Faecal Egg Count Reduction Test Research Articles

O-160 Prevalence of the resistance of gastrointestinal nematodes to benzimidazoles assessed by the faecal egg count reduction test in Polish goat herds

O-160 Prevalence of the resistance of gastrointestinal nematodes to benzimidazoles assessed by the faecal egg count reduction test in Polish goat herds

Multiple anthelmintic drug resistance in hookworms (Ancylostoma caninum) in a Labrador breeding and training kennel in Georgia, USA.

To evaluate the efficacy of the 3 major classes of anthelmintics used for the treatment of hookworms in dogs in the US and an extralabel treatment with an FDA-approved product for use in cats in a Labrador kennel with a history of persistent hookworm infections. 22 dogs housed in a single kennel comprised of the following breeds: 19 Labrador Retrievers, 1 English Cocker Spaniel, 1 Chesapeake Bay Retriever, and 1 Boykin Spaniel. We performed a fecal egg count (FEC) reduction test using 22 dogs that were allocated randomly to 1 of 5 treatment groups: pyrantel pamoate (Pyrantel pamoate suspension), fenbendazole (Safe-Guard suspension 10%), milbemycin oxime (Interceptor), moxidectin plus imidacloprid (Advantage Multi), and emodepside plus praziquantel (Profender topical solution for cats). FEC was performed on samples collected on days 0 and 11. FEC reductions for the milbemycin oxime, moxidectin plus imidacloprid, and emodepside plus praziquantel groups were 43.9%, 57.4%, and 100%, respectively. The FEC increased following treatment for the pyrantel and fenbendazole groups. These data demonstrate that the Ancylostoma caninum infecting the dogs in this kennel are highly resistant to all major anthelmintic classes approved for use in dogs in the US but are susceptible to emodepside. This was the first report of multiple anthelmintic drug-resistant A caninum in a dog kennel that does not involve Greyhounds.

Caprine Roundworm Nematode Resistance to Macrocyclic Lactones in Northeastern Thailand

Roundworm nematodes are a significant problem in goat meat farming worldwide. These parasites can cause production losses, reduce feed efficiency and compromise animal health and welfare. Macrocyclic lactones (MLs) are common anthelmintic drugs to treat roundworm nematode infection in livestock. The objective of study was to detect roundworm resistance to MLs in meat goats in Northeast Thailand. One hundred and nineteen goats from 6 herds were studied from June to December 2022. Each herd was randomly allocated to control (n=21), epinomectin (n=34), ivermectin (n=40) and moxidectin (n=24) groups. Anthelmintic resistance (AR) was assessed based on the Fecal Egg Count Reduction Test (FECRT) and larva culture at pre-treatment (D0) and 14 days post-treatment (D14). Prevalence of Strongyle nematodes and Trichuris spp. infection was 100% (6/6 herd), and 66.7% (4/6 herd), respectively. The number of Strongyle eggs was significantly reduced in the eprinomectin group (p < 0.01). In contrast, the ivermectin group was significantly increased (p < 0.01). The prevalence of ML resistance of Strongyle nematodes and Trichuris spp. was 83.3% (5/6 herd) and 25.0% (1/4 herd), respectively. The dominant larva was Haemonchus contortus at pre- and post-treatment in every herd. This study demonstrated the presence of ML resistant Strongyle nematodes as H. contortus and Trichuris spp. in this area. To reduce ML resistance it can be useful to use drugs in combination or rotate MLs with other classes of anthelmintics or in targeted treatment programs and integrated parasite management strategies. Consequently, the efficacy of anthelmintic drugs in small ruminants needs to be monitored and surveilled in this area.

Comparison of the therapeutic efficacy of five anthelmintics against natural Fasciola hepatica infections in dairy cattle from the Mantaro Valley, Peru.

