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Li Y, Zheng R, Wu Y, Chu K, Xu Q, Sun M, Smith ZJ. A low-cost, automated parasite diagnostic system via a portable, robotic microscope and deep learning. JOURNAL OF BIOPHOTONICS 2019; 12:e201800410. [PMID: 31081258 DOI: 10.1002/jbio.201800410] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 05/07/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
Manual hand counting of parasites in fecal samples requires costly components and substantial expertise, limiting its use in resource-constrained settings and encouraging overuse of prophylactic medication. To address this issue, a cost-effective, automated parasite diagnostic system that does not require special sample preparation or a trained user was developed. It is composed of an inexpensive (~US$350), portable, robotic microscope that can scan over the size of an entire McMaster chamber (100 mm2 ) and capture high-resolution (~1 μm lateral resolution) bright field images without need for user intervention. Fecal samples prepared using the McMaster flotation method were imaged, with the imaging region comprising the entire McMaster chamber. These images are then automatically segmented and analyzed using a trained convolution neural network (CNN) to robustly separate eggs from background debris. Simple postprocessing of the CNN output yields both egg species and egg counts. The system was validated by comparing accuracy with hand-counts by a trained operator, with excellent performance. As a further demonstration of utility, the system was used to conveniently quantify drug response over time in a single animal, showing residual disease due to Anthelmintic resistance after 2 weeks.
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Affiliation(s)
- Yaning Li
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, Hefei, China
| | - Rui Zheng
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, Hefei, China
| | - Yizhen Wu
- Anhui Agricultural University, Department of Animal Science and Technology, Hefei, China
| | - Kaiqin Chu
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, Hefei, China
| | - Qianming Xu
- Anhui Agricultural University, Department of Animal Science and Technology, Hefei, China
| | - Mingzhai Sun
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, Hefei, China
| | - Zachary J Smith
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, Hefei, China
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102
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Mravčáková D, Váradyová Z, Kopčáková A, Čobanová K, Grešáková Ľ, Kišidayová S, Babják M, Dolinská MU, Dvorožňáková E, Königová A, Vadlejch J, Cieslak A, Ślusarczyk S, Várady M. Natural chemotherapeutic alternatives for controlling of haemonchosis in sheep. BMC Vet Res 2019; 15:302. [PMID: 31429752 PMCID: PMC6700814 DOI: 10.1186/s12917-019-2050-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/13/2019] [Indexed: 03/20/2023] Open
Abstract
BACKGROUND Parallel in vitro and in vivo experiments were designed to evaluate promising chemotherapeutic alternatives for controlling haemonchosis in ruminants. In vitro anthelmintic activities (egg hatch test - EHT; larval development test - LDT) of aqueous and methanolic herbal extracts Mix1 and Mix2 were investigated. The in vivo effects of dietary supplementation with Mix1 and Mix2 on the parasitological status, inflammatory response, antioxidant parameters and microbial community of the lambs infected experimentally with Haemonchus contortus were investigated. Lambs were divided into four groups for the in vivo study: uninfected control lambs (C), infected lambs (I), infected lambs supplemented with Mix1 (I + Mix1) and infected lambs supplemented with Mix2 (I + Mix2). The experimental period was 70 days. RESULTS The number of eggs per gram (EPG) of feces was quantified 22, 30, 37, 44, 51, 58, 65 and 70 days post-infection, and mean abomasal worm counts were assessed 70 days post-infection. Quantitative analyses identified 57.3 and 22.2 mg/g phenolic acids, 41.5 and 29.5 mg/g flavonoids and 1.4 and 1.33 mg/g protoberberine-type alkaloids in Mix1 and Mix2, respectively. The methanolic extracts of the herbal mixtures in both in vitro tests had higher anthelmintic effects (P < 0.01) than the aqueous extracts, but the effects did not differ significantly between Mix1 and Mix2 (P > 0.05). I + Mix1 and I + Mix2 lowered mean EPGs between 44 and 70 d by 58.1 and 51.6%, respectively. The level of IgG antibodies against H. contortus increased significantly after infection in each infected group. CONCLUSION These results represent the first monitoring of the in vitro anthelmintic effects of herbal mixtures on H. contortus. The in vivo experiment indicated that the anthelmintic effect was not sufficient for the elimination of parasites, but this herbal treatment may affect the host over a longer term, reducing the parasitic infection in the host.
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Affiliation(s)
- Dominika Mravčáková
- Centre of Biosciences, Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Zora Váradyová
- Centre of Biosciences, Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Anna Kopčáková
- Centre of Biosciences, Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Klaudia Čobanová
- Centre of Biosciences, Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Ľubomíra Grešáková
- Centre of Biosciences, Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Svetlana Kišidayová
- Centre of Biosciences, Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Michal Babják
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovak Republic
| | - Michaela Urda Dolinská
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovak Republic
| | - Emília Dvorožňáková
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovak Republic
| | - Alžbeta Königová
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovak Republic
| | - Jaroslav Vadlejch
- Department of Zoology and Fisheries, Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Suchdol, Prague Czech Republic
| | - Adam Cieslak
- Department of Animal Nutrition, Poznan University of Life Sciences, Poznan, Poland
| | - Sylwester Ślusarczyk
- Department of Pharmaceutical Biology with Botanical Garden of Medicinal Plants, Medical University of Wroclaw, Wroclaw, Poland
| | - Marián Várady
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovak Republic
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103
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Baltrušis P, Halvarsson P, Höglund J. Molecular detection of two major gastrointestinal parasite genera in cattle using a novel droplet digital PCR approach. Parasitol Res 2019; 118:2901-2907. [PMID: 31388787 PMCID: PMC6754349 DOI: 10.1007/s00436-019-06414-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 07/26/2019] [Indexed: 01/25/2023]
Abstract
Cooperia sp. and Ostertagia sp. are two cosmopolitan parasitic nematodes often found in mixed gastrointestinal infections in cattle across temperate regions. In light of the recent increase in the emergence of anthelmintic resistance in these and other nematodes derived from cattle around the globe, and their negative impact on animal health and productivity, novel molecular assays need to be put forth in order to facilitate the monitoring of parasite burden in infected herds, using pasture and/or fecal samples. Here, we describe a novel droplet digital PCR platform–based concept for precise identification and quantification of the two most abundant and important parasite genera in grazing western European cattle. By exploiting a single nucleotide difference in the two parasites’ ITS2 sequence regions, we have developed two specific hydrolysis probes labeled with FAM™ or HEX™ fluorophores, which can not only distinguish between the DNA sequences of the two, but also quantify them in mixed DNA samples. A third, newly developed universal probe was also tested along the genus-specific probes to provide a robust and accurate reference. It was evident that the universal probe displayed congruent results to those obtained by the genus-specific probes when used with DNA from both parasites in a single sample. All in all, the results of our assay suggest that this novel protocol could be used to distinguish and quantify cattle parasites belonging to the two most important genera (i.e., Cooperia and Ostertagia) in a single mixed DNA sample.
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Affiliation(s)
- Paulius Baltrušis
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences, P.O. Box 7036, Uppsala, Sweden.
| | - Peter Halvarsson
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences, P.O. Box 7036, Uppsala, Sweden
| | - Johan Höglund
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences, P.O. Box 7036, Uppsala, Sweden
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104
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Malekpour SH, Rakhshandehroo E, Yektaseresht A. Molecular characterization of β-tubulin gene associated with benzimidazole resistance in larvae of field isolates of Parascaris (Nematoda: Ascarididae). J Parasit Dis 2019; 43:672-678. [PMID: 31749539 DOI: 10.1007/s12639-019-01146-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/17/2019] [Indexed: 11/25/2022] Open
Abstract
Since the past 2 decades, an increasing number of resistance to the Benzimidazoles (BZs) have been reported in nematode parasites of livestock. More recently, detection of single-nucleotide polymorphisms (SNPs) at codons of 167, 198 or 200 of the β-tubulin gene has been attributed to the occurrence of resistance. In the present study, we investigated the presence of those SNPs in the β-tubulin isotype-1 gene in different isolates of Parascaris in horse. Also, the mitochondrial (mt) and ribosomal genes were sequenced for species confirmation of the isolates. The analysis of sequences inferred from COII gene confirmed that those isolates were P. equorum. The distance between mt genes obtained here and several ascarid species in equids and other hosts suggests the need for the combination of more genetic data with morphologic and other diagnostic measures. The analysis on β-tubulin isotype-1 gene revealed no resistance-related SNPs or substitutions at the expected codon positions and selection pressure with BZs has not occurred for Parascaris worms. Although the molecular data showed the susceptibility of Parascaris isolates against BZs, other mechanisms of resistance should be also investigated to confirm the validity of molecular results.
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Affiliation(s)
- Seyed Hossein Malekpour
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, P.O. Box 71441-69155 Shiraz, Iran
| | - Ehsan Rakhshandehroo
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, P.O. Box 71441-69155 Shiraz, Iran
| | - Azadeh Yektaseresht
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, P.O. Box 71441-69155 Shiraz, Iran
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105
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Mortezaei S, Afgar A, Mohammadi MA, Mousavi SM, Sadeghi B, Harandi MF. The effect of albendazole sulfoxide on the expression of miR-61 and let-7 in different in vitro developmental stages of Echinococcus granulosus. Acta Trop 2019; 195:97-102. [PMID: 31051116 DOI: 10.1016/j.actatropica.2019.04.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 04/16/2019] [Accepted: 04/29/2019] [Indexed: 12/30/2022]
Abstract
Albendazole, as the main anti-echinococcal benzimidazole, has demonstrated safe and effective therapeutic outcomes in the treatment of echinococcosis. The emergence of resistance or reduced response to albendazole sulfoxide (ABZ_SOX) and other benzimidazoles have been demonstrated in several parasitic helminths of medical and veterinary importance. As the genetic makeup and miRNA profile of helminths affects their response to albendazole sulfoxide, the present study was conducted to investigate the expression of miRNAs in different developmental stages of Echinococcus granulosus exposed to albendazole sulfoxide in vitro. Different developmental stages of the helminth were obtained from in vitro cultured E. granulosus in monophasic and diphasic media. In both ABZ-SOX-treated and control parasites miRNAs were extracted from microcysts, intact protoscoleces and strobilated worms with one and three segments. Expression of two miRNAs, let-7 and miR-61 was evaluated using RT-qPCR for each stage. Results of the present study revealed significant differential expression of both let-7 and miR-61 at different drug concentrations. A significant difference of let-7 expression was observed between the strobilated and metacestode stages of E. granulosus exposed to ABZ-SOX. In the treated protoscoleces, let-7 expression was significantly reduced in the presence of ABZ-SOX at 1000 μg/ml concentration. In contrast higher expression levels were documented in the segmented worms. In the microcysts exposed to different drug concentrations a significant decline of miR-61 expression was demonstrated. Also, a significant increase in expression of miR-61 was observed in one proglottid worms as well as the protoscoleces. Under high drug concentration or long-term exposure of the protoscoleces to ABZ-SOX significantly higher miR-61 expression was observed compared to the controls. Our findings suggested that under in vitro benzimidazole exposure the expression of two E. granulosus miRNAs were significantly affected in the microcyst stage. This study presents the first evidence of the nature of benzimidazole effects on miRNA expression in platyhelminths.
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106
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Ruberanziza E, Owada K, Clark NJ, Umulisa I, Ortu G, Lancaster W, Munyaneza T, Mbituyumuremyi A, Bayisenge U, Fenwick A, Soares Magalhães RJ. Mapping Soil-Transmitted Helminth Parasite Infection in Rwanda: Estimating Endemicity and Identifying At-Risk Populations. Trop Med Infect Dis 2019; 4:tropicalmed4020093. [PMID: 31207897 PMCID: PMC6630518 DOI: 10.3390/tropicalmed4020093] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 01/17/2023] Open
Abstract
Soil-transmitted helminth (STH) infections are globally distributed intestinal parasite infections caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms (Ancylostoma duodenale and Necator americanus). STH infection constitutes a major public health threat, with heavy burdens observed in many of the world’s tropical and subtropical regions. Mass drug administration and sanitation improvements can drastically reduce STH prevalence and associated morbidity. However, identifying targeted areas in need of treatment is hampered by a lack of knowledge on geographical and population-level risk factors. In this study, we applied Bayesian geostatistical modelling to data from a national school-based STH infection survey in Rwanda to (1) identify ecological and population-level risk factors and (2) provide comprehensive precision maps of infection burdens. Our results indicated that STH infections were heterogeneously distributed across the country and showed signatures of spatial clustering, though the magnitude of clustering varied among parasites. The highest rates of endemic clustering were attributed to A. lumbricoides infection. Concordant infection patterns among the three parasite groups highlighted populations currently most at-risk of morbidity. Population-dense areas in the Western and North-Western regions of Rwanda represent areas that have continued to exhibit high STH burden across two surveys and are likely in need of targeted interventions. Our maps support the need for an updated evaluation of STH endemicity in western Rwanda to evaluate progress in MDA efforts and identify communities that need further local interventions to further reduce morbidity caused by STH infections.
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Affiliation(s)
- Eugene Ruberanziza
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Kei Owada
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, the University of Queensland, Gatton 4343, Queensland, Australia.
