Investigating anthelmintic efficacy against gastrointestinal nematodes in cattle by considering appropriate probability distributions for faecal egg count data.

The Faecal Egg Count Reduction Test (FECRT) is the most widely used field-based method for estimating anthelmintic efficacy and as an indicator of the presence of anthelmintic resistant nematodes in cattle, despite never having been validated against the gold standard of controlled slaughter studies. The objectives of this study were to assess the normality of cattle faecal egg count (FEC) data and their transformed versions, since confidence intervals used to aid the interpretation of the FECRT, are derived from data assumed to be normally distributed, and violation of this assumption could potentially lead to the misclassification of anthelmintic efficacy. Further, probability distributions and associated parameters were evaluated to determine those most appropriate for representing cattle FEC data, which could be used to estimate percentage reductions and confidence limits. FEC data were analysed from 2175 cattle on 52 farms using a McMaster method at two different diagnostic sensitivities (30 and 15 eggs per gram (epg)) and a sensitive centrifugal flotation technique (SCFT) with a sensitivity of 1 epg. FEC data obtained from all egg count methods were found to be non-normal even upon transformation; therefore, it would be recommended that confidence or credible intervals be generated using either a Bootstrapping or Bayesian approach, respectively, since analyses using these frameworks do not necessarily require the assumption of normality. FEC data obtained using the SCFT method were best represented by distributions associated with the negative binomial and hence arithmetic means could be used in FECRT calculations. Where FEC data were obtained with less sensitive counting techniques (i.e. McMaster 30 or 15 epg), zero-inflated distributions and their associated central tendency were the most appropriate and would be recommended to use, i.e. the arithmetic group mean divided by the proportion of non-zero counts present; otherwise apparent anthelmintic efficacy could be misrepresented.

An investigation of anthelmintic efficacy against strongyles on equine yards in Scotland.

REASONS FOR PERFORMING STUDY: Cyathostomins comprise 50 helminth species, considered the most problematic equine endoparasites. Three classes of anthelmintic are currently licensed for their control, namely the benzimidazoles (fenbendazole), tetrahydropyrimidines (pyrantel) and macrocyclic lactones (ivermectin and moxidectin). Anthelmintic resistance in cyathostomins is common. With no new classes expected in the near future, it is essential to determine the efficacy of the available anthelmintics to inform future control programmes. OBJECTIVES: To determine the efficacy of all 3 anthelmintic classes against strongyles in equids on livery yards in east and central Scotland. STUDY DESIGN: Anthelmintic efficacy testing using the faecal egg count reduction test (FECRT). METHODS: FECRTs were performed on equids with initial strongyle faecal egg counts (FECs) of ≥50 eggs per gram. Efficacy was determined by comparing pretreatment (Day 0) and 14 days post treatment (Day 14) FECs. The following chemicals were tested: fenbendazole, pyrantel, ivermectin and moxidectin. Group arithmetic mean FECR of >90% for fenbendazole and pyrantel, and >95% for ivermectin and moxidectin, represented efficacy, whereas lower mean FECR indicated potential resistance. RESULTS: A total of 447 FECRTs were performed on 15 yards, as follows (the numbers in parentheses represent the number of yards each anthelmintic was tested on): 55 equids (7 yards) fenbendazole, 111 (8 yards) pyrantel, 163 (13 yards) ivermectin and 118 (10 yards) moxidectin. Fenbendazole resistance was documented on all yards (range of mean FECR, 15.8-83.4%), whereas pyrantel (90.4-99.6%), ivermectin (99.5-100%) and moxidectin (99.4-100%) treatment had acceptable efficacy. CONCLUSIONS: Reduced efficacy of fenbendazole was widespread, whereas >90% efficacy was found after pyrantel, and >95% efficacy after ivermectin and moxidectin. Overall, efficacies were higher than reported previously in Europe and the USA, potentially reflecting differences in management and anthelmintic use on the yards surveyed. POTENTIAL RELEVANCE: The use of fenbendazole for strongyle control in Scotland should be questioned. Targeted use of pyrantel should be encouraged to reduce reliance on macrocyclic lactones. Further work to correlate management practices with the presence of anthelmintic resistance is warranted.

A questionnaire study of equine gastrointestinal parasite control in Scotland.

