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The Veterinary Clinics of North... Mar 2020Refugia-based strategies are intended to help slow the development of anthelmintic resistance by providing a population of parasites that are not exposed to the... (Review)
Review
Refugia-based strategies are intended to help slow the development of anthelmintic resistance by providing a population of parasites that are not exposed to the treatment. Evidence from field studies is lacking. There is no single way to incorporate refugia into a parasite control program. There are many options available varying greatly in complexity and practicality, and none are suitable for all situations. Incorporating refugia into production systems typically requires a change in farmer mindset and greater input of time, labor, and/or technology, but is necessary to help preserve anthelmintic efficacy and promote sustainable animal production systems.
Topics: Animal Husbandry; Animals; Anthelmintics; Cattle; Cattle Diseases; Drug Resistance; Goat Diseases; Goats; Livestock; Refugium; Sheep; Sheep Diseases
PubMed: 32029187
DOI: 10.1016/j.cvfa.2019.11.003 -
Experimental Parasitology Nov 2021More than 50 years after anthelmintic resistance was first identified, its prevalence and impact on the animal production industry continues to increase across the... (Review)
Review
More than 50 years after anthelmintic resistance was first identified, its prevalence and impact on the animal production industry continues to increase across the world. The term "anthelmintic resistance" (AR) can be briefly defined as the reduction in efficacy of a certain dose of anthelmintic drugs (AH) in eliminating the presence of a parasite population that was previously susceptible. The main aim of this study is to examine anthelmintic resistance in domestic herbivores. There are numerous factors playing a role in the development of AR, but the most important is livestock management. The price of AH and the need to treat a high number of animals mean that farmers face significant costs in this regard, yet, since 1981, little progress has been made in the discovery of new molecules and the time and cost required to bring a new AH to market has increased dramatically in recent decades. Furthermore, resistance has also emerged for new AH, such as monepantel or derquantel. Consequently, ruminant parasitism cannot be controlled solely by using synthetic chemicals. A change in approach is needed, using a range of preventive measures in order to achieve a sustainable control programme. The use of nematophagous fungi or of plant extracts rich in compounds with anthelmintic properties, such as terpenes, condensed tannins, or flavonoids, represent potential alternatives. Nevertheless, although new approaches are showing promising results, there is still much to do. More research focused on the control of AR is needed.
Topics: Animals; Anthelmintics; Drug Resistance; Flavonoids; Fungi; Horse Diseases; Horses; Nematoda; Nematode Infections; Phytotherapy; Proanthocyanidins; Ruminants
PubMed: 34627787
DOI: 10.1016/j.exppara.2021.108169 -
Parasitology Research Dec 2023The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals... (Review)
Review
The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals provides comprehensive awareness and potential solutions for issues relating to the health of people, animals, and the environment. This approach has increasingly gained appeal as the standard strategy for tackling emerging infectious diseases, most of which are zoonoses. Treatment with anthelmintics (AHs) without a doubt minimizes the severe consequences of soil-transmitted helminths (STHs); however, evidence of anthelmintic resistance (AR) development to different helminths of practically every animal species and the distinct groups of AHs is overwhelming globally. In this regard, the correlation between the application of anthelmintic drugs in both human and animal populations and the consequent development of anthelmintic resistance in STHs within the context of a One-Health framework is explored. This review provides an overview of the major human and animal STHs, treatment of the STHs, AR development and drug-related factors contributing towards AR, One-Health and STHs, and an outline of some One-Health strategies that may be used in combating AR.
