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Baudinette E, O’Handley R, Trengove C. Anthelmintic Resistance of Gastrointestinal Nematodes in Goats: A Systematic Review and Meta-Analysis. Vet Parasitol 2022; 312:109809. [DOI: 10.1016/j.vetpar.2022.109809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 12/01/2022]
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Mickiewicz M, Czopowicz M, Moroz A, Potărniche AV, Szaluś-Jordanow O, Spinu M, Górski P, Markowska-Daniel I, Várady M, Kaba J. Prevalence of anthelmintic resistance of gastrointestinal nematodes in Polish goat herds assessed by the larval development test. BMC Vet Res 2021; 17:19. [PMID: 33413368 PMCID: PMC7791792 DOI: 10.1186/s12917-020-02721-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 12/09/2020] [Indexed: 12/27/2022] Open
Abstract
Background Helminthic infections, in particular those caused by gastrointestinal nematodes (GIN), are found worldwide and are among the most economically important diseases of goats. Anthelmintic resistance (AR) in GIN of goats is currently present worldwide, and single- or multidrug resistant species are widespread. The aim of this study was to determine the prevalence of AR to benzimidazoles (BZ), macrocyclic lactones (ML) and imidazothiazoles represented by levamisole (LEV) in the Polish goat herds by using an in vitro larval development test, which is useful especially in large-scale epidemiological surveys. Results This cross-sectional study was conducted from September 2018 to June 2019 and enrolled 42 dairy goat herds scattered over the entire country. The most commonly used anthelmintic class in goat herds in Poland were BZ (92%), followed by ML (85%) and LEV (13%). BZ-resistant GIN populations were found in 37 herds (88%, CI 95%: 75 to 95%), ML-resistant GIN populations in 40 herds (95%, CI 95, 84 to 99%), and LEV-resistant GIN populations in 5 herds (12%, CI 95%: 5 to 25%). Multidrug resistance involving all three anthelmintic classes was found in 5 herds (12%, CI 95, 5 to 25%). Based on the morphological features of stage 3 larvae the main resistant GIN turned out to be Haemonchus contortus and Trichostrongylus spp. The use of BZ and frequency of anthelmintic treatments were significantly related to the presence of AR to BZ in Polish goat herds. Conclusions This cross-sectional study demonstrates the existence of AR to BZ, ML and LEV on Polish goat farms. Resistance to BZ and ML is widespread, while AR to LEV is currently at a low level. A considerable proportion of herds harbours multidrug resistant GIN, which requires further consideration. An effective anthelmintic treatment strategy, reasonable preventive measures and better understanding of the resistance-related management practices by farmers and veterinarians may delay further development of AR. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-020-02721-9.
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Affiliation(s)
- Marcin Mickiewicz
- Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159c, 02-786, Warsaw, Poland
| | - Michał Czopowicz
- Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159c, 02-786, Warsaw, Poland.
| | - Agata Moroz
- Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159c, 02-786, Warsaw, Poland
| | - Adrian-Valentin Potărniche
- Department of Infectious Diseases and Preventive Medicine, Law and Ethics, University of Agricultural Sciences and Veterinary Medicine, Calea Mănăștur 3-5, 400372, Cluj-Napoca, Romania
| | - Olga Szaluś-Jordanow
- Department of Small Animal Diseases with Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159c, 02-786, Warsaw, Poland
| | - Marina Spinu
- Department of Infectious Diseases and Preventive Medicine, Law and Ethics, University of Agricultural Sciences and Veterinary Medicine, Calea Mănăștur 3-5, 400372, Cluj-Napoca, Romania
| | - Paweł Górski
- Division of Parasitology and Invasiology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Ciszewskiego 8, 02-786, Warsaw, Poland
| | - Iwona Markowska-Daniel
- Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159c, 02-786, Warsaw, Poland
| | - Marián Várady
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 04001, Košice, Slovakia
| | - Jarosław Kaba
- Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159c, 02-786, Warsaw, Poland
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Abstract
SUMMARYSusceptability of Ascaridia galli to benzimidazole (BZ) was investigated using faecal egg count reduction test (FECRT), in ovo larval development test (LDT) and genetic markers (mutations at codons 167, 198 and 200 of β-tubulin gene). Six flocks (F1−F6) of a commercial laying hen farm with different number of exposure to BZ were recruited. The FECR was calculated by analyzing individual faeces (F1, F2, F4 and F5) before and 10 days after treatment. The LDT was performed on parasite eggs from pooled samples from F1 to F6 and LC50 and LC99 were calculated. DNA was extracted from 120 worms and sequenced for β-tubulin gene. In all flocks, the FECRs were above 95% (lower CI above 90%). No significant difference was observed (p > 0·05) among obtained LC50 (F1/F4 and F2/F5 vs F3/F6) in the LDT. However, LC50 and LC99 were higher than suggested values for declaration of resistance in other nematode species. No variation was observed in codon positions involved in BZ resistance. Overall, our results indicated lack of evidence of resistance to BZ in A. galli. More research is needed to confirm these results and to further optimize the existing tools for detection and monitoring of anthelmintic resistance in A. galli.
