World Association For The Advancement Of Veterinary Parasitology Research Articles

High rates of benzimidazole-resistance-associated alleles in Haemonchus contortus and detection of resistance against macrocyclic lactones in strongylids from German alpaca herds

The population of South American camelids (SAC) has been steadily growing in Europe, where they are confronted with the regional endoparasite population of ruminants. As there are no anthelmintic drugs registered for use against nematode infections in SACs, anthelmintics (AH) available for ruminants or horses are usually applied. Reports indicating potential failures in administered AH are increasing. However, the generally low egg counts in SACs complicate the application of resistance tests in the field. The present study reports a follow-up study on SAC farms where anthelmintic resistance (AR) was suspected. The aims were (i) to repeat faecal egg count reduction tests (FECRTs) on potentially affected farms identified in a previous study with larger sample sizes, (ii) to verify suspected AR of Haemonchus contortus against benzimidazoles (BZ) by performing a single-nucleotide polymorphism (SNP) analysis using digital polymerase chain reaction (dPCR), and (iii) to apply the mini-FLOTAC technique for more reliable results at low egg counts in line with current recommendations. Seven farms (9–46 animals each) were examined by coproscopy, larval differentiation and SNP analysis. A FECRT was performed on six of these farms with moxidectin (three farms), monepantel (two farms) and ivermectin (one farm). The FEC was calculated according to the current World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines with the clinical protocol (a newly introduced variant of FECRT which can be used for smaller sample sizes and lower egg counts on the cost of sensitivity) and an expected efficacy of 99%. A high level (> 90%) of BZ-resistance-associated SNPs on codon 200 of H. contortus was observed on all farms. With the FECRT, resistance was demonstrated for ivermectin (74% FECR), while it remained inconclusive for one farm for moxidectin treatment. Sustained efficacy was demonstrated for the remaining treatments. This study showed an advanced level of BZ resistance in H. contortus of SACs and the development of AR against macrocyclic lactones on some farms. Thus, constant monitoring of AH treatment and sustainable worm control methods both need to be applied.Graphical

First report of ivermectin resistance in cyathostomins (small strongyles) of horses in Argentina

In Argentina, as in the rest of the world, cyathostomins are the most common nematodes parasitizing horses. Control is based almost exclusively on the administration of benzimidazoles, pyrimidines, and macrocyclic lactones. However, intensive use of these drugs is resulting in the development of anthelmintic resistance (AR). For example, AR to benzimidazoles is currently distributed throughout Argentina, while incipient AR to pyrimidines (pyrantel embonate) is appearing in areas where this drug is used. Macrocyclic lactones and especially ivermectin, are by far the most used drugs by the vast majority of equine premises in the country. Although ivermectin has been used since 1982, its efficacy against equine strongylid parasites has remained very high until the present. In this study we report for the first time, the presence of a cyathostomin population with resistance to ivermectin in adult horses belonging to an equine premise located in central Argentina. Fecal egg count reduction tests (FECRT) were performed following the most recent guidelines of the World Association for the Advancement of Veterinary Parasitology (WAAVP) for the diagnosis of anthelmintic resistance (research protocol) and resistance was considered when the Upper 90% Credible Interval fell below the expected efficacy threshold of 99.9%. Calculations were carried out using two different online calculation interfaces suggested by WAAVP. For the 14-day post-treatment interval, ivermectin efficacy was 79.5% (90% Credible Interval: 68.1–88.8) and 79.3% (74.2–83.6.3%) with the two methods, respectively. At 19 days post treatment, fecal egg count reductions were 68.6% (50.5–83.1) and 68.4% (61.9–74.1), respectively. At both intervals, this cyathostomin population fullfilled the criteria for AR. These findings suggest dispersion of ivermectin resistant cyathostomins in Argentina. Given the widespread use of macrocyclic lactones, it is important that veterinarians and the equine industry promote a more selective and evidence-based use of these drugs and establish routine monitoring to determine anthelmintic field efficacy to detect treatment failures as early as possible and avoid potential health problems as well as further spread of resistant genes.

