scholarly journals PSV-37 Reemergence of cyathostomins species demonstrates anthelmintic resistance following drug administration in horses

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 335-335
Author(s):  
Alexa C Johnson ◽  
Amy S Biddle
Keyword(s):  
Anthelmintic Resistance ◽  
Macrocyclic Lactones ◽  
Number Of Species ◽  
Molecular Approaches ◽  
Pyrantel Pamoate ◽  
Drug Classes ◽  
Blast Database ◽  
Resistance Patterns ◽  
Near Future ◽  
Ncbi Blast

Abstract Arbitrary administration of anthelmintics to control equine gastrointestinal worms has led to increased resistance to the three broad-spectrum drug classes; benzimidazoles, tetrahydropyrimidines, and macrocyclic lactones. With little promise of new drug classes to target cyathostomins being introduced to the market in the near future, anthelmintic drugs must be administered judiciously to prevent complete anthelmintic parasite resistance. The objective of this study is to determine the reemergence rate of cyathostomins following three commercial horse dewormers during summer. Nine horses housed at two locations were enrolled to the study and was repeated June–September through 2017–2019. Horses were removed from the study if sequencing failed due to low egg recovery for more than 50% of the timepoints. Ivermectin (macrocyclic lactones; n = 6), Moxidectin (macrocyclic lactones; n = 8) and Strongid (pyrantel pamoate; n = 8) were administered to horses and fecal samples were collected every 14d for 98d. Samples were tested using fecal egg counts with a modified McMaster technique and 18S rRNA profiling of the V5.8 and ITS1 regions. Sequences were clustered and taxonomy was assigned against a custom NCBI Blast+ database with the aligned sequences of 19 cyathostomins. Data were analyzed using presence/absence methods in R studio. Treatment and Day significantly impacted the average number of species present (P < 0.001). Moxidectin had the lowest number of species present followed by Strongid then Ivermectin (7.14, 10.17, 11.09, respectively). Equine shedder status had no effect on the average number of species present (P > 0.05). Six species, CO. labiatus, CS. catinatum, CY. auriculatus, CY. elongatus, CT. goldi and CT. longibursatus, showed resistance to the three treatments (P > 0.05). Moxidectin was the most effective at eradicating cyathostomins infestations (P < 0.05). Identifying resistance patterns at the species level will enable mechanistic molecular approaches to determine anthelmintic resistance in cyathostomins.

Studies in African Tachinidae (Diptera).—II

1927 ◽  
Vol 18 (2) ◽  
pp. 103-128 ◽  
Author(s):  
C. H. Curran
Keyword(s):  
New Species ◽  
Considerable Progress ◽  
Number Of Species ◽  
Sufficient Detail ◽  
Near Future ◽  
Made In

In several previously published papers dealing with African Diptera I have described a number of species belonging to the genus Sturmia, Desvoidy, but up to the present time have not had sufficient material available to warrant the preparation of a key to the species, nor have I had an opportunity of studying the species in sufficient detail to decide upon characters of value in their classification. However, since many species were reared and it was desirable to have names for them in order that they might be used in reports by various Entomologists in Africa, a number of the species were described, and it has since been possible to make considerable progress in the study of the whole. As a result a key to the species belonging to this genus is now presented, and it is hoped that it will be of assistance in identifying the representatives of this difficult group.It is further hoped that arrangements may be made in the near future for the publication of a key to the genera of the Tachinidae, since it is obvious that with the very large number of genera described, the description of an additional genus, or even of new species in old genera, conveys little of the true relationships of the forms described and merely adds to the difficulty of making determinations.

scholarly journals Current Status and Future Perspective on Enzyme Involving in Biocontrol of Plant Pathogen

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Ami Chaudhari ◽  
Jesal Patel
Keyword(s):  
Crop Yield ◽  
Plant Diseases ◽  
Current Status ◽  
Future Perspective ◽  
Lytic Enzymes ◽  
Molecular Approaches ◽  
Yield And Quality ◽  
And Control ◽  
Near Future ◽  
Rhizosphere Microorganism

