title: Seasonal change in the number of Cryptosporidium parvum oocysts in water samples from the rivers in Hokkaido, Japan, detected by the ferric sulfate flocculation method.
abstract: An epidemiological study was carried out in natural water supplies of Hokkaido, one of the largest dairy prefectures in Japan. To investigate the prevalence of Cryptosporidium parvum (C. parvum) oocysts water samples were collected from three rivers in the eastern area of Hokkaido from August 1999 to October 2001, and C. parvum oocysts were collected and purified by the ferric sulfate flocculation method. The oocysts were detected using the immunofluorescent assay test (IFAT) and 4', 6-diamidino-2-phenylindole (DAPI) staining. The seasonal change in the number of oocysts detected was observed. Oocysts increased in numbers from the late summer to the early autumn (from August to November), thereafter, they exhibited a trend to decrease until December, when no oocysts could be detected. The maximum number of oocysts detected in the three rivers was 3.50, 5.00 and 3.33 oocysts/l, respectively. The oocyst density in river water changed in relation to the season in 1999, 2000 and 2001. This report first cleared up the seasonal changes in C. parvum oocysts number in river water.
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University, Hokkaido, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tsushima
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Karanis
authors.forename: Takenori
authors.initials: T
authors.lastname: Kamada
authors.forename: Levi
authors.initials: L
authors.lastname: Makala
authors.forename: Xuenan
authors.initials: X
authors.lastname: Xuan
authors.forename: Yukinobu
authors.initials: Y
authors.lastname: Tohya
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Akashi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Nagasawa
mesh_terms: D000818:Animals; D002417:Cattle; D016785:Cryptosporidium parvum / Q000302:isolation & purification*; D004785:Environmental Pollutants / Q000302:isolation & purification; D005243:Feces / Q000469:parasitology; D005290:Ferric Compounds; D005428:Flocculation Tests / Q000379:methods*; D005618:Fresh Water / Q000469:parasitology*; D007564:Japan; D033661:Oocysts / Q000302:isolation & purification*; D010270:Parasite Egg Count; D012621:Seasons; D014871:Water Microbiology
chemical_list: D004785:Environmental Pollutants; D005290:Ferric Compounds; C024823:ferric sulfate