Hostname: page-component-848d4c4894-pftt2 Total loading time: 0 Render date: 2024-05-31T13:14:06.729Z Has data issue: false hasContentIssue false
  • English
  • Français

Disruption of spermatogenesis in the liver fluke, Fasciola hepatica by two artemisinin derivatives, artemether and artesunate

Published online by Cambridge University Press:  16 March 2016

J.F. O'Neill ,
R.C. Johnston ,
L. Halferty ,
R.E.B. Hanna ,
G.P. Brennan  and
I. Fairweather
J.F. O'Neill
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, BelfastBT9 7BL, Northern Ireland, United Kingdom
R.C. Johnston
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, BelfastBT9 7BL, Northern Ireland, United Kingdom
L. Halferty
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, BelfastBT9 7BL, Northern Ireland, United Kingdom
R.E.B. Hanna
Affiliation:
Veterinary Sciences Division, Agri-Food and Biosciences Institute (AFBI), Stormont, BelfastBT4 3SD, United Kingdom
G.P. Brennan
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, BelfastBT9 7BL, Northern Ireland, United Kingdom
I. Fairweather*
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, BelfastBT9 7BL, Northern Ireland, United Kingdom
*
*Fax: +44-28-90975877 E-mail: i.fairweather@qub.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

An in vivo study in the laboratory rat model has been carried out to monitor changes to the spermatogenic cells in the testis tubules of adult Fasciola hepatica following treatment with the artemisinins, artemether and artesunate. Rats infected with the triclabendazole (TCBZ)-resistant Sligo isolate were dosed orally with artemether at a concentration of 200 mg/kg and flukes recovered at 24, 48 and 72 h post treatment (pt). Rats infected with the TCBZ-resistant Oberon isolate were dosed orally with artesunate at a concentration of 200 mg/kg and flukes recovered 24, 48, 72 and 96 h pt. The flukes were processed for histological and transmission electron microscope (TEM) examination. Changes to the spermatogenic cells were evident at 24 h pt with artemether. The spermatogonial and spermatocyte cells contained abnormal mitochondria, there were fewer spermatids and spermatozoa in the tubules than normal, and a number of cells showed signs of apoptosis. There was a further decline in cell numbers at 48 h pt and the organization of the spermatocyte and spermatid rosettes was atypical. Sperm formation had become abnormal and those spermatozoa present possessed only a single axoneme. By 72 h pt, the testis tubules were vacuolated and filled with abnormal cells and cell debris. Only spermatogonial cells could be identified and there was widespread evidence of apoptosis in the cells. Distinct cellular changes following artesunate treatment did not become apparent until 48 h pt. The changes seen were similar to those described for artemether, but were generally less severe at matching time-periods. The fine structural changes occurring in the spermatogenic cells were compared to those observed in other cell types and fluke tissues and the overall information was collated to identify the cellular targets for artemisinin action and to establish the time-line for drug action.

Type
Research Papers
Information
Journal of Helminthology , Volume 91 , Issue 1 , January 2017 , pp. 55 - 71
Copyright
Copyright © Cambridge University Press 2016 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Brockwell, Y.M., Elliott, T.P., Anderson, G.R., Stanton, R., Spithill, T.W. & Sangster, N.C. (2014) Confirmation of Fasciola hepatica resistant to triclabendazole in naturally infected Australian beef and dairy cattle. International Journal for Parasitology: Drugs and Drug Resistance 4, 48–54.Google Scholar
Chaturvedi, D., Goswami, A., Saikia, P.P., Barua, N.C. & Rao, P.G. (2010) Artemesinin and its derivatives: a novel class of anti-malarial and anti-cancer agents. Chemical Society Reviews 39, 435–454.Google Scholar