The first report of triple anthelmintic resistance on a French Thoroughbred stud farm

This study assessed the anthelmintic resistance in strongylid nematodes against commonly used anthelmintic (AH) drugs in a French galloping racehorse stud farm from March to December 2023. Faecal egg count reduction tests (FECRTs) were conducted in three different groups of Thoroughbred yearlings (a group of 6 males, a group of 13 females and a group of 8 females and 3 males) following the new World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines. The efficacy of fenbendazole was tested in two groups once during the monitoring period (in March), the efficacy of ivermectin in 3 groups twice (in March–April and in November–December) and the efficacy of pyrantel in one group once (in May–June). For each FECRT, the 90% confidence interval of the percentage faecal egg count reduction was calculated using the hybrid Frequentist/Bayesian analysis method. The resistance in strongylids was observed to fenbendazole, pyrantel and ivermectin in all the groups in which these drugs were tested. The number of animals in each group was sufficient to reach ≥80% power for the resistance test. The results highlight the first case of triple AH resistance in strongylids in France. Further studies involving more farms and equids are required to assess the prevalence of AH resistance in France and refine recommendations for owners.

A national survey of anthelmintic resistance in ascarid and strongylid nematodes in Australian Thoroughbred horses

This study quantified the extent of anthelmintic resistance (AR) in ascarid and strongylid nematodes against commonly used anthelmintics in Australian Thoroughbred horses. Faecal egg count reduction tests (FECRTs, n = 86) and egg reappearance period (ERP) tests were conducted on 22 farms across Australia. Faecal egg counts (FECs) were determined using the modified McMaster technique, and percent faecal egg count reduction (%FECR) was calculated using the Bayesian hierarchical model and hybrid Frequentist/Bayesian analysis method. The results were interpreted using old (published in 1992) and new (2023) research guidelines of the World Association for the Advancement of Veterinary Parasitology (WAAVP). The species composition of strongylid nematodes was detected utilising a DNA-metabarcoding method using pre- and post-treatment samples. Resistance was observed in strongylid nematodes to commonly used single-active and combination anthelmintics, including ivermectin (IVM %FECR range: 82%–92%; 95% lower credible interval (LCI) range: 80%–90%), abamectin (ABM: 73%–92%; 65%–88%), moxidectin (MOX: 89%–91%; 84%–89%), oxfendazole (OFZ: 0%–56%; 0%–31%) and its combination with pyrantel (OFZ + PYR: 0%–82%; 0%–78%). Resistance in Parascaris spp. was observed to IVM (10%–43%; 0%–36%), ABM (0%; 0%) and MOX (0%; 0%). When the new thresholds recommended by the WAAVP were used, AR was detected in six additional FECRTs for strongylids and three more tests for Parascaris spp., introducing resistance to OFZ and OFZ + PYR in the latter. Shortened ERPs (4–6 weeks) of strongylids were observed in 31 FECRTs in which AR was not detected at 2 weeks post-treatment for all the anthelmintics tested. Among cyathostomins, Cylicocyclus nassatus, Cylicostephanus longibursatus and Coronocyclus coronatus were the most prevalent species at 2 weeks post-treatment, whereas the main species appearing at five weeks following treatments with macrocyclic lactones were Cylicocyclus nassatus, Cylicostephanus longibursatus and Cylicocyclus ashworthi. After treatment with OFZ + PYR, the latter three, plus Coronocyclus coronatus and Cyathostomum catinatum, were detected at 5 weeks post-treatment. Overall, the study highlights the prevalence of AR in both ascarids and strongylid nematodes against commonly used anthelmintic products to control worms in Australian horses. The results indicate that ML combination products provided acceptable efficacy at 2 weeks. However, ERP calculations suggest that products work less effectively than previously measured. It is suggested to regularly monitor the efficacy of the anthelmintics and consider changing the worm control practices to better manage worms and AR in Australian horses.