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane 4101, Queensland, Australia.
| | - Nicholas J Clark
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, the University of Queensland, Gatton 4343, Queensland, Australia.
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane 4101, Queensland, Australia.
| | - Irenee Umulisa
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Giuseppina Ortu
- Schistosomiasis Control Initiative (SCI), Department of Infectious Diseases Epidemiology, Imperial College, London SW7 2AZ, UK.
| | | | - Tharcisse Munyaneza
- Microbiology Unit, National Reference Laboratory (NRL) Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Aimable Mbituyumuremyi
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Ursin Bayisenge
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda.
| | - Alan Fenwick
- Schistosomiasis Control Initiative (SCI), Department of Infectious Diseases Epidemiology, Imperial College, London SW7 2AZ, UK.
| | - Ricardo J Soares Magalhães
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, the University of Queensland, Gatton 4343, Queensland, Australia.
- Children Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane 4101, Queensland, Australia.
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107
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Mohammedsalih KM, Khalafalla A, Bashar A, Abakar A, Hessain A, Juma FR, Coles G, Krücken J, von Samson-Himmelstjerna G. Epidemiology of strongyle nematode infections and first report of benzimidazole resistance in Haemonchus contortus in goats in South Darfur State, Sudan. BMC Vet Res 2019; 15:184. [PMID: 31164118 PMCID: PMC6549335 DOI: 10.1186/s12917-019-1937-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/29/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Since pastoralists in South Darfur, Sudan, had complained about lack of albendazole (ABZ) efficacy to control nematodes in goats, the frequency of infection with gastrointestinal helminths was studied before in vivo faecal egg count reduction tests (FECRT) were conducted using ABZ orally either at the dose recommended for sheep, 5 mg/kg body weight (bw) or at 10 mg/kg bw. Experiments included goats naturally infected with gastrointestinal nematodes or experimentally infected with local Haemonchus contortus isolates. Three study areas (Nyala, Beleil and Kass) were visited in autumn or winter. RESULTS Out of 478 screened goats, 82.4% were infected with gastrointestinal helminths and 82% were shedding eggs of strongyle nematodes with 90% of the strongyle larvae representing Haemonchus spp. A FECRT using naturally infected goats (n = 225: 71 untreated, 104 and 50 treated with 5 and 10 mg ABZ/kg bw, respectively) detected reduced ABZ efficacy in Nyala and Kass. Paired and unpaired FECRT calculations detected reductions of 72-92% with samples taken at 8 days post treatment with 5 mg ABZ/kg bw and of 85-94% with 10 mg ABZ/kg bw. The FECRT based on day 14 post treatment samples showed reductions of 69-77% with 5 mg/kg and of 75-87% with 10 mg ABZ/kg bw. In Beleil, ABZ efficacy was 95%. In the egg hatch test EC50 values for Nyala and Kass ranged from 0.12-0.24 μg thiabendazole/ml, corresponding to benzimidazole resistant phenotypes. Only Haemonchus spp. larvae were present after treatments in coprocultures. When the efficacy was evaluated experimentally using isolates of H. contortus from Nyala and Kass, the 5 mg ABZ/kg dose revealed reductions of 76-78% on day 8 and of 62-70% on day 14 with the unpaired method. Using 10 mg ABZ/kg, the FECR was still only 77-82%. CONCLUSIONS Both, in vivo and in vitro methods detected resistant H. contortus populations in goats from South Darfur State. The time point 14 days post treatment was more sensitive for detection of ABZ resistance than 8 days post treatment. This is the first report on the occurrence of anthelmintic resistance in Sudan confirming that anthelmintic resistance selection is occurring in African subsistence farming systems.
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Affiliation(s)
- Khalid M Mohammedsalih
- Faculty of Veterinary Science, University of Nyala, P.O. Box 155, Nyala, Sudan.,Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Amna Khalafalla
- Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Ahmed Bashar
- Faculty of Veterinary Science, University of Nyala, P.O. Box 155, Nyala, Sudan
| | - Adam Abakar
- Faculty of Medical Laboratory Sciences, University of Gezira, P.O. Box 20, Wadmedani, Sudan
| | - Abdelhakaim Hessain
- Faculty of Veterinary Science, University of Nyala, P.O. Box 155, Nyala, Sudan
| | - Fathel-Rahman Juma
- Faculty of Veterinary Science, University of Nyala, P.O. Box 155, Nyala, Sudan
| | - Gerald Coles
- Ubley Biologics, P.O. Box 170, Bristol, Ubley, BS40 6JA, UK
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany.
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
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108
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Ceballos L, Canton C, Pruzzo C, Sanabria R, Moreno L, Sanchis J, Suarez G, Ortiz P, Fairweather I, Lanusse C, Alvarez L, Martinez-Valladares M. The egg hatch test: A useful tool for albendazole resistance diagnosis in Fasciola hepatica. Vet Parasitol 2019; 271:7-13. [PMID: 31303208 DOI: 10.1016/j.vetpar.2019.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 01/22/2023]
Abstract
In the current study, the egg hatch test (EHT) has been evaluated as an in vitro technique to detect albendazole (ABZ) resistance in Fasciola hepatica. The intra- and inter-assay variations of the EHT were measured by means of the coefficient of variation in different fluke isolates and over time; then, the results of the EHT were compared with the "gold standard" controlled efficacy test, which assesses the in vivo anthelmintic efficacy. The EHT was used later to evaluate the intra-herd variability regarding the level of ABZ resistance in calves infected by the same fluke isolate. Finally, several factors of the initial protocol were modified to improve the simplicity of the assay, including the incubation time of eggs with the drug and the use of eggs collected from faeces. The greatest uniformity between results within the assay and over time until 8 weeks after gallbladder collection (the deadline proposed for egg analysis) was obtained with an ABZ concentration of 0.5 μM. The length of exposure to ABZ was shown to be critical, as prolonged incubation (15 days) led to a change of ovicidal activity. The ABZ concentration of 0.5 μM is suggested as a possible discriminating dose to predict ABZ resistance, due to the close agreement between the results of the EHT at an ABZ concentration of 0.5 μM and those of the in vivo assays.
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Affiliation(s)
- Laura Ceballos
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Facultad de Ciencias Veterinarias, Campus Universitario, Tandil, Argentina
| | - Candela Canton
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Facultad de Ciencias Veterinarias, Campus Universitario, Tandil, Argentina
| | - Cesar Pruzzo
- Facultad de Ciencias Veterinarias, Universidad Nacional de la Plata (UNLP), La Plata, Argentina
| | - Rodrigo Sanabria
- Facultad de Ciencias Veterinarias, Universidad Nacional de la Plata (UNLP), La Plata, Argentina; INTECH, CONICET-UNSAM, Chascomus, Argentina
| | - Laura Moreno
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Facultad de Ciencias Veterinarias, Campus Universitario, Tandil, Argentina
| | - Jaime Sanchis
- Departamento de Parasitología, Universidad de la República (Regional Norte), Salto, Uruguay
| | - Gonzalo Suarez
- Área Farmacología, Facultad de Veterinaria, Universidad de la República (UDELAR), Montevideo, Uruguay
| | - Pedro Ortiz
- Facultad de Ciencias Veterinarias, Universidad Nacional de Cajamarca (UNC), Cajamarca, Peru
| | - Ian Fairweather
- School of Biological Sciences, The Queen´s University of Belfast, Belfast, Northern Ireland, United Kingdom
| | - Carlos Lanusse
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Facultad de Ciencias Veterinarias, Campus Universitario, Tandil, Argentina
| | - Luis Alvarez
- Laboratorio de Farmacología, Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Facultad de Ciencias Veterinarias, Campus Universitario, Tandil, Argentina.
| | - María Martinez-Valladares
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Department of Animal Health, Grulleros, León, Spain
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109
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Wilkes EJA, Woodgate RG, Raidal SL, Hughes KJ. The application of faecal egg count results and statistical inference for clinical decision making in foals. Vet Parasitol 2019; 270:7-12. [PMID: 31213242 DOI: 10.1016/j.vetpar.2019.04.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 04/20/2019] [Accepted: 04/24/2019] [Indexed: 11/26/2022]
Abstract
This study investigated the impact of variability in Parascaris spp. and strongyle faecal egg counts (FEC) from foals on treatment decision-making and detection of a patent infection. A single faecal sample was collected once daily for three days from 53 foals and a FEC was performed on three separate portions of each sample (total of nine egg counts per foal). Differences in the decision to administer an anthelmintic using the results of a single count (C1), the mean of three (X¯1-3) or nine counts (X¯1-9) and the upper 5% confidence limit of the gamma confidence interval (CI) of the estimate of the distribution mean (μ) from three (UCL1-3) and nine counts (UCL1-9) were determined for a range of egg count thresholds. The UCL1-9 was used as the best estimate of μ, hypothesis testing for treatment and the comparison of treatment decision-making using C1, X¯1-3, X¯1-9 and UCL1-3. The results of this study demonstrated that a point estimate (C1 or X¯1-3) was of limited value for estimating the distribution mean of egg counts in faeces and there was overall poor agreement in treatment decision-making for individual foals using C1 compared with UCL1-9. Of the foals with C1 of zero eggs per gram, 54% and 47% had Parascaris and strongyle eggs in subsequent counts, respectively. The egg density in faeces is inhomogeneous, resulting in considerable variability in egg count results for an individual foal: between faecal piles, different portions of a faecal pile and days. The use of the negative binomial distribution CI for μ takes this variability into account and is recommended for use when interpreting FEC data from horses.
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Affiliation(s)
- E J A Wilkes
- School of Animal & Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
| | - R G Woodgate
- School of Animal & Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia
| | - S L Raidal
- School of Animal & Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia
| | - K J Hughes
- School of Animal & Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia
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High Endemicity of Soil-Transmitted Helminths in a Population Frequently Exposed to Albendazole but No Evidence of Antiparasitic Resistance. Trop Med Infect Dis 2019; 4:tropicalmed4020073. [PMID: 31035610 PMCID: PMC6631243 DOI: 10.3390/tropicalmed4020073] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/19/2019] [Accepted: 04/24/2019] [Indexed: 01/22/2023] Open
Abstract
INTRODUCTION Soil-transmitted helminths (STHs) are gastrointestinal parasites widely distributed in tropical and subtropical areas. Mass drug administration (MDA) of benzimidazoles (BZ) is the most recommended for STH control. These drugs have demonstrated limited efficacy against Trichuris trichiura and the long-term use of single-dose BZ has raised concerns of the possible emergence of genetic resistance. The objective of this investigation was to determine whether genetic mutations associated with BZ resistance were present in STH species circulating in an endemic region of Honduras. METHODS A parasitological survey was performed as part of this study, the Kato-Katz technique was used to determine STH prevalence in children of La Hicaca, Honduras. A subgroup of children received anthelminthic treatment in order to recover adult parasite specimens that were analyzed through molecular biology techniques. Genetic regions containing codons 200, 198, and 167 of the -tubulin gene of Ascaris lumbricoides and Trichuris trichiura were amplified and sequenced. RESULTS Stool samples were collected from 106 children. The overall STH prevalence was 75.47%, whereby T. trichiura was the most prevalent helminth (56.6%), followed by A. lumbricoides (17%), and hookworms (1.9%). Eighty-five sequences were generated for adjacent regions to codons 167, 198, and 200 of the -tubulin gene of T. trichiura and A. lumbricoides specimens. The three codons of interest were found to be monomorphic in all the specimens. CONCLUSION Although the inability to find single-nucleotide polymorphisms (SNPs) in the small sample analyzed for the present report does not exclude the possibility of their occurrence, these results suggest that, at present, Honduras's challenges in STH control may not be related to drug resistance but to environmental conditions and/or host factors permitting reinfections.
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Noon JB, Schwarz EM, Ostroff GR, Aroian RV. A highly expressed intestinal cysteine protease of Ancylostoma ceylanicum protects vaccinated hamsters from hookworm infection. PLoS Negl Trop Dis 2019; 13:e0007345. [PMID: 31009474 PMCID: PMC6497320 DOI: 10.1371/journal.pntd.0007345] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/02/2019] [Accepted: 03/28/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Human hookworms (Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum) are intestinal blood-feeding parasites that infect ~500 million people worldwide and are among the leading causes of iron-deficiency anemia in the developing world. Drugs are useful against hookworm infections, but hookworms rapidly reinfect people, and the parasites can develop drug resistance. Therefore, having a hookworm vaccine would be of tremendous benefit. METHODOLOGY/PRINCIPAL FINDINGS We investigated the vaccine efficacy in outbred Syrian hamsters of three A. ceylanicum hookworm antigen candidates from two classes of proteins previously identified as promising vaccine candidates. These include two intestinally-enriched, putatively secreted cathepsin B cysteine proteases (AceyCP1, AceyCPL) and one small Kunitz-type protease inhibitor (AceySKPI3). Recombinant proteins were produced in Pichia pastoris, and adsorbed to Alhydrogel. Recombinant AceyCPL (rAceyCPL)/Alhydrogel and rAceySKPI3/Alhydrogel induced high serum immunoglobulin G (IgG) titers in 8/8 vaccinates, but were not protective. rAceyCP1/Alhydrogel induced intermediate serum IgG titers in ~60% of vaccinates in two different trials. rAceyCP1 serum IgG responders had highly significantly decreased hookworm burdens, fecal egg counts and clinical pathology compared to Alhydrogel controls and nonresponders. Protection was highly correlated with rAceyCP1 serum IgG titer. Antisera from rAceyCP1 serum IgG responders, but not nonresponders or rAceyCPL/Alhydrogel vaccinates, significantly reduced adult A. ceylanicum motility in vitro. Furthermore, rAceyCP1 serum IgG responders had canonical Th2-specific recall responses (IL4, IL5, IL13) in splenocytes stimulated ex vivo. CONCLUSIONS/SIGNIFICANCE These findings indicate that rAceyCP1 is a promising vaccine candidate and validates a genomic/transcriptomic approach to human hookworm vaccine discovery.
