Chuyên mục: Giun – Sán

Tháng Mười 11, 2017

Jong-Yil Chai1, Nguyen Van De2 and Woon-Mok Sohn3,*
1Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, and Institute of Endemic Diseases, Seoul National
University Medical Research Center, Seoul 110-799, Korea; 2Department of Parasitology, Hanoi Medical University, Hanoi, Vietnam; 3Department of
Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-751, Korea
Abstract: The prevalence of foodborne trematode (FBT) metacercariae was investigated in fsh from 2 localities of northern Vietnam in 2004-2005. Freshwater fsh (9 species) were collected from local markets in Hanoi City (n=76) and Nam
Dinh Province (n=79), and were examined for FBT metacercariae using the artifcial digestion technique. Adult flukes
were obtained from hamsters experimentally infected with the metacercariae at day 8 post-infection. Three (Haplorchis
pumilio, Centrocestus formosanus, and Procerovum varium) and 6 (Haplorchis taichui, H. pumilio, C. formosanus, P. varium, Stellantchasmus falcatus, and Heterophyopsis continua) species of FBT metacercariae were detected in the 2 regions, respectively. Overall, H. pumilio metacercariae were detected in 104 (80.0%) of 130 fsh examined (metacercarial
density per infected fsh; 64.2). C. formosanus metacercariae were found in 37 (40.2%) of 92 fsh (metacercarial density;
14.7). P. varium metacercariae were detected in 19 (63.3%) of 30 fsh (Anabas testudineus and Mugil cephalus) (metacercarial density; 247.7). S. falcatus metacercariae were found in all 10 M. cephalus examined (metacercarial density; 84.4).
H. continua metacercariae (2 in number) were detected in 1 fsh of Coilia lindmani. Morphologic characteristics of the FBT
metacercariae and their experimentally obtained adults were described. The results have demonstrated that various FBT
species are prevalent in northen parts of Vietnam.
Key words: Haplorchis taichui, Haplorchis pumilio, Centrocestus formosanus, Procerovum varium, Stellantchasmus falcatus, Heterophyopsis continua,
foodborne trematode, metacercaria, fsh, Vietnam

Tháng Mười 11, 2017

Paiboon Sithithaworn a,b,⁎, Ross H. Andrews a,b, Nguyen Van De c, Thitima Wongsaroj d, Muth Sinuon e,
Peter Odermatt f, Yukifumi Nawa g, Song Liang h, Paul J. Brindley i, Banchob Sripa b,j,
This review highlights the current status and control of liver fluke infections in the Mekong Basin countries
where Opisthorchis and Clonorchis are highly endemic. Updated data on prevalence and distribution have
been summarized from presentations in the “96 Years of Opisthorchiasis. International Congress of Liver
Flukes”. It is disturbing that despite treatment and control programs have been in place for decades, all countries of the Lower Mekong Basin are still highly endemic with O. viverrini and/or C. sinensis as well as alarmingly high levels of CCA incidence. A common pattern that is emerging in each country is the difference in
transmission of O. viverrini between lowlands which have high prevalence versus highlands which have
low prevalence. This seems to be associated with wetlands, flooding patterns and human movement and settlement. A more concerted effort from all community, educational, public health and government sectors is
necessary to successfully combat this fatal liver disease of the poor.
© 2011 Elsevier Ireland Ltd. All rights reserved.

Tháng Mười 11, 2017

Thanh Hoa Le,a Khue Thi Nguyen,a Nga Thi Bich Nguyen,a Huong Thi Thanh Doan,a Xuyen Thi Kim Le,a Chau Thi Minh Hoang,a and Nguyen Van Deb
Department of Immunology, Institute of Biotechnology, Vietnam Academy of Science and Technology, Cau Giay, Hanoi, Vietnam,a and Department of Parasitology, Hanoi Medical University, Dong Da, Hanoi, Vietnam.

A single-step multiplex PCR (here referred to as a duplex PCR) has been developed for simultaneous detection and diagnosis of. Fasciola hepatica and F. gigantica. These species overlap in distribution in many countries of North and East Africa and Central, and Southeast Asia and are similar in egg morphology, making identification from fecal samples difficult. Based on a comparative alignment of mitochondrial DNA (mtDNA) spanning the region of cox1-trnT-rrnL, two species-specific forward primers were designed, FHF (for F. hepatica) and FGF (for F. gigantica), and a single reverse primer, FHGR (common for both species). Conventional PCR followed by sequencing was applied using species-specific primer pairs to verify the specificity of primers and the identity of Fasciola DNA templates. Duplex PCR (using three primers) was used for testing with the DNA extracted from adult worms, miracidia, and eggs, producing amplicons of 1,031 bp for F. hepatica and 615 bp for F. gigantica. The duplex PCR failed to amplify from DNA of other common liver and intestinal trematodes, including two opisthorchiids, three heterophyids, an echinostomid, another fasciolid, and a taeniid cestode. The sensitivity assay showed that the duplex PCR limit of detection for each Fasciola species was between 0.012 ng and 0.006 ng DNA. Evaluation using DNA templates from 32 Fasciola samples (28 adults and 4 eggs) and from 25 field-collected stools of ruminants and humans revealed specific bands of the correct size and the presence of Fasciola species. This novel mtDNA duplex PCR is a sensitive and fast tool for accurate identification of Fasciola species in areas of distributional and zonal overlap.

