Hymenolepis microstoma Cysticercoid Activation and Excystation In vitro (Cestoda)

Goodchild, Chauncey G.; Davis, Bowman O.

doi:10.2307/3278302

Cited by 13 publications

(1 citation statement)

References 9 publications

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“…After 1 h of incubation, among the 50 cysticercoids from each group, only 10 cysticercoids were randomly chosen and used for excystation assays to evaluate viability as described by Dhakal et al . (2015) modified from Goodchild and Davis (1972). The experiment was repeated twice.…”

Section: Methodsmentioning

confidence: 99%

Timing of sub-lethal insecticide exposure determines parasite establishment success in an insect-helminth model

et al. 2019

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Environmental toxicants are pervasive in nature, but sub-lethal effects on non-target organisms and their parasites are often overlooked. Particularly, studies on terrestrial hosts and their parasites exposed to agricultural toxicants are lacking. Here, we studied the effect of sequence and timing of sub-lethal exposures of the pyrethroid insecticide alpha-cypermethrin on parasite establishment using the tapeworm Hymenolepis diminuta and its intermediate insect host Tenebrio molitor as a model system. We exposed T. molitor to alpha-cypermethrin (LD20) before and after experimental H. diminuta infection and measured the establishment success of larval tapeworms. Also, we conducted in vitro studies quantifying the direct effect of the insecticide on parasite viability. Our results showed that there was no direct lethal effect of alpha-cypermethrin on H. diminuta cysticercoids at relevant concentrations (LD10 to LD90 of the intermediate host). However, we observed a significantly increased establishment of H. diminuta in beetles exposed to alpha-cypermethrin (LD20) after parasite infection. In contrast, parasite establishment was significantly lower in beetles exposed to the insecticide before parasite infection. Thus, our results indicate that environmental toxicants potentially impact host-parasite interactions in terrestrial systems, but that the outcome is context-dependent by enhancing or reducing parasite establishment depending on timing and sequence of exposure.

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Section: Methodsmentioning

confidence: 99%

Timing of sub-lethal insecticide exposure determines parasite establishment success in an insect-helminth model

et al. 2019

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Excystation of Hymenolepis microstoma

Rycke

1973

Z. Parasitenk

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A comparative study of the two alternative larval forms of Hymenolepis nana, the dwarf tapeworm, with special reference to the process of excystment

Caley

1975

Z. F. Parasitenkunde

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Studies of the cysticercoids of Hymenolepis nana from insects and from mouse villi revealed important differences in cyst structure and function. The insect form resists low pH unless treated with bile salts which render the cyst permeable and reduce infectivity to mice. Bile salts are not essential for scolex activation. Activation is inhibited by pH 2.5 and under and by 1% succinic acid up to pH 4.0. The importance of scolex immobility and energy conservation in relation to cyst impermeability is discussed. The villus cysticercoid has no special insulating layer. It is vulnerable to low pH and cannot infect mice orally. Bile salts are without effect and excystment occurs unaided by external agents. The structural differences between the two forms revealed by the electron microscope may be attributed to changes in the relative rates of development of the various tissues.

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Hymenolepis microstoma Cysticercoid Activation and Excystation In vitro (Cestoda)

Cited by 13 publications

References 9 publications

Timing of sub-lethal insecticide exposure determines parasite establishment success in an insect-helminth model

Timing of sub-lethal insecticide exposure determines parasite establishment success in an insect-helminth model

Excystation of Hymenolepis microstoma

A comparative study of the two alternative larval forms of Hymenolepis nana, the dwarf tapeworm, with special reference to the process of excystment

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