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflammatory response in horses. It is unknown whether these larvae elicit a systemic acute phase response (APR), evidenced by changes in serum amyloid A (SAA), haptoglobin (Hp), iron (Fe), albumin, or albumin/globulin (A/G) ratio. In this study, 28 horses were randomly allocated to receive either pyrantel tartrate or a pelleted placebo formulation in their daily feed. Concurrent with treatment, all the horses were administered 5000 pyrantel-susceptible cyathostomin infective larvae once daily, 5 days a week, for 24 weeks. Beginning in the fifth week, the horses also received 25 S. vulgaris larvae once weekly for the remainder of the study. At regular biweekly intervals, fecal samples were collected for quantitative egg counts, and whole blood and serum samples were collected for measurement of packed cell volume, total protein, albumin, globulin, A/G ratio, SAA, Hp, and Fe. On days 161-164, all the horses were euthanatized and necropsied. Samples were collected for enumeration of total luminal worm burdens, encysted cyathostomin larval populations, and migrating S. vulgaris larvae. Concentrations of Hp, Fe, and A/G ratio were associated significantly with strongyle burdens. Only treated male horses had significant increases in serum albumin. Larval S. vulgaris did not associate with Fe, whereas Fe was associated negatively with both total cyathostomin burdens and encysted L4s. The A/G ratios differed significantly between the two treatment groups. Significant differences between groups and individual time points were also observed for Hp and Fe, whereas SAA concentrations remained low throughout the study. In general, this study illustrated that experimental inoculations with S. vulgaris and cyathostomins may be associated with changes in Hp, Fe, and serum proteins, but not with SAA. Overall, these changes suggest that mixed strongyle infections elicit a mild acute phase reaction.

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