Faecal Egg Count Reduction Test Research Articles

Treatment ineffectiveness towards Haemonchus contortus is highly prevalent in sheep and goat farms of North-Eastern Italy

BackgroundAnthelmintic resistance (AR) is a global threat to grazing livestock farming. In Italy, anthelmintic efficacy remains high compared to other European countries, but many parts of the country haven’t been investigated yet. Local veterinary practitioners from Trentino and Veneto regions reported suspected inefficacy towards anthelmintic drugs in some of their farms, prompting a study on AR in sheep and goat farms of northern Italy. The study aimed to assess anthelmintic effectiveness using genus-specific faecal egg count reduction tests (FECRT), to detect differences in treatment response among nematode genera involved in the infection.ResultsTwelve farms (6 sheep and 6 goat farms) were included based on clinical suspicion of AR. Treatments were carried out with either benzimidazoles (BZ) or macrocyclic lactones (ML) Treatment was effective in 3/6 goat trials, with reduced effectiveness to BZ in two farms and to ML the last one. In sheep farms (6/6), effectiveness was consistently and more severely insufficient. Ineffectiveness was particularly high towards Haemonchus contortus, while Oesophagostomum/Chabertia maintained susceptibility in nearly all trials. Trichostrongylus/Teladorsagia exhibited intermediate results.ConclusionsThis study reveals diminished efficacy of both BZ and ML in small ruminant farms in north-eastern Italy, an area previously lacking data on the topic, except for goats in South Tyrol. Variability in treatment responses among nematode genera support suspicions of AR, and further concerns are raised by the prevalence of treatment ineffectiveness against the highly pathogenic Haemonchus contortus. This finding underscores the urgent need for comprehensive AR monitoring in the area and improved management practices to prevent further resistance development and protect livestock health.

PSX-11 Behavior of Kentucky beef producers towards controlling internal parasites

Abstract Internal parasites can reduce production efficiency in livestock grazing systems. Increased concern has been expressed regarding the potential loss of efficacy of available products currently available to livestock managers to control internal parasites. A survey was conducted during the spring of 2023 of Kentucky beef producers participating in a Fecal Egg Count Reduction Test (FECRT) study to gain insight related to their behavior toward managing internal parasites. A total of 70 individuals completed or partially completed the survey instrument. Similar numbers of operations had a single calving season of either spring (35.8%) or fall (37.3%) with these being more prominent than having both spring and fall calving seasons or a year-round calving season. When asked if they had ever performed a FECRT within their herd previously, 96.9% of respondents indicated they had not. Administering an anthelmintic twice annually was reported most often at 69.2%, while 16.9% indicated once per year and more than twice annually being reported by only 6.2%. Sixty percent of beef cattle managers indicated that they rotated products. When asked about the frequency of product rotation, 33.9% indicated they rotated products at each application while 25.8% switched products annually with another 21% never switching products. It is unclear as to why these two questions yielded slightly different outcomes. As all anthelmintics dosage is based on body weight (BW), determination of dosage was asked. More than 75% estimated BW for dosage while 15.4% used a scale to set the dosage for each animal and 7.7% used a scale to obtain an average BW to set the dosage for all animals. Route of administration of product most frequently utilized was pour-on at 66.3% either alone or in combination with another product. Oral drench (17.5%) and injectable (13.8%) were the next most common routes of administration with a single report of product being provided in the feed. This information provides Extension educators with insight regarding beef cattle managers’ behaviors towards anthelmintic use and aid in developing educational programs focused on controlling internal parasites.