To sustain the quality and abundance of fruit, feed and fiber provided by farmers all over the world, plant diseases must be regulated. Plant diseases may be prevented, mitigated, or regulated using a variety of methods. Growers also rely on chemical fertilizers and pesticides for good agronomic and horticultural practices. Such agricultural inputs have taken a vital part in spectacular increases in crop yield and quality over the last 100 years. Microbial enzymes function as biocatalysts for key biochemical reactions and also assist microbes reproduce in a particular niche. The ability of rhizosphere microorganism to increase the growth of plant and control phytopathogens has long been known. Rhizosphere microbes may aid plants in several ways in their fight against phytopathogens. Of all recognized biocontrol pathways, the excretion of lytic enzymes is known as an important way to prevent phytopathogens from living in the region of the rhizosphere. Rhizosphere microorganism produces chitinases, cellulases, proteases, and glucanases in reaction to phytopathogen assault. For assessing antagonist-pathogen interactions, ecological characteristics of antagonists in the rhizosphere, and optimizing the effectiveness of bacterial, fungal, and viral biocontrol agents, new molecular approaches have become available. Given the experience of fungicides in near future, biological management would be another method to control diseases of plant. Since agro-ecosystem is a flexible and functioning structure that involves many variables that affect disease and production of crop, other IPM methods to control diseases of crop are also important in different surrounding conditions. As result, to successfully minimize disease production and crop yield loss in various crop systems, other IPM management mechanisms other than biological control should be considered and implemented.

scholarly journals A user guide to environmental protistology: primers, metabarcoding, sequencing, and analyses

2019 ◽  
Author(s):  
Stefan Geisen ◽  
Daniel Vaulot ◽  
Frédéric Mahé ◽  
Enrique Lara ◽  
Colomban de Vargas ◽  
...  
Keyword(s):  
Cost Efficiency ◽  
Major Part ◽  
High Throughput Sequencing ◽  
Ecosystem Processes ◽  
Universal Primers ◽  
Ecological Research ◽  
Ecological Studies ◽  
Great Cost ◽  
Molecular Approaches ◽  
Near Future

AbstractProtists – all eukaryotes besides fungi, animals, and plants - represent a major part of the taxonomic and functional diversity of eukaryotic life on the planet and drive many ecosystem processes. However, knowledge of protist communities and their diversity lags behind that of most other groups of organisms, largely due to methodological constraints. While protist communities differ markedly between habitats and biomes, they can be studied in very similar ways. Here we provide a guide to current molecular approaches used for studying protist diversity, with a particular focus on amplicon-based high-throughput sequencing (metabarcoding). We highlight that the choice of suitable primers artificially alters community profiles observed in metabarcoding studies. While there are no true ‘universal’ primers to target all protist taxa as a whole, we identify some primer combinations with a wide taxonomic coverage and provide detailed information on their properties. Although environmental protistan ecological research will probably shift towards PCR-free metagenomics or/and transcriptomic approaches in a near future, metabarcoding will remain the method of choice for in-depth community analyses and taxon inventories in biodiversity surveys and ecological studies, due its great cost-efficiency, sensitivity, and throughput. In this paper we provide a guide for scientists from a broad range of disciplines to implement protists in their ecological analyses.

scholarly journals Anthelmintic resistance of gastrointestinal cattle nematodes

2013 ◽  
Vol 82 (3) ◽  
pp. 113-123 ◽  
Author(s):  
J. De Graef ◽  
E. Claerebout ◽  
P. Geldhof
Keyword(s):  
Anthelmintic Resistance ◽  
Early Stage ◽  
Control Strategies ◽  
Small Ruminants ◽  
Sensitive Detection ◽  
Current Status ◽  
Diagnostic Assays ◽  
Cooperia Oncophora ◽  
Near Future ◽  
Sensitive Detection Technique