Crespo-Ortiz, M.P. & Wei, M.Q. (2012) Antitumor activity of artemisinin and its derivatives: from a well-known antimalarial agent to a potential anticancer drug. Journal of Biomedicine and Biotechnology 2012, 247597.Google Scholar
Cui, L.W. & Su, X.Z. (2009) Discovery, mechanisms of action and combination therapy of artemisinin. Expert Review of Anti-Infective Therapy 7, 999–1013.Google Scholar
Dawes, B. (1966a) Experimental fascioliasis: some effects on Fasciola hepatica of treatment of rat hosts with bithionol (‘Actamer’). Helminthologia 7, 297–307.Google Scholar
Dawes, B. (1966b) Some apparent effects of bithionol (‘Actamer’) on Fasciola hepatica . Nature 209, 424–425.CrossRefGoogle ScholarPubMed
Dawes, B. (1967) Experimental fascioliasis in small mammals: apparent effects of bithionol on Fasciola hepatica in rats. Helminthologia 8, 97–101.Google Scholar
Dawes, B. (1968) Further evidence on the effect of bithionol (‘Actamer’) on Fasciola hepatica . Wiadomości Parazytologiczne 14, 575–577.Google ScholarPubMed
Devine, C., Brennan, G.P., Lanusse, C.E., Alvarez, L.I., Trudgett, A., Hoey, E.M. & Fairweather, I. (2011) Enhancement of triclabendazole action in vivo against a triclabendazole-resistant isolate of Fasciola hepatica by co-treatment with ketoconazole. Veterinary Parasitology 177, 305–315.Google Scholar
Devine, C., Brennan, G.P., Lanusse, C.E., Alvarez, L.I., Trudgett, A., Hoey, E. & Fairweather, I. (2012) Potentiation of triclabendazole action in vivo against a triclabendazole-resistant isolate of Fasciola hepatica following its co-administration with the metabolic inhibitor, keteoconazole. Veterinary Parasitology 184, 37–47.Google Scholar
Ding, X.C., Beck, H.-P. & Raso, G. (2011) Plasmodium sensitivity to artemisinins: magic bullets hit elusive targets. Trends in Parasitology 27, 73–81.Google Scholar
Duthaler, U., Rinaldi, L., Cringoli, G. & Keiser, J. (2012) Evaluation of the pharmacokinetic profile of artesunate, artemether and their metabolites in sheep naturally infected with Fasciola hepatica . Veterinary Parasitology 25, 270–280.Google Scholar
Efferth, T., Glaisi, M., Merling, A., Krammer, P.H. & Li-Weber, M. (2007) Artesunate induces ROS-mediated apoptosis in Doxorubicin-resistant T leukemia cells. PLoS ONE 2, e693.CrossRefGoogle ScholarPubMed
Ellis, D.S., Li, Z.L., Gu, H.M., Peters, W., Robinson, B.L., Tovey, G. & Warhurst, D.C. (1985) The chemotherapy of rodent malaria. 39. Ultrastructural changes following treatment with artemisinine of Plasmodium berghei infection in mice, with observations of the localization of [H-3]-dihydroartemisinine in P. falciparum in vitro . Annals of Tropical Medicine and Parasitology 79, 367–374.Google Scholar
Fairweather, I. (2011a) Liver fluke isolates: a question of provenance. Veterinary Parasitology 176, 1–8.Google Scholar
Fairweather, I. (2011b) Reducing the future threat from (liver) fluke: realistic prospect or quixotic fantasy? Veterinary Parasitology 180, 133–143.CrossRefGoogle ScholarPubMed
Fairweather, I., McShane, D.D., Shaw, L., Ellison, S.E., O'Hagan, N.T., York, E.A., Trudgett, A. & Brennan, G.P. (2012) Development of an egg hatch assay for the diagnosis of triclabendazole resistance in Fasciola hepatica: proof of concept. Veterinary Parasitology 183, 249–259.Google Scholar
Gordon, D., Zadoks, R., Skuce, P. & Sargison, N. (2012) Confirmation of triclabendazole resistance in liver fluke in the UK. Veterinary Record 171, 159–160.Google Scholar
Halferty, L., Brennan, G.P., Hanna, R.E.B., Edgar, H.W., Meaney, M., McConville, M., Trudgett, A., Hoey, L. & Fairweather, I. (2008) Tegumental surface changes in juvenile Fasciola hepatica in response to treatment in vivo with triclabendazole. Veterinary Parasitology 155, 49–58.Google Scholar
Halferty, L., O'Neill, J.F., Brennan, G.P., Keiser, J. & Fairweather, I. (2009) Electron microscopical study to assess the in vitro effects of the synthetic trioxolane OZ78 against the liver fluke, Fasciola hepatica . Parasitology 136, 1325–1337.CrossRefGoogle ScholarPubMed