Efficacy of Commonly Used Anthelmintics Against Naturally Occurring Gastrointestinal Nematodes in Goats

Efficacy of four commonly used anthelmintics have been evaluated against naturally occurring gastrointestinal nematodes in goats following the method of faecal egg count reduction test (FECRT) in the present study. Fifty goats in the age group of 1 to 2 years old and of either sex, having infection with strongyle group of nematodes were selected in the sheep and goat farm under project ‘Biotech Kisan Hub”, West Bengal University of Animal and Fishery sciences and the goats were equally divided into five groups; group I (infected control), group II (albendazole treated), group III (fenbendazole treated), group IV (ivermectin treated) and group V (levamisole treated). Faecal egg count (FEC) in terms of eggs per gram of faeces (EPG) were estimated in all the experimental goats (n = 50) on 0-day post treatment (0 DPT) and again on 10 DPT. Efficacy of albendazole, fenbendazole, ivermectin and levamisole were 78.15%, 80.24%, 86.38% and 95.46%, respectively. Comparatively less efficacy of albendazole and fenbendazole indicated the emergence of anthelmintic resistance and lower efficacy of ivermectin might be due selection of resistant worms. Efficacy of levamisole was comparatively higher and it can be used strategically to control GI helminth parasites of goats in that farm.

Inefficacy of ivermectin and moxidectin treatments against Dictyocaulus viviparus in dairy calves.

The bovine lungworm Dictyocaulus viviparus negatively impacts bovine health and leads to substantial economic losses. Lungworm infections can be difficult to manage due to the unpredictable and severe nature of clinical outbreaks. Despite the widespread use of macrocyclic lactones (MLs) in grazing cattle in the UK, there have been no confirmed reports of resistant lungworms to date, with only one case of anthelmintic-resistant (ML) lungworm confirmed worldwide. Lungworm Baermann filtrations were conducted on first-season grazing dairy calves as part of a wider study investigating anthelmintic resistance in gastrointestinal nematodes in Scotland using the faecal egg count reduction test. Clinical signs and significant numbers of lungworm larvae in faeces were observed after treatment with either ivermectin or moxidectin. There are no established guidelines for the diagnosis of resistant lungworms in the field. Currently, resistance can only be diagnosed after a controlled efficacy test has been conducted. This limits the conclusions that can be drawn; however, they are highly suggestive of resistance. This short report describes the inefficacy of ivermectin and moxidectin against D. viviparus and is highly suggestive of ML resistance.

Occurrence of fenbendazole resistance in Parascaris spp. on breeding farms in Sweden

Anthelmintic resistance is an increasing problem in many gastrointestinal parasites of grazing animals. Among these, the equine roundworm, Parascaris spp., has developed wide-spread resistance to macrocyclic lactones over the past decades. Additionally, there are recent observations of emerging treatment failure of both tetrahydropyrimidine and fenbendazole. Therefore, the aims of this study were to further investigate the occurrence of fenbendazole resistance on breeding farms and to explore potential management-related risk factors associated with resistance in Parascaris spp. in Sweden. Eleven farms with 92 foals positive for Parascaris spp. were included in a faecal egg count reduction test during the years 2021–2023. According to the clinical protocol of the guidelines of the World Association for the Advancement of Veterinary Parasitology, fenbendazole resistance was present on four farms with efficacies varying from 45 % to 96 %. Having previously reported reduced efficacy on one of these farms, we can now confirm that fenbendazole resistance in Parascaris spp. has established. Farms with more than 40 yearly born foals had a significantly higher probability of having resistant Parascaris spp. Populations compared with smaller farms, (generalized linear model (GLM), t = 70.39, p < 0.001). In addition, there was a correlation between the number of foals on the farm and the frequency of yearly treatments showing that farms with < 20 foals were notably inclined to administer treatments twice during the first year (GLM, t=2.76, p < 0.05) in contrast to larger farms with > 40 foals that were using more frequent treatment intervals. In conclusion, this study confirms the establishment of fenbendazole resistance in Parascaris spp. populations on Swedish stud farms with the number of foals on the farm identified as a risk factor for development of anthelmintic resistance.

