Use Of Anthelmintics Research Articles

Gastrointestinal Helminth Infections in Dogs in Sheep and Goat Farms in Greece: Prevalence, Involvement of Wild Canid Predators and Use of Anthelmintics

The objectives of the present work were the investigation of gastrointestinal parasitic infections in dogs in small ruminant farms in Greece, the elucidation of potential predictors for these infections and the description of practices related to administration of anthelmintics to dogs. This study was carried out in 444 small ruminant farms in Greece. Faecal samples were collected directly from the rectum of the dogs in the farms. The samples were processed by means of conventional parasitological techniques, specifically, a combined sedimentation flotation technique. There were dogs in 92.8% of the farms, with a median number of four dogs per farm. The following variables were associated with the presence of dogs in the farms: the presence of wild mammal predators near the farms, the increased daily period of farmers’ presence at the farm, goats as the livestock species at the farm and the management system applied in the farm. Helminth eggs were detected in samples from 72.6% of the farms. The main helminth eggs detected were those of hookworms (Uncinaria/Ancylostoma) and Toxocara canis, in 68.6% and 51.3% of the farms, respectively. In our multivariable analyses, an association emerged between the presence of canid predators near a farm and the detection of these helminths in faecal samples: in 76% and 60% of the samples, respectively, versus in 58% and 39% of the samples from farms with no canid presence. Of farmers with dogs, 16.0% reported that they omitted the administration of anthelmintics to the animals. In multivariable analysis, the semi-extensive or extensive management system applied in the farm, the lower annual milk production per animal and the lack of collaboration with a veterinary practice were the significant predictors for the omission of anthelmintic administration to the farm dogs. There was also a clear association in the omission of anthelmintic administration to the dogs and to the livestock on the farm. The most frequently administered anthelmintic was praziquantel, which was used in 93.6% of the farms.

Control of Helminth Infections in Captive Herbivores: An Overview of Experience

There are numerous challenges associated with helminth control in captive animals. The aim of the present paper is to provide an overview of the research on deworming of captive herbivorous mammals, the associated problems and the solutions sought, in order to derive recommendations for practice in the relevant institutions. The research was conducted by searching electronic internet databases and following the bibliographies in the published articles. The articles found are presented in summarized form. Most of the results relate to herbivores of the family Bovidae, followed by the families Cervidae, Equidae, Elephantidae, Camelidae and Giraffidae. Systematic data are presented on the types of anthelmintics used, dosages and application regimens for different animal species. Anthelmintics were administered at doses similar to or even higher than those used in farm animals, with no evidence of side effects. Treatment results often depended on the animal and parasite species. Incomplete cure, reinfection, and resistance to anthelmintics were the most common problems in the field. Based on the literature reviewed, the optimal prevention measures include the following: quarantine of newly arrived animals; daily or as intensive as possible cleaning of droppings; regular change of substrate in the enclosures; and monitoring of possible infections and their qualitative and quantitative composition (monthly or at least every two months). For treatments and monitoring effectiveness, recommendations include the following: individual assessment of the need for treatment; selective choice of anthelmintics; post-treatment examination between the 10th and 14th day after deworming; carrying out a group treatment after a preliminary drug effect test; conducting mass deworming only in case of a significant increase in fecal egg counts, highly pathogenic helminth species and a deterioration in the condition of the animals. In the future, more attention should be paid to new approaches such as biological control by saprophytic fungi or natural compounds as an alternative to anthelmintics. This would help minimize the use of anthelmintics, protect refugia and allow animals to remain healthy by maintaining a balance with the low levels of parasites present.

The Pharmacokinetics of Subcutaneous Eprinomectin in Plasma and Milk in Dry Dairy Cattle.

Parasitic infections in dairy cattle reduce herd immunity, milk production, and conception rates. This leads to higher production costs, compromised animal welfare, and increased interest in extralabel drug use. The extralabel use of anthelmintics poses food safety risks for consumers since appropriate withdrawal intervals in milk have yet to be established. Although topical eprinomectin has no milk withdrawal time, more research is needed to determine the residues present in milk after subcutaneous administration. This study aimed to characterize the pharmacokinetics of injectable eprinomectin in dry dairy cows. We hypothesized that, when given at the labeled dose, eprinomectin residues in dry dairy cattle would be below the FDA milk tolerance at the onset of lactation. Plasma was collected daily from 13 mature dairy cattle for 7 days postadministration, followed by periodic samples for 90 days. After calving, milk was collected daily until 90 days. Eprinomectin concentrations were measured using HPLC-fluorescence detection. The maximum eprinomectin concentration in plasma and milk was approximately 36 ng/mL 43 h after administration and 3 ng/mL at the onset of lactation, respectively. The low eprinomectin levels in milk collected from these lactating dairy cattle suggest that administering eprinomectin at dry-off is unlikely to result in violative residues. However, subcutaneous eprinomectin in lactating dairy cattle would be hard to justify unless there is evidence that the approved topical formulation is clinically ineffective.