Anthelmintic resistance of parasites in small ruminants, cattle and horses is increasing worldwide as a consequence of the over usage of the currently available products. In Belgium, Cooperia oncophora is the most common cattle nematode in which resistance, especially against macrocyclic lactones, occurs. Once resistance has been diagnosed, a change to another drug with a different mode of action is advised. However, effective anthelmintics will be hardly available in the near future. Therefore, it is important that farmers and veterinarians find a balance between achieving good parasite control and the sustainability of their control strategies. In this way, anthelmintic resistance may be delayed, and the effectiveness of anthelmintic drugs may be prolonged. This requires sensitive detection tools. With a sensitive detection technique, anthelmintic resistance can be diagnosed in a very early stage. Hence, the spread of resistance alleles in the parasite population may be prevented. In this review, different diagnostic assays for the detection of anthelmintic resistance are discussed, an overview is given of the current status of anthelmintic resistance in Belgian cattle, and measures are suggested to avoid or delay the development of anthelmintic resistance.

scholarly journals High frequency of benzimidazole resistance alleles in Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis from Austrian sheep flocks in an alpine transhumance management system

2019 ◽  
Author(s):  
Barbara Hinney ◽  
Julia Schoiswohl ◽  
Lynsey Melville ◽  
Vahel J. Ameen ◽  
Walpurga Wille-Piazzai ◽  
...  
Keyword(s):  
Management System ◽  
Anthelmintic Resistance ◽  
Treatment Strategies ◽  
Small Ruminants ◽  
Nucleotide Polymorphisms ◽  
Sheep Population ◽  
Teladorsagia Circumcincta ◽  
Benzimidazole Resistance ◽  
Drug Classes ◽  
New Treatment

Abstract Infections of small ruminants with trichostrongyloid nematodes often result in reduced productivity and may be detrimental to the host. Anthelmintic resistance (AR) against most anthelmintic drug classes is now widespread amongst the trichostrongyloids. Baseline establishment, followed by regular monitoring of the level of AR, is necessary for farmers and veterinarians to make informed decisions about parasite management. The detection of single nucleotide polymorphisms (SNPs) is a sensitive method to detect AR against benzimidazoles (BZs), one of the most widely used anthelmintic classes. Alpine transhumance constitutes a special type of pasturing of sheep from many different farms, the aim of this study was to investigate the prevalence of benzimidazole resistance alleles in this particular management system. Sixteen sheep flocks in Styria and Salzburg in Austria were examined by pyrosequencing for SNPs at codons 167, 198 and 200 of the isotype-1 β-tubulin gene. The frequency of the resistance-associated mutation F200Y was 87–100% for H. contortus, 77–100% for T. colubriformis and <5–66% for T. circumcincta. Additionally, the F167Y polymorphism was detected in T. colubriformis from two farms at a frequency of 19% and 23% respectively. The high resistance allele frequency in H. contortus and T. colubriformis in the examined sheep population urgently calls for the development of new treatment strategies to sustainably control trichostrongyloid infections for this kind of pasturing, since the frequent mixing of flocks during the alpine summer grazing must be considered an important risk factor for the spread of resistant nematodes to a large number of farms.

scholarly journals Resistance of strongylid nematodes to anthelmintic drugs and driving factors at Czech goat farms

2021 ◽  
Author(s):  
Jaroslav Vadlejch ◽  
Iveta Angela Kyriánová ◽  
Marián Várady ◽  
Johannes Charlier
Keyword(s):  
Health Management ◽  
Anthelmintic Resistance ◽  
Animal Health ◽  
Dairy Goat ◽  
Dairy Goats ◽  
Univariate Logistic Regression Analysis ◽  
The Czech Republic ◽  
Livestock Productivity ◽  
Near Future