Demonstration of reduced efficacy against cyathostomins without change in species composition after pyrantel embonate treatment in Swedish equine establishments

Consisting of approximately 50 different species, the cyathostomin parasites are ubiquitous in grazing horses. Co-infection with several species is common, and large burdens can cause the fatal disease of larval cyathostominosis. Due to intense anthelmintic drug use, cyathostomin resistance has developed to all available anthelmintic drug groups. Resistance to the anthelmintic drug pyrantel (PYR) has been documented in over 90% of studies published over the past two decades. In Sweden, a study performed in the early 2000s only confirmed resistance in 4.5% of farms. Further, prescription-only administration of equine anthelmintic drugs was enforced in Sweden in 2007. However, it is unknown if this conservative drug use has maintained PYR efficacy in cyathostomins. The aim of the present study was to investigate the effect of PYR on cyathostomin infection in Sweden using fecal egg count reduction tests (FECRTs). Further, the effect of PYR treatment on cyathostomin species composition was studied using metabarcoding.Sixteen farms with at least six horses excreting a minimum of 100 eggs per gram feces were included. Using the current World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines, PYR resistance was demonstrated in nine of farms, with seven farms showing full susceptibility. Farms with low biosecurity measures had significantly lower efficacy of PYR treatment. The most common cyathostomin species were Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cys. calicatus, Cys. goldi, Cys. minutus, Coronocyclus coronatus and Cya. pateratum, accounting for 97% of all sequence reads prior to treatment. Of these, Cyc. nassatus and Cya. catinatum had the highest occurrence, accounting for 68% of all sequence reads prior to PYR treatment. Treatment did not significantly affect the species composition. The results highlight the importance of drug efficacy testing when using PYR to treat cyathostomin infection, even when selective anthelmintic treatment and thus low treatment intensity, is used on the farm.

Efficacy of levamisole and oxyclozanide treatment on gastrointestinal nematodes of ungulates at the Central Zoo, Nepal

The efficacy evaluation of levamisole and oxyclozanide treatment on the gastrointestinal nematodes of ungulates at the central zoo, Nepal was carried out from June—August 2021. A total of 40 fecal samples were collected from 10 species of ungulates from the central zoo for determining the efficacy of the anthelmintic given at day 0 of pretreatment and post-treatment analysis on day 07 and day 14. The concentration method (floatation concentration) was used for the microscopic examination of eggs, and quantitative examination (EPG) of nematode eggs was carried out with the help of modified McMaster slides. The identification was done using an optic micrometer and fecal egg culture. Anthelmintic resistance status was evaluated by the Fecal Egg Count Reduction Technique (FECRT) based on the method described by the World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines and with the Bayesian hierarchical model. Out of 40 samples, nematode prevalence was found to be 68%, in which single infection was detected in 48% and double infection in 52%. The efficacy of Zanide L forte (levamisole-0.75 g and oxyclozanide-1.00 g) was found to be 85% (UI 80-89) at day 07 and 89% (UI 85-92) at day 14 by using Hierarchical Modelling of Fecal Egg count based on ‘eggCounts-2.3 on R version 3.6.1 and 86% (CI 61.51–95%) at day 07 and 90% (CI 74.18–95%) at day 14 by WAAVP guidelines. This study represents the first documented case of ineffectiveness of anthelmintic treatment resulting in anthelmintic resistance in the central zoo. Thus, there is a requirement for a suitable and efficacious anthelmintic program.

