Schistosoma haematobium Cercarial Host-Finding and Host-Recognition Differs from That of S. mansoni

• Published in: The Journal of parasitology Vol. 80; no. 3; pp. 345 - 353
• Main Authors: Haas, Wilfried, Haberl, Bernhard, Schmalfuss, Gerold, Khayyal, Mohamed T.
• Format: Journal Article
• Language: English
• Published: Lawrence, KS American Society of Parasitologists 01-06-1994
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Arginine - metabolism; Autoecology; Behavior; Biological and medical sciences; Cercariae; Culture Media; Fatty acids; Fatty Acids - metabolism; Fundamental and applied biological sciences. Psychology; Host-Parasite Interactions; Hot Temperature; Humans; Invertebrates; Lipids; Movement; Parasite hosts; Parasitology; Petroleum; Protozoa. Invertebrata; Schistosoma haematobium - physiology; Schistosoma mansoni - physiology; Skin - chemistry; Skin - parasitology; Snails; Swimming; Temperature gradients; Unsaturated fatty acids; Host parasite relation; Schistosoma mansoni; Life history; Schistosoma haematobium; Exploratory behavior; Plathelmintha; Thermal stimulus; Trematoda; Cercaria; Penetration; Arginine; Helmintha; Substrate attachment; Skin; Invertebrata; Chemical stimulus; Adaptation
• ISSN: 0022-3395; 1937-2345
• DOI: 10.2307/3283401

Schistosoma haematobium cercarial host-finding responses differ from those of Schistosoma mansoni. The attachment response to warm substrata is more sensitive and intense and is inhibited by unphysiologically warm substrata. Attachment is also stimulated by L-arginine as the exclusive chemical cue of the human skin surface (threshold 3 µM); however, the response is drastically lower than that of S. mansoni cercariae. No chemical host stimulus could be identified for an enduring contact with the host after attachment. After attachment, the cercariae creep in a temperature gradient toward heat source; their response is, however, more sensitive than that of S. mansoni (threshold 0.03 vs. 0.15 C/mm). Creeping S. haematobium cercariae orientate in chemical gradients in the same way as S. mansoni cercariae toward L-arginine as the exclusive chemical signal of the human skin surface. The selective benefit of this behavior is not yet understood. The penetration of both species is stimulated by free fatty acids from the human skin surface, not by heat. Thus, S. haematobium responds more to thermal host signals, whereas S. mansoni prefers chemical host signals.