Reduced anthelmintic use on 13 New Zealand sheep farms: farmer motivations and practical implementation

ABSTRACT Aims: To describe the personal drivers, sources of information and gastro-intestinal parasite control methods used by a group of New Zealand sheep farmers identified as low users of anthelmintic (AHC), and their perception of the efficacy and impacts of this approach. Methods: A convenience sample of 13 sheep farmers farming with a policy of reduced AHC use (no pre-determined routine treatments of ewes >19 months old and/or lambs not routinely treated at pre-determined intervals from weaning through to late autumn) were identified. Semi-structured interviews were conducted regarding their farming philosophy, motivations for reducing AHC use, perceptions of the impacts of farming with reduced AHC use, and parasite control practices. Semi-quantitative data were analysed using descriptive statistics for demographic data and categorising participants’ use of AHC and non-chemical control methods. Qualitative data regarding participants’ motivations, approaches and rationale were analysed by systematic analysis of the transcripts and distillation of key concepts. Results: Participants had been operating with reduced AHC use for 3 to ≥20 years. Key motivators for reducing AHC use were a diagnosis of anthelmintic resistance (AR) or concerns about AR developing. Parasite management information came from a wide range of sources. All respondents expressed overall positive views regarding the impacts of reduced AHC use but detailed information was not available. All identified that regular monitoring, based primarily on subjective animal and non-animal factors was important for their parasite control strategy. Most used faecal egg counts (FEC), often in an ad hoc manner. Five never treated adult ewes, two routinely treated ewes prior to lambing with short-acting AHC and the remainder occasionally treated a small number in low body condition. Four routinely treated some or all lambs at 28–30-day intervals from weaning to late autumn while the remainder based their treatment decisions for lambs on monitored information. All placed heavy emphasis on feeding sheep well, ensuring high post-grazing residuals, and cross-grazing. Conclusions: AR was a key motivator for participants to reduce AHC use, and a range of information sources and decision-making processes were used. Key parasite management practices were monitoring, primarily using subjective assessments, emphasis on feeding stock well and cross-grazing. Clinical relevance: The rising prevalence of AR will likely result in increasing the motivation for sheep farmers to reduce their AHC use. Veterinarians will play a key role in providing advice and assistance to facilitate changes in parasite management.

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.

Immunohistochemistry analyses of the abomasal mucosa show differences in cellular-mediated immune responses to Haemonchus contortus infection in resistant and susceptible young lambs

Haemonchus contortus is known for its high pathogenicity in sheep, and the uncontrolled use of anthelmintics resulted in the emergence of multiple drug-resistant populations. Breeding sheep for gastrointestinal nematode resistance is a sustainable alternative to reduce dependence of anthelmintic drugs, and differences in the degree of resistance between breeds have been reported. Here we compare two sheep breeds (Santa Ines and Ile de France), concerning the differences in innate and adaptive immune response involved in the resistance against H. contortus infection. Immunohistochemical analyses of the abomasum were conducted in naïve Santa Ines (n = 14) and Ile de France (n = 12) lambs randomized into four groups: infected Santa Ines (n = 8), non-infected control Santa Ines (n = 6), infected Ile de France (n = 8), and non-infected control Ile de France (n = 4). The infected lambs were initially infected with H. contortus infective larvae at 14 days of age, and multiple infections were conducted every second day until they reached 66 days of age. There was a significant effect (P < 0.001) of the infection with increase in numbers of CD3+ T; CD79α+ B; GATA3+ Th2/ILC2; POU2F3+ tuft cells; FOXP3+ T reg; and IgE + cells in the fundus of the abomasal mucosa in both Santa Ines and Ile de France lambs. Nevertheless, the infected Santa Ines lambs presented the highest averages for CD79α+ B; GATA3+ Th2/ILC; IgE + cells; and POU2F3+ tuft cells and there was a significant association of the breed and infection status with regards to POU2F3+ tuft cells, with the highest mean in the infected Santa Ines group. The infected Santa Ines group had three lambs with high degree of resistance and five lambs that showed a moderate infection. Our results suggest a mechanism of synergistic coordination between different immune-cell types in promoting resistance of suckling lambs under H. contortus infection.