Investigation of the Efficacy of Pyrantel Pamoate, Mebendazole, Albendazole, and Ivermectin against Baylisascaris schroederi in Captive Giant Pandas

Baylisascaris schroederi is one of the main health risks threatening both wild and captive giant pandas. The administration of anthelmintics is a common method to effectively control B. schroederi infection, but there is a notable risk of anthelmintic resistance (AR) after long-term, constant use of anthelmintics. Four anthelmintics-pyrantel pamoate (PYR), mebendazole (MBZ), albendazole (ABZ), and ivermectin (IVM)-were each administered separately at intervals of 2 months to 22 enrolled giant pandas. The fecal egg count reduction (FECR) proportions were calculated by both the Markov chain Monte Carlo (MCMC) Bayesian mathematical model and the arithmetic mean. AR was assessed based on the criteria recommended by the World Association for the Advancement of Veterinary Parasitology (WAAVP). The estimated prevalence of B. schroederi infection was 34.1%. After treatment with PYR, MBZ, ABZ, and IVM, it was determined that MBZ, ABZ, and IVM were efficacious against B. schroederi, while nematodes were suspected to be resistant to PYR according to the fecal egg count reduction (FECR) proportions.

COMPARATIVE EFFICACY OF ORAL FORMULATIONS OF IVERMECTIN AND LEVAMISOLE UNDER IN VITRO CONDITIONS AGAINST HAEMONCHUS CONTORTUS

Anthelmintic resistance (AR) is the major constraint towards controlling parasitism of livestock. This study was executed to evaluate relative efficacy of oral formulation consisting of ivermectin (IVM) and levamisole (LEV) towards Haemonchus contortus under in-vitro condition. The worms were isolated from abomasa (n=384), collected from nearby slaughter house. The egg hatch test (EHT), adult motility test (AMT), and larval development test (LDT) were performed for estimation of lethal concentration (Lc) 90. A typical sigmoid dose response was converted to linear function by using Probit transformations. Different concentrations of LEV (0.172, 0.086, 0.043, 0.021, 0.010, 0.005 μl/mL), and IVM (0.002, 0.001, 0.0005, 0.00025, 0.000125, 0.0000625 μl/mL) were incubated with 100 eggs / concentration. The LC 90 values of LEV and IVM were found higher than values suggested by World Association for the Advancement of Veterinary Parasitology (WAAVP), which is (0.1µg/ml). The dose-dependency stipulates development of (AR) anthelmintic towards H. contortus.

In vitro Efficacy of Albendazole against Strongyle eggs recovered from Trade Goats slaughtered at the Nsukka Abattoir: A Preliminary Survey of Resistance to Albendazole

The efficacy of Albendazole against trichostrongyle nematode parasites in goats presented for slaughter at the Nsukka municipal abattoir was evaluated using the In vitro Egg hatch assay (EHA) model. The abattoir was visited once every week for 4 consecutive months during which a total of 240 goats were sampled. Fecal samples were collected per rectum from a minimum of 15 goats on each day of the visit. Egg Hatch Assay was performed on strongyle eggs recovered from pooled faecal sample on each day of sampling with a 2.5% W/V Albendazole. Faecal culture was also set up from the pooled faecal sample on each sampling day to recover and identify the nematode parasites present in the goats. Among the 240 goats sampled, the prevalence of trichostrongylosis as observed by the presence of strongyle eggs was 94.6% (227/240). Faecal culture and larval identification revealed 69.8% of the strongyles as Haemonchus contortus, while 25.5 and 4.8% were Trichostrongylus colubriformis and Oesophagostomum species respectively. In the EHA, Albendazole had mean LC50 value of 0.16 µg/ml which is slightly in excess of the discriminating dose of 0.1µg/ml as prescribed by the World Association for the Advancement of Veterinary Parasitology (WAAVP) as an indication of anthelmintic resistance. There is therefore an urgent need to screen the nematode parasite population in the Nigeria for the presence Albendazole resistance genes.
 Key words: GI nematode; egg hatch assay; goat; Albendazole; Resistance; Nigeria

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for studies evaluating the efficacy of parasiticides in reducing the risk of vector-borne pathogen transmission in dogs and cats