The intensive use of anthelmintic drugs to control Fasciola hepatica infections in dairy cattle has resulted in the emergence of anthelmintic resistance. Cases of resistance to triclabendazole (TCBZ) have been reported worldwide. The main goal of this research was to evaluate the main five fasciolicides to control fasciolosis in dairy cattle in the Mantaro Valley, Peru. Two fecal egg count reduction tests were performed. In a first study, 24 naturally F. hepatica infected cattle were randomly grouped into three experimental groups (n=8). Groups were treated with either TCBZ, nitroxynil (NTX) or closantel (CLOS). In a second experiment, 55 naturally infected cows were grouped into three experimental groups and treated with either TCBZ (n=18), rafoxanide (RFX)+albendazole (ABZ) (n=19) or clorsulon (CLN)+ivermectin (IVM) (n=18). Therapeutic efficacy was determined following the WAAVP guidelines by measuring reduction in fluke egg output at days 15 and 30 post-treatment. Bootstrapping method was used to obtain the 95% confidence intervals. The efficacy of TCBZ was inadequate in both studies (≤80.8%). Closantel showed high efficacy (≥ 90%) at both days, while NTX showed 92.9% (83-100) and 82.1% (53.6-100), efficacy, at days 15 and 30, respectively. Efficacy for RFX were 92.1% (79.6-98.9) and 97.4% (94.1-99.4); and for CLN, 98.8% (97.6-100) and 80.1% (44.7-99.4), at days 15 and 30, respectively. The outcome of this study indicates reduced therapeutic efficacy of TCBZ against F. hepatica in an important dairy area of the Peruvian central highlands but also demonstrates the validity of four alternatives.

First report of eprinomectin-resistant isolates of Haemonchus contortus in 5 dairy sheep farms from the Pyrénées Atlantiques département in France.

Infection of sheep by gastrointestinal nematodes (GIN) in pastoral systems such as those found in the South Western area of France, the Pyrénées Atlantiques, is one of the main reasons for economic loss and degradation of their welfare. In the present study, the efficacy of eprinomectin (EPN) was monitored on farms from this area following suspicion of lack of anthelmintic efficacy. Suspicions were raised by veterinarians, based on clinical signs ranging from milk and body condition loss, to anaemia, and mortality. Resistance was evaluated according to the World Association for the Advancement for Veterinary Parasitology (WAAVP) guidelines using fecal egg count reduction tests reinforced by individual analysis of drug concentration in the serum of all treated ewes by high-performance liquid chromatography (HPLC). EPN was administered by subcutaneous (SC) and topical (T) route according to manufacturer's requirements, as well as by the oral route (O) with the topical solution according to off-labelled practices in the field. For the first time in France, the presence of resistant isolates of Haemonchus contortus to EPN was observed in 5 dairy sheep farms. The HPLC dosages showed exposure of worms to concentrations compatible with anthelmintic activity for animals treated by the SC and O routes. By contrast, they showed under exposure to the drug of most individuals treated by the T route. EPN is the only null milk withdrawal anthelmintic molecule currently available. The presence of resistant isolates of the pathogenic H. contortus to EPN in this important dairy region requires an urgent change in grazing, and sometimes production, systems.

Pre-established anthelmintic protocols in horses: low efficacy and unnecessary treatments highlight the need for strategic deworming

Context Deworming all horses with commercial anthelmintics on a rotational basis every 90 days is still popular worldwide. Aims To investigate anthelmintic resistance and therapeutic requirements of adult horses on the basis of faecal examinations after a rotation between commercial anthelmintics commonly used in Brazil. Methods We followed up faecal egg counts and coprocultures of 29 horses for 7 months, after pre-established anthelmintic treatments, every 3 months (August and November 2019 and February 2020). The following commercial anthelmintics were used respectively: moxidectin (1), ivermectin + praziquantel (2) and trichlorfon + mebendazole (3). Faecal egg count (FEC), FEC reduction tests (FECRT) and coproculture were performed before (Day 0) and after 14 days for each of the three treatments. Wilcoxon test (95% confidence level, P < 0.05) was used to test the efficacy of the treatment on the FECRT and the occurrence of resistance to the treatments used. Results The FEC results and percentage of individual FECRT indicated parasite resistance, and 82 of 87 (94%) deworming treatments were unnecessary. The efficacy rate was 78%, 34% and 53% for Treatments 1, 2 and 3 respectively. In the coprocultures before deworming, 98.5% were small strongyles, 1.1% Strongylus equinus and 0.4% Gyalocephalus capitatus. After deworming, 98.7% of parasites were small strongyles and 1.3% Dictyocaulus arnfieldi. FEC values at Day 0 and 14 days after anthelminthics were different (lower) only for the moxidectin treatment (U = 271.5; P-value <0.01). For both ivermectin + praziquantel (U = 373; P-value >0.05) and mebendazole + trichlorfon (U = 391; P-value >0.05) treatments, there was no difference in FEC between Day 0 and Day 14 at 95% confidence level. Conclusions The anthelmintics used in the deworming protocol of this study had reduced efficacy against the parasites identified in the coprocultures and the pre-established treatments were probably unnecessary in 93% of the horses with a low level of infection. Implications This study has highlighted not only the issue of the indiscriminate use of anthelmintics regarding parasitic resistance, but also the exposure of horses to unnecessary treatments. Such widespread use is a costly waste of resources and further reinforces the discontinuation of schedule rather than strategic deworming protocols.

