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Yu QF, Zhang JY, Sun MT, Gu MM, Zou HY, Webster JP, Lu DB. In vivo praziquantel efficacy of Schistosoma japonicum over time: A systematic review and meta-analysis. Acta Trop 2021; 222:106048. [PMID: 34273315 DOI: 10.1016/j.actatropica.2021.106048] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/10/2021] [Accepted: 07/08/2021] [Indexed: 12/20/2022]
Abstract
Praziquantel (PZQ), the only choice of chemotherapy for schistosomiasis recommended by World Health Organization (WHO), has been widely used over 40 years. The long-term, and rapid expansion of, PZQ use for disease control across a large populations continues to raise concern regarding the potential for emergence and establishment of drug resistance. Recent research has also proposed that the long survival and low sensitivity of unpaired worms, derived from either incomplete treatment cure rates or single-sex schistosome infections within final hosts, could exacerbate the risk of PZQ resistance (PZQ-R) emerging. With the aim of assessing whether PZQ efficacy amongst S. japonicum may have changed over time in China, we performed a unique systematic review and meta-analyses on datasets which evaluated the efficacy of PZQ via laboratory assays of field S. japonicum isolates on experimental mice over time. Relevant published literatures from four electronic bibliographic databases and lists of article references were searched. Two indexes, d, a measure used in meta-analyses for worm burden difference between two groups, and r, a traditional measure for worm reduction percentage after treatment but without considering sample size were calculated for each study. A total of 25 papers including 127 experimental studies with eligible data on 2230 mice were retrieved. The pooled d (D) was 3.91 (3.56-4.25) and pooled r (R) was 54.52% (52.55%-56.52%). D significantly increased over time, whereas R non-significantly decreased; both estimates were significantly associated with the total drug dose. Such findings suggested no evidence of PZQ-R emergence S. japonicum to date. However, we consider the potential role of parasite origins, PZQ dosage, and single versus mixed gender infections of the results published to date, and the avenues now needed for further research.
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Affiliation(s)
- Qiu-Fu Yu
- Department of Epidemiology and Statistics, School of Public Health, Soochow University, Suzhou, China; Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Jie-Ying Zhang
- Department of Epidemiology and Statistics, School of Public Health, Soochow University, Suzhou, China; Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Meng-Tao Sun
- Department of Epidemiology and Statistics, School of Public Health, Soochow University, Suzhou, China; Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Man-Man Gu
- Department of Epidemiology and Statistics, School of Public Health, Soochow University, Suzhou, China; Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Hui-Ying Zou
- Department of Epidemiology and Statistics, School of Public Health, Soochow University, Suzhou, China; Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Joanne P Webster
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China; Centre for Emerging, Endemic and Exotic Diseases (CEEED), Department of Pathology and Population Sciences, Royal Veterinary College, University of London, Herts, United Kingdom
| | - Da-Bing Lu
- Department of Epidemiology and Statistics, School of Public Health, Soochow University, Suzhou, China; Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China.
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Jiz M, Mingala C, Fu ZQ, Adriatico M, Lu K, Jarilla B, Sagliba M, Moreno A, Park S, Lin JJ, Olveda R, Kurtis JD, Wu HW. High prevalence of Schistosoma japonicum by perfusion in naturally exposed water buffalo in a region of the Philippines endemic for human schistosomiasis. PLoS Negl Trop Dis 2021; 15:e0009796. [PMID: 34529663 PMCID: PMC8478178 DOI: 10.1371/journal.pntd.0009796] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/28/2021] [Accepted: 09/08/2021] [Indexed: 11/21/2022] Open
Abstract
In the past decade, ecological surveys emphasized rats and dogs as the most significant animal reservoirs for Schistosoma japonicum (S.j) in the Philippines. However, recent studies demonstrated 51-91% prevalence of schistosomiasis among water buffalo using qPCR in the Sj endemic regions in the Philippines. In order to resolve the inconsistency of reported surveys regarding Sj endemicity among carabao, a domestic water buffalo that is the most important draught animal, we introduced 42 schistosome negative water buffalo to Macanip, Jaro municipality, Leyte, the Philippines, a subsistence rice-farming village that has been the focus of schistosomiasis japonica studies of our group for the past 20 years. We conducted perfusion to the remaining 34 buffalo that survived 10 months of nature exposure and Typhoon Haiyan. Thirty-three water buffalo were found to be positive with at least 1 pair of worms from the mesenteric vein. The infection rate is 97%, with the worm burden of 94 (95% confidence interval, 49-138 worms) worms. To our knowledge, this is the first report about S. japonicum worm burden in naturally infected water buffalo in the Philippines. The fact that with less than one-year of exposure, in this human schistosomiasis endemic area, only 1 out of 34 water buffalo was uninfected is striking. Urgent attention is needed for a cost-effective technique for monitoring Sj infection in animals and humans. Meanwhile, intervention implementation, including water buffalo treatment and vaccination, should be taken into consideration.