These guidelines are intended to provide an in-depth review of current knowledge and assist the planning and implementation of studies for evaluating the efficacy of parasiticides in reducing transmission of vector-borne pathogens (VBPs) to dogs and cats. At present, the prevention of VBP transmission in companion animals is generally achieved through the administration of products that can repel or rapidly kill arthropods, thus preventing or interrupting feeding before transmission occurs. The present guidelines complement existing guidelines, which focus on efficacy assessment of parasiticides for the treatment, prevention and control of flea and tick infestations, but also give guidance for studies focused on other vectors (i.e. mosquitoes and phlebotomine sand flies). The efficacy of parasiticides in reducing VBP transmission can be evaluated through laboratory or field studies. As such, the present guidelines provide recommendations for these studies, representing a tool for researchers, pharmaceutical companies and authorities involved in the research, development and registration of products with claims for reducing VBP transmission in dogs and cats, respecting the overall principles of the 3Rs (replacement, reduction and refinement). Gaps in our current understanding of VBP transmission times are herein highlighted and the need for further basic research on related topics is briefly discussed.

First report of multiple resistance to eprinomectin and benzimidazole in Haemonchus contortus on a dairy goat farm in France

Pour-on eprinomectin was recently registered for lactating small ruminants. Given the high prevalence of benzimidazole resistance in gastrointestinal nematodes in dairy goats, many farmers use eprinomectin exclusively to treat their animals. On a French dairy goat farm, a veterinary practitioner noted a poor response to two types of eprinomectin treatment (pour-on application and injectable formulation). Therefore, we evaluated the efficacy of both formulations of eprinomectin, as well as moxidectin and fenbendazole, using the fecal egg count reduction test (FECRT) according to the World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines. Nematode species were identified at days 0 and post-treatment days 14 after bulk larval cultures, by morphology and real-time PCR. Plasma concentrations of eprinomectin were analyzed by high-performance liquid chromatography (HPLC) at post-treatment days 2 and 5 in the eprinomectin-treated groups. Egg count reductions were poor in animals treated with topical (−16.7%; 95% CI:[−237; 59]) or subcutaneous (21.5%; 95% CI:[−126; 73]) eprinomectin, and with fenbendazole (−5.8%; 95% CI:[−205; 63]). Haemonchus contortus was the main species identified by morphology and by real-time PCR before and after treatment. The plasma concentrations of eprinomectin were determined in all eprinomectin-treated animals and were above 2 ng/ml at post-treatment day 2, indicating that the lack of effect was not due to low exposure of the worms to the drug. Interestingly, moxidectin remained effective in all infected animals. This is the first report of multiple resistance to eprinomectin and benzimidazole in H. contortus on a French dairy goat farm with moxidectin as a relevant alternative.

Use of Complementary Natural Feed for Gastrointestinal Nematodes Control in Sheep: Effectiveness and Benefits for Animals.

Simple SummaryThe massive and frequent use of drugs to control helminthiasis in sheep might lead to anthelmintic resistance and the presence of residues in the environment. A solution must be found to reduce these risks and natural extracts could be a valid alternative to drugs. The authors report the results of an in vivo study on the effectiveness of a complementary feed, based on natural extracts, without residual risk for the environment, registered for gastrointestinal nematodes control in sheep and comparing its efficacy to the drug ivermectin. This study shows the better efficacy of ivermectin as compared with natural formulations and highlights the importance of in vivo studies for the evaluation of the natural mixtures registered for the treatment of gastrointestinal nematode infectionsThe treatments of gastrointestinal nematodes (GIN) infection in sheep is almost exclusively based on the use of synthetic drugs. In some European regions the intensive use of antiparasitic drugs is leading to widespread development of anthelmintic resistance (AR). Currently in southern Italy AR is rare, but a constant monitoring of anthelmintic efficacy and the use of effective alternative therapies is strongly recommended. The aim of our study was to evaluate the effectiveness of a complementary natural feed (natural vegetable mixture), based on natural extracts, registered for GIN treatment in sheep, and its comparison with the drug ivermectin. The study was conducted in two sheep breeding farms in southern Italy and 75 sheep were divided in groups of 15 animals each (treated and untreated groups), homogeneous by GIN eggs per gram (EPG) of faeces, using the natural anthelmintic administered at full dose (10 g/sheep/orally) in the first breeding and at double dose (20 g/sheep/orally) in the second. In the latter we compared the effectiveness of mixture with ivermectin administered at full dose (200 μg/kg/BW). To determine the effectiveness, individual faecal samples were collected to evaluate the faecal eggs count (FEC) using FLOTAC technique and FEC reduction (FECR) on different days. The formula used FECR = 100 × (1 − (T2/C2)), based on the comparison of post-treatment EPG mean of the treated and untreated group (T2 and C2, respectively), is the one recommended by World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines to monitor drug efficacy against GIN in livestock. The results reported that complementary natural feed, at two different dosages, was ineffective against GIN, while the drug, at conventional dosage, showed good anthelmintic efficacy, also confirming the importance of in vivo effectiveness studies.

