Document Detail


Behavioural strategies used by the hookworms Necator americanus and Ancylostoma duodenale to find, recognize and invade the human host.
MedLine Citation:
PMID:  15614587     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The infective third-stage larvae of the hookworms Necator americanus and Ancylostoma duodenale infect their human hosts by active skin invasion, but A. duodenale is in addition capable of oral infection. The behaviour of the larvae when crawling on surfaces has already been described. Here we analyse in various in vitro systems the other behavioural invasion phases: activation, penetration, and orientation within the host. The larvae normally remained in a motionless, energy-saving, resting posture. An activation to sinusoidal locomotion was stimulated in both species by similar cues such as touch, vibration, water currents, heat, light, and chemicals. Human breath in addition stimulated searching and waving ("nictating") behaviour, which facilitates a change-over to the host. Activating cues in air streams were warmth and moisture; CO2 activated only in combination with warmth and/or moisture. Penetration behaviour in both species was stimulated by warmth and skin extracts. The stimulating components of skin extracts were fatty acids, but their stimulating characteristics differed from those inducing schistosome cercarial skin penetration. After penetration into agar substrates, both species showed thermo-orientation, but only A. duodenale followed gradients of serum. The directing serum cues were not amino acids and glucose (the supposed cues for schistosome blood vessel localization), but Ringer's solution attracted the larvae. The host-finding and host-invasion behaviour of both hookworm species is well adapted to the invasion of the human skin, and there seems to be no particular adaptation of A. duodenale behaviour to the oral infection mode. Hookworm host-finding behaviour is not as complex as that of schistosome cercariae but seems well adapted to the ecological conditions in the transmission sites.
Authors:
Wilfried Haas; Bernhard Haberl; Syafruddin; Irfan Idris; Dennis Kallert; Stephanie Kersten; Petra Stiegeler;
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-11-20
Journal Detail:
Title:  Parasitology research     Volume:  95     ISSN:  0932-0113     ISO Abbreviation:  Parasitol. Res.     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2004-12-22     Completed Date:  2005-09-23     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8703571     Medline TA:  Parasitol Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  30-9     Citation Subset:  IM    
Affiliation:
Institute for Zoology I, University Erlangen-Nuernberg, Staudtstrasse 5, 91058, Erlangen, Germany. whaas@biologie.uni-erlangen.de
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MeSH Terms
Descriptor/Qualifier:
Ancylostoma / isolation & purification,  physiology*
Ancylostomiasis / parasitology
Animals
Feces / parasitology
Hot Temperature
Humans
Larva / pathogenicity,  physiology
Light
Movement
Necator americanus / isolation & purification,  physiology*
Necatoriasis / parasitology
Skin / parasitology
Species Specificity
Vibration
Water
Chemical
Reg. No./Substance:
7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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