Topics: Animals; Humans; Helminthiasis; Soil; One Health; Anthelmintics; Helminths
PubMed: 38114766
DOI: 10.1007/s00436-023-08088-8 -
Journal of Korean Medical Science Feb 2020
Topics: Anthelmintics; Antineoplastic Agents; Fenbendazole; Hepatitis; Humans; Neoplasms; Social Media
PubMed: 32056406
DOI: 10.3346/jkms.2020.35.e75 -
Current Topics in Medicinal Chemistry 2023Parasitic diseases affect millions of people and animals, predominantly in the tropics, including visitors to tropical countries and other areas. Efficient and low-cost... (Review)
Review
Parasitic diseases affect millions of people and animals, predominantly in the tropics, including visitors to tropical countries and other areas. Efficient and low-cost treatments for infections caused by various parasites are not yet available. Antiparasitic drugs have some drawbacks, such as toxicity and the development of resistance by parasites. This has motivated many researchers to focus on the discovery of safe, effective and affordable antiparasitic drugs, both among drugs already available for other diseases and new compounds synthesized or isolated from natural sources. Furthermore, steroid and triterpenoid compounds attract the attention of pharmacologists, chemists and biochemists owing to their broad application in the treatment of various diseases. Isolation of steroid and triterpenoid compounds from natural sources with antiparasitic efficacy is an attractive choice for scientists. On the other hand, these compounds can be transformed into more potent forms by modifying the basic skeleton. This review presents a collection of isolated and synthesized steroid and triterpenoid compounds from 2018 to 2021 that have been reported to be effective against certain parasitic protozoa and helminths. A total of 258 compounds have been identified with antimalarial, antitrypanosomal, antileishmanial, anti-Toxoplasma, and/or anthelmintic activity. The described investigations of antiparasitic compounds may be helpful for further drug development.
Topics: Animals; Antiparasitic Agents; Antiprotozoal Agents; Anthelmintics; Steroids; Antineoplastic Agents; Triterpenes; Trypanosoma cruzi
PubMed: 36703585
DOI: 10.2174/1568026623666230126162419 -
International Journal For Parasitology.... Dec 2022Anthelmintic resistance is reported in equine nematodes with increasing frequency in recent years, and no new anthelmintic classes have been introduced during the past... (Review)
Review
Anthelmintic resistance is reported in equine nematodes with increasing frequency in recent years, and no new anthelmintic classes have been introduced during the past 40 years. This manuscript reviews published literature describing anthelmintic resistance in cyathostomins, Parascaris spp., and Oxyuris equi with special emphasis on larvicidal efficacy against encysted cyathostomin larvae and strongylid egg reappearance periods (ERP). Resistance to benzimidazoles and pyrimidines is highly prevalent in cyathostomin populations around the world, and macrocyclic lactone resistance has been documented in cyathostomins in recent years as well. Two recent studies have documented resistance to the larvicidal regimen of fenbendazole, whereas the larvicidal efficacy of moxidectin is variable, but with no evidence of a reduction from historic levels. In the 1990s, ERP estimates were 8-10 and 12-16 weeks for ivermectin and moxidectin, respectively, while several studies published after year 2000 found ERPs to be 5 weeks for both compounds. This is a clear change in anthelmintic performance, but it remains unclear if this is due to development of anthelmintic resistance or selection for other biological traits leading to a quicker resumption of strongylid egg shedding following anthelmintic treatment. Macrocyclic lactone resistance is common in Parascaris spp. around the world, but recent reports suggests that resistance to the two other classes should be monitored as well. Finally, O. equi has been reported resistant to ivermectin and moxidectin in countries representing four continents. In conclusion, multi-drug resistance is becoming the norm in managed cyathostomin populations around the world, and a similar pattern may be emerging in Parascaris spp. More work is required to understand the mechanisms behind the shortened ERPs, and researchers and veterinarians around the world are encouraged to routinely monitor anthelmintic efficacy against equine nematodes.