Abstract Background: Strongylid nematode infections may negatively affect both animal health and welfare, with deleterious consequences for livestock productivity. Many farmers in recent decades have relied on anthelmintics as the sole strategy of control, but the intensive use of these chemotherapeutics has led to the development of anthelmintic resistance (AR). Knowledge of both the efficacy of anthelmintics and factors promoting AR are essential to effectively control nematode infections, but no information on these topics for goats in the Czech Republic (CR) is available. This survey aimed to determine the occurrence of AR at Czech goat farms and to identify risk factors for the development of AR. A total of 24 herds of dairy goats across the CR were evaluated using in vitro tests for detecting AR, and a questionnaire survey was carried out to evaluate factors associated with AR.Results: Resistance against benzimidazoles was confirmed at 18 (75%) farms, and the level of resistance was high in four (22%) of the affected herds based on the egg hatch test. Ivermectin-resistant nematodes were detected in 13 (54%) herds using the larval development test; Teladorsagia/Trichostrongylus and Haemonchus were the predominant types of resistant larvae. Eight (62%) of the affected herds were evaluated as highly resistant to ivermectin. Eleven (46%) of the herds were resistant to both benzimidazoles and ivermectin. This report is the first on dual AR in the CR. A univariate logistic regression analysis indicated that a high stocking rate and farmer inexperience were significantly associated with ivermectin and benzimidazole resistance, respectively.Conclusions: The results of our survey suggest that AR is widespread amongst herds of dairy goats in the CR, likely due to inappropriate practices of pasture and health management. AR may be an issue for expanding dairy-goat production in the CR in the near future unless both veterinary practitioners and farmers widely adopt strategies to prevent the development of AR.

Anthelmintic resistance and novel control options in equine gastrointestinal nematodes

Parasitology ◽  
2018 ◽  
Vol 146 (4) ◽  
pp. 425-437 ◽  
Author(s):  
Ali Raza ◽  
Abdul Ghaffar Qamar ◽  
Khizar Hayat ◽  
Shoaib Ashraf ◽  
Andrew R. Williams
Keyword(s):  
Anthelmintic Resistance ◽  
Early Stage ◽  
Control Strategies ◽  
Field Studies ◽  
Gastrointestinal Nematodes ◽  
Feed Additives ◽  
Macrocyclic Lactones ◽  
Fecal Egg Count ◽  
Worm Control ◽  
And Control

AbstractControl of equine nematodes has relied on benzimidazoles (BZs), tetrahydropyrimidines and macrocyclic lactones. The intensive use of anthelmintics has led to the development of anthelmintic resistance (AR) in equine cyathostomins and Parascaris equorum. Field studies indicate that BZ and pyrantel resistance is widespread in cyathostomins and there are also increasing reports of resistance to macrocyclic lactones in cyathostomins and P. equorum. The unavailability of reliable laboratory-based techniques for detecting resistance further augments the problem of nematode control in horses. The only reliable test used in horses is the fecal egg count reduction test; therefore, more focus should be given to develop and validate improved methodologies for diagnosing AR at an early stage, as well as determining the mechanisms involved in resistance development. Therefore, equine industry and researchers should devise and implement new strategies for equine worm control, such as the use of bioactive pastures or novel feed additives, and control should increasingly incorporate alternative and evidence-based parasite control strategies to limit the development of AR. This review describes the history and prevalence of AR in equine nematodes, along with recent advances in developing resistance diagnostic tests and worm control strategies in horses, as well as giving some perspective on recent research into novel control strategies.

scholarly journals Multidrug-Resistant Avian Pathogenic Escherichia coli Strains and Association of Their Virulence Genes in Bangladesh

2020 ◽  
Vol 8 (8) ◽  
pp. 1135
Author(s):  
Otun Saha ◽  
M. Nazmul Hoque ◽  
Ovinu Kibria Islam ◽  
Md. Mizanur Rahaman ◽  
Munawar Sultana ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Multidrug Resistant ◽  
Avian Pathogenic Escherichia Coli ◽  
E Coli ◽  
Molecular Approaches ◽  
Clade B ◽  
Pathogenic Escherichia Coli ◽  
Resistance Patterns

