Human infections of fish-borne trematodes in Vietnam: Prevalence and molecular specific identification at an endemic commune in Nam Dinh province

Tháng Mười 11, 2017

Human infections of fish-borne trematodes in Vietnam: Prevalence and
molecular specific identification at an endemic commune in Nam Dinh province

Nguyen Van De a, Thanh Hoa Le b,
a Hanoi Medical University, 1 Ton That Tung St., Hanoi, Viet Nam
b Institute of Biotechnology, 18 Hoang Quoc Viet Rd., Hanoi, Viet Nam

The prevalence of fish-borne trematodes in humans and their molecular identification was investigated
in the Rang Dong commune of Nam Dinh province, Vietnam, between January 2009 and December 2010.
A total of 405 people in this commune were interviewed on the habit of eating raw fish and all of their
stool samples were collected using the Kato-Katz technique for examination of the presence of fish-borne
trematodes. The worms (and eggs) were first morphologically examined, counted, described and identified, then the representative isolates were subjected for molecular species confirmation. A total of 385
adult flukes collected from 10 patients were morphologically identified to species and defined as
Clonorchis sinensis (14.58%) in Opisthorchiidae family, Haplorchis taichui (32.29%), Haplorchis pumilio
(52.08%) and Centrocestus formosanus (1.04%) in Heterophyidae family. A high rate (77.8%) of the interviewees was found to have the habit of eating raw fish. This habit was attributed to the high infection rate of
fish-borne trematode in humans (22.72%; OR = 2.486). The infection rate of fish-borne trematodes in
males was higher (29.3%) than that in females (16.0%) and increased by age, reaching the highest in
the patients aged 40–59 years (28.2–28.7%). The infection intensity of fish-borne trematode was found
light (336 EPG). Adult flukes were collected from a group of the patients with the highest intensity of
infection and subjected to molecular and phylogenetic analysis using a portion (326 bp) of mitochondrial
cox1. Phylogenetic tree inferred from cox1 sequences using sequence data for 34 isolates of opisthorchid,
heterophyid, fasciolid, paragonimid, schistosomid trematodes and taeniid cestodes revealed that they are
distinct groups. The newly collected with the known clonorchid and heterophyid isolates form the well
defined taxonomic groups, respectively, confirming that
C. sinensis and Haplorchis spp. (H. pumilio and H.
taichui
) were among the collected samples.
 2011 Elsevier Inc. All rights reserved

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