Economic impact of the use of anthelmintics in beef cattle in the rearing phase

The objective of the present study was to evaluate the effectiveness of anthelmintics and their influence on the performance of beef cattle supplemented during the rearing period, carrying out a cost analysis of the different treatments. 120 Nelore animals were used, with an average of 9 months of age, 60 males and 60 females. The animals were distributed into 6 groups of males and 6 of females, five treated with anthelmintics and a control group, G1: Moxidectin 1%, G2: Levamisole Phosphate 18.8%, G3: Ivermectin 0.8% + Albendazole Sulfoxide 10%, G4: Albendazole 10%, G5: Fenbendazole 10%, G6: Control (saline solution). Individual weighing was carried out using an electronic scale, at the beginning of the experiment (D0), fourteen days later (D14) and at the end of the experiment (D90), with performance assessed through weight gain (GP). Fecal collections were carried out on the same days as weighing, with individual egg counts per grams of feces (OPG) and stool culture to identify helminth genders. Economic viability was calculated based on the price of the calf and total production cost. The data obtained was subjected to the 5% Tukey test and the effectiveness of the anthelmintics was evaluated using the RESO program. It is concluded that the anthelmintics evaluated were effective, with the exception of Ivermectin 0.8% + Albendazole Sulfoxide 10%, which showed anthelmintic resistance. The anthelmintic treatment provided the animals with better performance, with the greatest weight gain observed in animals treated with Moxidectin 1%, demonstrating better economic indices.

The enhancive effect of the 2014-2016 El Niño-induced drought on the control of soil-transmitted helminthiases without anthelmintics: A longitudinal study.

Soil-transmitted helminthiases (STHs) are common in tropical and subtropical regions. Southern Thailand experiences an extended rainy season, leading to persistently moist soil. This condition supports the life cycle of STHs, hindering effective control due to reinfection and low drug efficacy. We implemented a novel STH control strategy during the dry season aimed at decreasing reinfection rates without enhancing sanitation or hygiene practices. However, there were unexpected, prolonged droughts linked to El Niño events from 2014 to 2016. Additionally, we assessed the effects of these drought conditions on further control measures without the use of anthelmintics. A longitudinal study was conducted from 2012 to 2016. Stool samples collected from 299 participants were analyzed using the Kato-Katz and agar plate culture methods. Participants who tested positive for STHs received a single 400 mg dose of albendazole. The efficacy of the treatment was evaluated three weeks later. To confirm the control measures were implemented during the dry season, we monitored the number of rainy days following albendazole treatment for 52 days, of which 38 were without rain. Follow-up stool examinations were carried out in 2013 and 2016, with no additional doses of albendazole administered. Rainfall and rainy day data, which served as indicators of unexpected droughts due to El Niño, were collected from the nearest local meteorological stations. Before the drought, there was a decrease in STH prevalence in 2013-except for trichuriasis-attributable to the dry season control efforts. Despite these efforts, STH prevalence remained high. Remarkably, in 2016, following the drought period, the prevalence of trichuriasis, which had not changed previously, spontaneously declined without further albendazole treatment compared to 2013. Furthermore, the prevalence of strongyloidiasis remained unchanged likely due to its low susceptibility to drought conditions, as it can reproduce within hosts. Conversely, the prevalence of other STHs consistently declined. The drought and possible improvements in sanitation and hygiene practices contributed to this decrease by reducing rates of reinfection and new infection and by increasing the natural cure rate. Additionally, some participants infected with hookworms or Trichuris who were not cured by albendazole experienced natural remission. Control measures implemented during the dry season, combined with a 14-month-long drought induced by the El Niño event of 2014-2016, and some improvements in sanitation and hygiene practices, contributed to a decrease in both the prevalence and intensity of STHs, except for S. stercoralis. Over time, S. stercoralis is likely to become the predominant species among the STHs.