Tháng Mười 11, 2017

Prevalence and Intensity of Fish-Borne Zoonotic Trematodes in Cultured Freshwater Fish From Rural and Urban Areas of Northern Vietnam

Nguyen Van De, Thanh Hoa Le*, and K. D. Murrell`, Department of Parasitology, Hanoi Medical University, 01. Ton Taht Tung Street, Hanoi, Vietnam; *Institute of Biotechnology of Vietnam, 18 Haong Quoc Viet Road, Hanoi, Vietnam; Department of Veterinary Pathobiology, Faculty of Life Science, University of Copenhagen, Denmark; `to whom correspondence should be addressed. e-mail: kdmurrell@comcast ABSTRACT: Consumption of raw freshwater fish produced in both rural farm and urban wastewater ponds is a common practice in Vietnam. The present study assessed the risk of fish-borne zoonotic trematode (FZT) infection from fish raised in both these aquaculture systems in northern Vietnam. The diversity, p

Tháng Mười 11, 2017

Nguyen Van De1,*, Thanh Hoa Le2 and Jong-Yil Chai3
1Department of Parasitology, Hanoi Medical University, Hanoi, Vietnam; 2Department of Immunology, Institute of Bio-Technology, Hanoi, Vietnam;
3Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul 110-799, Korea
Abstract: From 2006 to 2010, hospitals in Hanoi treated 10 human patients for diroflariasis. The worms were collected
from parasitic places, and identifcation of the species was completed by morphology and molecular methods. Ten parasites were recovered either from the conjunctiva (n=9) or subcutaneous tissue (n=1). The parasites were 4.0-12.5 cm in
length and 0.5-0.6 mm in width. Morphological observations suggested all parasites as Diroflaria repens. Three of the 10
parasites (1 from subcutaneous tissue and 2 from eyes) were used for molecular confrmation of the species identifcation. A portion of the mitochondrial cox1 (461 bp) was amplifed and sequenced. Nucleotide and amino acid homologies
were 95% and 99-100%, respectively, when compared with D. repens (Italian origin, GenBank AJ271614; DQ358814).
This is the frst report of eye diroflariasis and the second report of subcutaneous tissue diroflariasis due to D. repens in
Vietnam.
Key words: Diroflaria repens, case report, eye, subcutaneous tissue, PCR, mitochondrial cox1, Vietnam

Tháng Mười 11, 2017

Thanh Hoa Le,a Nga Thi Bich Nguyen,a Nam Hai Truong,b and Nguyen Van Dec
Department of Immunology, Institute of Biotechnology, Vietnam Academy of Science and Technology (VAST), Cau Giay District, Hanoi, Vietnama; Department of Genetic
Engineering, Institute of Biotechnology, VAST, Cau Giay District, Hanoi, Vietnamb; and Department of Parasitology, Hanoi Medical University, Dong Da District, Hanoi,
Vietnamc
Mitochondrial DNA sequences offer major advantages over the more usual nuclear targets for loop-mediated isothermal amplification approaches (mito-LAMP) because multiple copies occur in every cell. Four LAMP primers [F3, FIP(F1cF2),
BIP(B1cB2), and B3] were designed based on the mitochondrial nad1 sequence of Opisthorchis viverrini and used for a highly
specific assay (mito-OvLAMP) to distinguish DNA of O. viverrini from that of another opisthorchiid (Clonorchis sinensis) and
other trematodes (Haplorchis pumilio, Haplorchis taichui, Fasciola hepatica, and Fasciola gigantica). Conventional PCR was
applied using F3/B3 primer pairs to verify the specificity of the primers for O. viverrini DNA templates. All LAMP-positive samples could be detected with the naked eye in sunlight, by gel electrophoresis (stained with ethidium bromide), and by addition of
SYBR green I to the product in sunlight or under UV light. Only DNA from O. viverrini yielded amplification products by LAMP
(and by PCR verification), and the LAMP limit of detection was as little as 100 fg (104 ng DNA), indicating that this assay is 10
to 100 times more sensitive than PCR. Field testing was done using representative egg and metacercarial samples collected from
localities where the fluke is endemic. With the advantages of simplicity, rapidity, sensitivity, and cost effectiveness, mito-OvLAMP is a good tool for molecular detection and epidemiology studies in regions or countries where O. viverrini is endemic,
which can lead to more effective control of opisthorchiasis and trematodiasis.