Detection of anthelmintic resistance in gastrointestinal strongyles of cattle in Thrissur district, Kerala

Gastro intestinal parasite (GIP) infection is an economically important disease that affects cattle population worldwide and contributes to decreased productivity and profitability in the livestock sector. An important obstacle to the management of helminth infections in cattle is the failure of therapy owing to anthelmintic resistance. The present study is aimed to identify the predominant gastrointestinal strongyles in cattle of Thrissur district, Kerala and to determine the incidence of benzimidazole resistance against these gastrointestinal strongyles in organised cattle farms and small holder farmers’ herd. Coproculture studies revealed that predominant strongyle was Mecistocirrus spp. (29.75 per cent) followed by Haemonchus spp. (21.5 per cent) and Oesophagostomum spp. (13 per cent). The in vivo method of benzimidazole resistance detection by faecal egg count reduction test (FECRT) with albendazole was done in three organised cattle farms and three small holder farmers’ herd. The per cent FEC reduction in three organised farms were 38, 55 and 85 per cent and that of small holder farmers’ herd ranged between 75 - 100. This study forms the first report of anthelmintic resistance in cattle in south India and the results indicated that benzimidazole resistance was highly progressed in organised cattle farms and in a progression state in small holder farmers’ herd that necessitates the judicial utilisation of anthelmintics for the parasite control.

Detection of resistance against anti-helminths drugs in gastrointestinal nematodes of calves using fecal egg count reduction test FECRT

The species of parasite, low dose, and continual employ of the same drug may predispose to the evolution of anthelmintic resistance AR. In Mosul, Iraq, this is the first study investigating AR in gastrointestinal GIT nematodes of calves. Four hundred eighty fecal samples through a cross-sectional survey were examined using the Mini-FLOTAC. A herd of calves consisting of 60 male calves was divided into four groups of 15 calves: group A counted as control, group B was treated with Reemazol® 25% (Albendazole) 7.5 mg/kg of body weight orally, group C received Dufazan® (Levamisole and Oxyclozanide) 7.5 mg/kg BW orally, and group D gave Ivermectin 1% by S/C injection 0.2 mg/kg BW. The efficacy asset employs the Fecal Egg Reduction Test (FECRT). AR judgment obtains relying on the instructions of the World Association of advancement for Veterinary Parasitology (WAAVP). GIT nematode prevalence was 50.6%. The effectiveness of mentioned drugs was 84, 87, and 95%, respectively. The lower limit confidence interval 95% level was 89, 86, and 80%, respectively, indicating AR to albendazole and levamisole, while ivermectin was questionable. In conclusion, the high prevalence of GIT nematodes in Mosul indicate that AR is present against the three classes of deworming drugs. Awareness of the associated aspects and sources of resistance is essential to face and minimize the development of resistant worms.