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

The effect of anthelmintic treatment and efficacy on the faecal microbiota of healthy adult horses

Changes to the faecal microbiota of horses associated with administration of anthelmintic drugs is poorly defined. This study included horses with cyathostomin infection where susceptibility and resistance to oxfendazole and abamectin was known. This study assessed the changes to the faecal microbiota associated with administration of two different anthelmintics in this population. Twenty-four adult horses were included. Faecal egg counts were performed on all horses prior to random allocation into abamectin (n=8), oxfendazole (n=8) or Control groups (n=8) and at Day 14 post treatment. Faecal samples were collected for microbiota analysis prior to anthelmintic administration and on Day 3 and Day 14. From each faecal sample, DNA was extracted prior to PCR amplification, next generation sequencing and analysis using QIIME2. Anthelmintic treatment was associated with changes in alpha diversity (p <0.05), with increased evenness and diversity at Day 14 and increased richness at Day 3 within the abamectin group. Differences in relative abundance of bacteria at the phyla, family and genus taxonomic levels occurred after treatment; indicating that the microbiota was altered with anthelmintic administration. The results support that anthelmintic administration and removal of cyathostomins from the large intestine of horses is associated with changes in the faecal microbiota. The results suggest that removal of cyathostomins is associated with greater differences in microbiota, compared to anthelmintic drug administration that is ineffective in reducing cyathostomin infection. Cyathostomin removal was supported by adequate reduction of faecal egg counts, determined by faecal egg count reduction testing.

Unravelling the Effectiveness of Anthelmintic Treatments on Equine Strongyles on Irish Farms.

Over the preceding decades, the widespread dependence on anthelmintic drugs for managing nematodes in grazing equids has given rise to resistance against commonly used anthelmintics in various countries. This study explores the prevalence of anthelmintic resistance across 44 horse farms in Ireland. Anthelmintic efficacy was evaluated through fecal egg count reduction (FECR) tests employing the mini-FLOTAC technique. Resistance to benzimidazoles was identified in 12 out of 14 farms (FECR range: 0.00% to 86.2%). Ivermectin resistance was observed on two farms, one with an FECR of 80.70% and another with an FECR of 96.10% (lower 95% high probability density interval (HPD) <90%, 11.70%). On the remaining six farms, the reduction with ivermectin still exceeded 95%. The reduced efficacy of moxidectin was noted on two farms (FECR = 86.90% and 93.50%) and on a third farm with an FECR of 99.50 and a lower HPD interval < 90% at 24.00%. In summary, these findings emphasize the urgent need for alternative strategies in equine strongyle control that reduce reliance on anthelmintics and prioritize effective management practices on Irish equine farms to hinder the impending development of drug-resistant parasite populations.

First evaluation and detection of ivermectin resistance in gastrointestinal nematodes of sheep and goats in South Darfur, Sudan.

In Sudan, resistance to benzimidazoles has been reported recently in cattle and goats from South Darfur. Herein, ivermectin efficacy against gastrointestinal nematodes (GINs) was evaluated in sheep and goats in three study areas in South Darfur. The faecal egg count reduction test (FECRT) was used to evaluate the efficacy of ivermectin in sheep and goats naturally infected with GINs in the region of Bulbul (goats: n = 106), Kass (goats: n = 40) and Nyala (Domaia (sheep: n = 47, goats: n = 77) and the University farm (goats: n = 52)), using different treatment plans, and the efficacy was evaluated 12 days after treatment. Ivermectin efficacy was also evaluated in goats experimentally infected using local Haemonchus contortus isolates from Kass and Nyala. Nematodes surviving ivermectin treatment in goats in Bulbul and Nyala were harvested and larvae used to infect worm-free male sheep (n = 6, ≤6 months old). Infected sheep were dosed subcutaneously with ivermectin every eight days with increasing doses from 0.2 mg/kg to 1.6 mg/kg bodyweight (bw). Reduced ivermectin efficacy was identified in sheep and goats in the four study locations. Using a paired statistic, the efficacy of a therapeutic dose in sheep was 75.6% (90% upper credible limit (UCrL): 77.5%), while twice the recommended dose led to a reduction of 92.6% (90% UCrL: 93.3%). In goats, the FECRs of a therapeutic dose were 72.9-95.3% (90% UCrL range: 73.6-95.7%) in Bulbul, Nyala Domaia, Nyala University farm and Kass. Twice the dose recommended for goats in Bulbul revealed a 90% UCrL of 87.6%. All post-treatment faecal cultures contained only Haemonchus spp. larvae. The experimental infection trials in sheep and goats supported our findings from field trials and calculated upper 90% CrL of below 98.9%. For the first time highly ivermectin resistant H. contortus populations have been identified in sheep and goats in Sudan, and resistance was experimentally confirmed.