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Affiliation(s)
- Jason B. Noon
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Erich M. Schwarz
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Gary R. Ostroff
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Raffi V. Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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Rehman A, Ullah R, Uddin I, Zia I, Rehman L, Abidi S. In vitro anthelmintic effect of biologically synthesized silver nanoparticles on liver amphistome, Gigantocotyle explanatum. Exp Parasitol 2019; 198:95-104. [DOI: 10.1016/j.exppara.2019.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/24/2019] [Accepted: 02/11/2019] [Indexed: 11/26/2022]
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113
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Chamomile Methanolic Extract Mitigates Small Bowel Inflammation and ROS Overload Related to the Intestinal Nematodes Infection in Mice. Acta Parasitol 2019; 64:152-161. [PMID: 30671769 DOI: 10.2478/s11686-019-00027-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 12/03/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND Chamomile (Matricaria recutita L.) is a plant which has been reported to be effective in treating several parasitic and digestive diseases. The present study was conducted to evaluate the anthelmintic activity of chamomile methanolic extract (CME). METHODS In vitro, the anthelmintic activities of CME were investigated on the L3 larvae of Heligmosomoides polygyrus in comparison to albendazole. In vivo, Swiss albino mice were infected with infective third (L3) larval stage of H. polygyrus by intragastric administration. Moreover, the effect of CME and albendazole on worm eggs, adult worms, serum cytokine production, and oxidative stress was studied. RESULTS All used doses of CME showed a potent anthelmintic activity both in vitro and in vivo and the effect being similar to treatment with albendazole. Moreover, H. polygyrus infestation was accompanied by an intestinal oxidative stress status characterized by an increased lipoperoxidation, a depletion of antioxidant enzyme activity, as well as an overload of hydrogen peroxide. We have also recorded an increase of pro-inflammatory mediator (TNF-α, IL-6, and IL-1β) levels after treatment with CME (14 ± 0.8; 41 ± 2; 58 ± 4 pg/mg protein, respectively, with the concentration 800 mg/kg, body weight) when compared with infected control mice (20 ± 1; 59 ± 2, and 83 ± 4 pg/mg protein, respectively). However, extract treatment alleviated all the deleterious effects associated with H. polygyrus infection. CONCLUSION These findings suggest that CME can be used in the control of gastrointestinal helminthiasis and associated oxidative stress.
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Page AP, Roberts M, Félix MA, Pickard D, Page A, Weir W. The golden death bacillus Chryseobacterium nematophagum is a novel matrix digesting pathogen of nematodes. BMC Biol 2019; 17:10. [PMID: 30813925 PMCID: PMC6394051 DOI: 10.1186/s12915-019-0632-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/22/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Nematodes represent important pathogens of humans and farmed animals and cause significant health and economic impacts. The control of nematodes is primarily carried out by applying a limited number of anthelmintic compounds, for which there is now widespread resistance being reported. There is a current unmet need to develop novel control measures including the identification and characterisation of natural pathogens of nematodes. RESULTS Nematode killing bacilli were isolated from a rotten fruit in association with wild free-living nematodes. These bacteria belong to the Chryseobacterium genus (golden bacteria) and represent a new species named Chryseobacterium nematophagum. These bacilli are oxidase-positive, flexirubin-pigmented, gram-negative rods that exhibit gelatinase activity. Caenorhabditis elegans are attracted to and eat these bacteria. Within 3 h of ingestion, however, the bacilli have degraded the anterior pharyngeal chitinous lining and entered the body cavity, ultimately killing the host. Within 24 h, the internal contents of the worms are digested followed by the final digestion of the remaining cuticle over a 2-3-day period. These bacteria will also infect and kill bacterivorous free-living (L1-L3) stages of all tested parasitic nematodes including the important veterinary Trichostrongylids such as Haemonchus contortus and Ostertagia ostertagi. The bacteria exhibit potent collagen-digesting properties, and genome sequencing has identified novel metalloprotease, collagenase and chitinase enzymes representing potential virulence factors. CONCLUSIONS Chryseobacterium nematophagum is a newly discovered pathogen of nematodes that rapidly kills environmental stages of a wide range of key nematode parasites. These bacilli exhibit a unique invasion process, entering the body via the anterior pharynx through the specific degradation of extracellular matrices. This bacterial pathogen represents a prospective biological control agent for important nematode parasites.
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Affiliation(s)
- Antony P Page
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Scotland, UK.
| | - Mark Roberts
- School of Veterinary Medicine, University of Glasgow, Scotland, UK
| | - Marie-Anne Félix
- Institute of Biology of the Ecole Normale Supérieure (IBENS), Paris, France
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Andrew Page
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - William Weir
- School of Veterinary Medicine, University of Glasgow, Scotland, UK
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Kitchen S, Ratnappan R, Han S, Leasure C, Grill E, Iqbal Z, Granger O, O'Halloran DM, Hawdon JM. Isolation and characterization of a naturally occurring multidrug-resistant strain of the canine hookworm, Ancylostoma caninum. Int J Parasitol 2019; 49:397-406. [PMID: 30771359 DOI: 10.1016/j.ijpara.2018.12.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/07/2018] [Accepted: 12/12/2018] [Indexed: 10/27/2022]
Abstract
Soil-transmitted nematodes infect over a billion people and place several billion more at risk of infection. Hookworm disease is the most significant of these soil-transmitted nematodes, with over 500 million people infected. Hookworm infection can result in debilitating and sometimes fatal iron-deficiency anemia, which is particularly devastating in children and pregnant women. Currently, hookworms and other soil-transmitted nematodes are controlled by administration of a single dose of a benzimidazole to targeted populations in endemic areas. While effective, people are quickly re-infected, necessitating frequent treatment. Widespread exposure to anthelmintic drugs can place significant selective pressure on parasitic nematodes to generate resistance, which has severely compromised benzimidazole anthelmintics for control of livestock nematodes in many areas of the world. Here we report, to our knowledge, the first naturally occurring multidrug-resistant strain of the canine hookworm Ancylostoma caninum. We reveal that this isolate is resistant to fenbendazole at the clinical dosage of 50 mg/kg for 3 days. Our data shows that this strain harbors a fixed, single base pair mutation at amino acid 167 of the β-tubulin isotype 1 gene, and by using CRISPR/Cas9 we demonstrate that introduction of this mutation into the corresponding amino acid in the orthologous β-tubulin gene of Caenorhabditis elegans confers a similar level of resistance to thiabendazole. We also show that the isolate is resistant to the macrocyclic lactone anthelmintic ivermectin. Understanding the mechanism of anthelmintic resistance is important for rational design of control strategies to maintain the usefulness of current drugs, and to monitor the emergence of resistance. The isolate we describe represents the first multidrug-resistant strain of A. caninum reported, and our data reveal a resistance marker that can emerge naturally in response to heavy anthelminthic treatment.
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Affiliation(s)
- Shannon Kitchen
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Ramesh Ratnappan
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Suhao Han
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Caitlyn Leasure
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Emilia Grill
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Zahra Iqbal
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Olivia Granger
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA
| | - Damien M O'Halloran
- Department of Biological Sciences, The George Washington University, SEH 6000, 800 22nd St NW, Washington, DC 20052, USA
| | - John M Hawdon
- Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I St. NW, The George Washington University, Washington, DC 20052, USA.
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Ménez C, Alberich M, Courtot E, Guegnard F, Blanchard A, Aguilaniu H, Lespine A. The transcription factor NHR-8: A new target to increase ivermectin efficacy in nematodes. PLoS Pathog 2019; 15:e1007598. [PMID: 30759156 PMCID: PMC6391013 DOI: 10.1371/journal.ppat.1007598] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 02/26/2019] [Accepted: 01/27/2019] [Indexed: 11/18/2022] Open
Abstract
Resistance to the anthelmintic macrocyclic lactone ivermectin (IVM) has a great impact on the control of parasitic nematodes. The mechanisms by which nematodes adapt to IVM remain to be deciphered. We have identified NHR-8, a nuclear hormone receptor involved in the xenobiotic response in Caenorhabditis elegans, as a new regulator of tolerance to IVM. Loss-of-function nhr-8(ok186) C. elegans mutants subjected to larval development assays and electropharyngeogram measurements, displayed hypersensitivity to IVM, and silencing of nhr-8 in IVM-resistant worms increased IVM efficacy. In addition, compared to wild-type worms, nhr-8 mutants under IVM selection pressure failed to acquire tolerance to the drug. In addition, IVM-hypersensitive nhr-8(ok186) worms displayed low transcript levels of several genes from the xenobiotic detoxification network and a concomitant low Pgp-mediated drug efflux activity. Interestingly, some pgp and cyp genes known to impact IVM tolerance in many nematode species, were down regulated in nhr-8 mutants and inversely upregulated in IVM-resistant worms. Moreover, pgp-6 overexpression in nhr-8(ok186) C. elegans increased tolerance to IVM. Importantly, NHR-8 function was rescued in nhr-8(ok186) C. elegans with the homolog of the parasitic nematode Haemonchus contortus, and silencing of Hco-nhr-8 by RNAi on L2 H. contortus larvae increased IVM susceptibility in both susceptible and resistant H. contortus isolates. Thus, our data show that NHR-8 controls the tolerance and development of resistance to IVM in C. elegans and the molecular basis for this relates to the NHR-8-mediated upregulation of IVM detoxification genes. Since our results show that Hco-nhr-8 functions similarly to Cel-nhr-8, this study helps to better understand mechanisms underlying failure in drug efficacy and open perspectives in finding new compounds with NHR-8 antagonist activity to potentiate IVM efficacy. IVM is the most important broad-spectrum deworming drug used today but resistance to this drug has appeared in parasites of both animals and humans. This seriously jeopardizes the success of current parasite control. Preserving IVM efficacy is a public health issue, whose outcome depends on the understanding of the molecular basis of selection for resistance to these drugs. We unambiguously show that the nuclear hormone receptor NHR-8, is crucial for protection of the nematode model Caenorhabditis elegans against IVM toxicity. Worms deficient in NHR-8 are hypersensitive to IVM and fail to become resistant to IVM under drug pressure. NHR-8 functions in the parasitic nematode of ruminants Haemonchus contortus and similar mechanisms could occur in other target pathogens. By controlling the xenobiotic detoxification network, NHR-8 may contribute to the biotransformation and elimination of IVM and help to desensitize the worm to the drug. This provides novel molecular targets involved in IVM drug tolerance in parasitic nematodes. Such findings could be exploited for targeted therapeutic intervention to treat parasitic nematode infections and delay the process of resistance development to anthelmintic drugs.
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Affiliation(s)
- Cécile Ménez
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France
- * E-mail: (CM); (AL)
| | | | - Elise Courtot
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France
| | - Fabrice Guegnard
- INRA, UMR 1282 Infectiology and Public Health, Nouzilly, Université François Rabelais de Tours, France
| | - Alexandra Blanchard
- INRA, UMR 1282 Infectiology and Public Health, Nouzilly, Université François Rabelais de Tours, France
| | - Hugo Aguilaniu
- CNRS, detached to the Serrapilheira Institute, Rio de Janeiro, Brazil
| | - Anne Lespine
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France
- * E-mail: (CM); (AL)
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Idris OA, Wintola OA, Afolayan AJ. Helminthiases; prevalence, transmission, host-parasite interactions, resistance to common synthetic drugs and treatment. Heliyon 2019; 5:e01161. [PMID: 30775568 PMCID: PMC6357211 DOI: 10.1016/j.heliyon.2019.e01161] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/17/2018] [Accepted: 01/21/2019] [Indexed: 01/08/2023] Open
Abstract
The morbidity caused by parasite worms on susceptible hosts is of great concern and studies were carried out to explain the mechanism of infection, prevalence, host-parasite interaction and resistance of the parasite to treatment. This review elucidates the prevalence of parasitic worm infections; which is on the increases with the increase in the world population, global warming, poor standard of living particularly in troubled regions and developing nations. The neglect of the disease coupled with the resistance of these parasites to the few available drugs becomes a huge challenge that influences global disease burden. Helminths infections pose a life threat and increase the disability-adjusted life year (DALYs) of the poor and vulnerable people. On the other hand, exploration of medicinal plants as an alternative source of treatment against drugs resistance helminths, attract insufficient attention. This review focused on providing a general overview of the prevalence of helminths, host-parasite interactions, the resistance of helminths and the medicinal plants used to treat helminthic infections.