A statistical framework for calculating prospective sample sizes and classifying efficacy results for faecal egg count reduction tests in ruminants, horses and swine

The faecal egg count reduction test (FECRT) is the primary diagnostic tool used for detecting anthelmintic resistance at the farm level. It is therefore extremely important that the experimental design of a FECRT and the susceptibility classification of the result use standardised and statistically rigorous methods. Several different approaches for improving the analysis of FECRT data have been proposed, but little work has been published on how to address the issue of prospective sample size calculations. Here, we provide a complete and detailed overview of the quantitative issues relevant to a FECRT starting from basic statistical principles. We then present a new approach for determining sample size requirements for the FECRT that is built on a solid statistical framework, and provide a rigorous anthelminthic drug efficacy classification system for use with FECRT in livestock. Our approach uses two separate statistical tests, a one-sided inferiority test for resistance and a one-sided non-inferiority test for susceptibility, and determines a classification of resistant, susceptible or inconclusive based on the combined result. Since this approach is based on two independent one-sided tests, we recommend that a 90 % CI be used in place of the historically used 95 % CI. This maintains the desired Type I error rate of 5 %, and simultaneously reduces the required sample size. We demonstrate the use of this framework to provide sample size calculations that are rooted in the well-understood concept of statistical power. Tailoring to specific host/parasite systems is possible using typical values for expected pre-treatment and post-treatment variability in egg counts as well as within-animal correlation in egg counts. We provide estimates for these parameters for ruminants, horses and swine based on a re-examination of datasets that were available to us from a combination of published data and other sources. An illustrative example is provided to demonstrate the use of the framework, and parameter estimates are presented to estimate the required sample size for a hypothetical FECRT using ivermectin in cattle. The sample size calculation method and classification framework presented here underpin the sample size recommendations provided in the upcoming FECRT WAAVP guidelines for detection of anthelmintic resistance in ruminants, horses, and swine, and have also been made freely available as open-source software via our website (https://www.fecrt.com).

A Potential Anthelmintic Phytopharmacological Source of Origanum vulgare (L.) Essential Oil against Gastrointestinal Nematodes of Sheep.

The development of anthelmintic resistance in sheep gastrointestinal nematodes (GINs) requires novel strategies for the sustainable control of these parasites. This study aimed to evaluate the anthelmintic efficacy of the Origanum vulgare (L.) essential oil (EO) against sheep GINs and to evaluate the possibility of its use in control practice. The in vitro egg hatch test was conducted at eight different concentrations (50, 12.5, 3.125, 0.781, 0.195, 0.049, 0.025, and 0.0125 mg/mL) of the tested EO. For the in vivo fecal egg count reduction test, the EO of O. vulgare was administrated orally at a mean single dose of 150 mg/kg to sheep from two farms in Southern Italy, whereby potential toxic effects to the hosts were also evaluated. In the egg hatch test, the inhibition of egg hatchability varied from 71.3% to 93.7%, depending on the concentration used. The high anthelmintic potential was confirmed in the fecal egg count reduction test with an average reduction of nematode eggs in feces of 43.2% and 60.1% on days 7 and 14 after treatment, respectively. In addition, no toxic effects were noticed during the clinical examination of sheep or by observing blood count and liver or kidney function test results. The obtained results suggest the strong activity of the O. vulgare EO against sheep GINs, probably due to a high percentage of carvacrol (76.21%), whereby it can be considered safe for sheep at the dose tested in vivo. Therefore, it is suitable for use in veterinary practice as a part of an integrated strategy for the control of sheep GINs.

Anthelmintic Efficacy in Sheep and Goats under Different Management and Deworming Systems in the Region of Lisbon and Tagus Valley, Portugal.