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.

Strongylids of Domestic Horses in Eastern Slovakia: Species Diversity and Evaluation of Particular Factors Affecting Strongylid Communities

PurposeThis study aimed to examine the species diversity and structure of the strongylid community in domestic horses in Eastern Slovakia. Also, an analysis of the impact of age, sex, and collection location factors on the strongyid communities was performed.MethodsTwenty-seven horses 1.5–21 years old from two farms in eastern Slovakia with different horse-management conditions were studied. Strongylids were collected after horse treatments with Noromectin (0.2 mg ivermectin); 66,170 specimens were collected and identified. Faecal egg count reduction test (FECRT) was performed following fenbendazole (FBZ) and ivermectin (IVM) treatments.ResultsTwenty-four strongylid species were found; horses were infected with 6 to 16 (average = 11.7) species. Six cyathostomin species (Cylicocyclus nassatus, Cyathostomum catinatum, C. pateratum, Cylicostephanus longibursatus, C. goldi, C. calicatus) were the most prevalent; C. catinatum was the dominant species in both farms (Berger-Parker index 0.34 and 0.42). The structure of the strongylid community was multimodal with dominant, subdominant, background, and rare species. The Mantel test showed that horse age and sex did not significantly affect the nematode infracommunity composition (p > 0.05), while the impact of the collection location (farm) was significant (p = 0.03). Additionally, C. longibursatus was identified as the species contributing significantly to the observed farm differences. Strong resistance to FBZ was documented on both farms (FECRT was 36.4% and 22.7%); IVM resistance was not observed (FECRT = 100%).ConclusionThis study presents the first report on the strongylids parasitizing domestic horses in Eastern Slovakia and gives basic information for further studies of horse parasites and their control in the region.

Surveillance of Ancylostoma caninum in naturally infected dogs in Quebec, Canada, and assessment of benzimidazole anthelmintics reveal a variable efficacy with the presence of a resistant isolate in imported dogs.

Ancylostoma caninum is a widely prevalent parasitic nematode in dogs across the world. There has been a notable increase in reports of anthelmintic resistance in A. caninum within the United States of America in recent years, which has led us to investigate the potential of this scenario in Canada. The study objectives were to assess the prevalence of A. caninum in two different groups, including a colony of rescued dogs in Canada and three imported Greyhound dogs from USA, and to evaluate the efficacy of two benzimidazole (BZ) anthelmintics against A. caninum, complemented with a molecular genetic analysis adapted to low prevalence. Fecal samples were collected at pre- and post-treatment with fenbendazole for the native shelters-origin group, and a combination of anthelmintic formulations, including the pro-BZ febantel for the USA-origin group. The coprology analyses found several genera of internal parasites. Canine ancylostomiasis was the most prevalent parasitosis with 30.77% in the native group and 100% in the USA group, but with overall low average of A. caninum eggs per gram. Through the fecal egg count reduction test (FECRT), applying a cut-off at 90% as baseline of egg reduction for successful efficacy, BZ showed variable efficacy. Furthermore, molecular analysis confirmed the presence of A. caninum in both groups of dogs and found differences in the genetics linked to BZ resistance on the A. caninum β-tubulin isotype 1 gene. In the isolate from the native group, both codons 167 and 200 were homozygous without the presence of single nucleotide polymorphism (SNP). In contrast, the selected isolate from the USA group, showed a homozygous allele at position 200 and a heterozygous SNP at position 167. The latter was congruent with the low efficacy in FECRT and agrees with the recent findings of USA A. caninum isolate resistant phenotype to the BZ anthelmintics. The limitations of the study include an overall low eggs-per-gram in both canine groups, and the shortage of additional fecal samples from the USA group, restraining the molecular analysis only to one out of the three Greyhounds. This study provided some insights on the efficacy of BZs against A. caninum and revealed the presence of BZ resistant isolates in imported dogs in Quebec, Canada. All this information should be considered, for choosing the best strategy in the control of A. caninum using anthelmintic drugs.