Hamacher-Brady, A., Stein, H.A., Turschner, S., Toegel, I., Mora, R., Jennewein, N., Efferth, T., Eils, R. & Brady, N.R. (2011) Artesunate activates mitochondrial apoptosis in breast cancer cells via iron-catalysed lysosomal reactive oxygen species production. Journal of Biological Chemistry 286, 6587–6601.Google Scholar
Hanna, R.E.B. (2015) Fasciola hepatica: histology of the reproductive organs and differential effects of triclabendazole on drug-sensitive and drug-resistant fluke isolates and on flukes from selected field cases. Pathogens 4, 431–456.Google Scholar
Hanna, R.E.B., Cromie, L., Taylor, S.M. & Couper, A. (2006) The effect of a parenteral ivermectin/closantel injection on the growth and reproductive development of early immature Fasciola hepatica in cattle. Veterinary Parasitology 142, 78–90.Google Scholar
Hanna, R.E.B., Edgar, H., Moffett, D., McConnell, S., Fairweather, I., Brennan, G.P., Trudgett, A., Hoey, E.M., Cromie, L., Taylor, S.M. & Daniel, R. (2008) Fasciola hepatica: histology of the testis in egg-producing adults of several laboratory-maintained isolates of flukes grown to maturity in cattle and sheep and in flukes from naturally infected hosts. Veterinary Parasitology 157, 222–234.Google Scholar
Hanna, R.E.B., Edgar, H.W.J., McConnell, S., Toner, E., McConville, M., Brennan, G.P., Devine, C., Flanagan, A., Halferty, L., Meaney, M., Shaw, L., Moffett, D., McCoy, M. & Fairweather, I. (2010) Fasciola hepatica: histological changes in the reproductive structures of triclabendazole (TCBZ)-sensitive and TCBZ-resistant flukes after treatment in vivo with TCBZ and the related benzimidazole derivative, compound alpha. Veterinary Parasitology 168, 240–254.Google Scholar
Hanna, R.E.B., Gordon, A.W., Moffett, D., Edgar, H.W.J., Oliver, L.F., McConnell, S., Shaw, L., Brennan, G.P. & Fairweather, I. (2011) Fasciola hepatica: comparative effects of host resistance and parasite intra-specific interactions on size and reproductive histology in flukes from rats infected with isolates differing in triclabendazole sensitivity. Veterinary Parasitology 178, 251–263.Google Scholar
Hanna, R.E.B., Scarcella, S., Solana, H., McConnell, S. & Fairweather, I. (2012) Early onset of changes to the reproductive system of Fasciola hepatica following in vivo treatment with triclabendazole. Veterinary Parasitology 184, 341–347.Google Scholar
Hanna, R.E.B., Forster, F.I., Brennan, G.P. & Fairweather, I. (2013) Fasciola hepatica: histological demonstration of apoptosis in the reproductive organs of flukes of triclabendazole-sensitive and triclabendazole-resistant isolates, and in field-derived flukes from triclabendazole-treated hosts, using in situ hybridization to visualize endonuclease-generated DNA strand breaks. Veterinary Parasitology 191, 240–251.Google Scholar
Hanna, R.E.B., McMahon, C., Ellison, S., Edgar, H.W., Kajugu, P.-E., Gordon, A., Irwin, D., Barley, J.P., Malone, F.E., Brennan, G.P. & Fairweather, I. (2015) Fasciola hepatica: a comparative survey of adult fluke resistance to triclabendazole, nitroxynil and closantel on selected upland and lowland sheep farms in Northern Ireland using faecal egg counting, coproantigen ELISA testing and fluke histology. Veterinary Parasitology 207, 34–43.Google Scholar
Happich, F.A. & Boray, J.C. (1969) Quantitative diagnosis of chronic fascioliosis. 2. The estimation of daily total egg production of Fasciola hepatica and the number of adult flukes in sheep by faecal egg counts. Australian Veterinary Journal 45, 329–331.Google Scholar
Haynes, R. (2006) From artemisinin to new artemisinin antimalarials: biosynthesis, extraction, old and new derivatives, stereochemistry and medicinal chemistry requirements. Current Topics in Medicinal Chemistry 6, 509–537.Google Scholar
Ho, W.E., Peh, H.Y., Chan, T.K. & Wong, W.S.F. (2014) Artemisinins: pharmacological actions beyond anti-malarial. Pharmacology and Therapeutics 142, 126–139.Google Scholar