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Affiliation(s)
- Oladayo Amed Idris
- Medicinal Plants and Economic Development (MPED) Research Centre, Department of Botany, University of Fort Hare, Alice, 5700, South Africa
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An assessment of worm control practices used by alpaca farmers in Australia. Vet Parasitol 2018; 265:91-100. [PMID: 30638526 DOI: 10.1016/j.vetpar.2018.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 11/20/2022]
Abstract
This study aimed to assess current worm control practices used by Australian alpaca farmers with an online questionnaire survey. The questionnaire contained questions about farm demography and general husbandry practices, farmers' knowledge about gastrointestinal nematodes (GINs) and their importance, the use of worm control strategies and anthelmintics, and grazing management. A link for the questionnaire survey was sent to all (n = 954) registered members of the Australian Alpaca Association in July 2015. The response rate for the questionnaire was 25% (239/954). The majority of respondents were from small (≤ 50 alpacas; 64%, 153/239) followed by medium (50-100 alpacas; 24%, 57/239) and large (>100 alpacas; 12%, 29/239) farms. Findings revealed that the majority of respondents kept Huacaya alpacas to produce high-quality fibre and alpacas were usually kept with other domestic ruminants (e.g. cattle and sheep). Although half of alpaca farmers (114/220) perceived that GINs were an important health problem of alpacas, with Haemonchus spp. being the most common nematode, the majority of them (174/220) used anthelmintics for nematode control. Macrocyclic lactones, a commercial combination of four anthelmintics (abamectin, albendazole, closantel and levamisole) and monepantel were the three most commonly used dewormers by Australian alpaca farmers. Although a significant proportion (166/213) of respondents used a quarantine drench for alpacas, very few respondents were aware of strategic deworming and the issue of anthelmintic resistance. Alpaca farmers mostly used anthelmintics at the dose rate recommended for sheep (47%, 79/167) and cattle (9%, 15/167), though some used 1.5 (31%, 51/167) and 2 (13%, 22/167) times the dose rate recommended for sheep. The majority of small herds used anthelmintics at the dose rate recommended for sheep and cattle while medium and large herds used anthelmintics at 1.5 to 2 times the dose rate recommended for sheep. This study provides invaluable insights into the demography of alpaca farms in Australia, husbandry practices used by alpaca farmers and their knowledge about worms and their control, thereby paving the way for developing guidelines for the control of GINs of alpacas.
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Blanco MG, Vela Gurovic MS, Silbestri GF, Garelli A, Giunti S, Rayes D, De Rosa MJ. Diisopropylphenyl-imidazole (DII): A new compound that exerts anthelmintic activity through novel molecular mechanisms. PLoS Negl Trop Dis 2018; 12:e0007021. [PMID: 30557347 PMCID: PMC6312359 DOI: 10.1371/journal.pntd.0007021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/31/2018] [Accepted: 11/26/2018] [Indexed: 11/26/2022] Open
Abstract
Nematode parasites cause substantial morbidity to billions of people and considerable losses in livestock and food crops. The repertoire of effective anthelmintic compounds for treating these parasitoses is very limited, as drug development has been delayed for decades. Moreover, resistance has become a global concern in livestock parasites and is an emerging issue for human helminthiasis. Therefore, anthelmintics with novel mechanisms of action are urgently needed. Taking advantage of Caenorhabditis elegans as an established model system, we here screened the nematicidal potential of novel imidazolium and imidazole derivatives. One of these derivatives, diisopropylphenyl-imidazole (DII), is lethal to C. elegans at both mature and immature stages. This lethal effect appears to be specific because DII concentrations which prove to be toxic to C. elegans do not induce significant lethality on bacteria, Drosophila melanogaster, and HEK-293 cells. Our analysis of DII action on C. elegans mutant strains determined that, in the adult stage, null mutants of unc-29 are resistant to the drug. Muscle expression of this gene completely restores DII sensitivity. UNC-29 has been largely reported as an essential constituent of the levamisole-sensitive muscle nicotinic receptor (L-AChR). Nevertheless, null mutants in unc-63 and lev-8 (essential and non-essential subunits of L-AChRs, respectively) are as sensitive to DII as the wild-type strain. Therefore, our results suggest that DII effects on adult nematodes rely on a previously unidentified UNC-29-containing muscle AChR, different from the classical L-AChR. Interestingly, DII targets appear to be different between larvae and adults, as unc-29 null mutant larvae are sensitive to the drug. The existence of more than one target could delay resistance development. Its lethality on C. elegans, its harmlessness in non-nematode species and its novel and dual mechanism of action make DII a promising candidate compound for anthelmintic therapy. Intestinal helminth infections affect approximately one-third of the world’s population, particularly in developing countries. Paradoxically, drug development in this area has been delayed for years. In addition, resistance to currently available drugs is also an emerging global concern. Therefore, there is an urgent need for new and effective anthelmintics. In this work, we used C. elegans as a model for parasitic nematodes to screen the anthelmintic activity of several imidazole-derivative compounds. We found a compound, diisopropylphenyl-imidazole (DII), that is lethal to both mature and immature stages of C. elegans. The DII nematicidal mechanism of action depends on a novel UNC-29-containing AChR in adult C. elegans muscle. Since this mechanism is different from those of currently used anthelmintics, it could constitute a therapeutic option when traditional anthelmintic agents fail. In addition, we found that the DII larvicidal effect depends on a different target to that of adult stages. The fact that DII produces lethality through different targets may delay resistance development. The specificity and novel mode of action of DII, which includes differential targeting in larvae and adult nematodes, support its potential as a promising drug candidate to treat helminthiasis.
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Affiliation(s)
- María Gabriela Blanco
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - María Soledad Vela Gurovic
- Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina.,CERZOS UNS-CONICET CCT, Bahía Blanca, Argentina
| | - Gustavo Fabián Silbestri
- Dpto de Química, Universidad Nacional del Sur (UNS)-CONICET, Instituto de Química del Sur (INQUISUR), Bahía Blanca, Argentina
| | - Andrés Garelli
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Sebastián Giunti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Diego Rayes
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - María José De Rosa
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS-CONICET, Bahía Blanca, Argentina.,Dpto de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
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Emergence and the spread of the F200Y benzimidazole resistance mutation in Haemonchus contortus and Haemonchus placei from buffalo and cattle. Vet Parasitol 2018; 265:48-54. [PMID: 30638520 DOI: 10.1016/j.vetpar.2018.12.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 11/23/2022]
Abstract
Benzimidazoles have been intensively (for over 40 years) used in the livestock sector, particularly in small ruminants. This has been led to the widespread emergence of resistance in a number of small ruminant parasite species, especially Haemonchus contortus. In many countries benzimidazole resistance has severely compromised the control of H. contortus in small ruminants; but there is a little information on benzimidazole resistance in H. contortus infecting buffalo and cattle. Resistance to benzimidazoles have also been reported in the large ruminant parasite, Haemonchus placei, but again there is relatively little information on its prevalence. Hence it is very important to understand how resistance-conferring mutations emerge and spread in both parasites in buffalo and cattle hosts in order to develop approaches for the recognition of the problem at an early stage of its development. The present study suggests that the F200Y (TAC) mutation is common in H. contortus, being detected in 5/7 populations at frequencies between 7 and 57%. Furthermore, 6/10 H. placei populations contained the F200Y (TAC) mutation, albeit at low frequencies of between 0.4 and 5%. The phylogenetic analysis suggests that the F200Y (TAC) mutation in H. contortus has emerged on multiple occasions in the region, with at least three independent emergences across the populations. In contrast, the F200Y (TAC) resistance-conferring mutation in H. placei is only seen on a single haplotype. A high level frequency of the resistance haplotypes in the region, suggests that the unique resistance conferring-mutation has spread from a single emergence; likely by anthropogenic animal movement. Overall, these results provide the first clear genetic evidence for the spread of benzimidazole resistance-conferring mutations to multiple different locations from a single emergence in H. placei; while being consistent with previous small ruminant-based observations of multiple emergence of resistance mutations in H. contortus.
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Substrate type and age are risk factors for gastrointestinal parasitism in greyhound kennels. Vet Parasitol 2018; 265:7-14. [PMID: 30638523 DOI: 10.1016/j.vetpar.2018.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 01/31/2023]
Abstract
The control of parasitic infections is particularly challenging in environments that are conducive to the maintenance of parasite lifecycles, such as the greyhound kennel, where the long-term breeding and rearing of dogs is common. The prevalence of gastrointestinal (GI) parasites within the Australian greyhound population has never previously been assessed, which seriously constrains the implementation of effective control measures. The aims of this study were to determine the prevalence and risk factors for GI parasites in Australian greyhounds, identify parasites which may be detrimental to the health and performance of dogs, and evaluate the likelihood of zoonotic transmission to kennel staff. Faecal samples were collected from 721 individual greyhounds situated in kennels across five states of Australia; Western Australia, Queensland, New South Wales, Victoria and Tasmania. Animal husbandry and current parasite control protocols were obtained from each kennel and analysed in conjunction with the detected level of parasitism. Overall parasite prevalence was approximately 60%, ranging from 50 to 70% between states. Eleven parasite genera were identified, with Sarcocystis, hookworm, Giardia and Toxocara detected most frequently. Generalised linear mixed model analyses found the major risk factors associated with parasitism were: a) the type of substrate which dogs were housed; b) age of dogs; and c) geographic region. Parasitism was associated most frequently with young dogs housed on grass/sand substrates, which allowed parasite lifecycles to continue, with constant reinfection the likely outcome. Routine treatment with broad-spectrum anthelmintics did not provide effective control in these environments and the adoption of alternate parasite control strategies is recommended. A substantial risk from zoonotic parasites was also identified, with six of the eleven parasite genera detected considered to be zoonotic and a poor understanding of zoonotic transmission among kennel managers.
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Maté L, Ballent M, Cantón C, Ceballos L, Lifschitz A, Lanusse C, Alvarez L, Liron J. Assessment of P-glycoprotein gene expression in adult stage of Haemonchus contortus in vivo exposed to ivermectin. Vet Parasitol 2018; 264:1-7. [DOI: 10.1016/j.vetpar.2018.10.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/04/2018] [Accepted: 10/13/2018] [Indexed: 01/19/2023]
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Weeks JC, Robinson KJ, Lockery SR, Roberts WM. Anthelmintic drug actions in resistant and susceptible C. elegans revealed by electrophysiological recordings in a multichannel microfluidic device. Int J Parasitol Drugs Drug Resist 2018; 8:607-628. [PMID: 30503202 PMCID: PMC6287544 DOI: 10.1016/j.ijpddr.2018.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/17/2018] [Accepted: 10/18/2018] [Indexed: 12/22/2022]
Abstract
Many anthelmintic drugs used to treat parasitic nematode infections target proteins that regulate electrical activity of neurons and muscles: ion channels (ICs) and neurotransmitter receptors (NTRs). Perturbation of IC/NTR function disrupts worm behavior and can lead to paralysis, starvation, immune attack and expulsion. Limitations of current anthelmintics include a limited spectrum of activity across species and the threat of drug resistance, highlighting the need for new drugs for human and veterinary medicine. Although ICs/NTRs are valuable anthelmintic targets, electrophysiological recordings are not commonly included in drug development pipelines. We designed a medium-throughput platform for recording electropharyngeograms (EPGs)-the electrical signals emitted by muscles and neurons of the pharynx during pharyngeal pumping (feeding)-in Caenorhabditis elegans and parasitic nematodes. The current study in C. elegans expands previous work in several ways. Detecting anthelmintic bioactivity in drugs, compounds or natural products requires robust, sustained pharyngeal pumping under baseline conditions. We generated concentration-response curves for stimulating pumping by perfusing 8-channel microfluidic devices (chips) with the neuromodulator serotonin, or with E. coli bacteria (C. elegans' food in the laboratory). Worm orientation in the chip (head-first vs. tail-first) affected the response to E. coli but not to serotonin. Using a panel of anthelmintics-ivermectin, levamisole and piperazine-targeting different ICs/NTRs, we determined the effects of concentration and treatment duration on EPG activity, and successfully distinguished control (N2) and drug-resistant worms (avr-14; avr-15; glc-1, unc-38 and unc-49). EPG recordings detected anthelmintic activity of drugs that target ICs/NTRs located in the pharynx as well as at extra-pharyngeal sites. A bus-8 mutant with enhanced permeability was more sensitive than controls to drug treatment. These results provide a useful framework for investigators who would like to more easily incorporate electrophysiology as a routine component of their anthelmintic research workflow.
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Affiliation(s)
- Janis C Weeks
- Institute of Neuroscience, University of Oregon, 1254 University of Oregon, Eugene, OR, 97403-1254, USA.
| | - Kristin J Robinson
- Institute of Neuroscience, University of Oregon, 1254 University of Oregon, Eugene, OR, 97403-1254, USA.
| | - Shawn R Lockery
- Institute of Neuroscience, University of Oregon, 1254 University of Oregon, Eugene, OR, 97403-1254, USA.
| | - William M Roberts
- Institute of Neuroscience, University of Oregon, 1254 University of Oregon, Eugene, OR, 97403-1254, USA.