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Zvinorova PI, Halimani TE, Muchadeyi FC, Matika O, Riggio V, Dzama K. Breeding for resistance to gastrointestinal nematodes - the potential in low-input/output small ruminant production systems. Vet Parasitol 2016; 225:19-28. [PMID: 27369571 PMCID: PMC4938797 DOI: 10.1016/j.vetpar.2016.05.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 04/28/2016] [Accepted: 05/12/2016] [Indexed: 02/07/2023]
Abstract
The control of gastrointestinal nematodes (GIN) is mainly based on the use of drugs, grazing management, use of copper oxide wire particles and bioactive forages. Resistance to anthelmintic drugs in small ruminants is documented worldwide. Host genetic resistance to parasites, has been increasingly used as a complementary control strategy, along with the conventional intervention methods mentioned above. Genetic diversity in resistance to GIN has been well studied in experimental and commercial flocks in temperate climates and more developed economies. However, there are very few report outputs from the more extensive low-input/output smallholder systems in developing and emerging countries. Furthermore, results on quantitative trait loci (QTL) associated with nematode resistance from various studies have not always been consistent, mainly due to the different nematodes studied, different host breeds, ages, climates, natural infections versus artificial challenges, infection level at sampling periods, among others. The increasing use of genetic markers (Single Nucleotide Polymorphisms, SNPs) in GWAS or the use of whole genome sequence data and a plethora of analytic methods offer the potential to identify loci or regions associated nematode resistance. Genomic selection as a genome-wide level method overcomes the need to identify candidate genes. Benefits in genomic selection are now being realised in dairy cattle and sheep under commercial settings in the more advanced countries. However, despite the commercial benefits of using these tools, there are practical problems associated with incorporating the use of marker-assisted selection or genomic selection in low-input/output smallholder farming systems breeding schemes. Unlike anthelmintic resistance, there is no empirical evidence suggesting that nematodes will evolve rapidly in response to resistant hosts. The strategy of nematode control has evolved to a more practical manipulation of host-parasite equilibrium in grazing systems by implementation of various strategies, in which improvement of genetic resistance of small ruminant should be included. Therefore, selection for resistant hosts can be considered as one of the sustainable control strategy, although it will be most effective when used to complement other control strategies such as grazing management and improving efficiency of anthelmintics currently.
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Affiliation(s)
- P I Zvinorova
- Department of Animal Sciences, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa; Department of Para-clinical Veterinary Studies, University of Zimbabwe, P.O. MP167, Mt. Pleasant, Harare, Zimbabwe.
| | - T E Halimani
- Department of Animal Science, University of Zimbabwe, P.O. MP167, Mt. Pleasant, Harare, Zimbabwe.
| | - F C Muchadeyi
- Biotechnology Platform, Agriculture Research Council Private Bag X5, Onderstepoort, 0110, South Africa.
| | - O Matika
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, MidlothianEH25 9RG, UK.
| | - V Riggio
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, MidlothianEH25 9RG, UK.