Kawai, S., Kano, S. & Suzuki, M. (1993) Morphologic effects of artemether on Plasmodium falciparum in Aotus trivirgatus . American Journal of Tropical Medicine and Hygiene 49, 812–818.CrossRefGoogle ScholarPubMed
Keiser, J. & Morson, G. (2008) Fasciola hepatica: tegumental alterations in adult flukes following in vitro and in vivo administration of artesunate and artemether. Experimental Parasitology 118, 228–237.Google Scholar
Keiser, J. & Utzinger, J. (2012) Antimalarials in the treatment of schistosomiasis. Current Pharmaceutical Design 18, 3531–3538.Google Scholar
Keiser, J., Xiao, S.H., Tanner, M. & Utzinger, J. (2006a) Artesunate and artemether are effective fasciolicides in the rat model and in vitro . Journal of Antimicrobial Chemotherapy 57, 1139–1145.Google Scholar
Keiser, J., Utzinger, J., Tanner, M., Dong, Y. & Vennerstrom, J.L. (2006b) The synthetic peroxide OZ78 is effective against Echinostoma caproni and Fasciola hepatica . Journal of Antimicrobial Chemotherapy 58, 1193–1197.Google Scholar
Keiser, J., Utzinger, J., Vennerstrom, J.L., Dong, Y., Brennan, G. & Fairweather, I. (2007) Activity of artemether and OZ78 against triclabendazole-resistant Fasciola hepatica . Transactions of the Royal Society for Tropical Medicine and Hygiene 101, 1219–1222.CrossRefGoogle ScholarPubMed
Keiser, J., Rinaldi, L., Veneziano, V., Mezzino, L., Tanner, M., Utzinger, J. & Cringoli, G. (2008) Efficacy and safety of artemether against a natural Fasciola hepatica infection in sheep. Parasitology Research 103, 517–522.Google Scholar
Keiser, J., Gruyer, M.-S., Perrottet, N., Zanolari, B., Mercier, T. & Decosterd, L. (2009) Pharmacokinetic parameters of artesunate and dihydroartemisinin in rats infected with Fasciola hepatica . Journal of Antimicrobial Chemotherapy 63, 543–549.Google Scholar
Keiser, J., Veneziano, V., Rinaldi, L., Mezzino, L., Duthaler, U. & Cringoli, G. (2010a) Anthelmintic activity of artesunate against Fasciola hepatica in naturally infected sheep. Research in Veterinary Science 88, 107–110.Google Scholar
Keiser, J., Kirchhofer, C., Haschke, M., Huwyler, J., Dong, Y., Vennerstrom, L., Vanhoff, K., Kaminsky, R. & Malikides, N. (2010b) Efficacy, safety and pharmacokinetics of 1,2,4-trioxalane OZ78 against an experimental infection with Fasciola hepatica in sheep. Veterinary Parasitology 173, 228–235.Google Scholar
Kirchhofer, C., Vargas, M., Braissant, O., Dong, Y., Wang, X., Vennerstromm, J. & Keiser, J. (2011) Activity of OZ78 analogues against Fasciola hepatica and Echinostoma caproni . Acta Tropica 118, 56–62.Google Scholar
Kirchhofer, C., Vargas, M., Hawler, J. & Keiser, J. (2012) Pharmacokinetics of the fasciolicidal drug candidates MT04 and OZ78 in uninfected rats and in vitro pharmacodynamics studies. International Journal for Parasitology: Drugs and Drug Resistance 2, 121–125.Google Scholar
Lai, H.C., Singh, N.P. & Sasaki, T. (2013) Development of artemisinin compounds for cancer treatment. Investigational New Drugs 31, 230–246.Google Scholar
Li, P.C.H., Lam, E., Roos, W.P., Zdzienicka, M.Z., Kaina, B. & Efferth, T. (2008) Artesunate derived from traditional Chinese medicine induces DNA damage and repair. Cancer Research 68, 4347–4351.Google Scholar
Li, Q.-G., Peggins, J.O., Fleckenstein, L.L., Masonic, K., Heiffer, M.H. & Brewer, T.G. (1998) The pharmacokinetics and bioavailability of dihydroartemisin, arteether, artemether, artesunic acid and artelinic acid in rats. Journal of Pharmacy and Pharmacology 50, 173–182.Google Scholar
Li, W., Mo, W., Shen, D., Sun, L., Wang, J., Lu, S., Gitschier, J.M. & Zhou, B. (2005) Yeast model uncovers dual roles of mitochondria in the action of artemisinin. PloS Genetics 1, 329–334.Google Scholar
Maeno, Y., Toyoshima, T., Fujioka, H., Ito, Y., Mesnick, S.R., Benakis, A., Milhous, W.K. & Aikawa, M. (1993) Morphologic effects of artemisinin in Plasmodium falciparum . American Journal of Tropical Medicine and Hygiene 49, 485–491.Google Scholar