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Morgan ER, Aziz NAA, Blanchard A, Charlier J, Charvet C, Claerebout E, Geldhof P, Greer AW, Hertzberg H, Hodgkinson J, Höglund J, Hoste H, Kaplan RM, Martínez-Valladares M, Mitchell S, Ploeger HW, Rinaldi L, von Samson-Himmelstjerna G, Sotiraki S, Schnyder M, Skuce P, Bartley D, Kenyon F, Thamsborg SM, Vineer HR, de Waal T, Williams AR, van Wyk JA, Vercruysse J. 100 Questions in Livestock Helminthology Research. Trends Parasitol 2018; 35:52-71. [PMID: 30477758 DOI: 10.1016/j.pt.2018.10.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 12/22/2022]
Abstract
An elicitation exercise was conducted to collect and identify pressing questions concerning the study of helminths in livestock, to help guide research priorities. Questions were invited from the research community in an inclusive way. Of 385 questions submitted, 100 were chosen by online vote, with priority given to open questions in important areas that are specific enough to permit investigation within a focused project or programme of research. The final list of questions was divided into ten themes. We present the questions and set them briefly in the context of the current state of knowledge. Although subjective, the results provide a snapshot of current concerns and perceived priorities in the field of livestock helminthology, and we hope that they will stimulate ongoing or new research efforts.
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Affiliation(s)
- Eric R Morgan
- Queen's University Belfast, School of Biological Sciences, 97, Lisburn Road, Belfast, BT9 7BL, UK.
| | - Nor-Azlina A Aziz
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | | | | | - Claude Charvet
- ISP, INRA, Université Tours, UMR1282, 37380, Nouzilly, France
| | - Edwin Claerebout
- Laboratory for Parasitology, Faculty of Veterinary Medicine, Ghent University, B9820 Merelbeke, Belgium
| | - Peter Geldhof
- Laboratory for Parasitology, Faculty of Veterinary Medicine, Ghent University, B9820 Merelbeke, Belgium
| | - Andrew W Greer
- Faculty of Agriculture and Life Sciences, P.O. Box 85084, Lincoln University, Christchurch, 7647, New Zealand
| | - Hubertus Hertzberg
- Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland
| | - Jane Hodgkinson
- Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool, L3 5RF, UK
| | - Johan Höglund
- Swedish University of Agricultural Sciences, BVF-parasitology, Box 7036, 750 07, Uppsala, Sweden
| | - Hervé Hoste
- UMR 1225 IHAP INRA/ENVT, 23 Chemin des Capelles, 31076 Toulouse, France
| | - Ray M Kaplan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - María Martínez-Valladares
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Finca Marzanas, Grulleros, 24346 León, Spain
| | - Siân Mitchell
- Animal and Plant Health Agency, Carmarthen Veterinary Investigation Centre, Jobswell Road, Johnstown, Carmarthen, SA31 3EZ, UK
| | - Harm W Ploeger
- Utrecht University, Department of Infectious Diseases and Immunology, Yalelaan 1, 3584 CL, Utrecht, The Netherlands
| | - Laura Rinaldi
- Department of Veterinary Medicine and Animal Production, University of Napoli Federico II, Napoli, Italy
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Robert-von-Ostertag-Str. 7-13, 14163 Berlin, Germany
| | - Smaragda Sotiraki
- Veterinary Research Institute, HAO-DEMETER, Campus Thermi 57001, Thessaloniki, Greece
| | - Manuela Schnyder
- Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland
| | - Philip Skuce
- Moredun Research Institute, Pentlands Science Park, Edinburgh EH26 0PZ, UK
| | - David Bartley
- Moredun Research Institute, Pentlands Science Park, Edinburgh EH26 0PZ, UK
| | - Fiona Kenyon
- Moredun Research Institute, Pentlands Science Park, Edinburgh EH26 0PZ, UK
| | - Stig M Thamsborg
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Hannah Rose Vineer
- Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool, L3 5RF, UK; School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Theo de Waal
- University College Dublin, School of Veterinary Medicine, Belfield, Dublin, D04 W6F6, Ireland
| | - Andrew R Williams
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jan A van Wyk
- Department of Veterinary Tropical Diseases, University of Pretoria, Private Bag X20, Pretoria, South Africa
| | - Jozef Vercruysse
- Laboratory for Parasitology, Faculty of Veterinary Medicine, Ghent University, B9820 Merelbeke, Belgium
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Mphahlele M, Tsotetsi-Khambule AM, Moerane R, Mashiloane ML, Thekisoe OMM. Risk factors associated with occurrence of anthelmintic resistance in sheep of resource-poor farmers in Limpopo province, South Africa. Trop Anim Health Prod 2018; 51:555-563. [PMID: 30426339 DOI: 10.1007/s11250-018-1724-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/10/2018] [Indexed: 12/21/2022]
Abstract
Anthelmintic treatment is the most common way of controlling nematode infections in ruminants even though several countries have reported anthelmintic resistance (AR), resulting in limitation for sustainable small ruminant production. The aim of the present study was to evaluate the knowledge of resource-poor sheep farmers in Limpopo province of South Africa on the use of anthelmintics. A questionnaire regarding helminthosis control practices was administered to small ruminant farmers in five districts of Limpopo province namely Capricorn, Sekhukhune, Waterberg, Vhembe, and Mopani. A total of 77 resource-poor farmers were interviewed between June and August of 2017 using a structured questionnaire with a combination of qualitative and quantitative open-ended questions. The interviewed farmers were divided into three groups based on their farming experience (< 5; 6-10, and ˃ 10 years of farming experience). Limited farming experience was shown as one of the risks, as farmers that owned sheep for less than 10 years could not identify the symptoms of gastrointestinal parasites infection and did not know how nematodes are transmitted to animals. However, no significant difference (p < 0.05) was found to exist between the three groups of farmers in terms of clinical signs identification and correct application of anthelmintics. About 43% of the respondents were unaware of gastrointestinal nematodes (GI) that infect sheep, could not identify the clinical symptoms of gastrointestinal nematodes infection, and only 34% knew how animals become infected. Although 67.5% of farmers mentioned that they never dose their sheep, 32.5% use anthelmintics at varying times in a year. None of the farmers weighed their sheep before dosing them instead visual appraisal of individual weight was the most common means of estimating the anthelmintic dose. The above information is an indication of risks associated with possible occurrence of anthelmintic resistance in the study areas. There is therefore, a need to give training to resource-poor farmers of small stock on proper application of anthelmintic treatment and to educate them on how to prevent development of AR. Future studies on AR should also be conducted in the province in flocks with high-treatment frequencies to establish the occurrence of AR using both in vivo and in vitro methods. The most common risk factor associated with the occurrence of AR in all the five districts of Limpopo province was found to be the use of anthelmintics without weighing the animals to determine the correct dosage.
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Affiliation(s)
- Morutse Mphahlele
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2531, South Africa.
| | - Ana M Tsotetsi-Khambule
- Epidemiology, Parasites and Vectors Programme, Agricultural Research Council - Onderstepoort Veterinary Research, Onderstepoort, 0110, South Africa
| | - Rebone Moerane
- Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa
| | - Majela L Mashiloane
- Livestock Research Unit, Mara Research station, Limpopo Department of Agriculture, Louis Trichardt, 0920, South Africa
| | - Oriel M M Thekisoe
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2531, South Africa
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Comprehensive evaluation of stool-based diagnostic methods and benzimidazole resistance markers to assess drug efficacy and detect the emergence of anthelmintic resistance: A Starworms study protocol. PLoS Negl Trop Dis 2018; 12:e0006912. [PMID: 30388108 PMCID: PMC6235403 DOI: 10.1371/journal.pntd.0006912] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/14/2018] [Accepted: 10/09/2018] [Indexed: 02/02/2023] Open
Abstract
Background To work towards reaching the WHO goal of eliminating soil-transmitted helminth (STH) infections as a public health problem, the total number of children receiving anthelmintic drugs has strongly increased over the past few years. However, as drug pressure levels rise, the development of anthelmintic drug resistance (AR) is more and more likely to appear. Currently, any global surveillance system to monitor drug efficacy and the emergence of possible AR is lacking. Consequently, it remains unclear to what extent the efficacy of drugs may have dropped and whether AR is already present. The overall aim of this study is to recommend the best diagnostic methods to monitor drug efficacy and molecular markers to assess the emergence of AR in STH control programs. Methods A series of drug efficacy trials will be performed in four STH endemic countries with varying drug pressure (Ethiopia and Brazil: low drug pressure, Lao PDR: moderate drug pressure and Tanzania: high drug pressure). These trials are designed to assess the efficacy of a single oral dose of 400 mg albendazole (ALB) against STH infections in school-aged children (SAC) by microscopic (duplicate Kato-Katz thick smear, Mini-FLOTAC and FECPAKG2) and molecular stool-based diagnostic methods (quantitative PCR (qPCR)). Data will be collected on the cost of the materials used, as well as the time required to prepare and examine stool samples for the different diagnostic methods. Following qPCR, DNA samples will also be submitted for pyrosequencing to assess the presence and prevalence of single nucleotide polymorphisms (SNPs) in the β-tubulin gene. These SNPs are known to be linked to AR in animal STHs. Discussion The results obtained by these trials will provide robust evidence regarding the cost-efficiency and diagnostic performance of the different stool-based diagnostic methods for the assessment of drug efficacy in control programs. The assessment of associations between the frequency of SNPs in the β-tubulin gene and the history of drug pressure and drug efficacy will allow the validation of these SNPs as a marker for AR in human STHs. Trial registration The trial was retrospectively registered the 7th of March 2018 on Clinicaltrials.gov (ID: NCT03465488). Soil-transmitted helminths (STHs) affect 1.4 billion people worldwide and cause significant morbidity when the intensity of infection is high. Currently, these infections are controlled in school-aged children by preventive chemotherapy with the benzimidazole drugs albendazole (ALB) or mebendazole (MEB). However, for the success of these control programs, it is essential to keep track of the efficacy of these drugs and to screen parasite populations for a possible rise of anthelmintic resistance (AR). In this light, a series of trials will be performed to assess the efficacy of ALB treatment against STH in four endemic countries with varying drug pressure. Both microscopic and molecular stool-based diagnostic methods will be used to evaluate drug efficacy. DNA samples will also be analysed for the presence and prevalence of mutations in a gene that was previously linked to AR in animal STHs. The results of these trials will provide evidence on the efficacy of ALB, help select the optimal diagnostic method to assess drug efficacy and provide information regarding the usefulness of genetic markers for AR detection in human STHs.
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Chemical analyses and anthelmintic effects of Artemisia campestris essential oil. Vet Parasitol 2018; 263:59-65. [DOI: 10.1016/j.vetpar.2018.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/28/2018] [Accepted: 10/03/2018] [Indexed: 01/01/2023]
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128
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Robertson E, Harcus Y, Johnston CJC, Page AP, Walkinshaw MD, Maizels RM, Houston D. DEMONSTRATION OF THE ANTHELMINTIC POTENCY OF MARIMASTAT IN THE HELIGMOSOMOIDES POLYGYRUS RODENT MODEL. J Parasitol 2018; 104:705-709. [PMID: 30085900 DOI: 10.1645/18-33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In the course of a structure based drug discovery program the known anticancer candidate marimastat was uncovered as a potent inhibitor of an enzyme in nematode cuticle biogenesis. It was shown to kill Caenorhabditis elegans, and the sheep parasites Haemonchus contortus and Teladorsagia circumcinta via an entirely novel nematode-specific pathway, specifically by inhibiting cuticle-remodelling enzymes that the parasites require for the developmentally essential moulting process. This discovery prompted an investigation of the compound's effect on Heligmosomoides polygyrus parasites in a mouse model of helminth infection. Mice were administered the drug via oral gavage daily from day of infection for a period of 2 wk. A second group received the drug via intra-peritoneal implantation of an osmotic minipump for 4 wk. Control groups were administered identical volumes of water by oral gavage in both cases. Counts of H. polygyrus faecal egg and larval load showed that marimastat effected a consistent and significant reduction in egg laying, and a consistent but minor reduction in adult worm load when administered every day, starting on the first day of infection. However, the drug failed to have any significant effect on egg counts or worm burdens when administered to mice with established infections. Therefore, marimastat does not appear to show promise as an anthelmintic in gastrointestinal nematode infections, although other metalloproteases such as batimastat may prove more effective.