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Affiliation(s)
- Mario Jiz
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Claro Mingala
- Philippine Carabao Center, Science City of Munoz, Nueva Ecija, Philippines
| | - Zhi-Qiang Fu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Melika Adriatico
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Ke Lu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Blanca Jarilla
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Marianne Sagliba
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Ammabelle Moreno
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Sangshin Park
- Graduate School of Urban Public Health & Department of Urban Big Data Convergence, University of Seoul, Seoul, Republic of Korea
| | - Jiao-Jiao Lin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Remigio Olveda
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Jonathan D. Kurtis
- Center for International Health Research, Rhode Island Hospital, Brown University Medical School, Providence, Rhode Island, United States of America
| | - Hannah W. Wu
- Center for International Health Research, Rhode Island Hospital, Brown University Medical School, Providence, Rhode Island, United States of America
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Gray DJ, Thrift AP, Williams GM, Zheng F, Li YS, Guo J, Chen H, Wang T, Xu XJ, Zhu R, Zhu H, Cao CL, Lin DD, Zhao ZY, Li RS, Davis GM, McManus DP. Five-year longitudinal assessment of the downstream impact on schistosomiasis transmission following closure of the Three Gorges Dam. PLoS Negl Trop Dis 2012; 6:e1588. [PMID: 22506083 PMCID: PMC3323517 DOI: 10.1371/journal.pntd.0001588] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 02/07/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Schistosoma japonicum is a major public health concern in the Peoples' Republic of China (PRC), with about 800,000 people infected and another 50 million living in areas at risk of infection. Based on ecological, environmental, population genetic and molecular factors, schistosomiasis transmission in PRC can be categorised into four discrete ecosystems or transmission modes. It is predicted that, long-term, the Three Gorges Dam (TGD) will impact upon the transmission of schistosomiasis in the PRC, with varying degree across the four transmission modes. METHODOLOGY/PRINCIPAL FINDINGS We undertook longitudinal surveillance from 2002 to 2006 in sentinel villages of the three transmission modes below the TGD across four provinces (Hunan, Jiangxi, Hubei and Anhui) to determine whether there was any immediate impact of the TGD on schistosomiasis transmission. Eight sentinel villages were selected to represent both province and transmission mode. The primary end point measured was human incidence. Here we present the results of this five-year longitudinal cohort study. Results showed that the incidence of human S. japonicum infection declined considerably within individual villages and overall mode over the course of the study. This is also reflected in the yearly odds ratios (adjusted) for infection risk that showed significant (P<0.01) downward trends in all modes over the follow-up period. CONCLUSIONS/SIGNIFICANCE The decrease in human S. japonicum incidence observed across all transmission modes in this study can probably be attributed to the annual human and bovine PZQ chemotherapy. If an increase in schistosome transmission had occurred as a result of the TGD, it would be of negligible size compared to the treatment induced decline seen here. It appears therefore that there has been virtually no immediate impact of the TGD on schistosomiasis transmission downstream of the dam.
