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Infection dynamics of Centrocestus armatus cercariae (Digenea: Heterophyidae) to second intermediate fish hosts
V G V Paller1, D Kimura, S Uga
1Department of Parasitology, Faculty of Health Sciences, Kobe University School of Medicine, Kobe 654-0142, Japan. parasite@kobe-u.ac.jp
The Journal of Parasitology
|June 2, 2007
Summary
Centrocestus armatus cercariae survival and infectivity decline with age, impacting transmission dynamics to fish hosts. Transmission patterns are frequency-dependent, peaking shortly after cercariae emerge from snails.
Area of Science:
- Parasitology
- Ecology
- Helminthology
Background:
- Understanding parasite infection dynamics is crucial for controlling disease transmission.
- Centrocestus armatus cercariae are trematode larvae that infect fish, posing ecological and potential health concerns.
Purpose of the Study:
- To investigate the infection dynamics of Centrocestus armatus cercariae in relation to second intermediate fish hosts.
- To determine the influence of cercarial age on survival, infectivity, and transmission rates.
- To elucidate the transmission patterns of C. armatus cercariae to fish.
Main Methods:
- Cercariae were collected from naturally infected Semisuspira libertina snails.
- Cercarial survival and infectivity were monitored at 2-hour intervals.
- Age-dependent models were used to analyze survival and infectivity data.
- Transmission rates were assessed at varying cercarial densities and exposure times.
Main Results:
- Cercarial survival remained constant for 30 hours before abruptly decreasing, fitting an age-dependent model.
- Cercarial infectivity remained stable for 10 hours then declined, also fitting an age-dependent model.
- Transmission rate peaked at 85% after 1 hour of exposure to fish and plateaued for 5 hours.
- The transmission pattern was found to be frequency-dependent.
Conclusions:
- Cercarial age significantly influences survival, infectivity, and transmission efficiency.
- Age-dependent resource allocation likely explains cercarial mortality.
- Frequency-dependent transmission suggests density-dependent interactions in the host-parasite system.
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