| | - K Dzama
- Department of Animal Sciences, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
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Rupa APM, Portugaliza HP. Prevalence and risk factors associated with gastrointestinal nematode infection in goats raised in Baybay city, Leyte, Philippines. Vet World 2016; 9:728-34. [PMID: 27536034 PMCID: PMC4983124 DOI: 10.14202/vetworld.2016.728-734] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 06/21/2016] [Indexed: 11/22/2022] Open
Abstract
Aim: Gastrointestinal parasitism is a serious constraint affecting goat production in the Philippines. This study aimed to determine the prevalence and associated risk factors of gastrointestinal nematode infection in goat-populated barangays of Baybay City, Leyte. Materials and Methods: A total of 81 households or farms were interviewed, and 450 goats were sampled for fecalysis. Fecal egg count along with egg morphological identification and coproculture for third stage larvae identification were conducted. Descriptive statistics and logistic regression analyses were carried out to determine the farm- and animal-level prevalence and risk factors. Results: Fecalysis revealed the presence of strongyle and Trichuris spp. with a farm-level prevalence of 100% and 4.94%, respectively; and animal-level prevalence of 96.22% and 4.44%, respectively. The identified strongyle genera per barangay were Haemonchus spp. (34.79%), Trichostrongylus spp. (33.29%), Oesophagostomum spp. (24.21%), Cooperia spp. (6.93%), and Chabertia spp. (0.79%). Goats older than 12 months were four times more likely to present high strongyle burden when compared to goats <6 months. With each month increase in goat’s age, the odds of acquiring strongyle infection also increased by 1.07 times. Animals kept in goat house with cemented flooring have lower odds of acquiring strongyle (odds ratio=0.12). Goats raised for leisure purposes and fed with carabao grass (Paspalum conjugatum) were 8.12 and 5.52 times more likely to acquire Trichuris, respectively. Conclusion: Most of the backyard goat raisers in Baybay City, Leyte, do not practice sound helminth control measures as shown by the high prevalence of gastrointestinal nematodes. The most relevant risk factors for gastrointestinal nematode infection were the age of the goat, type of goat house’s flooring, purpose of raising goats, and feeding practices.
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Affiliation(s)
- Ariel Paul M Rupa
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Visayas State University, Visca, Baybay City, Leyte 6521-A, Philippines
| | - Harvie P Portugaliza
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Visayas State University, Visca, Baybay City, Leyte 6521-A, Philippines
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Falzon LC, O'Neill TJ, Menzies PI, Peregrine AS, Jones-Bitton A, vanLeeuwen J, Mederos A. A systematic review and meta-analysis of factors associated with anthelmintic resistance in sheep. Prev Vet Med 2014; 117:388-402. [PMID: 25059197 DOI: 10.1016/j.prevetmed.2014.07.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/27/2014] [Accepted: 07/03/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND Anthelmintic drugs have been widely used in sheep as a cost-effective means for gastro-intestinal nematode (GIN) control. However, growing anthelmintic resistance (AHR) has created a compelling need to identify evidence-based management recommendations that reduce the risk of further development and impact of AHR. OBJECTIVE To identify, critically assess, and synthesize available data from primary research on factors associated with AHR in sheep. METHODS Publications reporting original observational or experimental research on selected factors associated with AHR in sheep GINs and published after 1974, were identified through two processes. Three electronic databases (PubMed, Agricola, CAB) and Web of Science (a collection of databases) were searched for potentially relevant publications. Additional publications were identified through consultation with experts, manual search of references of included publications and conference proceedings, and information solicited from small ruminant practitioner list-serves. Two independent investigators screened abstracts for relevance. Relevant publications were assessed for risk of systematic bias. Where sufficient data were available, random-effects Meta-Analyses (MAs) were performed to estimate the pooled Odds Ratio (OR) and 95% Confidence Intervals (CIs) of AHR for factors reported in ≥2 publications. RESULTS Of the 1712 abstracts screened for eligibility, 131 were deemed relevant for full publication review. Thirty publications describing 25 individual studies (15 observational studies, 7 challenge trials, and 3 controlled trials) were included in the qualitative synthesis and assessed for systematic bias. Unclear (i.e. not reported, or unable to assess) or high risk of selection bias and confounding bias was found in 93% (14/15) and 60% (9/15) of the observational studies, respectively, while unclear risk of selection bias was identified in all of the trials. Ten independent studies were included in the quantitative synthesis, and MAs were performed for five factors. Only high frequency of treatment was a significant risk factor (OR=4.39; 95% CI=1.59, 12.14), while the remaining 4 variables were marginally significant: mixed-species grazing (OR=1.63; 95% CI=0.66, 4.07); flock size (OR=1.02; 95% CI=0.97, 1.07); use of long-acting drug formulations (OR=2.85; 95% CI=0.79, 10.24); and drench-and-shift pasture management (OR=4.08; 95% CI=0.75, 22.16). CONCLUSIONS While there is abundant literature on the topic of AHR in sheep GINs, few studies have explicitly investigated the association between putative risk or protective factors and AHR. Consequently, several of the current recommendations on parasite management are not evidence-based. Moreover, many of the studies included in this review had a high or unclear risk of systematic bias, highlighting the need to improve study design and/or reporting of future research carried out in this field.