Efficacy of a Haemonchus contortus vaccine under field conditions in young alpacas

Anthelmintic resistance to Haemonchus contortus creates increasing management challenges with small ruminants and camelids. The commercial vaccine, Barbervax®, contains H11 and H-gal-GP antigens, derived from gut mucosal membrane enzymes of H. contortus involved in digesting blood. Antibody neutralization of these antigens causes failure of H. contortus to digest blood, resulting in parasite death. H11 and H-gal-GP are considered “hidden” antigens, meaning the host immune system does not encounter these proteins under natural infection. Therefore, repeat immunization is required to maintain protective humoral responses. One previous study evaluated the safety of Barbervax® in camelids but the efficacy could not be assessed due to lack of successful infection in the controls. The objective of the current study was to evaluate clinical parameters of anemia, fecal egg counts (FECs), and humoral immune responses of healthy alpacas after immunizing with Barbervax® compared to non-vaccinated controls, all under natural environmental exposure on parasite-laden pastures. A crossover-like study was performed where twenty alpacas (298 ± 66 days of age) were assigned to be initially vaccinated with Barbervax® (n=10) or receive no treatment (n=10). Three doses of Barbervax® were administered at three-week intervals. Feces and blood were collected on Day −10, 0, 21, 43, 64, 85, 106, and 135 to evaluate FECs, packed cell volume (PCV), and antibody titers. Each group was kept on separate adjacent pastures. Tracer sheep (n=2 per study group) were introduced on Day 43 for a three-week period to ensure parasite acquisition. For the crossover-like component on Day 85, the initial non-vaccinated group was administered Barbervax® with dosing repeated on Day 106 and 135. Results indicated all initially vaccinated alpacas produced antibody titers to vaccine antigen that corresponded to lower mean FECs compared to the initially non-vaccinated group. A reduced mean FEC in the vaccinate group was observed 21 days after peak antibody titers. Similarly, when pooled vaccinate antibody titers were noted to wane on Day 106, an increase in FEC was observed at the following time point (Day 135). Conclusions from our study support the use of Barbervax® to reduce H. contortus burdens in alpacas. Furthermore, a less than 30-day lag time between antibody titer and resultant effect in FECs was observed. Additional studies assessing the ability of Barbervax® to reduce H. contortus burdens during subsequent grazing seasons would provide even greater information regarding the use of Barbervax® within alpaca herds to modulate H. contortus infections, refugia, and anthelmintic use.

Fecal egg counts and individual milk production in temperate pastoral dairy systems of Australia

Anthelmintic use in lactating dairy cattle, has been shown to result in a milk production response in some previous studies. If individual animals within a herd could be identified that would most benefit from anthelmintic treatment, this may reduce anthelmintic resistance. Australian dairy systems are predominantly pasture-based, allowing sustained exposure and immune stimulation of cattle to gastrointestinal nematodes. We assessed the relationship between milk production and early lactation fecal egg counts (FEC) to determine whether cows with higher FEC produced less milk. Ten pasture-based dairy farms in south-west Victoria, Australia, entered an observational study. Individual FECs at a minimum detectable count of 2.5 eggs per gram of feces (epg) were recorded for recently calved primiparous and multiparous cohorts on each farm. All animals were calved ≤30 d at sampling. Body condition scores were assessed at sampling and milk production data was collected from daily milk meters and herd tests to give first 100-d milk production. When separated by primiparous or multiparous status, no difference in the milk production between cows with FEC = 0 and FEC ≥2.5 epg was identified. Between farm variation was large for FEC and milk production. Fecal egg count at a minimum detectable count of 2.5 epg detected parasitism in primiparous cows post calving but the presence and magnitude of parasitism measurable by FEC was not related to milk production in pasture based Australian dairy systems. In multiparous cows, the rate detection of worm eggs at this analytical sensitivity was lower and the significance of a positive FEC at this analytical sensitivity requires further assessment to ascertain the effect on milk production. Based on our study, it seems unlikely that individual FEC results would be useful as a basis to select individual cows in southwest Victorian dairy herds for anthelmintic treatment.