Tháng Mười 11, 2017

Nguyen Van De1,*, Nguyen Vu Trung2, Nguyen Hong Ha2, Vu Thi Nga3, Nguyen Minh Ha2, Pham Thanh Thuy4,
Le Van Duyet2 and Jong-Yil Chai5
1Department of Parasitology, Hanoi Medical University, Vietnam; 2National Hospital of Tropical Diseases, Hanoi, Vietnam; 3National Centre for
Veterinary Diagnosis, Hanoi, Vietnam; 4Bach Mai Hospital, Hanoi, Vietnam; 5Department of Parasitology and Tropical Medicine, Seoul National
University College of Medicine, Seoul 110-799, Korea
Abstract: The 5th outbreak of trichinosis occurred in a mountainous area of North Vietnam in 2012, involving 24 patients
among 27 people who consumed raw pork together. Six of these patients visited several hospitals in Hanoi for treatment.
Similar clinical symptoms appeared in these patients within 5-8 days after eating infected raw pork, which consisted of
fever, muscle pain, diffcult moving, edema, diffcult swallowing, and diffcult breathing. ELISA revealed all (6/6) positive
reactions against Trichinella spiralis antigen and all cases showed positive biopsy results for Trichinella sp. larvae in the
muscle. The larvae detected in the patients were identifed as T. spiralis (Vietnamese strain) by the molecular analysis of
the mitochondrial cytochrome c oxidase subunit III (cox3) gene.
Key words: Trichinella spiralis, muscle pain, pork, fever, ELISA, Vietnam

Tháng Mười 11, 2017

Nguyen Van De1,*, Thanh Hoa Le2 and Jong-Yil Chai3
1Department of Parasitology, Hanoi Medical University, Hanoi, Vietnam; 2Department of Immunology, Institute of Bio-Technology, Hanoi, Vietnam;
3Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul 110-799, Korea
Abstract: A 26-year-old man residing in a village of Thai Nguyen Province, North Vietnam, visited the Thai Nguyen Provincial Hospital in July 2008. He felt a bulge-sticking pain in his left eye and extracted 5 small nematode worms by himself
half a day before visiting the hospital. Two more worms were extracted from his left eye by a medical doctor, and they were
morphologically observed and genetically analyzed on the mitochondrial cytochrome c oxidase 1 gene. The worms were
1 male and 1 female, and genetically identical with those of Thelazia callipaeda. By the present study, the presence of human T. callipaeda infection is frst reported in Vietnam.
Key words: Thelazia callipaeda, oriental eyeworm, eye, human case, Vietnam

Tháng Mười 11, 2017

Jong-Yil Chai1, Woon-Mok Sohn2,*, Byoung-Kuk Na2 and Nguyen Van De3
1Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul 110-799, Korea; 2Department of
Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-751, Korea; 3Department of
Parasitology, Hanoi Medical University, Hanoi, Vietnam
Abstract: We detected metacercariae of Echinostoma revolutum in Filopaludina sp. snails purchased from a local market
in Nam Dinh Province for the frst time in Vietnam. Adult flukes were harvested from experimentally infected hamsters at
days 14 and 17 post-infection. The metacercariae were round, 170-190 μm (n=15) in diameter, with a cyst wall thickness
of about 12 μm. A total of 37 collar spines were arranged around the head collar, and large excretory granules were seen
in 2 canals of the excretory bladder. The 14-day old adult flukes were elongated, ventrally curved, and 5.0-7.2×0.8-1.3 mm
(n=20). The head collar had a total of 37 collar spines arranged in 2 alternating rows, including 5 corner spines on each
side. The cirrus sac contained a saccular seminal vesicle, a prostatic gland, and an unarmed cirrus. Two tandem testes
were smooth or slightly lobed. Eggs were ovoid to elliptical, 110-118×70-75 μm. These morphological characters were
similar to those of E. revolutum and E. jurini. We tentatively identifed it as E. revolutum because the validity of E. jurini remains to be elucidated. The taxonomic relationship of E. revolutum and E. jurini is discussed.
Key words: Echinostoma revolutum, Echinostoma jurini, echinostome, metacercaria, Filopaludina snail, Vietnam

Tháng Mười 11, 2017

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