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Affiliation(s)
- L C Falzon
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Liebefeld, Bern, Switzerland.
| | - T J O'Neill
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - P I Menzies
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - A S Peregrine
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - A Jones-Bitton
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - J vanLeeuwen
- Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - A Mederos
- National Institute of Agricultural Research of Uruguay, Montevideo, Uruguay
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7
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Nielsen M, Reinemeyer C, Donecker J, Leathwick D, Marchiondo A, Kaplan R. Anthelmintic resistance in equine parasites—Current evidence and knowledge gaps. Vet Parasitol 2014; 204:55-63. [DOI: 10.1016/j.vetpar.2013.11.030] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 09/13/2013] [Accepted: 11/07/2013] [Indexed: 10/25/2022]
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Detection of benzimidazole resistance in gastrointestinal nematodes of sheep and goats of sub-Himalyan region of northern India using different tests. Vet Parasitol 2013; 198:312-8. [PMID: 24126090 DOI: 10.1016/j.vetpar.2013.09.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 08/30/2013] [Accepted: 09/16/2013] [Indexed: 11/22/2022]
Abstract
The present investigation was planned with the objective of studying the status of benzimidazole (BZ) resistance in gastrointestinal nematodes (GIN) of sheep and goats of different agro-climatic zones of sub-Himalyan region of northern India using in vivo faecal egg count reduction test (FECRT) and in vitro tests namely egg hatch assay (EHA) and larval development assay (LDA). Out of fourteen flocks, FECRT detected resistance in eight flocks (two sheep flocks and six goat flocks) with FECR% ranging from 54.95 to 90.86. Pre treatment coproculture contained predominantly Haemonchus contortus, followed by Trichostrongylus spp., Oesophagostomum and Strongyloides, while post treatment coproculture results showed that only H. contortus survived fenbendazole (FBZ) (in FECRT) or thiabendazole (TBZ) (in LDA) treatment except in three flocks of Tarai region {one sheep flock (Us1), and two goat flocks (Ug1 and Ug5)} where BZ resistant Trichostrongylus were also detected. The GIN of those eight farms which were found resistant by FECRT were also detected resistant by EHA. Arithmetic mean and range of ED50 value of susceptible group was found to be 0.059 μg/ml and 0.037-0.096 μg/ml, respectively, and the same for the resistant group were found to be 0.119 μg/ml and 0.101-0.147 μg/ml, respectively. With LDA, the arithmetic mean and range of LC50 value of susceptible group was found 0.0030 μg/ml and 0.001-0.005 μg/ml, respectively, and those of resistant group was found 0.0105 μg/ml and 0.009-0.012 μg/ml, respectively. The values of Spearman rank correlation coefficient indicated that negative correlation was found between FECR% and ED50 and between FECR% and LC50 while positive correlation existed between ED50 and LC50 value and the p-values indicated that these correlations were statistically highly significant. In the present study, FECRT and EHA gave comparable results with regard to detection of BZ resistance in GIN in sheep and goats. Although with LDA, the threshold LC50 value could not be established as for EHA but LDA indicated the presence of low level of resistance in GIN of both sheep and goats. For effective worm control, regular monitoring for anthelmintic resistance is important to know the status of anthelmintic efficacy in a particular agro-climatic zone. The baseline information thus generated will enable timely management of benzimidazoles resistance in GIN.