Faecal egg counts in Australian pasture-based dairy herds

In Australian pastoral dairy systems, a variety of ‘routine’ anthelmintic programs are used in lactating cows varying from nil anthelmintic use to bi-annual application. Anthelmintic resistance has been repeatedly diagnosed on dairy farms and studies have indicated variable milk production benefits from anthelmintics internationally. We aimed to identify the predominant gastrointestinal parasites in recently calved dairy cows in south-west Victoria and examined the relationship between individual faecal egg counts (FEC) and other cow and management factors such as body condition score, age, and historical anthelmintic use. This study included 18 pasture-based dairy farms in south-west Victoria. FECs were measured in recently calved primiparous and multiparous cows. Individual FEC tests with a minimum detectable FEC of 2.5 eggs per gram of faeces (epg) and group larval cultures were completed. Farm management data and cow information was recorded for data analysis with the Jamovi statistical package. Overall, 35% of all cows had FEC ≥ 2.5 epg (26% of multiparous and 45% of primiparous). Ostertagi ostertagi was the predominant gastrointestinal nematode in all cohorts. Cooperia pectinata or C. punctata were also present in mixed infestations alongside C. oncophora. Multiparous cows in low body condition score post calving (<4) were more likely to have a FEC of >5 epg. Faecal egg counts at a minimum detectable FEC of 2.5 epg are effective indicators of parasitism in recently calved primiparous and poorly conditioned multiparous dairy cows. Increasing the test sensitivity (minimum detectable count) of FECs from 10 epg to 2.5 epg resulted in increasing the overall positive FEC rate from 15% to 35%. Further investigation of sensitive FECs and their relevance to production along with the timing and value of anthelmintic use in dairy cattle is warranted.

Equine worming protocols: tackling the increasing problem of anthelmintic resistance

Anthelmintic resistance is a growing global problem in the equine sector. Only three classes of anthelmintics are authorised for use against equine nematodes, and resistance to all of them has been reported in the UK. Resistance to praziquantel, which is effective against equine tapeworms, has also been reported. The use of anthelmintics therefore needs to be restricted, and adoption of diagnostic-led targeted treatment regimens is essential to protect efficacy and slow further development of resistance. This article discusses current recommendations regarding helminth treatment and control in horses and summarises Controlling ANTiparasitic resistance in Equines Responsibly and British Equine Veterinary Association guidelines published in 2024.

A survey of gastrointestinal helminth infestation in smallholder backyard pigs and the first molecular identification of the two zoonotic helminths Ascaris suum and Trichuris suis in Myanmar

BackgroundParasitic infestations have a substantial economic impact on pig production. This study aimed to investigate the gastrointestinal (GI) helminths in pigs and to molecularly characterise two important nematodes, Ascaris and Trichuris species.Materials and methodsA total of 500 pig faecal samples were collected from small holder backyard pig farms in five townships within Nay Pyi Taw, Myanmar. Microscopic examination was conducted to estimate the prevalence of GI helminth infestation in the pigs. DNA extraction and PCR were performed on faecal samples that were morphologically positive for Ascaris and Trichuris eggs. Molecular analysis was then conducted to characterise A. suum and T. suis, the most common and zoonotic helminths.ResultsAccording to microscopic examination, 69.2% (346/500) were positive for GI helminth eggs. The GI helminth species observed were A. suum, Strongyle, Strongyloides spp., T. suis, Metastrongylus spp., Hyostrongylus spp., Fasciolopsis spp., Paragonimus spp., and Schistosoma spp., with occurrences of 34.8%, 29.6%, 21.4%, 20.0%, 4.0%, 1.6%, 1.0%, 1.0%, and 0.4%, respectively. Mixed infections of GI helminths were noted in 31.0% of the samples. Overall, sampled pigs excreted mostly low levels (< 100 EPG) or moderate levels (> 100–500 EPG) of GI helminth eggs. The highest mean EPG for each parasite species was noted in A. suum. The presence of A. suum and T. suis was confirmed molecularly. The sequences of the internal transcribed spacer 1 (ITS1) region of A. suum showed high similarity with previously reported sequences. Likewise, the sequences of T. suis exhibited high similarity with the sequences reported from humans and pigs. Age was noted as an associated factor (P < 0.05) for GI helminth infection status.ConclusionsIn this report, A. suum and T. suis were molecularly identified for the first time in Myanmar. It is important to extend the information among the farmers to be aware of the necessity of preventing zoonotic parasites by practicing regular deworming, proper use of anthelmintics and maintaining hygienic conditions in their pig farms.