World association for the advancement of veterinary parasitology (WAAVP) guideline for testing the efficacy of ectoparasiticides for fish

This guideline is intended to assist in the planning and execution of studies designed to assess the efficacy of ectoparasiticides for fish. It is the first ectoparasite-specific guideline to deal with studies set in the aquatic environment and therefore provides details for the maintenance of environmental standards for finfish. Information is included on a range of pre-clinical study designs as well as clinical studies in commercial/production sites, set within a regulatory framework. It provides information on the study animals, their welfare, husbandry and environmental requirements during the study. The most commonly pathogenic ectoparasites are presented with relevant points regarding life history, host challenge and numeric evaluation. Preparation and presentation of both topical and oral test treatments is provided, together with guidance on data collection and analysis. The guideline provides a quality standard or efficacy studies on finfish, which will assist researchers and regulatory authorities worldwide and contribute to the wider objective of harmonisation of procedures.

Efficacy of selected anthelmintic drugs against cyathostomins in horses in the federal state of Brandenburg, Germany

Cyathostomins are currently the most common internal parasites of horses. With the intensive use of anthelmintic drugs over the past decades, resistance of cyathostomins to anthelmintics is becoming a growing problem in many countries. The aim of this study was to assess the current situation on horse farms in the German federal state of Brandenburg. A pre-selected population of horses from 24 premises that had shown a prevalence of cyathostomins higher than the average in a previous study was examined for anthelmintic efficacy. Faecal egg count reduction tests (FECRTs) were performed for ivermectin (IVM) and pyrantel (PYR). For IVM, the egg reappearance period (ERP) was also examined, as a shortened ERP can be indicative of developing resistance. The efficacy of IVM on cyathostomins was high: 99.1% of 224 horses had a zero egg count 14days after treatment. No shortening of the ERP was detected. For the data of the FECRT for PYR, three different methods of calculation were employed: (a) the method as recommended by the World Association for the Advancement of Veterinary Parasitology (WAAVP), (b) a bootstrapping method and (c) a Markov chain Monte Carlo method. Two methods of interpretation for these data were used: Resistance was declared (a) when FECR was <90% and the lower 95% confidence interval (LCL) <80% and (b) when additionally the upper 95% confidence level (UCL) was <95%. When applying the first interpretation, resistance against PYR was found on four yards, while, when considering the UCL, all three methods for calculation only detected resistance on one single yard. Twelve species of cyathostomins were detected in larval cultures derived from strongyle egg positive faecal samples collected 14days after treatment with PYR by reverse line blot hybridization (RLB). In order to generate comparable data, it is suggested to establish international standards for the calculation of FECRT data.

Eficácia de Chenopodium ambrosioides (erva-de-santa-maria) no controle de endoparasitos de Coturnix japônica (codorna japonesa)