REASONS FOR PERFORMING STUDY: Anthelmintic resistance in equine gastrointestinal nematodes is a threat to equine health and welfare. Detailed knowledge of anthelmintic use and parasite control methods is a prerequisite to identification of potential risk factors for resistance. OBJECTIVES: To identify parasite control practices employed by equine owners in Scotland and investigate management factors associated with anthelmintic resistance. STUDY DESIGN: Questionnaire study of equine parasite control in Scotland. METHODS: Questionnaires were available electronically, distributed at a conference and mailed to clients. Key areas explored included general background, grazing management, anthelmintic treatment practices and use of diagnostic tests. RESULTS: A total of 193 responses detailing information on parasite control programmes of 993 equids were analysed. Moxidectin (MOX) and ivermectin or related combination products were the most commonly administered anthelmintics in the preceding 12 months. Treatments licensed for use against cyathostomin encysted larvae and tapeworms were administered by 80% and 90% of respondents, respectively. This was often achieved through indiscriminate use of MOX and MOX-praziquantel products. Faecal egg count (FEC) analysis had been performed on 62% of yards and regular use of FECs reduced annual anthelmintic treatment frequency. Veterinarians had the greatest influence on control practices. While 40% of respondents believed that they practised targeted dosing, this was not associated with delaying treatment beyond the egg reappearance period of the anthelmintic used. CONCLUSIONS: Responses indicated increasing veterinary involvement and use of FECs. The majority of respondents administered anthelmintics licensed against cyathostomin encysted larvae and tapeworms. However, responses suggested that owners did not understand the definition of 'targeted' dosing regimens. POTENTIAL RELEVANCE: The high frequency of MOX use represents a potential risk factor for macrocyclic lactone resistance. As veterinarians were the most influential factor in anthelmintic choice, awareness of macrocyclic lactone resistance and potential risk factors for its development and spread should be incorporated into client advice.

Faecal worm egg count analysis for targeting anthelmintic treatment in horses: points to consider.

Equine gastrointestinal nematodes are ubiquitous; in horses that graze contaminated pasture and that are not treated appropriately, large numbers of worms can accumulate, which can lead to serious clinical disease. Nematode control has traditionally followed interval treatment regimens, which involve regular anthelmintic administration to all horses based on the strongyle egg reappearance periods of each drug, usually defined around the time of licensing. Interval treatment programmes have resulted in substantial reductions in large strongyle disease, but have made major contributions to the development of anthelmintic resistance, particularly in cyathostomins. Cyathostomin resistance to 2 of the 3 available anthelmintic classes is widespread, and resistance to both classes in single populations is not uncommon. Reduced efficacy of the most commonly used macrocyclic lactone anthelmintics, as measured by shortened egg reappearance periods after treatment, is emerging in cyathostomins. Macrocyclic lactone resistance is also now commonly reported in Parascaris equorum on stud farms. Faecal worm egg counts (FWEC) are increasingly being used as part of targeted approaches to parasite control, whereby only those horses with moderate to high FWEC within a group are treated with an anthelmintic. The objective of this approach is to reduce environmental contamination, while leaving a proportion of the worm population in some horses unexposed to selection pressure for anthelmintic resistance. This article reviews recent findings in equine parasitology research that will underpin guidelines for control, with a particular focus on how to optimise the value of FWEC methodologies and anthelmintic efficacy analyses.

Anthelmintic efficacy against cyathostomins in horses in Southern England.