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Affiliation(s)
- Elaine Robertson
- * Ashworth Laboratories, Institute of Immunology and Infection, University of Edinburgh, EH9 3FL, U.K
| | - Yvonne Harcus
- † The Queen's Medical Research Institute, 47 Little France Crescent, University of Edinburgh, EH16 4TJ, U.K
| | - Chris J C Johnston
- ‡ Department of Clinical Surgery, Royal Infirmary of Edinburgh, University of Edinburgh, EH16 4SA, U.K
| | - Antony P Page
- § Urquhart Building, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G61 1QH, U.K
| | - Malcolm D Walkinshaw
- ¶ Michael Swann Building, Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, EH9 3BF, U.K
| | - Rick M Maizels
- ⑊ Sir Graeme Davies Building, Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, G12 8TA, U.K
| | - Douglas Houston
- ** University of Edinburgh School of Biological Sciences Michael Swann Building, Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, EH9 3BF, U.K
- †† 0000-0002-3469-1546
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Odden A, Denwood MJ, Stuen S, Robertson LJ, Ruiz A, Hamnes IS, Hektoen L, Enemark HL. Field evaluation of anticoccidial efficacy: A novel approach demonstrates reduced efficacy of toltrazuril against ovine Eimeria spp. in Norway. Int J Parasitol Drugs Drug Resist 2018; 8:304-311. [PMID: 29777962 PMCID: PMC6039322 DOI: 10.1016/j.ijpddr.2018.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 01/29/2023]
Abstract
Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced anticoccidial efficacy in lambs, necessitate evaluation of anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6-8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7-11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but <0.75 (7 farms) were evaluated with caution, and drug efficacy on farms with increases of <0.5 (16 farms) was not estimated. Reduction in oocyst excretion between samples from treated lambs compared with controls from the 20 farms with a threshold of ≥0.5 were then analysed using a generalised linear mixed model. The results were classified based on 95% CI obtained using parametric bootstrapping. Among these 20 farms, two exhibited reduced drug efficacy (upper 95% CI < 95%), 13 had good efficacy (lower 95% CI > 90%), and for 5 the results were inconclusive. This is the first evidence-based report of reduced anticoccidial efficacy in ovine Eimeria spp. Additionally, we highlight the problem of sub-optimal timing of treatment (16/36 farms), which could potentially result in incorrect conclusions being reached regarding lack of drug efficacy.
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Affiliation(s)
- Ane Odden
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Production Animal Clinical Sciences, Kyrkjevegen 332/334, 4325 Sandnes, Norway.
| | - Matthew J Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Snorre Stuen
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Production Animal Clinical Sciences, Kyrkjevegen 332/334, 4325 Sandnes, Norway
| | - Lucy J Robertson
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Food Safety and Infection Biology, P.O. Box 369 Sentrum, 0102 Oslo, Norway
| | - Antonio Ruiz
- Parasitology Unit, Department of Animal Pathology, Faculty of Veterinary Medicine, University of Las Palmas de Gran Canaria, 35416 Arucas, Las Palmas, Spain
| | - Inger Sofie Hamnes
- Norwegian Veterinary Institute, Ullevålsveien 68, P.O. Box 750 Sentrum, 0106 Oslo, Norway
| | - Lisbeth Hektoen
- Animalia, Norwegian Meat and Poultry Research Centre, P.O. Box 396, Økern, 0513 Oslo, Norway
| | - Heidi L Enemark
- Norwegian Veterinary Institute, Ullevålsveien 68, P.O. Box 750 Sentrum, 0106 Oslo, Norway
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Elmahalawy ST, Halvarsson P, Skarin M, Höglund J. Genetic variants in dyf-7 validated by droplet digital PCR are not drivers for ivermectin resistance in Haemonchus contortus. Int J Parasitol Drugs Drug Resist 2018; 8:278-286. [PMID: 29758488 PMCID: PMC6019680 DOI: 10.1016/j.ijpddr.2018.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/18/2018] [Accepted: 04/22/2018] [Indexed: 12/01/2022]
Abstract
Resistance to ivermectin (IVM) in the nematode Haemonchus contortus in small ruminants is an increasing problem throughout the world. Access to molecular diagnostics will allow early detection of IVM resistance, which in turn can limit the spread of resistant isolates. One candidate gene which has recently been suggested as a marker for IVM resistance is that for dye-filling protein (dyf-7). In this study, we critically investigated the suitability of A141G and G153T single nucleotide polymorphisms (SNP) of dyf-7 as a marker in larval cultures collected from sheep farms in Sweden, involving several isolates for which resistance status had been characterised by the faecal egg count reduction test (FECRT). Initially, we designed dyf-7 primers from a worldwide collection of adult Haemonchus contortus DNA. With the sequence data, we created a haplotype network. We then optimised and used the same sets of primers and probes in a droplet digital PCR (ddPCR) assay for precise quantification of dyf-7 allele frequencies in pre- and post-anthelmintic treatment faecal larval cultures. The fractional abundance (FA) of the mutant SNP was within the range 7.8 and 31%. However, the FA was generally stable in samples collected from the same farms, even though they were obtained on different occasions up to 25 months apart. There was also no indication that the level of IVM resistance as measured by the faecal egg count reduction test was higher on farms with high FA. Furthermore, by comparing FA in samples from the same farms pre- and post-IVM treatment, we found no evidence of a correlation between dyf-7 and level of IVM resistance. Based on these results, dyf-7 is not a suitable marker for field testing of IVM resistance in H. contortus.
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Affiliation(s)
- Safaa T Elmahalawy
- Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, P.O. Box 7036, Uppsala, Sweden
| | - Peter Halvarsson
- Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, P.O. Box 7036, Uppsala, Sweden
| | - Moa Skarin
- Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, P.O. Box 7036, Uppsala, Sweden
| | - Johan Höglund
- Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, P.O. Box 7036, Uppsala, Sweden.
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131
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Molina JM, Hernández YI, Martín S, Ferrer O, Rodríguez F, Ruiz A. Immune response in goats vaccinated with thiol-binding proteins from Haemonchus contortus. Parasite Immunol 2018; 40:e12569. [PMID: 29959770 DOI: 10.1111/pim.12569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 06/26/2018] [Accepted: 06/28/2018] [Indexed: 11/30/2022]
Abstract
The experimental protocol of immunization tested here confirms its protective effect against Haemonchus contortus in goats. This protection translated into a 65.5% mean reduction in adult worm burden after a homologous challenge, and a significant decrease (73.2%) in cumulative faecal egg counts (FECs). These parasitological findings were consistent with the levels of some biopathological parameters. Thus, the reduction in adult worms and FEC observed in immunized animals were associated with increased levels of packed cell volume as well as plasma proteins. This response seems to be related to an important increase in specific antibodies (in serum and gastric mucus) and eosinophilia in response to challenge. At the local level, a cellular response was also observed in which CD4+ lymphocytes and globule leucocytes played a predominant role. Finally, it should be noted that the study of immunolocalization of proteins used in the vaccination trial suggests that these antigens have an internal location (at intestinal and reproductive tissues) in the adult worm. This observation, in conjunction with the kinetics of specific antibody levels after the challenge, suggests that these antigens may be part of excretory/secretory (E/S) products.
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Affiliation(s)
- José Manuel Molina
- Department of Animal Pathology, Faculty of Veterinary Medicine, University of Gran Canaria, Gran Canaria, Spain
| | - Yeray Isidoro Hernández
- Department of Animal Pathology, Faculty of Veterinary Medicine, University of Gran Canaria, Gran Canaria, Spain
| | - Sergio Martín
- Department of Animal Pathology, Faculty of Veterinary Medicine, University of Gran Canaria, Gran Canaria, Spain
| | - Otilia Ferrer
- Department of Animal Pathology, Faculty of Veterinary Medicine, University of Gran Canaria, Gran Canaria, Spain
| | - Francisco Rodríguez
- Department of Anatomy and Compared Anatomy Pathology, Faculty of Veterinary Medicine, University of Gran Canaria, Gran Canaria, Spain
| | - Antonio Ruiz
- Department of Animal Pathology, Faculty of Veterinary Medicine, University of Gran Canaria, Gran Canaria, Spain
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Hailu T, Abera B, Mulu W, Alemu M, Yizengaw E, Genanew A. Efficacy of single dose albendazole and praziquantel drugs among helminth-infected school children at Rural Bahir Dar, northwest Ethiopia. Trop Doct 2018; 48:270-272. [PMID: 30001683 DOI: 10.1177/0049475518786835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The resistance of anthelminthic drugs makes helminth control difficult. The aim of our study was to assess the efficacy of single dose albendazole and praziquantel drugs among helminth-infected children. A cross-sectional study was conducted from April to June, 2017. Stool examination was done by the Formol-Ether concentration technique. Students infected with geohelminths and s chistosoma mansoni were treated with a single dose of albendazole and praziquantel, respectively. Post-treatment stool examination was performed after two weeks. The magnitude of parasite infection, percentage of egg count reduction and cure rate following treatment were calculated using descriptive statistics. A total of 409 Sebatamet primary school students were included. The total prevalence of intestinal parasitosis was 58%. The cure rate of albendazole against hookworm was only 76.8%. Praziquantel had a 91.4% cure rate against Schistosoma mansoni. Therefore, periodic evaluation of the efficacy of anthelminthic drugs is required.
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Affiliation(s)
- Tadesse Hailu
- 1 Associate Professor of Medical Parasitology, School of Health Sciences, College of Medicine and Health Science, Bahir Dar University, Ethiopia
| | - Bayeh Abera
- 2 Associate Professor of Medical Microbiology, School of Health Sciences, College of Medicine and Health Science, Bahir Dar University, Ethiopia
| | - Wondemagegn Mulu
- 2 Associate Professor of Medical Microbiology, School of Health Sciences, College of Medicine and Health Science, Bahir Dar University, Ethiopia
| | - Megbaru Alemu
- 3 Assistant Professor of Medical Parasitology, School of Health Sciences, College of Medicine and Health Science, Bahir Dar University, Ethiopia
| | - Endalew Yizengaw
- 4 Lecturer of Immunology, School of Health Sciences, College of Medicine and Health Science, Bahir Dar University, Ethiopia
| | - Ashenafi Genanew
- 5 Lecturer of Pharmacology, School of Health Sciences, College of Medicine and Health Science, Bahir Dar University, Ethiopia
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Sangster NC, Cowling A, Woodgate RG. Ten Events That Defined Anthelmintic Resistance Research. Trends Parasitol 2018; 34:553-563. [DOI: 10.1016/j.pt.2018.05.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/24/2018] [Accepted: 05/01/2018] [Indexed: 11/30/2022]
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135
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Vaz Nery S, Qi J, Llewellyn S, Clarke NE, Traub R, Gray DJ, Vallely AJ, Williams GM, Andrews RM, McCarthy JS, Clements ACA. Use of quantitative PCR to assess the efficacy of albendazole against Necator americanus and Ascaris spp. in Manufahi District, Timor-Leste. Parasit Vectors 2018; 11:373. [PMID: 29954461 PMCID: PMC6025744 DOI: 10.1186/s13071-018-2838-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/09/2018] [Indexed: 11/21/2022] Open
Abstract
Background Soil-transmitted helminths (STHs) including Ascaris lumbricoides, Necator americanus, Ancylostoma spp. and Trichuris trichiura are cause of significant global morbidity. To mitigate their disease burden, at-risk groups in endemic regions receive periodic mass drug administration using anthelmintics, most commonly albendazole and mebendazole. Assessing the efficacy of anthelmintic drugs is important for confirming that these regimens are working effectively and that drug resistance has not emerged. In this study we aimed to characterise the therapeutic efficacy of albendazole against Ascaris spp. and N. americanus in Timor-Leste, using a quantitative polymerase chain reaction (qPCR) method for parasite detection and quantification. Results A total of 314 participants from 8 communities in Timor-Leste provided stool samples before and 10–14 days after the administration of a single 400 mg dose of albendazole. Helminth infection status and infection intensity (measured in Ct-values and relative fluorescence units) were determined using qPCR. Efficacy was determined by examining the cure rates and infection intensity reduction rates. Albendazole was found to be highly efficacious against Ascaris spp., with a cure rate of 91.4% (95% CI: 85.9–95.2%) and infection intensity reduction rate of 95.6% (95% CI: 88.3–100%). The drug was less efficacious against N. americanus with a cure rate of 58.3% (95% CI: 51.4–64.9%) and infection intensity reduction rate of 88.9% (95% CI: 84.0–97.0%). Conclusions The observed cure rates and infection intensity reduction rates obtained for Ascaris spp. and to a lower extent N. americanus, demonstrate the continued efficacy of albendazole against these species and its utility as a mass chemotherapy agent in Timor-Leste. Furthermore, this study demonstrates the usefulness of qPCR as a method to measure the efficacy of anthelminthic drugs. Additional research is necessary to translate Ct-values into eggs per gram in a systematic way. Trial registration Australian and New Zealand Clinical Trials Registry 12614000680662 (registered 27 June 2014).