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Affiliation(s)
- Darren J. Gray
- Molecular Parasitology Laboratory, Infectious Diseases Division, Queensland Institute of Medical Research, Herston, Brisbane, Queensland, Australia
- Griffith Health Institute, Griffith University, Meadowbrook, Queensland, Australia
- School of Population Health, University of Queensland, Brisbane, Queensland, Australia
| | - Aaron P. Thrift
- School of Population Health, University of Queensland, Brisbane, Queensland, Australia
- Cancer Control Group, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
| | - Gail M. Williams
- School of Population Health, University of Queensland, Brisbane, Queensland, Australia
| | - Feng Zheng
- National Institute of Parasitic Disease, Chinese Centre for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Yue-Sheng Li
- Molecular Parasitology Laboratory, Infectious Diseases Division, Queensland Institute of Medical Research, Herston, Brisbane, Queensland, Australia
- Hunan Institute of Parasitic Diseases, World Health Organization Collaborating Centre for Research and Control on Schistosomiasis in Lake Region, Yueyang, People's Republic of China
| | - Jiagang Guo
- National Institute of Parasitic Disease, Chinese Centre for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Honggen Chen
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, People's Republic of China
| | - Tianping Wang
- Anhui Institute for Schistosomiasis Control, Hefei, People's Republic of China
| | - Xin Jiang Xu
- Hubei Institute for Schistosomiasis Control, Wuhan, People's Republic of China
| | - Rong Zhu
- National Institute of Parasitic Disease, Chinese Centre for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Hongqing Zhu
- National Institute of Parasitic Disease, Chinese Centre for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Chun Li Cao
- National Institute of Parasitic Disease, Chinese Centre for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Dan Dan Lin
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, People's Republic of China
| | - Zhen Yuan Zhao
- Hunan Institute of Parasitic Diseases, World Health Organization Collaborating Centre for Research and Control on Schistosomiasis in Lake Region, Yueyang, People's Republic of China
| | - Robert S. Li
- Griffith Health Institute, Griffith University, Meadowbrook, Queensland, Australia
- School of Population Health, University of Queensland, Brisbane, Queensland, Australia
| | - George M. Davis
- Department of Microbiology and Tropical Medicine, George Washington University Medical Centre, Washington D.C., United States of America
| | - Donald P. McManus
- Griffith Health Institute, Griffith University, Meadowbrook, Queensland, Australia
- * E-mail:
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Liu R, Dong HF, Guo Y, Zhao QP, Jiang MS. Efficacy of praziquantel and artemisinin derivatives for the treatment and prevention of human schistosomiasis: a systematic review and meta-analysis. Parasit Vectors 2011; 4:201. [PMID: 22004571 PMCID: PMC3207908 DOI: 10.1186/1756-3305-4-201] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Accepted: 10/17/2011] [Indexed: 01/08/2023] Open
Abstract
Background Praziquantel has been used as first-line drug for chemotherapy of schistosomiasis since 1984. Besides praziquantel, artemether and artesunate have also been used for the control of this infectious disease since late 1990s. In this article, we conducted a systematic review and meta-analysis to evaluate the antischistosomal efficacy of different medication strategies including monotherapy or combination therapies of these drugs. Results A number of 52 trials from 38 articles published in peer-reviewed journals before July 2011 were selected for analysis after searching the following literature databases: the Cochrane Library, PubMed/Medline, ISI Web of Science, Chinese Biomedicine Literature Database, and China National Knowledge Infrastructure. Our meta-analyses showed that a dosage of 30-60 mg/kg praziquantel compared with placebo produced a protection rate of about 76% (95% CI: 67%-83%) for treating human schistosomiasis, which varied from 70% to 76% with no significant differences among the subspecies S. haematobium, S. japonicum or S. mansoni. Protection rates were higher when praziquantel doses were elevated, as concluded from the nRCTs results: the protection rate of praziquantel at 40 mg/kg was 52% (95% CI: 49%-55%), and it increased to 91% (95% CI: 88%-92%) when the dosages were elevated to 60/80/100 mg/kg divided two or more doses. Multiple doses of artemether or artesunate over 1- or 2-week intervals resulted in protection rates of 65% to 97% for preventing schistosomiasis, and increased doses and shorter medication intervals improved their efficacies. Praziquantel and artemisinin derivatives (artemether or artesunate) in combination resulted in a higher protection rate of 84% (95% CI: 64%-91%) than praziquantel monotherapy for treatment. praziquantel and artesunate in combination had a great protection rate of 96% (95% CI: 78%-99%) for preventing schistosomes infection. Conclusions According to the results, praziquantel remains effective in schistosomiasis treatment, and multiple doses would improve its efficacy; meanwhile, praziquantel is also a good drug for preventing acute schistosomiasis morbidity. It's better to use multiple doses of artemether or artesunate with 1- or 2-week intervals for prevention against schistosome infection. Praziquantel and artemether or artesunate in combination perform better in treatment than praziquantel monotherapy, and they are especially suitable for treating the patients with repeated exposure to infected water.