Cyathostomins are considered to be the most important group of helminths to affect equids due to their high prevalence, potential pathogenicity and ability to develop anthelmintic resistance. Their control relies almost exclusively on frequent anthelmintic use. Currently, fenbendazole (FBZ), pyrantel embonate (PYR), ivermectin (IVM) and moxidectin (MOX) are licensed for use in horses in the UK. With no new anthelmintics likely to be licensed in the near future, it is essential that investigations into the efficacy of current anthelmintics in different locations are performed to help inform control programmes. Here, efficacy of FBZ, PYR, IVM and MOX in horse populations in the South of England was investigated. Horses with a strongyle faecal egg count (FEC) of ≥50 eggs per gram (EPG) were enrolled onto a faecal egg count reduction test (FECRT) study. Efficacy was determined by calculating the percentage reduction in FEC between the group mean at Day 0 and 14 days post-treatment. Efficacy was indicated when a group arithmetic faecal egg count reduction (FECR) of ≥90% was recorded for FBZ and PYR, and ≥95% for IVM and MOX. Between March and December 2012, 404 FECRT were performed on 12 yards examining 101, 110, 93 and 100 equids for FBZ, PYR, IVM, and MOX, respectively. FBZ resistance was identified on all yards (mean FECR range 0-65.8%). On 10 of 12 yards, PYR efficacy was >90% (91.0-99.4%) and on two yards, PYR resistance was suspected (86.8-87.2%). IVM (96.4-100%) and MOX (99.9-100%) were >95% efficacious on all yards. As the prevalence of FBZ resistance was 100%, the future use of this anthelmintic for the control of strongyles should be questioned. PYR should be used strategically to reduce reliance on the macrocyclic lactone class products. Over-dispersion of FEC between horses was observed (average k=0.21) with 80% of the strongyle eggs counted measured in 15% of horses tested, strongly supporting the application of targeted helminth control programmes in this host species.

Development of a patient experience questionnaire for primary care mental health.

INTRODUCTION: There are no validated measures available for use in assessing patients' views of the quality of primary care mental healthcare at practice level. METHODS: The Patient Experience Questionnaire was developed through an initial information-gathering phase with focus groups followed by questionnaire development and validation with patients in nine general practices in the West Midlands. Statistical analyses were performed to test the internal consistency, validity and reliability of the questionnaire. RESULTS: Fifty-six patients participated in focus groups, and 241 patients completed the questionnaire. The 20-item questionnaire had good internal consistency (Cronbach alpha = 0.94) and test-retest reliability (r = 0.859; p = 0.01). DISCUSSION: The Patient Experience Questionnaire appears to be a valid and reliable instrument, able to assess patients' views of the quality of primary care mental healthcare at practice level.

Development and validation of the Attitudes Towards the Homeless Questionnaire.

CONTEXT: The homeless are a significant group within society, which is increasing in size. They have demonstrably greater physical and mental health needs than the housed, and yet often have difficulty accessing primary health care. Medical 'reluctance' to look after homeless people is increasingly suggested as part of the problem. Medical education may have a role in ameliorating this. OBJECTIVES: This paper reports on the development and validation of a questionnaire specifically developed to measure medical students' attitudes towards the homeless. METHOD AND RESULTS: The Attitudes Towards the Homeless Questionnaire, developed using the views of over 370 medical students, was shown to have a Pearson test-retest reliability correlation coefficient of 0.8 and a Cronbach's alpha coefficient of 0.74. CONCLUSIONS: The Attitudes Towards the Homeless Questionnaire appears to be a valid and reliable instrument, which can measure students' attitudes towards the homeless. It could be a useful tool in assessing the effectiveness of educational interventions.

Survey of research activity, training needs, departmental support, and career intentions of junior academic general practitioners.

BACKGROUND: Recent changes in the organization of the National Health Service have created new roles and responsibilities for academic general practice. Previous work on the constraints and opportunities of a career in academic general practice is largely anecdotal and is often based on the views of more senior members of the profession. AIM: To survey the research activity, perceived level of training, support needs, and career intentions of junior academic general practitioners (GPs). METHOD: A postal, validated, semistructured questionnaire was sent to the 121 eligible junior academic GPs in the academic departments of general practice in the United Kingdom and Dublin. Main outcome measures were 'research activity score', as measured by publications in peer-reviewed journals and involvement in research projects, 'training score' devised from 13 skills required for both research and teaching, and perceived level of departmental support assessed by six different support mechanisms. RESULTS: Response rate was 89% (n = 108). Forty-six responders (43%) had no publications. Twenty-five responders (23%) had no principal project. Thirty-nine responders (37%) had a mentor. Research activity appeared to be dependent on sex, having a predominantly research role rather than a full-time teaching role, and a positive perception of academic training (P < 0.05). Increasing departmental 'support scores' and length of time in the department were both significantly associated with more positive perceptions of academic training (P < 0.05). Only 29 (27%) responders wanted to progress to senior positions within academic general practice. CONCLUSION: Training and departmental support and guidance available to junior academics in primary care are perceived as variable and often inadequate. If academic general practice is to thrive, improved academic training is required, such as taught Master's degrees, supervised personal projects or 'apprenticeship' as a co-investigator, and improved methods of departmental support.