The avian pathogenic Escherichia coli (APEC) strains are the chief etiology of colibacillosis worldwide. The present study investigated the circulating phylotypes, existence of virulence genes (VGs), and antimicrobial resistance (AMR) in 392 APEC isolates, obtained from 130 samples belonged to six farms using both phenotypic and PCR-based molecular approaches. Congo red binding (CRB) assay confirmed 174 APEC isolates which were segregated into ten, nine, and eight distinct genotypes by RAPD assay (discriminatory index, DI = 0.8707), BOX-PCR (DI = 0.8591) and ERIC-PCR (DI = 0.8371), respectively. The combination of three phylogenetic markers (chuA, yjaA and DNA fragment TspE4.C2) classified APEC isolates into B23 (37.36%), A1 (33.91%), D2 (11.49%), B22 (9.20%), and B1 (8.05%) phylotypes. Majority of the APEC isolates (75–100%) harbored VGs (ial, fimH, crl, papC, and cjrC). These VGs (papC and cjrC) and phylotypes (D2 and B2) of APEC had significant (p = 0.004) association with colibacillosis. Phylogenetic analysis showed two distinct clades (clade A and clade B) of APEC, where clade A had 98–100% similarity with E. coli APEC O78 and E. coli EHEC strains, and clade B had closest relationship with E. coli O169:H41 strain. Interestingly, phylogroups B2 and D2 were found in the APEC strains of both clades, while the strains from phylogroups A1 and B1 were found in clade A only. In this study, 81.71% of the isolates were biofilm formers, and possessed plasmids of varying ranges (1.0 to 54 kb). In vitro antibiogram profiling revealed that 100% isolates were resistant to ≥3 antibiotics, of which 61.96%, 55.24%, 53.85%, 51.16% and 45.58% isolates in phylotypes B1, D2, B22, B23, and A1, respectively, were resistant to these antimicrobials. The resistance patterns varied among different phylotypes, notably in phylotype B22, showing the highest resistance to ampicillin (90.91%), nalidixic acid (90.11%), tetracycline (83.72%), and nitrofurantoin (65.12%). Correspondence analysis also showed significant correlation among phylotypes with CRB (p = 0.008), biofilm formation (p = 0.02), drug resistance (p = 0.03), and VGs (p = 0.06). This report demonstrated that B2 and A1 phylotypes are dominantly circulating APEC phylotypes in Bangladesh; however, B2 and D2 are strongly associated with the pathogenicity. A high prevalence of antibiotic-resistant APEC strains from different phylotypes suggest the use of organic antimicrobial compounds, and/or metals, and the rotational use of antibiotics in poultry farms in Bangladesh.

scholarly journals Gene expression analysis of ABC transporters in a resistant Cooperia oncophora isolate following in vivo and in vitro exposure to macrocyclic lactones

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 499-508 ◽  
Author(s):  
J. DE GRAEF ◽  
J. DEMELER ◽  
P. SKUCE ◽  
M. MITREVA ◽  
G. VON SAMSON-HIMMELSTJERNA ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Abc Transporters ◽  
Anthelmintic Resistance ◽  
Life Stage ◽  
Resistant Isolate ◽  
Gene Transcript ◽  
Macrocyclic Lactones ◽  
Transcript Levels ◽  
Cooperia Oncophora

SUMMARYMembers of the ATP-binding cassette (ABC) transporter family (P-glycoproteins, Half-transporters and Multidrug Resistant Proteins) potentially play a role in the development of anthelmintic resistance. The aim of this study was to investigate the possible involvement of ABC transporters in anthelmintic resistance in the bovine parasite, Cooperia oncophora. Partial sequences of 15 members of the ABC transporter protein family were identified, by mining a transcriptome dataset combined with a degenerate PCR approach. Reverse transcriptase PCR showed that most of the ABC transporters identified were constitutively transcribed throughout the life cycle of C. oncophora. Constitutive differences in gene transcript levels between a susceptible and resistant isolate were only observed for Con-haf-9 and Con-mrp-1 in eggs of the resistant isolate, while no differences were observed in L3 or the adult life stage. Analysis of resistant adult worms, collected from calves 14 days after treatment with either ivermectin or moxidectin, showed a significant 3- to 5-fold increase in the transcript levels of Con-pgp-11 compared to non-exposed worms. Interestingly, a 4-fold transcriptional up-regulation of Con-pgp-11 was also observed in L3 of the resistant isolate, after in vitro exposure to different concentrations of ivermectin, whereas this effect was not observed in exposed L3 of the susceptible isolate. The results suggest that the worms of this particular resistant isolate have acquired the ability to up-regulate Con-pgp-11 upon exposure to macrocyclic lactones. Further work is needed to understand the genetic basis underpinning this process and the functional role of PGP-11.

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