Faecal egg count reduction tests and nemabiome analysis reveal high frequency of multi-resistant parasites on sheep farms in north-east Germany involving multiple strongyle parasite species

Anthelmintic resistance in sheep parasitic gastrointestinal nematodes is widespread and a severe health and economic issue but prevalence of resistance and involved parasite species are unknown in Germany. Here, the faecal egg count reduction test (FECRT) was performed on eight farms using fenbendazole, ivermectin and moxidectin and on four farms using only moxidectin. A questionnaire was used to obtain data on management practices to potentially identify risk factors for presence of resistance. All requirements of the recently revised WAAVP guideline for diagnosing anthelmintic resistance using the FECRT were applied. Nematode species composition in pre- and post-treatment samples was analysed with the nemabiome approach. Using the eggCounts statistic package, resistance against fenbendazole, ivermectin and moxidectin was found on 7/8, 8/8 and 8/12 farms, respectively. No formal risk factor analysis was conducted since resistance was present on most farms. Comparison with the bayescount R package results revealed substantial agreement between methods (Cohen's κ = 0.774). In contrast, interpretation of data comparing revised and original WAAVP guidelines resulted in moderate agreement (Cohen's κ = 0.444). The FECR for moxidectin was significantly higher than for ivermectin and fenbendazole. Nemabiome data identified 4 to 12 species in pre-treatment samples and treatments caused a small but significant decrease in species diversity (inverse Simpson index). Non-metric multidimensional scaling and k-means clustering were used to identify common patterns in pre- and post-treatment samples. However, post-treatment samples were scattered among the pre-treatment samples. Resistant parasite species differed between farms. In conclusion, the revised FECRT guideline allows robust detection of anthelmintic resistance. Resistance was widespread and involved multiple parasite species. Resistance against both drug classes on the same farm was common. Further studies including additional drugs (levamisole, monepantel, closantel) should combine sensitive FECRTs with nemabiome data to comprehensively characterise the anthelmintic susceptibility status of sheep nematodes in Germany.

93 Evaluating the efficacy of anthelmintics in an upper Midwest horse herd

Abstract Cyathostomins in the gastrointestinal tract are ubiquitous in horses around the world and remain a target in parasite control programs. Resistance to anthelmintics has risen in recent years with widespread resistance to benzimidazoles and pyrantels and emerging resistance to macrocyclic lactones. Thus, investigating the efficacy of anthelmintics in different locations is important to direct future parasite control programs. This 2-yr study evaluated the efficacy of three anthelmintic drugs in a university-owned equine herd in the upper Midwest using fecal egg count reduction tests (FECRT). Additionally, the effect of age group and body condition score (BCS) on fecal egg shedding was evaluated. We hypothesized that drug resistance is present in the parasite population of this equine herd. Fecal egg counts (FEC) of strongelid eggs were determined using the McMaster method. The efficacy of anthelmintics was determined by calculating the percentage of reduction in FEC between d 0 and d 14 post-treatment. Eighteen horses of various breeds were used in the study. The horses were grouped by age (&amp;lt; 10, 10-16, and &amp;gt; 16 yr; n = 6 in each group) and BCS using the Henneke system (5.0-5.5, n = 9; 6.0-6.5., n = 6; and 7.0-8.0, n = 3). In yr 1, horses within age group were randomly assigned to anthelmintic treatment: pyrantel pamoate, fenbendazole, or ivermectin. In yr 2, all horses received ivermectin. Individual FEC were performed on the day of anthelmintic treatment (d 0) using freshly voided feces. FEC were repeated 14 d after treatment. FEC were log transformed before analysis. Efficacy of the anthelmintics were compared using a mixed model ANOVA with repeated measures (SAS 9.4). Results were considered significant when P &amp;lt; 0.05. The FECRT was greater when treated with ivermectin and pyrantel pamoate (94.8 ± 11.6 % and 96.6 ± 14.3 %, respectively) compared with fenbendazole (54.4 ± 10.8 %; P &amp;lt; 0.05). The FECRT increased from 54.4% when treated with fenbendazole to 100% when the same horses were treated with ivermectin (P &amp;lt; 0.05). Age tended to affect egg shedding in horses (P = 0.0548). Young horses (&amp;lt; 10 yr) had a greater FEC compared with older horses (&amp;gt;16 yr; P &amp;lt; 0.05) but were not different from horses aged 10 to 16 yr (P &amp;gt; 0.05). There was no effect of BCS on strongelid egg shedding in this study (P = 0.9468). These results indicate the efficacy was within the expected range with no signs of resistance to pyrantel pamoate (93.3 to 100% reduction). There was evidence of emerging resistance to ivermectin (70.4 to 100% reduction) and significant resistance to fenbendazole (0 to 71.5% reduction) in the cyathostomin population in this horse herd. The findings of this study agree with previous research demonstrating resistance to anthelmintics. These results highlight the importance of designing improved parasite control programs to limit the spread of drug resistance with the ultimate goal of improving overall health of the horse.