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Affiliation(s)
- Susana Vaz Nery
- Research School of Population Health, Australian National University, 62 Mills Rd, Canberra, 2601, ACT, Australia. .,Present Address: Kirby Institute, University of New South Wales, Wallace Wurth Building, Sydney, 2052, NSW, Australia.
| | - Jessica Qi
- Medical School, Australian National University, Building 42, Canberra, ACT, 2601, Australia
| | - Stacey Llewellyn
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Brisbane, QLD 4006, Australia
| | - Naomi E Clarke
- Research School of Population Health, Australian National University, 62 Mills Rd, Canberra, 2601, ACT, Australia
| | - Rebecca Traub
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Darren J Gray
- Research School of Population Health, Australian National University, 62 Mills Rd, Canberra, 2601, ACT, Australia
| | - Andrew J Vallely
- Kirby Institute, University of New South Wales, Wallace Wurth Building, Sydney, 2052, NSW, Australia
| | - Gail M Williams
- School of Public Health, The University of Queensland, Corner of Herston Road and Wyndham Street, Brisbane, QLD 4006, Australia
| | - Ross M Andrews
- Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, NT 0811, Australia
| | - James S McCarthy
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Brisbane, QLD 4006, Australia
| | - Archie C A Clements
- Research School of Population Health, Australian National University, 62 Mills Rd, Canberra, 2601, ACT, Australia
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136
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Lack of efficacy of monepantel against trichostrongyle nematodes in a UK sheep flock. Vet Parasitol 2018; 257:48-53. [DOI: 10.1016/j.vetpar.2018.05.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 01/20/2023]
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Bacillus thuringiensis Cry5B protein as a new pan-hookworm cure. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:287-294. [PMID: 29772478 PMCID: PMC6039361 DOI: 10.1016/j.ijpddr.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/27/2018] [Accepted: 05/03/2018] [Indexed: 11/20/2022]
Abstract
Hookworms are intestinal nematode parasites that infect nearly half a billion people and are globally one of the most important contributors to iron-deficiency anemia. These parasites have significant impacts in developing children, pregnant women and working adults. Of all the soil-transmitted helminths or nematodes (STNs), hookworms are by far the most important, with disease burdens conservatively estimated at four million DALYs (Disability-Adjusted Life Years) and with productivity losses of up to US$139 billion annually. To date, mainly one drug, albendazole is used for hookworm therapy in mass drug administration, which has on average ∼80% cure rate that is lower (<40%) in some places. Given the massive numbers of people needing treatment, the threat of parasite resistance, and the inadequacy of current treatments, new and better cures against hookworms are urgently needed. Cry5B, a pore-forming protein produced by the soil bacterium Bacillus thuringiensis (Bt) has demonstrated good efficacy against Ancylostoma ceylanicum hookworm infections in hamsters. Here we broaden studies of Cry5B to include tests against infections of Ancylostoma caninum hookworms in dogs and against infections of the dominant human hookworm, Necator americanus, in hamsters. We show that Cry5B is highly effective against all hookworm parasites tested in all models. Neutralization of stomach acid improves Cry5B efficacy, which will aid in practical application of Cry5B significantly. Importantly, we also demonstrate that the anti-nematode therapeutic efficacy of Cry5B is independent of the host immune system and is not itself negated by repeated dosing. This study indicates that Bt Cry5B is a pan-hookworm anthelmintic with excellent properties for use in humans and other animals.
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138
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Anthelmintic efficacy of glycolipid biosurfactant produced by Pseudomonas plecoglossicida: an insight from mutant and transgenic forms of Caenorhabditis elegans. Biodegradation 2018; 30:203-214. [PMID: 29663166 DOI: 10.1007/s10532-018-9831-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/12/2018] [Indexed: 12/15/2022]
Abstract
The current research focuses on the production and characterization of glycolipid biosurfactant (GB) from Pseudomonas plecoglossicida and its anthelmintic activity against Caenorhabditis elegans. The GB was purified and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography and Mass Spectrometry (GC-MS) analysis. Anthelmintic activity of GB was studied at six different pharmacological doses from 10 to 320 µg/mL on C. elegans. Exposure of different developmental stages (L1, L2, L3, L4 and adult) of C. elegans to the GB reduced the survivability of worms in a dose and time-dependent manner. Adult and L4 worms were least susceptible, while L1, L2 and L3 were more susceptible to GB when compared to the untreated control. An increased exposure period drastically reduced the survival rate of worms and reduction in LC50 value. The GB significantly inhibited the development of C. elegans with an IC50 value of 53.14 µg/mL and even reduced the adult body length and egg hatching. Fecundity rate of the worms treated with GB at 20, 40 and 80 µg/mL decreased from 261.90 ± 3.21 to 239.70 ± 5.58, 164.20 ± 5.94 and 44.80 ± 6.22 eggs per worm, respectively. Besides the toxicological effects, prolonged exposure to GB significantly decreased (p ≤ 0.0001) the lifespan of wild type worms under standard laboratory conditions. Additionally, GB was found to be lethal towards ivermectin and albendazole resistant C. elegans strains. Overall, the data indicated that the GB extracted from P. plecoglossicida could be utilized for the control of non-susceptible and resistant gastrointestinal nematodes towards broad spectrum anthelmintic drugs, ivermectin and albendazole.
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139
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Borlase A, Webster JP, Rudge JW. Opportunities and challenges for modelling epidemiological and evolutionary dynamics in a multihost, multiparasite system: Zoonotic hybrid schistosomiasis in West Africa. Evol Appl 2018; 11:501-515. [PMID: 29636802 PMCID: PMC5891036 DOI: 10.1111/eva.12529] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 08/01/2017] [Indexed: 01/01/2023] Open
Abstract
Multihost multiparasite systems are evolutionarily and ecologically dynamic, which presents substantial trans-disciplinary challenges for elucidating their epidemiology and designing appropriate control. Evidence for hybridizations and introgressions between parasite species is gathering, in part in line with improvements in molecular diagnostics and genome sequencing. One major system where this is becoming apparent is within the Genus Schistosoma, where schistosomiasis represents a disease of considerable medical and veterinary importance, the greatest burden of which occurs in sub-Saharan Africa. Interspecific hybridizations and introgressions bring an increased level of complexity over and above that already inherent within multihost, multiparasite systems, also representing an additional source of genetic variation that can drive evolution. This has the potential for profound implications for the control of parasitic diseases, including, but not exclusive to, widening host range, increased transmission potential and altered responses to drug therapy. Here, we present the challenging case example of haematobium group Schistosoma spp. hybrids in West Africa, a system involving multiple interacting parasites and multiple definitive hosts, in a region where zoonotic reservoirs of schistosomiasis were not previously considered to be of importance. We consider how existing mathematical model frameworks for schistosome transmission could be expanded and adapted to zoonotic hybrid systems, exploring how such model frameworks can utilize molecular and epidemiological data, as well as the complexities and challenges this presents. We also highlight the opportunities and value such mathematical models could bring to this and a range of similar multihost, multi and cross-hybridizing parasites systems in our changing world.
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Affiliation(s)
- Anna Borlase
- Department of Pathobiology and Population SciencesCentre for Emerging, Endemic and Exotic DiseasesRoyal Veterinary CollegeUniversity of LondonLondonUK
- Department of Infectious Disease EpidemiologyLondon Centre for Neglected Tropical Disease ResearchSchool of Public HealthImperial College LondonLondonUK
| | - Joanne P. Webster
- Department of Pathobiology and Population SciencesCentre for Emerging, Endemic and Exotic DiseasesRoyal Veterinary CollegeUniversity of LondonLondonUK
- Department of Infectious Disease EpidemiologyLondon Centre for Neglected Tropical Disease ResearchSchool of Public HealthImperial College LondonLondonUK
| | - James W. Rudge
- Department of Infectious Disease EpidemiologyLondon Centre for Neglected Tropical Disease ResearchSchool of Public HealthImperial College LondonLondonUK
- Communicable Diseases Policy Research GroupLondon School of Hygiene and Tropical MedicineLondonUK
- Faculty of Public HealthMahidol UniversityBangkokThailand
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140
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Stroehlein AJ, Young ND, Gasser RB. Advances in kinome research of parasitic worms - implications for fundamental research and applied biotechnological outcomes. Biotechnol Adv 2018; 36:915-934. [PMID: 29477756 DOI: 10.1016/j.biotechadv.2018.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/15/2018] [Accepted: 02/21/2018] [Indexed: 12/17/2022]
Abstract
Protein kinases are enzymes that play essential roles in the regulation of many cellular processes. Despite expansions in the fields of genomics, transcriptomics and bioinformatics, there is limited information on the kinase complements (kinomes) of most eukaryotic organisms, including parasitic worms that cause serious diseases of humans and animals. The biological uniqueness of these worms and the draft status of their genomes pose challenges for the identification and classification of protein kinases using established tools. In this article, we provide an account of kinase biology, the roles of kinases in diseases and their importance as drug targets, and drug discovery efforts in key socioeconomically important parasitic worms. In this context, we summarise methods and resources commonly used for the curation, identification, classification and functional annotation of protein kinase sequences from draft genomes; review recent advances made in the characterisation of the worm kinomes; and discuss the implications of these advances for investigating kinase signalling and developing small-molecule inhibitors as new anti-parasitic drugs.
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Affiliation(s)
- Andreas J Stroehlein
- Melbourne Veterinary School, Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Neil D Young
- Melbourne Veterinary School, Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Robin B Gasser
- Melbourne Veterinary School, Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
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141
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Anthelmintic resistance in goat herds-In vivo versus in vitro detection methods. Vet Parasitol 2018; 254:10-14. [PMID: 29656993 DOI: 10.1016/j.vetpar.2018.02.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 11/20/2022]
Abstract
Anthelmintic resistance (AR) is a serious threat to animal health and has a major economic impact worldwide due to production and financial losses. The aim of this study was to determine the occurrence of AR on 30 goat farms in Slovakia during the pasturing seasons and to compare three widely used in vitro and in vivo methods for detecting AR in field conditions. A three-year survey was conducted during the pasturing seasons of 2014-2016. Goats on each farm were split into treated and control groups and were treated by recommended (5 mg/kg body weight) and double doses (10 mg/kg b.w.) of albendazole. Comparisons between percent reduction in a faecal egg count reduction test (FECRT) and an egg hatch test (EHT) and the presence of L3 larvae in a larval development test (LDT) using resistant concentrations of benzimidazole (BZ) were monitored after treatment. The FECRT indicated percent reductions of 69.2-86.2% for the single dose and of 36.3-45.4% for the double dose. The EHT indicated that all farms had BZ-resistant nematodes. Low (<15% hatching) and high (>15% hatching) levels of resistance were detected on 13 and 17 farms, respectively. The LDT failed to detect resistant larvae on seven farms but detected low and high levels of resistance on seven and 14 farms, respectively. The data indicate a moderate correlation between in vitro and in vivo tests for detecting BZ resistance among the 30 goat farms. The hatching detected by the EHT and the presence of L3 larvae by the LDT at resistant BZ concentrations provided reasonable identification of low levels of resistance in the parasite populations, but the use of a double dose for a treatment may underestimate the real occurrence of low levels of resistant parasites on goat farms.
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Figueiredo LA, Rebouças TF, Ferreira SR, Rodrigues-Luiz GF, Miranda RC, Araujo RN, Fujiwara RT. Dominance of P-glycoprotein 12 in phenotypic resistance conversion against ivermectin in Caenorhabditis elegans. PLoS One 2018; 13:e0192995. [PMID: 29474375 PMCID: PMC5825046 DOI: 10.1371/journal.pone.0192995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 02/03/2018] [Indexed: 12/16/2022] Open
Abstract
While diseases caused by nematodes remains a considerable drawback for the livestock, agriculture and public health, anthelmintics drug resistance has been observed over the past years and is a major concern for parasite control. Ivermectin, initially considered as a highly potent drug, currently presents a reduced anti-helminthic efficacy, which is influenced by expression of several ATP-binding cassette transporters (ABC), among them the P-glycoproteins (Pgps). Here we present some evidences of Pgps dominance during Ivermectin resistance/susceptibility using Pgps double silencing in C. elegans and the phylogenetic relationship of Pgps among nematodes, which strengthen the use of this model for study of drug resistance in nematodes. Firstly, we evaluated the quantitative gene expression of 12 out the 15 known Pgps from resistant and WT strains of C. elegans, we demonstrated the upregulation of Pgps 12 and 13 and downregulation of all remaining Pgps in ivermectin resistant strain. By using an RNAi loss-of-function approach we observed that Pgp 12 gene silencing reverts the resistance phenotype to ivermectin, while Pgp 4 gene silencing does not alter the resistance phenotype but induces a resistance in wild type strain. Interestingly, the dual silencing of Pgp 12 and Pgp 4 expression demonstrates the dominance of phenotype promoted by Pgp 12 silencing. Finally, in silico analysis reveals a close relationship between Pgps from C. elegans and several nematodes parasites. Taken together, our results indicate that Pgp 12 is crucial for the resistance to ivermectin and thus a good candidate for further studies aiming to develop specific inhibitors to this transporter, allowing the continuous use of ivermectin to control the burden on animal and human health inflicted by nematode parasites globally.
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Affiliation(s)
- Luiza Almeida Figueiredo
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Thais Fuscaldi Rebouças
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Sebastião Rodrigo Ferreira
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Gabriela Flavia Rodrigues-Luiz
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Ricardo Nascimento Araujo
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo Toshio Fujiwara
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Sinnathamby G, Henderson G, Umair S, Janssen P, Bland R, Simpson H. The bacterial community associated with the sheep gastrointestinal nematode parasite Haemonchus contortus. PLoS One 2018; 13:e0192164. [PMID: 29420571 PMCID: PMC5805237 DOI: 10.1371/journal.pone.0192164] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/17/2018] [Indexed: 11/23/2022] Open
Abstract
Culture-independent methods were used to study the microbiota of adult worms, third-stage larvae and eggs, both in faeces and laid in vitro, of Haemonchus contortus, a nematode parasite of the abomasa of ruminants which is a major cause of production losses and ill-health. Bacteria were identified in eggs, the female reproductive tract and the gut of adult and third-stage larvae (L3). PCR amplification of 16S rRNA sequences, denaturing gradient gel electrophoresis (DGGE) and clone libraries were used to compare the composition of the microbial communities of the different life-cycle stages of the parasites, as well as parasites and their natural environments. The microbiomes of adult worms and L3 were different from those in the abomasum or faeces respectively. The H. contortus microbiota was mainly comprised of members of the phyla Proteobacteria, Firmicutes and Bacteroidetes. Bacteria were localised in the gut, inside eggs and within the uterus of adult female worms using the universal FISH Eub338 probe, which targets most bacteria, and were also seen in these tissues by light and transmission electron microscopy. Streptococcus/Lactococcus sp. were identified within the distal uterus with the probe Strc493. Sequences from the genera Weissella and Leuconostoc were found in all life-cycle stages, except eggs collected from faeces, in which most sequences belonged to Clostridium sp. Bacteria affiliated with Weissella/Leuconostoc were identified in both PCR-DGGE short sequences and clone libraries of nearly full length 16S rRNA bacterial sequences in all life-cycle stages and subsequently visualised in eggs by fluorescent in situ hybridisation (FISH) with group-specific probes. This strongly suggests they are vertically transmitted endosymbionts. As this study was carried out on a parasite strain which has been maintained in the laboratory, other field isolates will need to be examined to establish whether these bacteria are more widely dispersed and have potential as targets to control H. contortus infections.
