Determination of Tilmicosin in Bovine, Swine, Chicken, and Turkey Tissues by Liquid Chromatography With Tandem Mass Spectrometry, Single-Laboratory Validation.

Background: An LC-MS/MS method was developed for determination and confirmation of tilmicosin in bovine, swine, chicken, and turkey tissues (liver, kidney, muscle, and skin/fat) and bovine milk.

Objective: The method was subjected to single-laboratory validation to establish method performance parameters.

Method: Animal tissues and bovine milk were fortified at four concentrations ranging from 0.

Plasma lipopolysaccharide elevations in cattle associated with early-stage infection by Fasciola hepatica.

Fasciolosis is an endemic zoonotic parasitic disease with significant impacts on human health and both animal health and production. Early post-infection impacts on the host remain unclear. The objective of this study was to determine the changes, if any, to levels of endotoxin in cattle plasma in response to early-stage infection with Fasciola hepatica.

Comparative assessment of faecal diagnostics for detection and predictive modelling of endemic infection in sheep and cattle on Australian farms.

The diagnosis, monitoring and flukicide efficacy testing of fasciolosis on-farm is reliant on non-terminal methods. The coproantigen ELISA (cELISA) has been recommended for diagnosis of fasciolosis and associated flukicide efficacy testing as an alternative to fluke egg counts for monitoring parasitism. Recently experimental multi-age infections have suggested that the reliability of efficacy results can be improved by a second cELISA testing at 6 weeks post-treatment (wpt) in addition to the generally accepted 1 wpt.

Comparative assessment of faecal diagnostics for detection and predictive modelling of endemic Fasciola hepatica infection in sheep and cattle on Australian farms.

The diagnosis, monitoring and flukicide efficacy testing of fasciolosis on-farm is reliant on non-terminal methods. The coproantigen ELISA (cELISA) has been recommended for diagnosis of fasciolosis and associated flukicide efficacy testing as an alternative to fluke egg counts for monitoring parasitism. Recently experimental multi-age infections have suggested that the reliability of efficacy results can be improved by a second cELISA testing at 6 weeks post-treatment (wpt) in addition to the generally accepted 1 wpt.

Comparison of early detection of Fasciola hepatica in experimentally infected Merino sheep by real-time PCR, coproantigen ELISA and sedimentation.

Fasciolosis due to infection with Fasciola hepatica, Fasciola gigantica or their hybrids is a significant global cause of livestock production loss. Infection is commonly diagnosed by a labour-intensive sedimentation and faecal egg count (FEC), which has limited throughput and is only applicable after completion of the 8-12 week pre-patent period (PPP). A commercially-available ELISA for the detection of coprological antigen (coproELISA) enables detection prior to the completion of the PPP and is suitable for diagnosis of larger sample sizes, although the sensitivity reported under experimental infection settings can be difficult to replicate in the field, particularly in cattle.

Characterization of multiple life stages of two Australian Fasciola hepatica isolates in sheep.

Information on the susceptibility status of Fasciola hepatica isolates is lacking in the literature, even for those isolates considered to be laboratory reference strains. Four controlled efficacy studies were conducted on two Fasciola hepatica isolates from Australia, viz. 'Oberon' and 'Sunny Corner' with treatment at either 2, 6 or 10 weeks post-infection (wpi) as defined in each study.

Application of a coproantigen ELISA as an indicator of efficacy against multiple life stages of Fasciola hepatica infections in sheep.

At present diagnosis of true resistance and determination of drug efficacy in Fasciola hepatica infection rely solely on terminal experiments. The coproantigen ELISA (cELISA) has been reported previously as a sensitive and specific tool appropriate to detect treatment failure, and potentially drug resistance. Two studies were conducted to determine whether the cELISA was appropriate for on-farm efficacy and resistance testing in Australian Merino sheep.

The comparative efficacy of abamectin, monepantel and an abamectin/derquantel combination against fourth-stage larvae of a macrocyclic lactone-resistant Teladorsagia spp. isolate infecting sheep.

Anthelmintic resistance by gastrointestinal nematodes of sheep continues to be an issue of global interest. While the recent introduction in some countries of one or two new anthelmintic classes (amino-acetonitrile derivatives [AAD] and spiroindoles [SI]) has been welcomed, it is important that there is no relaxation in parasite control and the management of drug resistance. Monepantel (an AAD) was the first new anthelmintic to be approved for use (New Zealand, 2009) and was followed a year later in the same country by a combination of derquantel (a SI) and abamectin.