Infections caused by gastrointestinal parasites have been described worldwide as one of the most important issues impacting small ruminant production. The systematic administration of anthelmintic (AH) drugs without following good practice principles has led to an increase in anthelmintic resistance (AR). There is scarce information regarding AH efficacy in small ruminants in Portugal. This study aimed to characterize by in vivo methods the presence and level of AR in four farms in the region of Lisbon and Tagus Valley. All four farms kept small herds in extensive management systems and used different deworming protocols. The active substances used were fenbendazole and a combination of mebendazole plus closantel in a dosage according to the manufacturers' instructions. On day 0 (T0), fecal samples were collected from all study animals, and animals in the treatment group (n = 40) were dewormed with the AH previously chosen by the assistant veterinarian. Animals in the control group (n = 30) did not receive any AH drug. The fecal sample collection was repeated on day 15 (T15), and the control group was treated. Egg counts were performed using the McMaster method for the eggs per gram (EPG), and AR was evaluated by the fecal egg count reduction test (FECRT) with a 95% confidence level (CL). The results from this experiment indicated that the four farms presented AR with two farms to fenbendazole (FECRT of 48% and 85%) and two farms to mebendazole plus closantel (FECRT of 66% and 79%). These results indicate that the gastrointestinal parasites of the four studied Portuguese farms are resistant to benzimidazoles, which suggests an increase in AR regarding nematodes in small ruminant production systems in Portugal.

Signs of multiple anthelmintic resistance in sheep gastrointestinal nematodes in Sweden.

Gastrointestinal nematodes in small ruminants are clinically and economically important parasites that often are controlled with anthelmintics. In this study, we compiled information on the anthelmintic efficacy collected on sheep farms according to routines established by Farm & Animal Health in Sweden. The efficacies of benzimidazoles (i.e. albendazole or fenbendazole, n=30), ivermectin (n=47), levamisole (n=2) or moxidectin (n=2) were examined between 2015 and 2021 in 81 treatment groups on 49 non-randomly selected farms in south-central Sweden. Drug efficacies were estimated with the faecal egg count reduction test. In addition, efficacy data were in most cases supplemented with data on the abundance of the three most common nematode genera in sheep by performing droplet digital (dd) PCR on coprocultures. Efficacies of <95% for benzimidazoles or ivermectin were identified in 37% and 77% of the tested groups, respectively. In addition, on 27 (55%) of the 49 farms where both benzimidazoles and ivermectin were tested, multiple resistance was found on 8 (30%). In contrast, on each of the two farms tested for levamisole and moxidectin both drugs proved to be 100% effective. However, because post-sampling was performed earlier than recommended in several susceptible groups (benzimidazoles=15, and ivermectin=10 groups), this could have underestimated the severity of the situation. Mainly larvae from the genus Haemonchus were detected in post-treatment coprocultures, in all groups with declared resistance, suggesting that this parasite was primarily associated with anthelmintic resistance. Unexpectedly, the DNA of larvae, which survived treatment, was also detected on farms declared as susceptible. Taken together, this indicates that the situation regarding the anthelmintic efficacy has deteriorated compared with the latest nationwide study on Swedish sheep farms conducted more than a decade ago. Unlike the previous study, the farm selection here was not strictly randomized but rather opportunistic i.e., only farms with a recognized parasite problem were included. Thus, there is a need for a truly randomized study to get an update on the extent of the situation of anthelmintic resistance at a national level, as well as to identify risk factors involved in the resistance selection. Research is also required to establish the optimal intervals for sampling post-treatment.

Potential New Therapeutic Approaches Based on Punica granatum Fruits Compared to Synthetic Anthelmintics for the Sustainable Control of Gastrointestinal Nematodes in Sheep.