Assessing the applications and efficacy of using helminthophagous fungi to control canine gastrointestinal parasites

Helminths are a major challenge in dog breeding, particularly affecting young animals and posing a significant zoonotic risk. The widespread use of anthelmintics to treat gastrointestinal helminth infections in companion animals is common. However, these chemical products generate residues that can have adverse effects on animal, human and environmental health. In addition to the challenge of parasite resistance to treatment, there is an urgent need to explore and discuss complementary and sustainable methods of controlling helminthiases in these animals. In this context, nematophagous or helminthophagous fungi have emerged as a potential tool for the control of environmental forms of helminths. The purpose of this review is to emphasize the importance of these fungi in the control of free-living forms of helminth parasites in companion animals by highlighting the research that has been conducted for this purpose. In vitro experiments demonstrated the efficacy of fungi like Pochonia chlamydosporia, Arthrobotrys robusta, and Monacrosporium thaumasium in trapping and reducing helminth infective forms. These findings, along with soil contamination studies, suggest the feasibility of using helminthophagous fungi as a sustainable and effective strategy for environmental control. The current literature supports the potential of these fungi as an environmentally friendly solution for managing helminthiasis in dogs, benefiting both animal health and public welfare.

Gastrointestinal disorders in donkeys

Donkeys with colic may have subtle clinical signs of pain that delay detection, so a methodical clinical examination is needed to make a diagnosis. Using donkey-specific pain scoring can be helpful in monitoring progress and responses to analgesia. Hyperlipaemia is often secondary to the underlying disease process, and will reduce the prognosis for successful treatment, so assessing triglycerides and treating any elevation alongside other required blood testing is necessary. Ultrasound evaluation is helpful in donkeys which are too small for safe palpation per-rectum, and serum and peritoneal lactate values may be useful in guiding prognosis. Surgical treatment of colic in donkeys has a poorer success rate that in the horse, largely due to delays in diagnosis and referral as a result of the lack of overt pain signs, postoperative complications and hyperlipaemia. Preventative care is often lacking in donkeys, so provision of regular routine dental management, routine parasite monitoring and control (including appropriate use of anthelmintics and dietary management to ensure a healthy body weight) are areas that veterinarians and nurses can assist with. Donkeys cope poorly with stress, so when undergoing treatment, any bonded companion should be kept close by.

Patterns of Equine Small Strongyle Species Infection after Ivermectin Intervention in Thailand: Egg Reappearance Period and Nemabiome Metabarcoding Approach.

The indiscriminate use of anthelmintics to control parasitic nematodes in horses has led to the emergence of anthelmintic resistance worldwide. However, there are no data available on using ivermectin for treating strongyle infections within domesticated horses in Thailand. Therefore, this study aimed to use the fecal egg count reduction (FECR) test to determine the strongylid egg reappearance period (ERP). Additionally, the nemabiome metabarcoding approach is incorporated to study patterns of strongyle species infection following ivermectin treatment. The study results indicate that, although ivermectin effectively eliminated adult strongyle parasites within two weeks post-treatment, the ERP was shortened to 6 weeks post-treatment with a mean FECR of 70.4% (95% CI 46.1-84.0). This potentially indicates a recent change in drug performance. In addition, nemabiome metabarcoding revealed that strongyle species have different levels of susceptibility in response to anthelmintic drugs. The reduction in ERP was associated with the early reappearance of specific species, dominated by Cylicostephanus longibursatus and Cylicocyclus nassatus, indicating the lower susceptibility of these species. In contrast, Poteriostomum imparidentatum, Triodontophorus nipponicus, and Triodontophorus serratus were not found post-treatment, indicating the high level of susceptibility of these species. This information is vital for comprehending the factors contributing to the emergence of resistance and for devising strategies to manage and control strongyle infections in horses.

Genomic Regions Associated with Resistance to Gastrointestinal Nematode Parasites in Sheep-A Review.

Gastrointestinal nematodes (GINs) can be a major constraint and global challenge to the sheep industry. These nematodes infect the small intestine and abomasum of grazing sheep, causing symptoms such as weight loss, diarrhea, hypoproteinemia, and anemia, which can lead to death. The use of anthelmintics to treat infected animals has led to GIN resistance, and excessive use of these drugs has resulted in residue traced in food and the environment. Resistance to GINs can be measured using multiple traits, including fecal egg count (FEC), Faffa Malan Chart scores, hematocrit, packed cell volume, eosinophilia, immunoglobulin (Ig), and dagginess scores. Genetic variation among animals exists, and understanding these differences can help identify genomic regions associated with resistance to GINs in sheep. Genes playing important roles in the immune system were identified in several studies in this review, such as the CFI and MUC15 genes. Results from several studies showed overlapping quantitative trait loci (QTLs) associated with multiple traits measuring resistance to GINs, mainly FEC. The discovery of genomic regions, positional candidate genes, and QTLs associated with resistance to GINs can help increase and accelerate genetic gains in sheep breeding programs and reveal the genetic basis and biological mechanisms underlying this trait.