Influence of fasting on the efficacy of anthelminthics in naturally infected sheep

The aim of this study was to verify the effect of fasting on the anti-helminthic efficiency of ivermectin-albendazole-levamisole (IAL) combination (first stage) and the closantel and albendazole (second stage) in sheep naturally infected with gastrointestinal nematodes. To this end, fecal samples from young (4 to 6 months), male and female sheep were evaluated seven and 14 days after the treatments, using the Egg count Per Gram of feces (EPG) and the Fecal Egg Count Reduction Test (FECRT). In the first stage of the experiment, the mean EPG of the animals treated and fasted beforehand was lower than the mean EPG of the animals treated, but not fasted 14 days after treatment. Moreover, the group of fasted animals exhibited a better reduction in fecal egg count rate. In the second stage, there was no significant decrease in the mean EPG of the animals in any group (closantel and albendazole) and the efficiency calculated by FECRT was low for the closantel group and zero for the albendazole group. However, the decrease in EPG in animals treated with closantel after fasting was 326.8% greater than the decrease in EPG in animals treated without prior fasting. It was evident that fasting had a positive influence on the reduction of the genera Haemonchus, Cooperia, Trichostrongylus and Oesophagostomum in the animals treated with closantel. The anthelminthic effect of closantel, albendazole and ivermectin-albendazole-levamisole (IAL) combination in sheep was significantly enhanced by previous fasting. Therefore, it is strongly recommended to withhold solid food for a minimum of 12 hours before administering these treatments.

Anthelmintic Activity of Saussurea costus (Falc.) Lipsch. Against Ascaridia galli, a Pathogenic Nematode in Poultry: In Vitro and In Vivo Studies.

The growing resistance of helminth parasites to currently available commercial anthelmintic drugs, combined with apprehensions regarding detrimental chemical residues in livestock products, has sparked an interest in exploring medicinal plants as an alternative strategy for treating helminthiasis. As a result, this study was designed to investigate the anthelmintic activity of crude methanolic extracts (CME) of Saussurea costus root on Ascaridia.galli, a pathogenic nematode of poultry. In vitro, the anthelmintic effect of Saussurea costus root was evaluated in comparison to commercial anthelmintic, levamisole on the adult nematode parasites, A.galli using worm motility inhibition (WMI) test. The CME of S.costus was also evaluated for in vivo anthelmintic activity in chickens experimentally infected with Ascaridia galli. For the in vivo study, one hundred-day-old chickens were orally infected with embryonated eggs of A. galli worms. The efficacy of the plant extract as an anthelmintic was assessed through two tests: faecal egg count reduction (FECR) test and worm count reduction (WCR) test. The study investigated three distinct doses of plant extract under in vivo setup: 500mgkg-1 body weight (bw), 1000mgkg-1 bw, and 2000mgkg-1 bw. In vitro, all the tested concentrations of S.costus (25mg/ml, 50mg/ml, and 100mg/ml) showeda significant (P < 0.001) anthelmintic effects on live adult A. galli worms in terms of inhibition of worm motility at different hours post-treatment. At the highest concentration of the extract, we observed worm motility inhibition of 100% at 24h post-exposure. On day 14 post-treatment, all birds were slaughtered, and adult A. galli worms were subsequently retrieved from their small intestines. Birds treated with CME extract of S. costus root exhibited a significant (P < 0.001) reduction in faecal egg count. However, the administration of the extract at the dosage of 500mgkg-1bw to the birds did not reveal any significant (P > 0.05) differences in the worm count compared to the negative control group. The CME of S. costus at a dose of 2000mgkg-1bw showed the highest anthelmintic activity by inducing 83.10% FECR and 76.47% WCR. In conclusion, the root extract of S. costus has a promising anthelmintic activity on A. galli as demonstrated by the results of the present experiment.

