Prevalence of gastrointestinal nematodes, parasite control practices and anthelmintic resistance patterns in a working horse population in Egypt

Could Mesquite (Prosopis juliflora) Help Control Gastrointestinal Parasites in Horses?

Exploring new natural-origin antiparasitic alternatives is essential in addressing the resistance issues that have emerged due to the widespread use of chemical or synthetic antiparasitic compounds. This area remains relatively underexplored despite the increasing recognition of plants like Prosopis juliflora (mesquite) for their antiparasitic properties and nutritional value as a high-protein animal feed. This review aims to investigate the antiparasitic potential of P. juliflora against gastrointestinal parasites in horses. The review incorporates sources from 2005 to 2024. It was found that various phytochemical compounds from P. juliflora, particularly alkaloids, have demonstrated significant antiparasitic activity. Alkaloids are the most studied group due to their antibacterial, antiparasitic, and cytotoxic properties. According to the literature, the phytochemicals produced by P. juliflora hold promise as a potential solution for combating gastrointestinal parasites in horses. However, while preliminary findings suggest promising results, in vivo studies are necessary to evaluate the precise antiparasitic efficacy of these compounds and to determine the appropriate IC50 doses of P. juliflora alkaloids in horses, as well as to assess potential toxicity and side effects associated with their use.

Prevalence, risk factors, and species diversity of strongylid nematodes in domesticated Thai horses: insights from ITS-2 rDNA metabarcoding

Strongylid nematodes represent a major health and performance concern for equids globally. However, the epidemiology of strongylid infections in horse populations remains largely unexplored in Thailand. This study investigated the prevalence of strongylid parasites and the associated risk factors in domesticated horses in Thailand. Additionally, the study utilized ITS-2 rDNA metabarcoding to characterize the diversity and co-occurrence patterns of strongylid species. Of the 408 horses examined, 50.98% tested positive for strongyle infection, with an average intensity of 445.67 ± 639.58 eggs. Notably, only 25.74% exhibited fecal egg counts of ≥ 200 eggs per gram (EPG), highlighting the need for targeted deworming protocols. Significantly higher EPG values were observed in yearling horses (p = 0.001) and those kept in outdoor pastures (p = 0.0001). Metabarcoding identified 15 strongylid species, with Cylicostephanus longibursatus being the most abundant (mean relative abundance: 37.30%, SD = 31.16%). No Strongylus species were detected. Alpha diversity analysis revealed no significant differences in species richness and evenness across horse groups, while beta diversity analysis showed significant dissimilarities (p = 0.004), primarily driven by Cylicostephanus longibursatus, Cyathostomum pateratum, and Cylicostephanus calicatus, which contributed to over 60% of the variation. Species co-occurrence patterns were largely random, with a limited number of positive (n = 5) and negative (n = 2) species pair associations. These findings provide essential insights into the current state of strongylid infections in Thai horses and offer a foundation for future research and management strategies.

Comparative transcriptome analysis of doramectin-producing Streptomyces avermitilis N72 and its mutant strains

Doramectin, an essential animal anthelmintic, is synthesized through the fermentation process of Streptomyces avermitilis. This study delves into the transcriptomic profiles of two strains, namely the doramectin-producing wild-type S. avermitilis N72 and its highly doramectin-producing mutant counterpart, S. avermitilis XY-62. Comparative analysis revealed 860 up-regulated genes and 762 down-regulated genes in the mutant strain, notably impacting the expression of key genes pivotal in doramectin biosynthesis, including aveA1, aveA2, aveA3, aveA4, aveE, and aveBI. These findings shed light on the molecular mechanisms underpinning the heightened doramectin production in S. avermitilis XY-62, presenting promising avenues for optimizing doramectin production processes.

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.

A systematic review and meta-analysis on the current status of anthelmintic resistance in equine nematodes: A global perspective

BACKGROUND

The intensive application of anthelmintics in equine has led to considerable resistance in cyathostomins and Parascaris equorum. It has been well documented that benzimidazole (BZ) and pyrantel resistance is widespread in cyathostomins and Parascaris equorum. Since no new classes of anthelmintic have been introduced in the last 40 years, it is critical to be aware of the current risk factors of anthelmintic application to avoid further resistance.

OBJECTIVE

To review the factors affecting the level of anthelmintics resistance in equine around the world, type of anthelmintics, mode of application, dosage, nematode species, and location of anthelmintics application were evaluated and summarized.

DESIGN/PROCEDURE

A systematic review and meta-analyses following the PRISMA Framework were conducted to identify, evaluate, and synthesize primary literature reporting the efficacy of anthelmintic drugs in equines. Information on the bibliographic data, anthelmintic drugs, animals, continents, parasite genera, type of anthelmintics, and dosage was collected. Nonparametric tests (Kruskal-Wallis and Mann-Whitney) were used in SPSS (v.27) to investigate the association between variables. Factors that have a significant impact on efficacy have been subjected to binary logistic regression. Six meta-analyses were conducted in Microsoft Excel (2021) to qualify current resistance issues of the three major anthelmintics classes.