Resumo:O objetivo foi testar in vitro e in vivo a eficácia da planta medicinal Chenopodium ambrosioidesLinnaeus, 1786 (erva-de-santa-maria), nas formas fitoterápica e homeopática, como meios alternativos para o controle de endoparasitos de Coturnix japonica Temminck &amp; Schlegel, 1849 (codorna japonesa), um sério problema que afeta a criação e desempenho de aves domésticas, ocasionando morte quando muito intenso, retardo de crescimento, redução de índice de conversão alimentar e aumento na suscetibilidade às doenças infecciosas. As metodologias utilizadas foram preconizadas por Coles et al. (1992), creditada pela World Association for the Advancement of Veterinary Parasitology (WAAVP). A pesquisa evidenciou a presença dos gêneros Ascaridiae Eimeria. O ensaio in vitro demonstrou alta taxa de redução na inibição de eclosão de ovos de Ascaridiasp. (100,00%) e significativa taxa de redução na destruição de oocistos de Eimeriasp. (47,06%). O ensaio in vivodemonstrou alta taxa de redução na contagem de ovos de Ascaridiasp. nas fezes (100,00%) e expressiva taxa de redução na contagem de oocistos de Eimeriasp. nas fezes (60,33%). Chenopodium ambrosioides mostrou em certos momentos superioridade frente ao produto tradicional (Thiabendazole/Mebendazole) e índices superiores aos preconizados pelo Ministério da Agricultura do Brasil e Organização Mundial da Saúde como indicativos de eficácia.

World Association for the Advancement of Veterinary Parasitology (WAAVP): Guideline for the evaluation of drug efficacy against non-coccidial gastrointestinal protozoa in livestock and companion animals

The current guideline was written to aid in the design, implementation and interpretation of studies for the assessment of drug efficacy against non-coccidial gastrointestinal protozoan parasites, with Giardia spp. as the leading example. The information provided in this guideline deals with aspects of how to conduct controlled studies using experimental infection models (dose determination and dose confirmation) and efficacy studies in commercial facilities (field effectiveness studies). Furthermore, the selection of suitable animals, housing, infection procedure, choice of diagnostic technique and data analysis are discussed. This guideline is intended to assist investigators in conducting specific studies, to provide specific information for registration authorities involved in the decision-making process, to assist in the approval and registration of new drugs and to facilitate the worldwide adoption of uniform procedures. The primary parameter for drug efficacy is the reduction in either parasite excretion or parasite counts and a minimum efficacy of 90% is required against non-coccidial gastrointestinal protozoa. A supporting efficacy parameter is a significant difference in the proportion of infected animals between treated and non-treated groups. Persistent efficacy is considered as an additional claim to therapeutic efficacy.

World Association for the Advancement of Veterinary Parasitology (WAAVP): The 50th anniversary in 2013—History, achievements, and future perspectives

In 2013 the World Association for the Advancement of Veterinary Parasitology (WAAVP) can celebrate its 50th anniversary. At this occasion in this article selected historical data are updated, and the achievements and future perspectives of the WAAVP are discussed. Although the WAAVP is a small association with only a few hundred members, it has been able to develop remarkable activities. Between 1963 and 2011 the WAAVP has organized 23 international scientific congresses, and the 24th conference will take place in Perth, Western Australia, in 2013. These conferences have achieved a high degree of international recognition as indicated by relatively large numbers of participants (up to ∼800). Furthermore, the WAAVP has promoted veterinary parasitology in various ways, such as publishing international guidelines (efficacy evaluation of antiparasitic drugs, parasitological methods, standardized nomenclature of animal parasitic diseases “SNOAPAD”), stimulating international discussions on teaching and continued education (“colleges of veterinary parasitology”) and by supporting the high quality journal “Veterinary Parasitology” which is the official organ of the WAAVP. In retrospect, the development of the WAAVP can be classified as very successful. New challenges associated with global changes (growth of the world population, urbanization, climate change, new developments in animal and plant production, etc.) will require new efforts in research in various fields, including veterinary parasitology. Future activities of WAAVP may include inter alia: (a) support of international parasitological networks; (b) stimulation of coordinated research aimed at the solution of defined problems; (c) increasing the exposure of WAAVP to parasitology from hitherto neglected regions of the world; (d) strengthening of official links to international organizations (FAO, WHO, etc.); (e) continuation of guideline preparation; and (d) preparation and international distribution of high quality electronic programs for self-education in veterinary parasitology.

