title: Patterns of trematode infections of Opisthorchis viverrini (Opisthorchiidae) and Haplorchis taichui (Heterophyidae) in human populations from two villages in Savannakhet Province, Lao PDR.
abstract: The liver fluke, Opisthorchis viverrini, and the minute intestinal fluke, Haplorchis taichui, are prevalent in many Asian countries. This study analysed the patterns of infections of O. viverrini and H. taichui in Lahanam and Thakhamlien villages (Savannakhet Province, Lao PDR), in two cross-sectional investigations. Out of a total of 207 human participants, post-anthelmintic treatment positivity rates for expelled worms were 170 (82.1%) for H. taichui and 65 (31.4%) for O. viverrini. Both these species co-exist in the study villages. When each parasite was analysed separately, H. taichui infections reached a plateau among people aged >20 years. Opisthorchis viverrini infection rates were highest in the age group 21-30 years, with decreasing infection rates after the age of 30. Our findings indicated that fish-borne trematode infections were more prevalent among adults. Fish, common intermediate hosts, were acquired in the study area for analysis. The examination of 35 species of fish as intermediate hosts found O. viverrini metacercariae in only six species, and these were found mostly during the month of November. Many farmers who live on the rice fields obtain their food from their immediate environment, including these intermediate-host fish, potentially putting them at greater risk of O. viverrini infection. By contrast, H. taichui metacercariae were found in three species of fish obtained from the market, meaning that anyone could consume them and become infected. If people who work in rice fields limit the species of fish they consume, or avoid consuming raw fish during the month of November, they may reduce their risk of O. viverrini infection.
authors.affiliation: School of Health Sciences, Faculty of Medicine, Niigata University,Niigata,Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sato
authors.affiliation: Station of Malariology, Parasitology, and Entomology of Savannakhet Province, Lao PDR.
authors.forename: T
authors.initials: T
authors.lastname: Pongvongsa
authors.affiliation: Department of Helminthology,Faculty of Tropical Medicine, Mahidol University,Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Sanguankiat
authors.affiliation: Department of Helminthology,Faculty of Tropical Medicine, Mahidol University,Thailand.
authors.forename: T
authors.initials: T
authors.lastname: Yoonuan
authors.affiliation: Department of Global Health,School of Health Sciences, Faculty of Medicine, University of the Ryukyus,Okinawa,Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kobayashi
authors.affiliation: Institute of Public Health, Lao PDR.
authors.forename: B
authors.initials: B
authors.lastname: Boupha
authors.affiliation: Research Institute for Humanity and Nature,Japan.
authors.forename: F
authors.initials: F
authors.lastname: Nishimoto
authors.affiliation: Research Institute for Humanity and Nature,Japan.
authors.forename: K
authors.initials: K
authors.lastname: Moji
authors.affiliation: School of Medicine, Universidade Federal do Tocantins, Palmas,Tocantins,Brazil.
authors.forename: M O
authors.initials: MO
authors.lastname: Sato
authors.affiliation: Department of Helminthology,Faculty of Tropical Medicine, Mahidol University,Thailand.
authors.forename: J
authors.initials: J
authors.lastname: Waikagul
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D018509:DNA, Helminth / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D007812:Laos / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009891:Opisthorchis; D014200:Trematoda / Q000145:classification* / Q000235:genetics; D014201:Trematode Infections / Q000453:epidemiology / Q000469:parasitology*; D055815:Young Adult
chemical_list: D018509:DNA, Helminth