Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-23T05:57:14.538Z Has data issue: false hasContentIssue false
  • English
  • Français

Age-dependent survival and infectivity of Schistosoma mansoni cercariae

Published online by Cambridge University Press:  09 October 2003

P. J. WHITFIELD ,
A. BARTLETT ,
N. KHAMMO  and
R. H. CLOTHIER
P. J. WHITFIELD
Affiliation:
Division of Life Sciences, King's College London, Franklin Wilkins Building, 150 Stamford Street, London SE1 9NN
A. BARTLETT
Affiliation:
Division of Life Sciences, King's College London, Franklin Wilkins Building, 150 Stamford Street, London SE1 9NN
N. KHAMMO
Affiliation:
University of Nottingham, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, Medical School, Queens Medical Centre Nottingham NG7 2UH
R. H. CLOTHIER
Affiliation:
University of Nottingham, Faculty of Medicine and Health Sciences, School of Biomedical Sciences, Medical School, Queens Medical Centre Nottingham NG7 2UH
Get access Rights & Permissions [Opens in a new window]

Abstract

The age dependency of the mortality, spontaneous de-tailing and infectivity of cercariae of Schistosoma mansoni has been determined at 25 °C. Infectivity was assessed with respect to stratum corneum-like differentiated human keratinocyte cultures (validated by comparison with fresh human skin samples) and displayed a complex age-dependent pattern. From 1 to 9 h post-emergence cercariae showed a plateau of maximal infectivity (around 90% attachment). Thereafter, infectivity declined. Immediately after release, infectivity at around 60% was significantly lower than the plateau values and this could be an adaptation for spatial dispersal of cercariae. Age-dependent patterns of cercarial mortality and spontaneous de-tailing closely mirrored the infectivity pattern except in relation to the low initial infectivity value. These findings suggest that, at a population level, the age-dependent decline in cercarial infectivity towards human skin is essentially driven by cercarial mortality. The recently described phenomenon of delayed tail loss (DTL) in S. mansoni cercariae infecting human skin is confirmed in the present study. For cercariae aged up to 13·5 h post-emergence, 90% or more of invading cercariae took their tails with them into the keratinocyte culture. The infection dynamics described in this study suggest that diurnally shed S. mansoni cercariae, with peak emergence around mid-day, will have near maximal infectivity towards humans in contact with water through all remaining daylight hours in the tropics.

Keywords

Schistosoma mansonicercariaeinfectivitysurvivaltail loss
Type
Research Article
Information
Parasitology , Volume 127 , Issue 1 , July 2003 , pp. 29 - 35
Copyright
2003 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

ANDERSON, R. M. & WHITFIELD, P. J. (1975). Survival characteristics of the free-living cercarial population of the ectoparasitic digenean, Transversotrema patialense. Parasitology 70, 295–310.CrossRefGoogle Scholar
BARTLETT, A., BROWN, M., MARRIOTT, C. & WHITFIELD, P. J. (2000). The infection of human skin by schistosome cercariae: studies using Franz cells. Parasitology 121, 49–54.CrossRefGoogle Scholar
COMBES, C., BARTOLI, P. & THÉRON, A. (2002). Trematode transmission strategies. In The Behavioural Ecology of Parasites ( ed. Lewis, E. E., Campbell, J. F. & Sukhedeo, M. V. K.), pp. 1–12. CABI Publishing, Wallingford, UK.CrossRef
EVANS, N. A. & GORDON, D. M. (1983). Experimental studies on the transmission dynamics of the cercariae of Echinoparyphium recurvatum (Digenea, Echinostomatidae). Parasitology 87, 167–174.CrossRefGoogle Scholar
JOURDANE, J. & THÉRON, A. (1987). Larval development: eggs to cercariae. In The Biology of Schistosomes: from Genes to Latrines (ed. Rollinson, D. & Simpson, A. J. G.), pp. 83–113. Academic Press, London.
KHAMMO, N., BARTLETT, A., CLOTHIER, R. H. & WHITFIELD, P. J. (2002). The attachment of Schistosoma mansoni cercariae to human skin cells. Parasitology 124, 25–30.CrossRefGoogle Scholar
LAWSON, J. R. & WILSON, R. A. (1980). The survival of the cercariae of Schistosoma mansoni in relation to water temperature and glycogen utilization. Parasitology 81, 337–348.CrossRefGoogle Scholar
LAWSON, J. R. & WILSON, R. A. (1983). The relationship between the age of Schistosoma mansoni cercariae and their ability to penetrate and infect the mammalian host. Parasitology 87, 481–492.CrossRefGoogle Scholar
LLEWELLYN, J. (1972). Behaviour of Monogeneans. In Behavioural Aspects of Parasite Transmission (ed. Canning, E. U. & Wright, C. A.), pp. 19–30. Academic Press, London.
STANDEN, O. D. (1949). Experimental schistosomiasis II: Maintenance of Schistosoma mansoni in the laboratory, with some notes on experimental infection with S. haematobium. Annals of Tropical Medicine and Parasitology 43, 268–283.CrossRefGoogle Scholar
STIREWALT, M. A. & FREGEAU, W. A. (1968). Effect of selected experimental conditions on penetration and maturation of cercariae of Schistosoma mansoni in mice. II. Parasite-related conditions. Experimental Parasitology 22, 73–95.CrossRefGoogle Scholar
ULMER, M. J. (1971). Site finding behaviour in helminths in intermediate and definitive hosts. In Ecology and Physiology of Parasites (ed. Fallis, A. M.), pp. 123–160. University of Toronto Press, Toronto.
WHITFIELD, P. J., BARTLETT, A., KHAMMO, N., BRAIN, A. P. R., BROWN, M. B., MARRIOTT, C. & CLOTHIER, R. (2003). Delayed tail loss during invasion of human skin by schistosome cercariae. Parasitology 126, 135–140.CrossRefGoogle Scholar
WOLMARANS, C. T., DE KOCK, K. N., STRAUSS, H. D. & BORNMAN, M. (2002). Daily emergence of Schistosoma mansoni and S. haematobium cercariae from naturally infected snails under field conditions. Journal of Helminthology 76, 273–277.Google Scholar