Simple SummaryThe spread of helminths resistant to the most common classes of anthelmintic drugs in sheep and the presence of drug residues in the environment has prompted research to find sustainable alternative solutions for gastrointestinal nematodes control. This study reports the results of in vivo studies on the efficacy of an aqueous Punica granatum-based macerate, used in southern Italy for the control of gastrointestinal nematodes in sheep. The anthelmintic efficacy was evaluated in parallel in sheep infected with gastrointestinal nematodes, using, as a positive control, the treatment with Ivermectin and Albendazole. The results of the study show a good anthelmintic efficacy, suggesting the use of this ethnoveterinary macerate as an alternative and sustainable therapeutical remedy for the helminthiasis control in the sheep.Parasites, in particular, gastrointestinal nematodes (GINs) represent one of the main burdens affecting small ruminant farming and pose a serious threat to their health, welfare, productivity, and reproduction. The correct management of animals and the correct use of anthelmintic drugs are the pillars of the GIN control programs for small ruminants. However, globally due to the indiscriminate use of synthetic anthelmintics, there is a significant increase in anthelmintic resistance phenomena to one or more classes of drugs. Even if such a problem never represented a serious threat in southern Italy because of the favourable environmental conditions and because of the good farm management, the phenomenon is actually showing a steep increasing trend and requires alternative treatment measures and constant monitoring. The use of phytotherapies is considered a valuable alternative approach for GIN control in small ruminants and could help with reducing the amount of synthetic drugs used and the forthcoming anthelmintic resistance. From this perspective, the Calabria territory offers a wide number of plants with anthelmintic efficacy that could be helpful for this purpose. The aim of this study was to evaluate the anthelmintic efficacy of aqueous pomegranate (Punica granatum L.) macerate compared to the treatment with Ivermectin and Albendazole in sheep naturally infected with GINs. The pomegranate macerate derives from the ethnoveterinary knowledge of the Calabria region, Southern Italy. The anthelmintic efficacy was evaluated according to the faecal egg count reduction test (FECRt) using the FLOTAC techniques in two sheep farms in Southern Italy. The FECR was calculated from individual samples using the formula FECR = 100 × (1 − [T2/C2]). The treatment with Albendazole in the first farm showed an efficacy of 99.8% after 14 days and 94.8% after 21 days, while the treatment with Ivermectin in the second farm showed an efficacy of 99.9% after 14 days and 96.5% after 21 days of treatment. The pomegranate macerate, in both farms, showed a value of efficacy of around 50% from day 7 to day 21 after the treatment. Previous studies highlighted the presence of gallic acid as the main component in the pomegranate macerate, and its efficacy in nematode control has been as well previously demonstrated in other plant extracts. This in vivo study demonstrated the unequivocal efficacy of plant macerate in easily reducing 50% of the number of GIN eggs in sheep faeces. These results, obtained without the use of synthetic anthelmintics, indicate the use of green veterinary pharmacology as a sustainable alternative to the use of synthetic drugs to reduce the increase in drug resistance phenomena and the environmental impact.

In vitro and in vivo anthelmintic properties of Caesalpinia coriaria fruits against Haemonchus contortus

The purpose of the present study was to assay the in vitro and in vivo anthelmintic activity (AA) of Caesalpinia coriaria (Cc) mature fruits against the nematode Haemonchus contortus (Hc). The Hc infective larvae were used to assess the in vitro AA through larval mortality assay. The exposure of larvae to the different treatments was performed in 96-well microtitration plates. The treatments were as follows: hydroalcoholic extract (HA-E, at 25–100 mg/mL), aqueous fraction (Aq-F, at 12.5–50 mg/mL), organic fraction (EtOAc-F at 12.5–50 mg/mL), compounds (1, methyl gallate and 2, gallic acid at 1.25–10 mg/mL), positive control (ivermectin at 5 mg/mL) and two negative controls (distilled water and 4% methanol). After exposure, dead and live larvae were quantified and results were compared to their controls. The in vivo assay was carried out by a faecal egg count reduction test (FECRT); artificially infected goat kids (F1: Boer x Nubia) were treated with Cc ground dried fruits to assess the AA. The treatments were established as follows: G1—untreated goats (negative control), G2—goats dewormed with ivermectin (positive control), G3—goats fed with Cc mature fruits (10% of their diet). Results in both in vitro and in vivo assays were analysed using an ANOVA through random design, applying a general linear model and mixed models. The in vitro results showed an evident larvicidal effect of the HA-E, EtOAc-F from Cc, indicating that the compound responsible for the AA was gallic acid. The results of the in vivo study corroborated the anthelmintic properties of Cc, reaching 78.6% reduction in the elimination of Hc eggs per gram of faeces. This plant represents a potential natural anthelmintic for the control of haemonchosis in goats under grazing conditions. Future studies should standardise the Cc extract or dried fruits for use in the management of nematodiasis in goat herds.