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Demeler J, Schein E, von Samson-Himmelstjerna G. Advances in laboratory diagnosis of parasitic infections of sheep. Vet Parasitol 2012; 189:52-64. [DOI: 10.1016/j.vetpar.2012.03.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Gray G, Connell J, Phimphachanhvongsod V. Worms in smallholder livestock systems: Technologies and practices that make a difference. Vet Parasitol 2012; 186:124-31. [DOI: 10.1016/j.vetpar.2011.11.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Matthews JB, McArthur C, Robinson A, Jackson F. The in vitro diagnosis of anthelmintic resistance in cyathostomins. Vet Parasitol 2012; 185:25-31. [DOI: 10.1016/j.vetpar.2011.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Hussain A, Khan MN, Iqbal Z, Sajid MS. An account of the botanical anthelmintics used in traditional veterinary practices in Sahiwal district of Punjab, Pakistan. JOURNAL OF ETHNOPHARMACOLOGY 2008; 119:185-90. [PMID: 18657602 DOI: 10.1016/j.jep.2008.06.034] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 06/25/2008] [Accepted: 06/27/2008] [Indexed: 05/18/2023]
Abstract
AIM OF THE STUDY The present study was aimed at documentation of botanical anthelmintics used in the traditional veterinary practices in Sahiwal district of Punjab, Pakistan. MATERIALS AND METHODS In rapid rural appraisal, 331 traditional veterinary healers (TVH) were identified as key respondents in the study area followed by participatory rural appraisal for data collection using a well-structured questionnaire. Information was collected through interviews, focused group discussions and field visits over a period of 2 years. RESULTS A total of 49 traditional recipes, with 41 plant species representing 39 genera and 27 families, were recorded for the treatment of helminthosis in animals. Most frequently used plants (> or = 5 times) were Brassica campestris L. and Mallotus philippinensis (Lam.) Muell.-Arg. and most frequently used families (> or = 5 times) were Brassicaceae, Euphorbiaceae and Solanaceae. Most frequently used part of the plant was leaves (n=10) followed in order by seeds (n=9), whole fruit (n=5), aerial parts and whole plant (n=4), fruit (n=3), bulb (n=2) and bark, rhizome, stem, stem plus root and twigs (n=1). Five recipes out of 49 (10.2%) contained more than one plant species and rest 44 (89.8%) contained single plant species. CONCLUSIONS Twenty out of 41 plants (48.78%) are reported for the first time for their traditional use as anthelmintics in Pakistan. Further studies on pharmacokinetics using scientific procedures may prove these plants as promising candidates for their future use as anthelmintics.
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Affiliation(s)
- Altaf Hussain
- Department of Veterinary Parasitology, University of Agriculture, Faisalabad 38040, Pakistan.
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Díez-Baños P, Pedreira J, Sánchez-Andrade R, Francisco I, Suárez JL, Díaz P, Panadero R, Arias M, Painceira A, Paz-Silva A, Morrondo P. Field Evaluation for Anthelmintic-Resistant Ovine Gastrointestinal Nematodes by In Vitro and In Vivo Assays. J Parasitol 2008; 94:925-8. [DOI: 10.1645/ge-1366.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Accepted: 01/02/2008] [Indexed: 11/10/2022] Open
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Várady M, Cudeková P, Corba J. In vitro detection of benzimidazole resistance in Haemonchus contortus: egg hatch test versus larval development test. Vet Parasitol 2007; 149:104-10. [PMID: 17697753 DOI: 10.1016/j.vetpar.2007.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 06/29/2007] [Accepted: 07/06/2007] [Indexed: 11/28/2022]
Abstract
The present study was designed to compare the egg hatch test (EHT) and the larval development test (LDT) as in vitro tools for detection of benzimidazole (BZ) resistance in Haemonchus contortus, a nematode parasite of small ruminants. Comparisons were made during a course of infection and changes in both EHT and LDT were monitored to measure the correlation between resistance and susceptibility in different parasite stages (eggs and larvae). In addition, mixed doses of known numbers of susceptible and BZ-resistant H. contortus eggs were used to assess the sensitivity of LDT for the detection of low levels of resistance. The degree of resistance for each test was expressed as resistance factor (RF). The LDT showed a greater ability to distinguish between four susceptible and four resistant isolates of H. contortus with higher resistance factors compared to the EHT. For the EHT the RF by using ED(50) criterion ranged from 3.2 to 13.3 and from 7.4 to 25.2 by using LC(99). For LDT the resistant isolates were 4.3-63.1 times more tolerant than the susceptible isolates using the ED(50) criterion and 91.1-1411.0 times more tolerant using the LC(99) criterion. The LDT was also able to clearly indicate the presence of low level (4%) of resistant larvae amongst a susceptible background population.
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Affiliation(s)
- M Várady
- Parasitological Institute of the Slovak Academy of Sciences, Hlinkova 3, 040 01 Kosice, Slovak Republic.
