TY - JOUR
T1 - Schistosoma mansoni
T2 - Assessment of effects of oleic acid, cercarial age and water temperature on parasite-host attraction
AU - Lee, Vivien S.T.
AU - Burgess, Jefferey L.
AU - Sterling, Charles R.
AU - Lutz, Eric A.
N1 - Funding Information:
This project was supported by the Science Foundation of Arizona, USA . We would like to thank Biodefense and Emerging Infections (BEI) Resources, USA for providing infected snails for this research. Special thanks to Sally Littau for her assistance in the laboratory as well as to Gerald Poplin for his guidance in statistical analysis.
PY - 2013/9
Y1 - 2013/9
N2 - Although the lifecycle of Schistosoma spp. and pathophysiology of schistosomiasis have been established, the mechanism by which cercariae find their host is not well understood. Speculatively, host infection by random and accidental host contact is not as biologically plausible as a biochemical mechanism of mammalian attraction. A few studies have indicated that biochemical cues and temperature gradients may play a role in host identification, attraction and attachment triggers. This study aimed to elucidate these mechanisms more specifically through evaluation of biochemical, age and temperature influences leading to Schistosoma mansoni cercariae attraction and attachment behaviors. Oleic acid, a common unsaturated free fatty acid in the outer layer of human skin, was tested for cercariae attraction across biologically relevant concentrations. Influence of media type (beeswax, nail varnish and agar), age-dependent behavior variability and environmentally appropriate temperatures (22 and 30. °C) were also evaluated. Results indicated that oleic acid at concentrations of 0.3, 0.9 and 1.8. g/mL in beeswax significantly increased median attachment to media (median attachment of 7.50%, 4.20% and 3.71%, respectively, P<. 0.001), compared with plain beeswax, with maximal attachment of 30.30% at 0.3. g/mL of oleic acid. In media containing 0.3. g/mL of oleic acid, cercarial attachment was highest for freshly emerged cercariae to 5. h post-emergence, with a significant decrease in attachment behavior at 10. h post-emergence (P<0.01). Aquatic temperature at which cercariae were exposed to media did not yield significant results (P value >0.05). Biochemical, age and environmental factors influencing cercarial host attraction and attachment behavior have been elucidated by this study. This information will inform further development of devices for environmental surveillance and potentially improve cercarial exposure prevention strategies.
AB - Although the lifecycle of Schistosoma spp. and pathophysiology of schistosomiasis have been established, the mechanism by which cercariae find their host is not well understood. Speculatively, host infection by random and accidental host contact is not as biologically plausible as a biochemical mechanism of mammalian attraction. A few studies have indicated that biochemical cues and temperature gradients may play a role in host identification, attraction and attachment triggers. This study aimed to elucidate these mechanisms more specifically through evaluation of biochemical, age and temperature influences leading to Schistosoma mansoni cercariae attraction and attachment behaviors. Oleic acid, a common unsaturated free fatty acid in the outer layer of human skin, was tested for cercariae attraction across biologically relevant concentrations. Influence of media type (beeswax, nail varnish and agar), age-dependent behavior variability and environmentally appropriate temperatures (22 and 30. °C) were also evaluated. Results indicated that oleic acid at concentrations of 0.3, 0.9 and 1.8. g/mL in beeswax significantly increased median attachment to media (median attachment of 7.50%, 4.20% and 3.71%, respectively, P<. 0.001), compared with plain beeswax, with maximal attachment of 30.30% at 0.3. g/mL of oleic acid. In media containing 0.3. g/mL of oleic acid, cercarial attachment was highest for freshly emerged cercariae to 5. h post-emergence, with a significant decrease in attachment behavior at 10. h post-emergence (P<0.01). Aquatic temperature at which cercariae were exposed to media did not yield significant results (P value >0.05). Biochemical, age and environmental factors influencing cercarial host attraction and attachment behavior have been elucidated by this study. This information will inform further development of devices for environmental surveillance and potentially improve cercarial exposure prevention strategies.
KW - Age-dependent
KW - Attraction properties
KW - Cercariae
KW - Host-detection
KW - Oleic acid
KW - Schistosoma mansoni
KW - Temperature
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U2 - 10.1016/j.ijpara.2013.05.005
DO - 10.1016/j.ijpara.2013.05.005
M3 - Article
C2 - 23770037
AN - SCOPUS:84881556291
SN - 0020-7519
VL - 43
SP - 837
EP - 842
JO - International Journal for Parasitology
JF - International Journal for Parasitology
IS - 10
ER -