The Effectiveness of Various Brands of the Drugs Fenbendazole and Ivermectin in Treating Horses with Strongyle Nematodes in Holeta, Oromia, Central Ethiopia

Introduction: Gastrointestinal parasites have always been a problem, and they are likely to continue to be a long-term issue that threatens the livestock industry. Methods: The purpose of this study was to assess the efficacy of various fenbendazole and ivermectin brands against Strongyle nematodes in naturally infected horses in Holeta, central Ethiopia. A total of 120 horses were divided into three groups at random. Group 1 horses were left untreated (n=12), while group 2 horses were given five different brands of ivermectin (SG-Ivermectin 1%, Tecmectin, Ivertong, ivermectin 1%, and Ivervik 1%), and group 3 horses were given four different brands of fenbendazole (Fenbendazole, Fenacure 750 mg, Hunter 22%, and Fenacure 22%). Fecal samples were collected rectally and parasitologically processed using the modified McMaster method and fecal culture, respectively, to determine egg per gram (EPG) and Strongyle species. The efficacy of these anthelmintics was determined by comparing the EPG before (day 0) and after treatment using a fecal egg count reduction test (FECRT) (day 14). Results: The results of this study revealed that the efficacy of ivermectin brands was superior to that of fenbendazole brands. Horses treated with Ivervik 1%, Hunter 22%, SG-Ivermectin 1%, Tecmectin, Ivertong, and Fenacure 22% had the highest reduction in fecal egg counts, followed by horses treated with fenbendazole, ivermectin 1%, and Fenacure 750 mg. Conclusion: Based on the results of this field study, it can be concluded that the various brands of ivermectin and fenbendazole are effective against Strongyle spp. and P. equorum in horses.

Resistance of Gastrointestinal Nematodes to Anthelmintics in Sheep Production in Zimbabwe

Introduction: Sheep play a crucial role in enhancing the socio-economic welfare of individuals in numerous nations. Within sub-Saharan Africa, productivity levels are hindered by various factors, such as prevalent diseases, inadequate nutrition, climate variations, predators, severe weather, as well as infestations of both external and internal parasites. The purpose of the present study was to assess the extent of anthelmintic resistance (AR) observed on a sheep farm operating for commercial purposes in Zimbabwe. Materials and methods: Forty female weaner Dorper sheep, averaging 43 kg in body weight, were selected from Ballineety commercial sheep farm in Mashonaland Central, Zimbabwe. These sheep were then divided into four groups of ten each, receiving different treatments including ivermectin, albendazole, levamisole, and no treatment as a control. Each treatment was administered according to the manufacturer’s recommendations. Pre-treatment faecal samples (day zero) and post-treatment (day 14) were collected and subjected to the Faecal Egg Count Reduction Test (FECRT). Anthelminthic resistance was suggested (AR) by the presence of faecal eggs after treatment. Results: All the drugs indicated a decrease in egg counts by less than 90%. The effectiveness of ivermectin, albendazole, and levamisole was measured at 58.5%, 70.1%, and 85.8% respectively. These findings indicate that nematodes have developed resistance to all treatments. The larval cultures of the samples before and after treatment indicated a significant presence of Haemonchus spp. in the pooled samples. In contrast, the quantities of Trichostrongylus spp. and Oesophagostomum spp. were low but present in all treatments. Cooperia spp. was recovered in post-treatment larval cultures of groups that received anthelmintic. The present study reports lower-than-expected efficacy for ivermectin, albendazole, and levamisole based on the reduction of egg excreted post-treatment. Conclusion: A common worms population in sheep are AR in the current study area. Therefore, comprehensive nematode management programs along with complementary eradication strategies are essential for sustainable sheep production.