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Affiliation(s)
- Gajenathirin Sinnathamby
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
| | | | - Saleh Umair
- AgResearch Ltd, Palmerston North, New Zealand
| | | | - Ross Bland
- AgResearch Ltd, Palmerston North, New Zealand
| | - Heather Simpson
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
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Turnbull F, Jonsson NN, Kenyon F, Skuce PJ, Bisset SA. P-glycoprotein-9 and macrocyclic lactone resistance status in selected strains of the ovine gastrointestinal nematode, Teladorsagia circumcincta. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:70-80. [PMID: 29414109 PMCID: PMC6114102 DOI: 10.1016/j.ijpddr.2018.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 12/05/2022]
Abstract
The Teladorsagia circumcincta P-glycoprotein-9 (Tci-pgp-9) gene has previously been implicated in multiple-anthelmintic resistance in this parasite. Here we further characterise genetic diversity in Tci-pgp-9 and its possible role in ivermectin (IVM) and multi-drug resistance using two UK field isolates of T. circumcincta, one susceptible to anthelmintics (MTci2) and the other resistant to most available anthelmintics including IVM (MTci5). A comparison of full-length Tci-pgp-9 cDNA transcripts from the MTci2 and MTci5 isolates (∼3.8 kb in both cases) indicated that they shared 95.6% and 99.5% identity at the nucleotide and amino acid levels, respectively. Nine non-synonymous SNPs were found in the MTci5 sequences relative to their MTci2 counterparts. Twelve genomic sequence variants of the first internucleotide binding domain of Tci-pgp-9 were identified and up to 10 of these were present in some individual worms, strongly supporting previous evidence that amplification of this gene has occurred in T. circumcincta. On average, fewer distinct sequence variants of Tci-pgp-9 were present in individual worms of the MTci5 isolate than in those of the MTci2 isolate. A further reduction in the number of sequence variants was observed in individuals derived from an IVM-treated sub-population of MTci5. These findings suggest that Tci-pgp-9 was under purifying selection in the face of IVM treatment in T. circumcincta, with some sequence variants being selected against. Tci-pgp-9 cDNA sequences from the MTci2 and MTci5 isolates shared 95.6% identity. Comparison of Tci-pgp-9 sequences from MTci5 and MTci2 showed 9 non-synonymous SNPs. Multiple Tci-pgp-9-IBDA sequence variants occurred in the majority of individual larvae. Tci-pgp-9 appears to be under purifying selection after anthelmintics are applied.
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Affiliation(s)
- Frank Turnbull
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, EH26 0PZ, United Kingdom; Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, United Kingdom.
| | - Nicholas N Jonsson
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, United Kingdom
| | - Fiona Kenyon
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, EH26 0PZ, United Kingdom
| | - Philip J Skuce
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, EH26 0PZ, United Kingdom
| | - Stewart A Bisset
- AgResearch, Hopkirk Research Institute, Palmerston North, 4442, New Zealand
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Ramos F, Portella LP, Rodrigues FDS, Reginato CZ, Cezar AS, Sangioni LA, Vogel FS. Anthelminthic resistance of gastrointestinal nematodes in sheep to monepantel treatment in central region of Rio Grande do Sul, Brazil. PESQUISA VETERINARIA BRASILEIRA 2018. [DOI: 10.1590/1678-5150-pvb-5188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT: Given the numerous reports of anthelminthic resistance of sheep nematodes to different anthelmintic compounds, this study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected sheep to monepantel in the state of Rio Grande do Sul. Four farms that present extensive raising system and absence of anthelmintic treatment for 60 days were selected for the study. Lambs that present counts of eggs per gram of feces (EPG) ≥200 (sensitivity of 50 EPG) one day (D-1) before the treatment were select for the study and randomly separated into two groups, a control group and an experimental group treated with monepantel. Feces were collected 9 days after the treatment (D+9) for EPG counts and fecal culture. The monepantel was 100% effective only on 2. The efficacy found on farm 1, 3, and 4 were 2.82%, 25.8%, and 78.4%, respectably. There were no viable larvae post-treatment at farm 2, but the genera Haemonchus, Trichostrongylus, Cooperia, and Strongyloides were resistant to it at the other farms. This study shows the presence of parasites resistant to the treatment with monepantel, pointing to the importance of monitoring its efficacy in sheep flocks of Rio Grande do Sul, Brazil.
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146
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Amel MK, Mohamed ISA, Heba T, Maha GH, Eman GH. Phytochemical and biological analyses of Citharexylum spinosum. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/jpp2017.0479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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147
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Abstract
X-ray micro-computed tomography (μCT) is a technique which can obtain three-dimensional images of a sample, including its internal structure, without the need for destructive sectioning. Here, we review the capability of the technique and examine its potential to provide novel insights into the lifestyles of parasites embedded within host tissue. The current capabilities and limitations of the technology in producing contrast in soft tissues are discussed, as well as the potential solutions for parasitologists looking to apply this technique. We present example images of the mouse whipworm Trichuris muris and discuss the application of μCT to provide unique insights into parasite behaviour and pathology, which are inaccessible to other imaging modalities.
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148
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Response of drug-susceptible and -resistant Haemonchus contortus larvae to monepantel and abamectin alone or in combination in vitro. Vet Parasitol 2017; 249:57-62. [PMID: 29279087 DOI: 10.1016/j.vetpar.2017.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/09/2017] [Accepted: 11/17/2017] [Indexed: 01/29/2023]
Abstract
There is an increasing interest in the use of combination anthelmintic products for the control of intestinal nematode parasites of livestock. These products are seen as attractive options for parasite control in the face of increasing levels of resistance to the different anthelmintic drug classes, as well as a means to slow the rate at which resistance develops to the individual components of the combination. With the recent introduction of an anthelmintic combination product containing abamectin and monepantel (at 1:12.5), we were interested in measuring the response of drug-susceptible and drug-resistant isolates of Haemonchus contortus to these two drugs alone and in combination, using larval development assays. The GWBII isolate showed resistance to abamectin (12-fold) alongside susceptibility to monepantel. The resistance ratio was reduced from 12- to 3.2-fold when the two drugs were combined. The MPL-R isolate was resistant to both drugs, with resistance factors of 6-fold towards abamectin, and 10.6- and 1008-fold towards monepantel in two sub-populations present in the isolate. This isolate showed 6.4-fold resistance to the drug combination. Hence, for both GWBII and MPL-R, the level of resistance towards the combination was reduced compared to the resistance towards abamectin or monepantel alone, respectively, but was not abolished. However, for GWBII, this in vitro resistance to the drug combination would be expected to have no impact on the in vivo efficacy of the combination drench product as the isolate is resistant to only the abamectin component of the drench, with monepantel remaining effective. On the other hand, the observed in vitro resistance to the combination shown by the MPL-R isolate is derived from significant levels of resistance towards both components separately, and hence may impact on in vivo efficacy of the combination. Isobologram analysis did not find any evidence for a synergistic interaction between the two drugs in larval development assays. We examined the predicted effects of varying the abamectin:monepantel ratio in drug combinations, assuming that the two drugs acted in an additive fashion. For GWBII, resistance to the drug combination was reduced to almost zero as the abamectin:monepantel ratio increased from 1:12.5 to 1:100, reflecting its resistance to only the abamectin component of the combination. For MPL-R, on the other hand, the resistance increased as the relative proportion of monepantel in the combination was increased, reflecting the extreme level of in vitro resistance shown by this isolate to monepantel.
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149
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ARAVIND M, SARAVANAN BC, MANJUNATHACHAR HV, SANKAR M, SARAVANAN R, PRASAD A, MILTON AAP, PRIYA GBHUVANA. Molecular expression and characterization of GCP7 gene of Haemonchus contortus. THE INDIAN JOURNAL OF ANIMAL SCIENCES 2017. [DOI: 10.56093/ijans.v87i11.75853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Haemonchus contortus is a highly pathogenic and most economically important parasite of sheep and goats worldwide. The cysteine proteases from H. contortus are prime targets for vaccine development. In the present communication we report the molecular expression and characterization of cathepsin B-like cysteine protease, GCP7 gene of H. contortus to study its efficiency as target protein for immunoprophylaxis against haemonchosis in sheep and goats. The complete ORF of GCP7 gene, devoid of the signal sequence, was amplified by RT-PCR from mRNA isolated from H. contortus and was cloned initially into pTZ57R/T cloning vector and then sub-cloned in the pET32a(+) expression vector to produce GCP7 antigen. The nucleotide and deduced amino acid sequence of the GCP7 was aligned against the related sequences of H. contortus available in public domain for in silico analysis by DNA STAR and MEGA version 4.0 softwares. The nucleotide sequence revealed that the GCP7 gene of H.contortus (Indian isolate) encodes 324 amino acids (devoid of signal sequence) and its nucleotide sequence had 95.9% to 99.4% sequence homology with that of U.S.A. and previously published Indian isolates. A high level expression of recombinant (r) GCP7 protein was observed in the molecular range (Mr) of 55 kDa. The rGCP7 protein was confirmed by its specific immunoreactivity against known reference positive sheep sera.
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150
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Charlier J, Thamsborg SM, Bartley DJ, Skuce PJ, Kenyon F, Geurden T, Hoste H, Williams AR, Sotiraki S, Höglund J, Chartier C, Geldhof P, van Dijk J, Rinaldi L, Morgan ER, von Samson-Himmelstjerna G, Vercruysse J, Claerebout E. Mind the gaps in research on the control of gastrointestinal nematodes of farmed ruminants and pigs. Transbound Emerg Dis 2017; 65 Suppl 1:217-234. [PMID: 29124904 DOI: 10.1111/tbed.12707] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Indexed: 12/31/2022]
Abstract
Gastrointestinal (GI) nematode control has an important role to play in increasing livestock production from a limited natural resource base and to improve animal health and welfare. In this synthetic review, we identify key research priorities for GI nematode control in farmed ruminants and pigs, to support the development of roadmaps and strategic research agendas by governments, industry and policymakers. These priorities were derived from the DISCONTOOLS gap analysis for nematodes and follow-up discussions within the recently formed Livestock Helminth Research Alliance (LiHRA). In the face of ongoing spread of anthelmintic resistance (AR), we are increasingly faced with a failure of existing control methods against GI nematodes. Effective vaccines against GI nematodes are generally not available, and anthelmintic treatment will therefore remain a cornerstone for their effective control. At the same time, consumers and producers are increasingly concerned with environmental issues associated with chemical parasite control. To address current challenges in GI nematode control, it is crucial to deepen our insights into diverse aspects of epidemiology, AR, host immune mechanisms and the socio-psychological aspects of nematode control. This will enhance the development, and subsequent uptake, of the new diagnostics, vaccines, pharma-/nutraceuticals, control methods and decision support tools required to respond to the spread of AR and the shifting epidemiology of GI nematodes in response to climatic, land-use and farm husbandry changes. More emphasis needs to be placed on the upfront evaluation of the economic value of these innovations as well as the socio-psychological aspects to prioritize research and facilitate uptake of innovations in practice. Finally, targeted regulatory guidance is needed to create an innovation-supportive environment for industries and to accelerate the access to market of new control tools.
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Affiliation(s)
- J Charlier
- Kreavet, Kruibeke, Belgium.,Avia-GIS, Zoersel, Belgium
| | - S M Thamsborg
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg C, Denmark
| | | | - P J Skuce
- Moredun Research Institute, Edinburgh, UK
| | - F Kenyon
- Moredun Research Institute, Edinburgh, UK
| | | | - H Hoste
- UMR IHAP 1225, INRA, ENVT, Université de Toulouse, Toulouse, France
| | - A R Williams
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg C, Denmark
| | - S Sotiraki
- VetResInst, HAO-DEMETER, Thessaloniki, Greece
| | - J Höglund
- BVF, Section for Parasitology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - P Geldhof
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - J van Dijk
- Institute of Infection and Global Health, University of Liverpool, Neston, Cheshire, UK
| | - L Rinaldi
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Napoli, Italy
| | - E R Morgan
- Institute for Global Food Security, Queen's University Belfast, Belfast, UK.,School of Veterinary Science, University of Bristol, North Somerset, UK
| | | | - J Vercruysse
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - E Claerebout
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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