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Affiliation(s)
- Rong Liu
- Department of Medical Parasitology, School of Basic Medical Science, Wuhan University, Wuhan 430071, People's Republic of China.
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Xu J, Zhu XJ, Li YH, Dai Y, Zhu YC, Zheng J, Feng ZQ, Guan XH. Expression, characterization and therapeutic efficacy of chimeric Fab of anti-idiotypic antibody NP30 against Schistosoma japonicum. Acta Trop 2011; 118:159-64. [PMID: 21376700 DOI: 10.1016/j.actatropica.2011.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 11/15/2022]
Abstract
The murine monoclonal anti-idiotypic antibody NP30 is a promising therapeutic antibody against Schistosoma japonicum. However, the immunogenicity of murine NP30 limits its further study and application in humans. Here the chimeric Fab of NP30 (chFab-NP30) comprising the variable regions of murine NP30 and constant regions of human antibody was assembled. chFab-NP30 was expressed and purified as a soluble and functional protein. Administration of chFab-NP30 in vivo increased the survival rate, reduced egg burdens and ameliorated organ pathology of mice with acute schistosomiasis. Our study indicated that chFab-NP30 is a promising candidate to be used as a specific and efficient recombinant antibody against acute schistosomiasis japonica. Further studies on function mechanism of chFab-NP30 needs to be carried out in the future.
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Affiliation(s)
- Jing Xu
- Key Lab of Antibody Technique of Ministry of Health, Nanjing Medical University, China
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Zhu R, Gray DJ, Thrift AP, Williams GM, Zhang Y, Qiu DC, Zheng F, Li YS, Guo J, Zhu HQ, Wu WP, Li RS, McManus DP. A 5-year longitudinal study of schistosomiasis transmission in Shian village, the Anning River Valley, Sichuan Province, the Peoples' Republic of China. Parasit Vectors 2011; 4:43. [PMID: 21429229 PMCID: PMC3072348 DOI: 10.1186/1756-3305-4-43] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 03/24/2011] [Indexed: 11/10/2022] Open
Abstract
Background Schistosoma japonicum is a major public health concern in the Peoples' Republic of China (PRC), with over one million people infected and another 50 million living in areas at risk of infection. Based on ecological, environmental, population genetic and molecular factors, schistosomiasis transmission in PRC can be categorised into four discrete ecosystems or transmission modes. It is predicted that the Three Gorges Dam (TGD) will impact upon the transmission of schistosomiasis in the PRC, with varying degree across the four transmission modes. We undertook longitudinal surveillance from 2002 to 2006 in sentinel villages both above and below the TGD across five provinces (Hunan, Jiangxi, Hubei, Anhui and Sichuan) to determine whether there was any impact of the TGD on schistosomiasis transmission during its construction. Here we present the results from a schistosomiasis-endemic village located above the dam in Sichuan Province. Results Baseline results showed a human S. japonicum prevalence of 42.0% (95% CI: 36.6-47.5). At follow-up, results showed that the incidence of S. japonicum infection in the selected human cohort in Shian decreased by three quarters from 46% in 2003 to 11.3% in 2006. A significant (P < 0.01) downward trend was also evident in the yearly adjusted (for water contact) odds ratios. Over the four years of follow-up, the incidence of S. japonicum infection in bovines declined from 11.8% in the first year to zero in the final year of follow-up. Conclusions The substantial decrease in human (75%) and bovine (100%) incidence observed in Shian village can probably be attributed to the annual human and bovine PZQ treatment of positives; as seen in drug (PZQ) intervention studies in other parts of PRC. If an increase in schistosome transmission had occurred as a result of the TGD, it would be of negligible size compared to the treatment induced decline seen here. It appears therefore that the construction of the TGD had virtually no impact on schistosomiasis transmission in Shian village over the period of study. Furthermore, contrary to previous reports from Sichuan downplaying the role of animals in human schistosome transmission, bovines may indeed play a role.
