title: Pooling sheep faecal samples for the assessment of anthelmintic drug efficacy using McMaster and Mini-FLOTAC in gastrointestinal strongyle and Nematodirus infection.
abstract: In small ruminants, faecal egg counts (FECs) and reduction in FECs (FECR) are the most common methods for the assessment of intensity of gastrointestinal (GI) nematodes infections and anthelmintic drug efficacy, respectively. The main limitation of these methods is the time and cost to conduct FECs on a representative number of individual animals. A cost-saving alternative would be to examine pooled faecal samples, however little is known regarding whether pooling can give representative results. In the present study, we compared the FECR results obtained by both an individual and a pooled examination strategy across different pool sizes and analytical sensitivity of the FEC techniques. A survey was conducted on 5 sheep farms in Scotland, where anthelmintic resistance is known to be widespread. Lambs were treated with fenbendazole (4 groups), levamisole (3 groups), ivermectin (3 groups) or moxidectin (1 group). For each group, individual faecal samples were collected from 20 animals, at baseline (D0) and 14 days after (D14) anthelmintic administration. Faecal samples were analyzed as pools of 3-5, 6-10, and 14-20 individual samples. Both individual and pooled samples were screened for GI strongyle and Nematodirus eggs using two FEC techniques with three different levels of analytical sensitivity, including Mini-FLOTAC (analytical sensitivity of 10 eggs per gram of faeces (EPG)) and McMaster (analytical sensitivity of 15 or 50 EPG).For both Mini-FLOTAC and McMaster (analytical sensitivity of 15 EPG), there was a perfect agreement in classifying the efficacy of the anthelmintic as 'normal', 'doubtful' or 'reduced' regardless of pool size. When using the McMaster method (analytical sensitivity of 50 EPG) anthelmintic efficacy was often falsely classified as 'normal' or assessment was not possible due to zero FECs at D0, and this became more pronounced when the pool size increased. In conclusion, pooling ovine faecal samples holds promise as a cost-saving and efficient strategy for assessing GI nematode FECR. However, for the assessment FECR one will need to consider the baseline FEC, pool size and analytical sensitivity of the method.
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK. Electronic address: FionaKenyon@moredun.ac.uk.
authors.forename: Fiona
authors.initials: F
authors.lastname: Kenyon
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Rinaldi
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK.
authors.forename: Dave
authors.initials: D
authors.lastname: McBean
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Pepe
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bosco
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK.
authors.forename: Lynsey
authors.initials: L
authors.lastname: Melville
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK.
authors.forename: Leigh
authors.initials: L
authors.lastname: Devin
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK.
authors.forename: Gillian
authors.initials: G
authors.lastname: Mitchell
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Ianniello
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Belgium.
authors.forename: Johannes
authors.initials: J
authors.lastname: Charlier
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Vercruysse
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cringoli
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Belgium.
authors.forename: Bruno
authors.initials: B
authors.lastname: Levecke
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology* / Q000627:therapeutic use; D005243:Feces / Q000469:parasitology*; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D009348:Nematoda / Q000187:drug effects*; D057808:Nematodirus / Q000187:drug effects; D010270:Parasite Egg Count; D010274:Parasitology / Q000379:methods*; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy / Q000469:parasitology; D017206:Strongylida Infections / Q000175:diagnosis / Q000188:drug therapy / Q000662:veterinary*
chemical_list: D000871:Anthelmintics
keywords: Anthelmintic drug efficacy; Faecal egg count; Gastrointestinal strongyles; McMaster; Mini-FLOTAC; Nematodirus; Pooling faecal samples; Scotland; Sheep