First Report of Benzimidazole Resistance in Field Population of Haemonchus contortus from Sheep, Goats and Cattle in Bosnia and Herzegovina.

Haemonchus contortus is a globally significant parasitic nematode in ruminants, with widespread resistance to benzimidazole due to its excessive and prolonged use. Given the extensive use of benzimidazole anthelmintics in Bosnia and Herzegovina, we hypothesized that resistance is prevalent. The aim of this study was to identify the presence of anthelmintic resistance to benzimidazole in H. contortus from naturally infected sheep, goats and cattle in Bosnia and Herzegovina through the detection of the Phe/Tyr polymorphism in the amino acid at position 200 of the β-tubulin protein. From 19 locations in Bosnia and Herzegovina, a total of 83 adult H. contortus were collected from the abomasum of ruminants. Among these, 45 H. contortus specimens were isolated from sheep, 19 from goats and 19 from cattle. Results showed that 77.8% of H. contortus in sheep exhibited homozygous resistant genotypes at position 200 of the β-tubulin gene, with 15.5% being heterozygous. In goats, all tested H. contortus (100%) were homozygous resistant, and no heterozygous resistant or homozygous sensitive genotypes were found. Cattle had 94.7% homozygous resistant H. contortus, with no heterozygous resistant genotypes detected. In H. contortus from sheep and cattle, 6.7% and 5.3%, respectively, displayed homozygous sensitive genotypes. This study, for the first time, highlights the presence of a resistant population of H. contortus in sheep, goats and cattle in Bosnia and Herzegovina, using the rt-qPCR method. The resistance likely spread from sheep or goats to cattle, facilitated by shared pastures and the practice of transhumance, indicating a widespread and growing issue of anthelmintic resistance.

BEVA primary care clinical guidelines: Equine parasite control.

There is a lack of consensus on how best to balance our need to minimise the risk of parasite-associated disease in the individual horse, with the need to limit the use of anthelmintics in the population to preserve their efficacy through delaying further development of resistance. To develop evidence-based guidelines utilising a modified GRADE framework. A panel of veterinary scientists with relevant expertise and experience was convened. Relevant research questions were identified and developed with associated search terms being defined. Evidence in the veterinary literature was evaluated using the GRADE evidence-to-decision framework. Literature searches were performed utilising CAB abstracts and PubMed. Where there was insufficient evidence to answer the research question the panel developed practical guidance based on their collective knowledge and experience. Search results are presented, and recommendation or practical guidance were made in response to 37 clinically relevant questions relating to the use of anthelmintics in horses. There was insufficient evidence to answer many of the questions with any degree of certainty and practical guidance frequently had to be based upon extrapolation of relevant information and the panel members' collective experience and opinions. Equine parasite control practices and current recommendations have a weak evidence base. These guidelines highlight changes in equine parasite control that should be considered to reduce the threat of parasite-associated disease and delay the development of further anthelmintic resistance.

SheepEye: a based-web app for real-time diagnosis of sheep anemia.

Haemonchus contortus is an extremely harmful blood-feeding nematode affecting small ruminants, leading to anemia, weight loss, and, in severe cases, animal death. Traditional methods of monitoring anemia in sheep, such as regular physical examinations by veterinarians and laboratory tests, can be expensive and time-consuming. In this work, we propose an anemia monitoring system that uses a web-based app. The methodology for the SheepEye app is based on deep learning algorithms, including the U-net model for segmentation and the VGG19 model for classification. All learning algorithms, as well as the development of the app, were implemented in Python. The SheepEye web-based app is a promising technology that can facilitate and improve the diagnosis of parasitic infections in sheep and enhance sheep productivity. By using the app, farmers can detect anemia in their flocks and implement target selective treatment, which reduces the use of anthelmintics and consequently minimizes the risk of parasitic resistance. The SheepEye app is still in a prototype stage, but its prospective is extremely promising and our goal is to further develop it so that it can be made available for producers to use.