A SURVEY OF ANTHELMINTIC EFFICACY IN DAIRY GOAT FARMS IN SOUTH-EAST FRANCE

Goat’s milk production is an important activity in France. Gastrointestinal nematodes (GIN) remain a main threat for grazing goats, usually controlled using anthelmintic drugs (AH). However, 1) eprinomectin (EPN) is the sole molecule yet available without withdrawal time for milk in France; 2) nematodes AH resistances increase dramatically. First, a survey was performed on 13 farms in the Auvergne-Rhône-Alpes (AURA) region to evaluate the efficacy of 2 AH authorized for dairy goats: a benzimidazole (BZ) and a macrocyclic lactone (EPN pour-on). Fecal Egg Count Reduction Tests (FECRT) were carried out using 3 groups of 10 goats per farm: a control group, one treated with BZ (oxfendazole) and one treated with EPN. The results indicate a resistance to BZ in 11 out of 13 farms (84.6%) and a lack of efficacy for EPN pour-on in at least 10 farms (76.9%). Secondly, EPN was given orally or subcutaneously in 4 farms of the previous trial showing a lack of efficacy to EPN pour-on. A resistance to EPN was confirmed in 3 out of 4 farms. Although based on a few farms, these results confirm the high prevalence of resistance of GIN to BZ in dairy goat farms. They also highlight a high level of resistance to EPN and the lack of efficacy of EPN when used pour-on. Given the level of resistance to marketed drugs, there is an urgent need to explore alternative options to AH to prepare integrated, sustainable control of GIN.

58 United States Department of Agriculture National Animal Health Monitoring System Goat 2019 study: Distribution of gastrointestinal nematodes

Abstract One objective of the United States Department of Agriculture National Animal Health Monitoring System Goat 2019 study was to describe practices producers use to control gastrointestinal nematodes (GIN) and reduce anthelmintic resistance through the examination of anthelmintic treatment efficacy via fecal egg count reduction tests and fecal cultures. The fecal cultures were used to determine what GIN were present across the areas of the US included in the study (September 2019-April 2020). Bulk cultures were processed from 318 operations in 24 states and results were consolidated into 4 regions: Northwest (3 states, 34 operations), Northeast (9 states, 89 operations), Southeast (9 states, 132 operations) and Southwest (3 states, 63 operations). GIN identification included Haemonchus, Trichostrongylus, Teladorsagia, Oesophagostomumand Nematodirus. In addition to GIN, lungworm presence was also noted. Haemonchus were found on 18.6% of the operations (Northwest, 27.0%; Northeast, 13.1%; Southeast, 15.9% and Southwest, 29.2%). Trichostrongylus were found on 97.2% of the operations (Northwest, 100%; Northeast, 98%; Southeast, 97.0% and Southwest, 95.7%). Teladorsagia were found on 80.3% of the operations (Northwest, 97.1%; Northeast, 71.6%; Southeast, 88.6% and Southwest (75.7%). Oesophagostomum were found on 38.2% of the operations (Northwest, 73.1%; Northeast, 39.6%, Southeast, 46.4% and Southwest, 15.5%). Nematodiruswere found on 7% of the operations (Northwest, 7%; Northeast, 5.2%, Southeast, 20.8% and Southwest, 0%). Lungworms were found on 35.4% of the operations (Northwest, 69.1%; Northeast, 52.2%, Southeast, 33.4% and Southwest, 8.3%). Due to sampling logistics, fecal collection was conducted during autumn through early spring which may have influenced number of more pathogenic GIN. This study provided valuable insight into regional prevalence of GIN in goats. In depth analyses continues and will be forthcoming.