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Affiliation(s)
- Rong Zhu
- National Institute of Parasitic Disease, Chinese Centre for Disease Control and Prevention, Shanghai, PR China
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Lamberton PHL, Hogan SC, Kabatereine NB, Fenwick A, Webster JP. In vitro praziquantel test capable of detecting reduced in vivo efficacy in Schistosoma mansoni human infections. Am J Trop Med Hyg 2011; 83:1340-7. [PMID: 21118946 PMCID: PMC2990056 DOI: 10.4269/ajtmh.2010.10-0413] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Although great reductions in human schistosomiasis have been observed after praziquantel (PZQ) mass drug administration (MDA), some individuals remain infected after multiple treatments. Many MDA programs now require monitoring for drug efficacy as a key component. No molecular tools for PZQ resistance currently exist and investigations into the dose of PZQ required to kill 50% of adult worms in vivo (ED(50)) present ethical, logistical, and temporal restraints. We, therefore, assessed the feasibility and accuracy of a rapid, inexpensive in vitro PZQ test in the laboratory and directly in the field in Uganda under MDA in conjunction with highly detailed infection intensity, clearance, and reinfection data. This test strongly differentiated between subsequently cleared and uncleared infections as well as differences between parasite populations pre- and post-PZQ treatments, advocating its use for on-the-spot monitoring of PZQ efficacy in natural foci. After only a few treatments, uncleared parasites were identified to be phenotypically different from drug-sensitive parasites, emphasizing the urgent need for monitoring of these repeatedly PZQ-treated populations.
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Affiliation(s)
- Poppy H L Lamberton
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom.
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Krautz-Peterson G, Ndegwa D, Vasquez K, Korideck H, Zhang J, Peterson JD, Skelly PJ. Imaging schistosomes in vivo. FASEB J 2009; 23:2673-80. [PMID: 19346298 DOI: 10.1096/fj.08-127738] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Schistosomes are intravascular, parasitic helminths that cause a chronic, often debilitating disease afflicting over 200 million people in over 70 countries. Here we describe novel imaging methods that, for the first time, permit visualization of live schistosomes within their living hosts. The technology centers on fluorescent agent uptake and activation in the parasite's gut, and subsequent detection and signal quantitation using fluorescence molecular tomography (FMT). There is a strong positive correlation between the signal detected and parasite number. Schistosoma mansoni parasites of both sexes recovered from infected experimental animals exhibit vivid fluorescence throughout their intestines. Likewise, the remaining important human schistosome parasites, S. japonicum and S. hematobium, also exhibit gut fluorescence when recovered from infected animals. Imaging has been used to efficiently document the decline in parasite numbers in infected mice treated with the antischistosome drug praziquantel. This technology will provide a unique opportunity both to help rapidly identify much-needed, novel antischistosome therapies and to gain direct visual insight into the intravascular lives of the major schistosome parasites of humans.
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Affiliation(s)
- Greice Krautz-Peterson
- Department of Biomedical Sciences, Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Rd., North Grafton, MA 01536, USA
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Coles GC, Jackson F, Pomroy WE, Prichard RK, von Samson-Himmelstjerna G, Silvestre A, Taylor MA, Vercruysse J. The detection of anthelmintic resistance in nematodes of veterinary importance. Vet Parasitol 2006; 136:167-85. [PMID: 16427201 DOI: 10.1016/j.vetpar.2005.11.019] [Citation(s) in RCA: 572] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 10/13/2005] [Accepted: 11/22/2005] [Indexed: 10/25/2022]
Abstract
Before revised World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines on the detection of anthelmintic resistance can be produced, validation of modified and new methods is required in laboratories in different parts of the world. There is a great need for improved methods of detection of anthelmintic resistance particularly for the detection of macrocyclic lactone resistance and for the detection of resistant nematodes in cattle. Therefore, revised and new methods are provided here for the detection of anthelmintic resistance in nematodes of ruminants, horses and pigs as a basis for discussion and with the purpose that they are evaluated internationally to establish whether they could in the future be recommended by the WAAVP. The interpretation of the faecal egg count reduction test has been modified and suggestions given on its use with persistent anthelmintics and continuous release devices. An egg hatch test for benzimidazole (BZ) resistance is described. A microagar larval development test for the detection of benzimidazole and levamisole resistance provides third stage larvae for the identification of resistant worms. The sensitivity of these two tests can be increased by using discriminating doses rather than LD(50) values. Details are given of a PCR based test for the analysis of benzimidazole resistance in strongyles of sheep and goats, horses and cattle. Although promising for ruminant trichostrongyles, quantitative determination of gene frequency using real time PCR requires further development before PCR tests will be used in the field. Apart from faecal egg count reduction tests there are currently no satisfactory tests for macrocylic lactone resistance despite the great importance of this subject. Except for treatment and slaughter trials there are no validated tests for fasciolicide resistance or for the detection of resistance in cestodes.