McConville, M., Hanna, R.E.B., Brennan, G.P., McCoy, M., Edgar, H.W.J., McConnell, S., Castillo, R., Hernández-Campos, A. & Fairweather, I. (2010) Fasciola hepatica: disruption of spermatogenesis by the fasciolicide compound alpha. Parasitology Research 106, 311–323.Google Scholar
McKinstry, B., Fairweather, I., Brennan, G.P. & Forbes, A.B. (2003) Fasciola hepatica: tegumental surface alterations following treatment in vivo and in vitro with nitroxynil (Trodax). Parasitology Research 91, 251–263.Google Scholar
McKinstry, B., Brennan, G.P., Halferty, L., Forbes, A.B. & Fairweather, I. (2007) Ultrastructural changes induced in the tegument and gut of Fasciola hepatica following in vivo and in vitro drug treatment with nitroxynil (Trodax). Parasitology Research 101, 929–941.Google Scholar
Meaney, M., Fairweather, I., Brennan, G.P., McDowell, L.S.L. & Forbes, A.B. (2003) Fasciola hepatica: effects of the fasciolicide clorsulon in vitro and in vivo on the tegumental surface, and a comparison of the effects on young- and old-mature flukes. Parasitology Research 91, 238–250.Google Scholar
Meaney, M., Fairweather, I., Brennan, G.P. & Forbes, A.B. (2004) Transmission electron microscope study of the ultrastructural changes induced in the tegument and gut of Fasciola hepatica following in vivo drug treatment with clorsulon. Parasitology Research 92, 232–241.Google Scholar
Meaney, M., Savage, J., Brennan, G.P., Hoey, E., Trudgett, A. & Fairweather, I. (2013) Increased susceptibility of a triclabendazole (TCBZ)-resistant isolate of Fasciola hepatica to TCBZ following co-incubation in vitro with the P-glycoprotein inhibitor, R(+)-verapamil. Parasitology 140, 1286–1302.Google Scholar
Meister, I., Duthaler, U., Huwyler, J., Rinaldi, L., Bosco, A., Cringoli, G. & Keiser, J. (2013) Efficacy and pharmacokinetics of OZ78 and MT04 against a natural infection with Fasciola hepatica in sheep. Veterinary Parasitology 198, 102–110.Google Scholar
Olaechea, F., Lovera, V., Larroza, M., Raffo, F. & Cabrera, R. (2011) Resistance of Fasciola hepatica against triclabendazole in cattle in Patagonia (Argentina). Veterinary Parasitology 178, 364–366.Google Scholar
O'Neill, J.F. (2014) Studies on the activity of artemisinin compounds against the liver fluke Fasciola hepatica . PhD thesis, The Queen's University of Belfast.Google Scholar
O'Neill, J.F., Johnston, R.C., Halferty, L., Brennan, G.P., Keiser, J. & Fairweather, I. (2009) Adult triclabendazole-resistant Fasciola hepatica: morphological changes in the tegument and gut following in vivo treatment with artemether in the rat model. Journal of Helminthology 83, 151–163.Google Scholar
O'Neill, J.F., Johnston, R.C., Halferty, L., Brennan, G.P. & Fairweather, I. (2015a) Ultrastructural changes in the tegument and gut of adult Fasciola hepatica following in vivo treatment with artesunate. Experimental Parasitology 154, 143–154.Google Scholar
O'Neill, J.F., Johnston, R.C., Halferty, L., Hanna, R.E.B., Brennan, G.P. & Fairweather, I. (2015b) A comparative study on the impact of two artemisinin derivatives, artemether and artesunate, on the female reproductive system of Fasciola hepatica . Veterinary Parasitology 211, 182–194.Google Scholar
Ortiz, P., Scarcella, S., Cerna, C., Rosales, C., Cabrera, M., Guzmán, M., Lamenza, P. & Solana, H. (2013) Resistance of Fasciola hepatica against triclabendazole in cattle in Cajamarca (Peru): a clinical trial and an in vivo efficacy test in sheep. Veterinary Parasitology 195, 118–121.Google Scholar
Savage, J., Meaney, M., Brennan, G.P., Hoey, E., Trudgett, A. & Fairweather, I. (2013a) Effect of the P-glycoprotein inhibitor, R(+)-verapamil on the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica . Veterinary Parasitology 195, 72–86.Google Scholar