Efficacy of monepantel and anthelmintic combinations against multiple-resistant Haemonchus contortus in sheep, including characterisation of the nematode isolate.

Three experiments defined the resistance profile of a population of Haemonchus contortus, which was shown to express multiple resistances to the benzimidazole, levamisole, macrocyclic lactone and salicylanilide anthelmintic classes when given as a registered combination. Study 1 was a faecal egg count reduction (FECR) test and the efficacies for the anthelmintics were monepantel, 100%; abamectin+levamisole+oxfendazole, 40.0%; and abamectin+levamisole+oxfendazole+naphthalophos, 100%.

Safety and efficacy against fourth-stage gastrointestinal nematode larvae, of monepantel in 6-week old lambs.

A controlled, blinded study was undertaken in 6-week old, pre-weaned lambs to demonstrate the safety and efficacy against fourth-stage gastrointestinal nematode larvae, of monepantel administered per os at 2.5mg/kg body weight. Worm burdens of 10 monepantel-treated lambs were compared to those from 10 untreated control lambs.

Effect of route of administration on the efficacy and pharmacokinetics of an experimental formulation of the amino-acetonitrile derivative monepantel in sheep.

The effect of the route of administration (oral, intraruminal and intra-abomasal) on the efficacy and pharmacokinetics of the new anthelmintic monepantel in sheep was investigated. The target nematodes were fourth-stage Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis and Cooperia curticei. A clear difference in efficacy was identified between the routes of administration, although the difference did not consistently reach statistical significance; oral treatment was most effective, followed by intraruminal and then intra-abomasal administration.

The control of inhibited fourth-stage larvae of Haemonchus contortus and Teladorsagia spp. in sheep in Australia with monepantel.

Monepantel is the first molecule from the amino-acetonitrile derivatives to be developed for controlling gastro-intestinal nematodes in sheep. Two studies were undertaken to examine the drug's efficacy against inhibited fourth-stage larvae of Haemonchus contortus and Teladorsagia spp. in sheep when administered as an oral solution at 2.

The effect of sheep breed, age, and gender on the pharmacokinetics and efficacy of monepantel, an amino-acetonitrile derivative.

This analysis investigated the influence of breed and gender on the pharmacokinetics of monepantel, and influence of breed, age, and gender on its efficacy against gastrointestinal nematodes of sheep. In a comparison of pharmacokinetic profiles from two studies, Merino lambs had significantly greater maximum concentrations of monepantel and monepantel sulfone, and faster times to reach these concentrations than Dorset cross lambs. Males had a statistically greater area under the curve (0-504 h) than females for monepantel sulfone.

Clinical field study to evaluate the efficacy and safety of the amino-acetonitrile derivative, monepantel, compared with registered anthelmintics against gastrointestinal nematodes of sheep in Australia.

Objective: To determine the efficacy of monepantel, a developmental compound from the amino-acetonitrile derivative class of anthelmintics, against field infections of gastrointestinal nematodes in sheep.

Procedures: Comparisons of efficacy (using standard faecal worm egg count reduction tests) and safety (on the basis of visual observations) were made in a large-scale field study in Australia, between groups of sheep treated with either an oral solution of monepantel or a registered anthelmintic. The sheep were naturally infected with the major gastrointestinal nematode genera present in Australia.

A pooled analysis of the efficacy of monepantel, an amino-acetonitrile derivative against gastrointestinal nematodes of sheep.

Monepantel is the first compound from the amino-acetonitrile derivative class of anthelmintics to be developed for the control of gastrointestinal nematodes of sheep. An analysis of pooled data from a series of controlled studies is reported providing a single point of efficacy (+/- 95% confidence interval) for each gastrointestinal nematode tested at the fourth larval and/or adult stages. For most nematode species, the pooled efficacy was greater than 99%, and for the remaining few species, efficacy was greater than 90%.

Pharmacokinetics of monepantel and its sulfone metabolite, monepantel sulfone, after intravenous and oral administration in sheep.