RESULTS

The final database was composed of 60 articles published between 1994 and 2022 with a total of 11835 animals. Anthelmintic class as well as anthelmintic active principle selection did have a significant effect on resistance (P < 0.01), whilst no correlation of the type of anthelmintics, mode of application, and dosage with efficacy were found. Anthelmintics resistance in ascarid was significantly more severe than in strongyle (P < 0.01). Macrocyclic lactone (ML) class and the benzimidazole and probenzimidazole (BP) class have the lowest efficacy against ascarid and strongyle, respectively (67.83% and 69.85%). The effect of location (by continent) also had a significant influence on the resistance of the ML class (P < 0.01). The resistance of the BP class which is the most prevalently applied was demonstrated in all six continents. Binary logistic regression revealed that parasite genera and drug class independently influenced the presence of drug resistance. The forest plots included in this study did not show a significant difference over time.

CONCLUSION

Current evidence indicated that anthelmintics resistance of ML and BP class were common in ascarid and strongyle. A combination of anthelmintics may reduce anthelmintics resistance, but multi-drug resistance may be a concern. Customerised anthelmintics strategy could help reduce resistance.

Prevalence of Cryptosporidium spp. infection in a working horse population in Egypt

Working horses support the livelihoods of smallholder farmers in Egypt. No previous study has investigated the prevalence of cryptosporidiosis in working horses in Egypt. Faecal samples were collected from 607 working horses recruited from thirty-seven villages/areas in two Egyptian governorates and examined for Cryptosporidium spp. infection using the modified Zielh-Neelsen staining technique. Data on signalment, history of recent diarrhoea, and strongyle burden were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for infection were investigated using mixed-effects logistic regression models that included sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5-33.9). None of the variables investigated, which include age, sex of the animals, and strongyle burden, were associated with risk of infection. This study provided evidence-based information on the prevalence of Cryptosporidium spp. infection in the study area. However, the potential zoonotic risk of Cryptosporidium cannot be confirmed until further studies are conducted to genotype these parasites.

Prevalence of intestinal nematodes in equines with an assessment of the therapy using Albendazole and Doramectin.. [DOI: 10.21203/rs.3.rs-2889716/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: Intestinal nematode parasites of equines have emerged as a pressing and urgent challenge due to their significant impact on the health and performance of these animals worldwide; therefore, implementing a deworming regimen has become vital to keeping a horse's parasite load at an acceptable level. Thus, the current study aimed to estimate the prevalence of nematodes infection , associated risk factors and evaluate the chemotherapeutic efficacy of different anthelmintic drugs by enrolling 195 fecal matter samples of working equines using flotation concentration techniques. Equines treatment were divided into four groups; Group 1 standard treatment (Albendazole orally), Group 2 intervention treatment (Doramectin injection), Group 3 intervention treatment (combination of Albendazole and Doramectin), and Group 4 was left untreated as a positive control. Results: The overall prevalence of intestinal nematode parasites in working equines was 70.25%. The recovered nematodes were Strongylus species, with 87.17% followed by Parascaris equorum 30.76%, and Oxyuris equi was 12.82%. Concerning treatment efficacy, the highest cure rate was among Group 3 (77.14%), followed by Group 2 (68.57%) and Group 1 (40%), but the difference between Groups 2 and 3 is statistically insignificant. Interestingly, the effect of Doramectin injection is highly significant than other, especially for the reduction of Strongylus spp. and Parascaris equorum eggs according to Cohen's D test. Conclusions: Translating such a potent combination of drugs into endemic areas will provide significant support for deworming and control programs against intestinal parasites of equines, especially those in the migratory phase, more than Albendazole alone, which has poor absorption as it requires a full stomach during administration.

Moringa oleifera as a Natural Alternative for the Control of Gastrointestinal Parasites in Equines: A Review

Studies have shown a wide variety of parasites that infect horses, causing major gastrointestinal damage that can lead to death, and although the main method of control has been synthetic anthelmintics, there are parasites that have developed resistance to these drugs. For generations, plants have been used throughout the world as a cure or treatment for countless diseases and their symptoms, as is the case of Moringa oleifera, a plant native to the western region. In all its organs, mainly in leaves, M. oleifera presents a diversity of bioactive compounds, including flavonoids, tannins, phenolic acids, saponins, and vitamins, which provide antioxidant power to the plant. The compounds with the greatest antiparasitic activity are tannins and saponins, and they affect both the larvae and the oocytes of various equine gastrointestinal parasites. Therefore, M. oleifera is a promising source for the natural control of gastrointestinal parasites in horses.