Improving the detection of anthelmintic resistance: Evaluation of faecal egg count reduction test procedures suitable for farm routines

The faecal egg count reduction test (FECRT) is the main method of detection of anthelmintic resistance (AR) in nematodes of veterinary importance. However, although the FECRT is standardised, the diagnostic performance of this method has not been fully characterised. In this survey Monte Carlo routines were used to simulate the estimation of faecal egg count reduction (FECR) with several FECRT protocols that were performed under different field and laboratory conditions. The goal was to determine, from a practical viewpoint, the most suitable protocols for farm routines and to evaluate the diagnostic performance of FECRTs across different parasitological scenarios with several levels of AR. The simulated field procedures included variations in the sample size and the sampling (or not) of a control group, whereas the simulated laboratory procedures comprised group mean individual-based vs. composite-based FECR estimations and variations in the egg detection threshold of the McMaster technique. For composite procedures, the random weight variations among individual samples and an increased number of McMaster chamber counts were also simulated. The results showed that FECRTs were moderately affected by inaccuracy but crucially affected by imprecision, and both parameters were clearly dependent on the parasitological conditions and the laboratory and field procedures used. An individual-based FECRT method performed without a control group was the most appropriate to quantify the AR, whereas a composite-based method with a control group was the easiest method for discriminating susceptible and resistant parasite populations. More interestingly, the diagnostic performance of the simulated FECRT methods was low for the procedures that are currently recommended by the World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) and for many of the typical field and laboratory procedures that are currently implemented. Therefore, the results suggest that the diagnostic performance of the FECRT should be re-evaluated, and the recommendations of the W.A.A.V.P. should be redefined. Finally, theoretic critical conditions for FECRT procedures have been defined to improve future AR surveys and to allow the interpretation of FECRT results with the necessary caution according to the diagnostic performance expected for every FECRT procedure and parasitological scenario.

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) second edition: Guidelines for evaluating the efficacy of parasiticides for the treatment, prevention and control of flea and tick infestations on dogs and cats

These second edition guidelines, updated from the 2007 version (Marchiondo et al., 2007), are intended to assist the planning and conduct of laboratory and clinical studies to assess the efficacy of ectoparasiticides applied to dogs or cats for the purpose of treating, preventing and controlling flea and tick infestations. Major revisions to this second edition include guidelines on the assessment of systemic flea and tick products, an update of the geographical distribution of the common fleas and ticks species on dogs and cats, determination of flea and tick efficacy based on geometric versus arithmetic means with respect to geographic regulatory agencies, modification of tick categorization in the assessment of efficacy, expanded guidelines on repellency and anti-feeding effects, enhanced practical field study guidance, and considerations on the ranges of flea and ticks for infestations in laboratory studies. The term ectoparasiticide includes insecticidal and acaricidal compounds, as well as insect growth regulators. The range of biological activities from animal treatment that are considered include: repellency and anti-feeding effects, knockdown, speed of kill, immediate and persistent lethal effects, and interference with egg fertility and subsequent development of off-host life cycle stages. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping, interpretation of results and animal welfare. These guidelines are also intended to assist regulatory authorities involved in the approval and registration of new topical or systemic ectoparasiticides, and to facilitate the worldwide adoption of harmonized procedures.

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) Guideline: Anthelmintic combination products targeting nematode infections of ruminants and horses

Increasing threats from anthelmintic resistant nematode populations warrant and motivate a reappraisal of chemotherapeutic strategies for nematode control in ruminant livestock and horses. The objective of this paper is to present a guideline for the evaluation of products containing two or more constituent anthelmintic actives in a single dosage form for the treatment of nematode infections in these animals. At present, regulatory policies on the approval of such products vary across jurisdictions, and this World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guideline should enable the harmonization of the requirements. This guideline makes clear recommendations on the minimal standards needed, but stresses that registration dossiers for combination anthelmintic products submitted for approval must conform to the standards and practices already established in existing guidelines for anthelmintics.