Epidemiological study on Centrocestus armatus metacercariae in the Chikusa River, Hyogo Prefecture, Japan
10.2149/tmh.33.7
- Author:
DAISUKE KIMURA
;
SHOJI UGA
- Publication Type:Journal Article
- Keywords:
Centrocestus armatus metacercariae;
epidemiological study;
freshwater fish;
Chikusa River, Japan
- From:Tropical Medicine and Health
2005;33(1):7-11
- CountryJapan
- Language:English
-
Abstract:
The prevalence of Centrocestus armatus metacercariae in fresh water fishes were examined in Hyogo Prefecture, western Japan for a period of one year from April 2003 to March 2004. Three species of cyprinoid fish, namely Zacco temminckii, Zacco platypus, and Pseudogobio esocinus, were found to harbor metacercariae of C. armatus. The infection rate of metacercariae in Zacco temminckii, Zacco platypus, and Pseudogobio esocinus was 99% (371⁄377), 100% (8⁄8), and 100% (2⁄2), respectively. The mean number of metacercariae recovered was 232 for Z. temminckii, 2,123 for Z. platypus, and 20 for P. esocinus. However, we focused on Z. temminckii in this study because it was found to be the most predominant fish species in the Chikusa River and to have high a metacercariae prevalence as well. In Z. temminckii, metacercariae were distributed in the brain (37%), viscera (35%), muscles (29%) and gills (0%). No metacercariae were recovered from the scales and fins. This is the first report of the occurrence of C. armatus metacercariae in the brain region of the second intermediate fish. The prevalence of C. armatus metacercariae was almost constant throughout the year, and no positive correlation was found between the prevalence and seasonal changes. However, a positive relationship was observed between prevalence of metacercariae and fish length, I.e., the intensity of infection increases with the size of the fish host (p < 0.05). People in the survey area sometimes eat fish raw, indicating enlightenment as well as the countermeasures to prevent C. armatus infection is needed.
