ANHYDROBIOSIS INCREASES SURVIVAL OF TRICHOSTRONGYLE NEMATODES

• Published in: The Journal of parasitology 2006-10, Vol.92 (5), p.1002-1009
• Main Authors: Lettini, S. E, Sukhdeo, M. V K
• Format: Article
• Language: English
• Subjects: ambient temperature; Animals; Biological and medical sciences; Carbon dioxide; Carbon Dioxide - metabolism; cell respiration; cold tolerance; dehydration (animal physiology); Desiccation; desiccation resistance; Energy Metabolism; Environmental conditions; Ethanol; Field tests; Freezing; Fundamental and applied biological sciences. Psychology; gastrointestinal nematodes; General aspects; General aspects and techniques. Study of several systematic groups. Models; Glycerol; Haemonchus - physiology; Haemonchus contortus; Humidity; Infective stages; Intestinal parasites; Invertebrates; Larva - physiology; Larvae; LIFE CYCLES-SURVEY; lipid content; Lipid metabolism; Lipids; Lipids - analysis; Low temperature; Metabolism; mortality; Nemathelminthia. Plathelmintha; Nematode larvae; Nematodes; Nematospiroides dubius - physiology; Nippostrongylus - physiology; Parasitology; Pastures; Rehydration; Relative humidity; resistance mechanisms; Respiration; Ruminants; Sheep; Survival; Temperature; Trichostrongylidae; Trichostrongylus - physiology; Trichostrongylus colubriformis
• ISSN: 0022-3395; 1937-2345
• DOI: 10.1645/GE-784R.1

This study demonstrates that infective-stage larvae of 2 trichostrongyle ruminant gastrointestinal nematodes, Haemonchus contortus and Trichostrongylus colubriformis, can enter into anhydrobiotic states when completely desiccated. Larvae of control trichostrongyle species, Heligmosomoides polygyrus and Nippostrongylus brasiliensis, that infect mice were unable to survive desiccation or to enter into anhydrobiosis. Ruminant larvae were able to survive up to 7 desiccation/rehydration cycles, and, during anhydrobiosis, metabolic activity was decreased and survival of the larvae was prolonged both in the laboratory and in the field. Relative humidity had no effect on ruminant larval survival after anhydrobiosis compared with controls. Temperature had a significant effect, 85.8 ± 2.3% of larvae in anhydrobiosis could survive low temperatures (0 C) that killed all control larvae. Metabolic activity, measured by changes in lipid content and CO2 respiration, was significantly lower in larvae that entered anhydrobiosis compared with controls (P < 0.05). In field experiments using open-meshed chambers under ambient environmental conditions, larvae in anhydrobiosis had significantly higher survival rates in the field compared with controls (P < 0.05) during summer and winter trials. These data suggest that anhydrobiosis in ruminant larvae promotes survival at freezing temperatures, decreases metabolic activity, and prolongs survival under natural field conditions.