Topics: Horses; Animals; Horse Diseases; Anthelmintics; Fenbendazole; Macrolides; Ivermectin; Ascaridoidea; Drug Resistance; Parasite Egg Count; Feces
PubMed: 36342004
DOI: 10.1016/j.ijpddr.2022.10.005 -
Tierarztliche Praxis. Ausgabe G,... Feb 2022
Topics: Animals; Anthelmintics; Goat Diseases; Goats
PubMed: 35235986
DOI: 10.1055/a-1643-7267 -
Trends in Parasitology Dec 2019There is increasing attention on the complex interactions occurring between schistosome parasites and their hosts. However, little is known about the occurrence,... (Review)
Review
There is increasing attention on the complex interactions occurring between schistosome parasites and their hosts. However, little is known about the occurrence, epidemiology, and mechanisms of schistosomiasis-associated infertility. In this article, we argue that an in-depth understanding of the interplay between parasites and the host endocrine system may significantly enhance current knowledge of infertility in infected individuals. We discuss the basic hormonal mechanisms that may lead to the discovery of entirely novel anthelmintic interventions against schistosomiasis.
Topics: Animals; Anthelmintics; Endocrine System; Host-Parasite Interactions; Humans; Infertility; Schistosoma; Schistosomiasis
PubMed: 31623951
DOI: 10.1016/j.pt.2019.09.001 -
Trends in Parasitology Sep 2021Most anthelmintics were discovered through in vivo screens using animal models of infection. Developing in vitro assays for parasitic worms presents several challenges.... (Review)
Review
Most anthelmintics were discovered through in vivo screens using animal models of infection. Developing in vitro assays for parasitic worms presents several challenges. The lack of in vitro life cycle culture protocols requires harvesting worms from vertebrate hosts or vectors, limiting assay throughput. Once worms are removed from the host environment, established anthelmintics often show no obvious phenotype - raising concerns about the predictive value of many in vitro assays. However, with recent progress in understanding how anthelmintics subvert host-parasite interactions, and breakthroughs in high-content imaging and machine learning, in vitro assays have the potential to discern subtle cryptic parasite phenotypes. These may prove better endpoints than conventional in vitro viability assays.
Topics: Animals; Anthelmintics; Drug Evaluation, Preclinical; Helminthiasis; Helminths; Host-Parasite Interactions
PubMed: 34092518
DOI: 10.1016/j.pt.2021.05.004 -
Scientific Reports Dec 2023Parasitic roundworms cause significant sickness and mortality in animals and humans. In livestock, these nematodes have severe economic impact and result in losses in...
Parasitic roundworms cause significant sickness and mortality in animals and humans. In livestock, these nematodes have severe economic impact and result in losses in food production on a global scale. None of the currently available drugs ideally suit all treatment circumstances, and the development of drug-resistant nematode strains has become a challenge to control the infection. There is an urgent need to develop novel anthelmintic compounds. According to our previous report, N-methylbenzo[d]oxazol-2-amine (1) showed anthelmintic activity and lowest cytotoxicity. In this study, in vivo anthelmintic properties were evaluated using Trichinella spiralis infected mice. Toxicity was evaluated using the rats and mode of action using molecular docking and metabolomics approaches. The in vivo results demonstrate that a dose of 250 mg/kg reduced the T. spiralis abundance in the digestive tract by 49%. The 250 mg/kg Albendazole was served as control. The relatively low acute toxicity was categorized into chemical category 5, with an LD greater than 2000 mg/kg body. Molecular docking analysis showed the T. spiralis tubulin beta chain and glutamate-gated channels might not be the main targets of compound 1. Metabolomics analysis was used to explain the effects of compound 1 on the T. spiralis adult worm. The results demonstrated that compound 1 significantly up-regulated the metabolism of purine, pyrimidine and down-regulated sphingolipid metabolism. In conclusion, compound 1 could be a potential molecule for anthelmintic development. The bioavailability, pharmacokinetics, and absorption of this compound should be studied further to provide information for its future efficacy improvement.
Topics: Humans; Mice; Rats; Animals; Molecular Docking Simulation; Anthelmintics; Albendazole; Nematoda; Trichinella spiralis
PubMed: 38129499
DOI: 10.1038/s41598-023-50305-y