The pharmacokinetic properties of the developmental Amino-Acetonitrile Derivative (AAD), monepantel and its sulfone metabolite, monepantel sulfone were investigated in sheep following intravenous (i.v.) and oral administrations.

Effect of fasting sheep for a short period on the efficacy and safety of monepantel.

Eighteen, six- to seven-month-old lambs were infected experimentally with larvae of Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Cooperia curticei and Nematodirus spathiger, and allocated to three equal groups. The infections were timed to ensure that fourth-stage larvae were present when groups 1 and 2 were treated orally with monepantel. Group 1 was not fed for 24 hours before the treatment, group 2 was fed two hours before the treatment and group 3 was fed at the same time as group 2 but not treated with monepantel.

Reproductive safety of an amino-acetonitrile derivative (AAD), monepantel, in rams following repeated oral administration.

Aim: To demonstrate the clinical and reproductive safety in rams of repetitive oral doses of monepantel, an amino-acetonitrile derivative (AAD), when administered at three times the proposed maximum recommended dose (MRD) over an entire spermatogenic cycle and during mating with ewes.

Methods: A randomised controlled blinded study design was used with 28 rams randomly divided into two groups. The control group was treated with saline, and the other group was given three times the MRD (11.

Safety of an amino-acetonitrile derivative ( AAD ), monepantel, in weaned lambs following repeated oral administration.

Aim: To demonstrate the safety in weaned lambs of repetitive oral doses of monepantel, an amino-acetonitrile derivative (AAD), when administered at the proposed maximum recommended dose (MRD) and three and five times the MRD over 24 weeks.

Methods: A randomised controlled blinded study design was used. Fifty-six weaned lambs were randomly allocated into a control group, the MRD (3.

Dose determination studies for monepantel, an amino-acetonitrile derivative, against fourth stage gastro-intestinal nematode larvae infecting sheep.

Monepantel is the first compound from the recently discovered amino-acetonitrile derivative (AAD) class of anthelmintics to be developed for use in sheep. Three dose determination studies were conducted in Australia and Switzerland to identify the minimum therapeutic dose of monepantel when formulated for the oral treatment of sheep to control fourth stage (L4) gastro-intestinal nematode larvae. In each study, sheep infected with the target nematodes (selected from Haemonchus contortus, Teladorsagia (Ostertagia) circumcincta, Teladorsagia trifurcata, Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Cooperia curticei, Cooperia oncophora, Nematodirus battus, Nematodirus filicollis, Nematodirus spathiger, Chabertia ovina and Oesophagostomum venulosum) were treated with either 1.

Prevalence of Neospora caninum infection in Australian (NSW) dairy cattle estimated by a newly validated ELISA for milk.

Aim: To determine the performance characteristics of an Institut Pourquier (IP) enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against Neospora caninum in bovine milk and subsequent determination of the prevalence of N. caninum infection in New South Wales (NSW) dairy cattle.

Methods: Matching serum and milk samples from 93 cattle were assayed in two commercially available ELISAs for the detection of anti-N.

Performance characteristics and optimisation of cut-off values of two enzyme-linked immunosorbent assays for the detection of antibodies to Neospora caninum in the serum of cattle.

Aim: To determine the performance characteristics of two enzyme-linked immunosorbent assays (ELISAs) manufactured by Institut Pourquier (IP) for the detection of antibodies against Neospora caninum in bovine sera.

Methods: Sera from 526 cattle were assayed in two ELISAs (IP) for the detection of anti-N. caninum antibodies.

Performance characteristics of an enzyme-linked immunosorbent assay performed in milk for the detection of liver fluke (Fasciola hepatica) infection in cattle.

Aim: To determine the performance characteristics of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against liver fluke (Fasciola hepatica) in bovine milk.

Methods: Serum and milk from liver fluke infected and non-infected cattle was assayed in a commercially available enzyme-linked immunosorbent assay. Serum test results were used to determine the "gold standard" infection status of cattle and milk ELISA results assessed by ROC analysis.

Neospora abortions in dairy cattle: diagnosis, mode of transmission and control.

Aim: To determine the contribution of Neospora caninum to abortions on a dairy farm in NSW (Australia), determine the mode of transmission and develop and trial a control option for infection.

Methods: Two whole herd bleeds were conducted 12 months apart and the association between serological status and abortion events were calculated for a number of bovine abortifacients. Family trees were constructed for N.