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Suter RJ, McKinnon EJ, Perkins NR, Besier RB. The effective life of ivermectin on Western Australian sheep farms—A survival analysis. Prev Vet Med 2005; 72:311-22. [PMID: 16183154 DOI: 10.1016/j.prevetmed.2005.07.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 07/28/2005] [Accepted: 07/28/2005] [Indexed: 11/27/2022]
Abstract
A mail survey of 235 Western Australian sheep farmers who had performed faecal egg count reduction tests for anthelmintic resistance in 1999 or 2000 was conducted, with some telephone follow-up. A response of 56% was achieved. Resistance to ivermectin, a member of the macrocyclic lactone class of anthelmintics, had developed on 44% of the farms surveyed. We used time to occurrence of resistance to ascertain factors that contributed to extending the time ivermectin remained an effective drench on these farms (median time=10.5 years). This time was significantly longer when farmers implemented more worm control practices on their farms (P=0.003). We developed a multivariable survival model that contained the following main effects: reduced winter drenching frequency, 0-2 flock treatments in 5 years (hazard ratio (HR) 0.52); availability of alternative effective anthelmintic classes on the farm (HR 0.30); always using safe pastures (HR 0.23); and veterinarians as the primary source of worm control advice (HR 0.58). The relationship of these findings to the understanding of anthelmintic resistance is discussed.
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Affiliation(s)
- R J Suter
- School of Veterinary and Biomedical Sciences, Division of Health Sciences, Murdoch University, Murdoch, WA 6150, Australia.
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Várady M, Cernanská D, Corba J. Use of two in vitro methods for the detection of anthelmintic resistant nematode parasites on Slovak sheep farms. Vet Parasitol 2005; 135:325-31. [PMID: 16289329 DOI: 10.1016/j.vetpar.2005.10.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Revised: 09/22/2005] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
A survey of the prevalence of anthelmintic resistant nematode populations was conducted on 32 sheep farms in the Slovak Republic. In vitro egg hatch test and larval development tests were used for the detection of resistance to benzimidazole anthelmintics and they were compared with in vivo faecal egg count reduction tests. There was agreement in the declaration of resistance between the faecal egg count reduction test and both in vitro tests. The presence of resistant populations was determined on two farms using egg hatch test. In both farms, the LD(50) values were higher than 0.1 microg TBZ/ml, indicating resistance. By using LD(99) values it might be possible to reveal relatively small proportion of resistant larvae in the population. The prevalence of benzimidazole resistance has not change on Slovak sheep farms during last decade.
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Affiliation(s)
- Marián Várady
- Parasitological Institute of the Slovak Academy of Sciences, Hlinkova 3, 040 01 Kosice, Slovak Republic
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Kotze AC, Coleman GT, Mai A, McCarthy JS. Field evaluation of anthelmintic drug sensitivity using in vitro egg hatch and larval motility assays with Necator americanus recovered from human clinical isolates. Int J Parasitol 2005; 35:445-53. [PMID: 15777920 DOI: 10.1016/j.ijpara.2004.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 12/08/2004] [Accepted: 12/13/2004] [Indexed: 11/25/2022]
Abstract
A field-applicable assay for testing anthelmintic sensitivity is required to monitor for anthelmintic resistance. We undertook a study to evaluate the ability of three in vitro assay systems to define drug sensitivity of clinical isolates of the human hookworm parasite Necator americanus recovered from children resident in a village in Madang Province, Papua New Guinea. The assays entailed observation of drug effects on egg hatch (EHA), larval development (LDA), and motility of infective stage larvae (LMA). The egg hatch assay proved the best method for assessing the response to benzimidazole anthelmintics, while the larval motility assay was suitable for assessing the response to ivermectin. The performance of the larval development assay was unsatisfactory on account of interference caused by contaminating bacteria. A simple protocol was developed whereby stool samples were subdivided and used for immediate egg recovery, as well as for faecal culture, in order to provide eggs and infective larvae, respectively, for use in the egg hatch assay and larval motility assay systems. While the assays proved effective in quantifying drug sensitivity in larvae of the drug-susceptible hookworms examined in this study, their ability to indicate drug resistance in larval or adult hookworms remains to be determined.
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Affiliation(s)
- A C Kotze
- CSIRO Livestock Industries, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Qld 4067, Australia.
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