Savage, J., Meaney, M., Brennan, G.P., Hoey, E., Trudgett, A. & Fairweather, I. (2013b) Increased action of triclabendazole (TCBZ) in vitro against a TCBZ-resistant isolate of Fasciola hepatica following its co-incubation with the P-glycoprotein inhibitor, R(+)-verapamil. Experimental Parasitology 135, 642–653.Google Scholar
Savage, J., Meaney, M., Brennan, G.P., Hoey, E., Trudgett, A. & Fairweather, I. (2014) Disruption of vitellogenesis and spermatogenesis by triclabendazole (TCBZ) in a TCBZ-resistant isolate of Fasciola hepatica following incubation in vitro with a P-glycoprotein inhibitor. Parasitology 141, 1064–1079.Google Scholar
Scarcella, S., Fiel, C., Guzman, M., Alzola, R., Felipe, A., Hanna, R.E.B., Fairweather, I., McConnell, S. & Solana, H. (2011) Reproductive disruption in Fasciola hepatica associated with incomplete efficacy of a new experimental formulation of triclabendazole. Veterinary Parasitology 176, 157–164.Google Scholar
Stammers, B.M. (1975a) The effects of rafoxanide and nitroxynil on the survival, growth and morphology of Fasciola hepatica in rabbits. Zeitschrift für Parasitenkunde 46, 153–161.Google Scholar
Stammers, B.M. (1975b) Disruption of spermatogenesis in Fasciola hepatica by some anthelmintics. Zeitschrift für Parasitenkunde 47, 145–150.CrossRefGoogle ScholarPubMed
Stammers, B.M. (1976) The effects of nitroxynil on the survival, growth and morphology of Fasciola hepatica in sheep. Research in Veterinary Science 20, 174–179.Google Scholar
Stitt, A.W. & Fairweather, I. (1990) Spermatogenesis and the fine structure of the mature spermatozoon of the liver fluke, Fasciola hepatica (Trematoda: Digenea). Parasitology 101, 395–407.Google Scholar
Stitt, A.W. & Fairweather, I. (1992) Spermatogenesis in Fasciola hepatica: an ultrastructural comparison of the effects of the anthelmintic, triclabendazole (‘Fasinex’) and the microtubule inhibitor, tubulozole. Invertebrate Reproduction and Development 22, 139–150.Google Scholar
Toner, E., Brennan, G.P., Wells, K., McGeown, J.G. & Fairweather, I. (2008) Physiological and morphological effects of genistein against the liver fluke, Fasciola hepatica . Parasitology 135, 1189–1203.Google Scholar
Toner, E., Brennan, G.P., Hanna, R.E.B. & Fairweather, I. (2011) Disruption of egg formation by Fasciola hepatica following treatment in vivo with triclabendazole in the sheep host. Veterinary Parasitology 117, 79–89.Google Scholar
Utzinger, J., Xiao, S.H., Tanner, M. & Keiser, J. (2007) Artemisinins for schistosomiasis and beyond. Current Opinion in Investigational Drugs 8, 105–116.Google Scholar
Wakabayashi, T. & Karbowski, M. (2001) Structural changes of mitochondria related to apoptosis. Biological Signals and Receptors 10, 26–56.Google Scholar
Wang, J., Huang, L., Li, J., Fan, Q., Long, Y., Li, Y. & Zhou, B. (2010) Artemisinin directly targets malarial mitochondria through its specific mitochondrial activation. PLoS ONE 5, e9582.Google Scholar
Wang, X., Zhao, Q., Vargas, M., Dong, Y., Sriraghavan, K., Keiser, J. & Vennerstrom, J.L. (2011) The activity of dispiro peroxides against Fasciola hepatica . Bioorganic and Medicinal Chemistry Letters 21, 5320–5323.Google Scholar
Xiao, S.H., Binggui, S., Utzinger, J., Chollet, J. & Tanner, M. (2002a) Transmission electron microscopic observations on ultrastructural damage in juvenile Schistosoma mansoni caused by artemether. Acta Tropica 81, 53–61.Google ScholarPubMed
Xiao, S.H., Binggui, S., Utzinger, J., Chollet, J. & Tanner, M. (2002b) Ultrastructural alterations in adult Schistosoma mansoni caused by artemether. Memorias do Instituto Oswaldo Cruz 97, 717–724.Google Scholar
Zhao, Q., Vargas, M., Dong, Y., Zhou, L., Wang, X., Sriraghavan, K., Keiser, J. & Vennerstrom, J.L. (2010) Structure–activity relationship of an ozonide carboxylic acid (OZ78) against Fasciola hepatica . Journal of Medicinal Chemistry 53, 4223–4233.Google Scholar
Supplementary material: Image

O'Neill Supplementary Material

Figure S1

Download O'Neill Supplementary Material(Image)
Image 2 MB