Oxyclozanide in dairy cattle in the Cajamarca valley, as an alternative in the control of Calicophoron microbothrioides

The present investigation evaluates oxyclozanide's efficacy in controlling Calicophoron microbothrioides in dairy cows from a cattle farm in the Cajamarca valley. Fifteen Holstein Friesian cows naturally infected with C. microbothrioides, were orally administered oxyclozanide at a single therapeutic dose of 17 mg/kg live weight. Coproparasitological analyses were performed using the Fecal Egg Count Reduction Test at 10, 20 and 30 days after administration of the antiparasitic. The results show that oxyclozanide was effective at days 10 (100 %), 20 (98.96 %), and 30 (97.92 %). It is concluded that the evaluated antiparasitic caused a drastic reduction in the egg count, so it is considered an effective paranfistomicide in the control of C. microbothrioides in cattle of the evaluated farm.

MULTIPLE ANTHELMINTIC RESISTANCE AMONG DORPER SHEEP DETECTED WITH PHENOTYPIC MARKERS AGAINST PARASITIC GASTROENTERITIS

Parasitic gastroenteritis (PGE) is a significant disease that affects small ruminant production. PGE is controlled exclusively by chemical anthelmintics but restricted by anthelmintic resistance. Hence, dependence on anthelmintics needs to be reduced. This study aimed to investigate the anthelmintic resistance status of a Dorper sheep farm while determining the phenotypic markers of resistance to PGE. Sheep that met the criteria of the Faecal Egg Count Reduction Test (FECRT) were divided into a control and four treatment groups of 11 to 13 animals per group. Faecal and blood samples at pre- and post-treatments were subjected to faecal egg counts (FEC), faecal culture, packed cell volume (PCV) and peripheral eosinophil counts (PEC). The data were analysed by Spearman rank correlation and two-way ANOVA. FECRT showed resistance towards albendazole, levamisole, fenbendazole and ivermectin which was predominated by Haemonchus contortus. Significant negative correlations were observed between FEC and PCV in control (r=-0.88, p&lt;0.01), fenbendazole (r=-0.58, p&lt;0.01) and ivermectin (r=-0.69, p&lt;0.01) groups. Significant positive correlations were detected between FEC and PEC in control (r=0.95, p&lt;0.01) and levamisole (r=0.56, p&lt;0.01) groups. This study shows multiple anthelmintic resistance with promising resistant characteristics against PGE among sheep.

Anthelmintic resistance of horse strongyle nematodes to fenbendazole in Lithuania

BackgroundControl of strongyle infections presents a global challenge for horse practitioners due to the development of anthelmintic resistance (AR), however comprehensive information on AR in Lithuania is still lacking. The aim of this study was to assess the current situation of fenbendazole (FBZ) AR in horses at stable level in Lithuania.ResultsFaecal samples from 121 horses from six stables were examined using the Mini-FLOTAC method. Of these, 89 horses met the inclusion criteria that included strongyle faecal egg counts (FEC) exceeding 200 eggs per gram (EPG). Faecal egg count reduction tests (FECRTs) were performed in these. AR was evaluated at horse stable level based on faecal egg count reduction (FECR) and the lower limit of the 95% credible interval (LLCI) using the Bayesian hierarchical model. This study confirmed that strongylids (Cyathostominae (CYA)) resistant to FBZ are pervasive in Lithuania. FBZ was ineffective in three of the six stables (FECR 77.1–79.0%; 49.8–99.8 LLCI), was suspected to be ineffective in one stable (FECR 93.6%; 85.4–100 LLCI) and was effective (FECR 99.8–100%; 99.8–100 LLCI) in two stables. FEC showed a significant (P < 0.01) difference between the treatment and control groups. Only CYA larvae were detected in larval cultures derived from strongyle-positive faecal samples collected 14 days after treatment of a test group with FBZ.ConclusionThis in vivo study showed that resistance to FBZ in the treatment of strongyle nematodes is prevalent in horse stables in Lithuania. These findings should guide the implementation of more sustainable management of strongyle infections in horses in Lithuania.

Efficacy of clinically used anthelmintics against toxocariasis of buffalo calves in Bangladesh.