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Affiliation(s)
- G C Coles
- Department of Clinical Veterinary Science, University of Bristol, Langford House, UK.
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Hagan P, Appleton CC, Coles GC, Kusel JR, Tchuem-Tchuenté LA. Schistosomiasis control: keep taking the tablets. Trends Parasitol 2004; 20:92-7. [PMID: 14747023 DOI: 10.1016/j.pt.2003.11.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Despite the limited reports of praziquantel resistance, the relative success of chemotherapy-based control programmes for schistosomiasis has prompted overdue efforts to expand the use of cheap, generic, praziquantel in sub-Saharan Africa. The likely impact of such programmes on the development and spread of praziquantel resistance is uncertain, but this possibility reinforces the need for monitoring the spectrum of praziquantel sensitivity of schistosome populations and for an improved knowledge of the precise targets for the action of the drug. The search for alternatives to praziquantel and other tools for control of schistosomiasis must continue.
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Affiliation(s)
- Paul Hagan
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building (B4-09d), University of Glasgow, G12 8QQ, UK.
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Tandon R, Kaplan RM. Evaluation of a larval development assay (DrenchRite®) for the detection of anthelmintic resistance in cyathostomin nematodes of horses. Vet Parasitol 2004; 121:125-42. [PMID: 15110410 DOI: 10.1016/j.vetpar.2003.09.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 09/29/2003] [Accepted: 09/29/2003] [Indexed: 10/26/2022]
Abstract
A larval development assay (LDA, DrenchRite) was evaluated to determine the effectiveness of this method in detecting anthelmintic resistance in cyathostomin nematodes of horses. A total of 15 horse farms from Georgia and South Carolina (USA) and Population S ponies from the University of Kentucky (USA) were included in this study. Nematode eggs were extracted from pooled fecal samples and placed into the wells of a DrenchRite plate for testing against thiabendazole (TBZ), levamisole (LEV) and 2 ivermectin (IVM) analogs (IVM-1, IVM-2). After a 7-day incubation larvae in each well were counted and data were analyzed by logistic regression. Resistance status of each farm for different drugs was determined in a separate study using a fecal egg count reduction test. LDA were performed on the 15 farms once, however, the Population S cyathostomins were assayed on 3 separate occasions to estimate the consistency of results between assays. Mean TBZ LC50 for oxibendazole resistant, suspected resistant and sensitive farms were 0.2015, 0.1625, and 0.1355 microM, respectively. For LEV, mean LC50 for PYR resistant, suspected resistant and sensitive farms were 1.590, 1.8018 and 1.4219 microM, respectively. All 15 farms had worms susceptible to IVM; mean LC50 for IVM-1 and for IVM-2 were 7.5727 and 87.9718 nM, respectively. A linear mixed model was fitted to the data to determine the relationship between LC50 and LC95 and resistance status for each farm. No meaningful relations were found. Consistency of assays varied between drugs, being best for TBZ and worst for LEV and IVM-1. All farms in this study had benzimidazole-resistant nematodes; therefore usefulness of DrenchRite for discriminating susceptibility versus resistance to this drug class could not be accurately assessed. Moreover, since all farms tested were sensitive to IVM and resistance to this drug class has not yet been reported in cyathostomins, it is not possible to assess accurately the usefulness of DrenchRite LDA for detecting IVM resistance at this time. Assay results for LEV suggest that LEV in a LDA does not yield data that is useful in estimating PYR efficacy in vivo. Based on results for PYR/LEV, the current high prevalence of benzimidazole resistance, no known cases of IVM resistance, and the sometimes extreme variation in results seen in many of the assays, DrenchRite LDA cannot be considered a useful tool for the diagnosis of resistance in cyathostomins of horses at present.
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Affiliation(s)
- R Tandon
- Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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