Prevalence of Cryptosporidium spp. infection in working horses in Egypt.. [DOI: 10.21203/rs.3.rs-2363022/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Working horses support the livelihoods of smallholder farmers in Egypt but can pose potential zoonotic risk to their handlers such as cryptosporidiosis. Working horses were recruited into the study from 37 villages/areas in two Egyptian governorates. Faecal samples were collected from 607 horses and were examined for Cryptosporidium spp. infection using modified Zielh-Neelsen staining technique. Data about signalment, concurrent disease and level of strongyle infection were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for the infection were investigated using mixed-effects logistic regression models that included the sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5–33.9). None of the variables investigated including age and sex of the animals were associated with the risk of the infection. The study identified greater prevalence of Cryptosporidium spp. infection in the study area and further studies may be required to genotype these parasites. Personal hygiene such as hand sanitation should be practiced when managing these horses.

Anthelmintic efficacy in strongyles of horses in Northern Minas Gerais, Brazil

The intensive use of anthelmintics has resulted in resistant parasite populations in horses. The objective of this trial was to evaluate the anthelmintic efficacies of the anthelmintics fenbendazole, ivermectin and abamectin in 24 horse farms in Northern Minas Gerais. Egg counts per gram of faeces (EPG) were performed individually in 619 animals. Animals presenting EPG counts greater than or equal to 150 were used in the tests on faecal egg count reduction (FECR), totalling 436 equines. These animals received the anthelmintics, fenbendazole, ivermectin, and abamectin. Faeces were collected 14 days after the administration of anthelmintics to perform the EPG. Pre- and post-treatment EPG counts were used to calculate the FECR for each anthelmintic group, and faecal culture was used to identificy of the strongyles. The resistance status was evaluated based on the FECR and LCL95%. Fenbendazole was effective in 11 (45.8%) of the horse farms. Ivermectin was effective in 17 (77.3%) and abamectin in 17 (74%) of the farms; side-resistance was detected in 3 (12.5%) of the farms. Intestinal strongyle resistance to anthelmintics was observed in 14 (58.3%) of the farms. Cyathostomin larvae were found in 100% of the farms, Strongylus vulgaris in 13 (54.2%), and S. equinus in 3 (12.5%). Only cyathostomins larvae were detected post-treatment with ivermectin and abamectin.

Very low intraspecific sequence variation in selected nuclear and mitochondrial Parascaris univalens genes

Equines were over decades considered to be infected by two morphologically virtually indistinguishable ascarid species, Parascaris univalens and Parascaris equorum. Reliable species discrimination is only possible using enzyme isoelectric focussing and karyotyping with P. univalens having one and P. equorum two chromosome pairs. However, presumably the complexity of both methods prevented their routine use in nearly all previous studies about prevalence and drug resistance of Parascaris spp. These have barely been performed on the species level although most studies stated presence of one or the other species. Recently, only P. univalens has been identified by karyotyping and the last published study identifying P. equorum dates back to 1989. In order to improve species-specific detection, molecular markers are required. Here, partial 12S rRNA, cytochrome oxidase I (COI) and complete internal transcribed spacer (ITS)-1 and - 2 sequences were obtained from 24 karyotyped Parascaris specimens from Poland and 6 German specimens (not karyotyped) and used in phylogenetic analyses with orthologous sequences from GenBank. All karyotyped specimens were identified as P. univalens. In the phylogenetic analysis, they formed very homogenous clusters for all target genes and in a multi-locus analysis. Within this cluster, almost all sequences from GenBank were also included, no matter if they had been assigned to P. univalens or P. equorum. However, a small number of P. univalens ITS and COI sequences originating from donkeys from a single farm in China formed a highly supported sister cluster suggesting that they might represent another Parascaris genotype or species. Our data also strongly suggest that nearly all ITS and COI sequences previously deposited in GenBank and assigned to P. equorum actually represent P. univalens. The fact that significantly different sequences can be found in Parascaris spp. suggests that PCR-based species diagnosis will be possible once molecular markers have been identified for P. equorum from karyotyped specimens.

Anthelmintics for drug repurposing: Opportunities and challenges

Drug repositioning is defined as a process to identify a new application for drugs. This approach is critical as it takes advantage of well-known pharmacokinetics, pharmacodynamics, and toxicity profiles of the drugs; thus, the chance of their future failure decreases, and the cost of their development and the required time for their approval are reduced. Anthelmintics, which are antiparasitic drugs, have recently demonstrated promising anticancer effects in vitro and in vivo. This literature review focuses on the potential of anthelmintics for repositioning in the treatment of cancers. It also discusses their pharmacokinetics and pharmacodynamics as antiparasitic drugs, proposed anticancer mechanisms, present development conditions, challenges in cancer therapy, and strategies to overcome these challenges.

Study design synopsis: Battle in the stable: Bayesianism versus Frequentism

Frequentism dominates scientific practice although Bayesianism may provide an alternative, especially when analysing data from complex, high-dimensional models. The key differences between Bayesianism and Frequentism are highlighted in the introduction. Next, I review the different stages of Bayesian statistical reasoning in a research setting, explain the key concepts and illustrate them with toy examples taken in equine veterinary medicine. An extension to more complex models (Bayes network) is introduced and guidelines are offered as a conclusion.