Toxocariasis is a paramount parasitic disease having > 50% prevalence among newborn buffalo calves in Bangladesh. The objective of this study was to compare the efficacy of clinically used anthelmintics and their subsequent effect on the haematological parameters and body weight in buffalo calves in commercial buffalo farms in coastal region. Thirty-two buffalo calves below 3months of age with clinical Toxocara infection had been selected and treated with albendazole (ABZ), levamisole (LVM) and ivermectin (IVM). The EPG counts, hematological parameters and initial body weight of buffalo calves were recorded on the day of anthelmintic treatment (day 0). Fecal samples were collected on day 14 and 28 including hematological parameters and body weight were recorded on day 28 post-treatment. The efficacy (%) of anthelmintics were estimated by fecal egg count reduction test (FECRT). The parameters like Hb, PCV, ESR, TEC, TLC were analyzed from the blood samples. The FECRT revealed 96.83% efficacy for IVM followed by 94.23% and 85.84% for LVM and ABZ, respectively. Anthelmintic treated calves showed significant (p < 0.01) increase in Hb, PCV, TEC and body weight, and decrease in ESR and TLC as a result of worm expulsion from buffalo calves after 28days of post-treatment. Among the tested anthelmintics, IVM was found to be more effective against toxocariasis in buffalo calves. This is a novel information on anthelmintics efficacy in buffalo calves in Bangladesh. Details study is recommended on the efficacy of anthelmintics in different buffalo management systems by in vitro egg hatch assay (EHA) test.

Lack of efficacy of topical administration of eprinomectin against gastrointestinal nematode in a French dairy sheep farm: A case of underexposure of worms

AbstractResistance to eprinomectin was suspected in a dairy sheep farm in southwestern France. The efficacy of topical and injection formulations of eprinomectin against gastrointestinal nematodes (GINs) was compared using a faecal egg count reduction test. GIN species were identified by real‐time PCR, and eprinomectin concentrations were measured in serum by High‐Performance Liquid Chromatography 2 and 5 days after treatment. Efficacies were 99.6% and 86.1% for injection and topical formulations, respectively. Before treatment, the three species Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis were identified in both groups. After treatment, H. contortus and T. colubriformis were identified in the topical group only. Two days after treatment, eprinomectin concentrations were above 2 ng/ml in the injection group and under this value in the topical group, suggesting underexposure of GIN to eprinomectin in this latter group. High levels of exposure to eprinomectin are important to avoid loss of efficacy in the field.

Population replacement of benzimidazole-resistant Haemonchus contortus with susceptible strains: evidence of changes in the resistance status.

The spread of anthelmintic resistance (AR) in nematode populations threatens the viability of sheep production systems worldwide, and warrants the adoption of sensitive, practical, and standardized tests to detect AR. The aim of this study was to characterize the replacement of an Haemonchus contortus population resistant to benzimidazoles (BZDs) by a susceptible one, by means of both phenotypic and genotypic techniques. Phenotypic methods to assess BZD resistance included in vivo tests, such as the fecal egg count reduction test (FECRT), and in vitro tests, such as the egg hatch assay (EHA). Additionally, genotypification of polymorphisms associated with BZD resistance by sequencing a fragment of the isotype 1 β-tubulin gene was carried out. The initial, BZD-resistant population (initial Balcarce population) exhibited an egg count reduction (ECR) of 59.3%. Following refugium replacement, the final population (final Balcarce population) exhibited an ECR of 95.2%. For the initial Balcarce population, the median effective dose (ED50) for the EHA was 0.607 μg thiabendazole (TBZ)/mL, with a rate of eclosion at a discriminating dose (EDD) of 0.1 μg TBZ/mL of 76.73%. For the final Balcarce population, ED50 was 0.02 μg TBZ/mL, and EDD was 1.97%. In the initial population, 93% of the analyzed individuals exhibited genotypic combinations associated with BZD resistance (53% Phe/Phe167-Tyr/Tyr200, 37% Phe/Tyr167-Phe/Tyr200, and 3% Phe/Tyr167-Glu/Leu198). Conversely, no combination associated with resistance was found in individuals from the final population. All of the tests were useful for detecting AR to BZDs. The results from the genetic and phenotypical studies were consistent, and the resulting information greatly aided in interpreting the outcomes of the population replacement and the potential impact of this strategy on management of AR.