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Nguyen S.T.,Central Vietnam Veterinary Institute | Fukuda Y.,Tohoku University | Nguyen D.T.,Central Vietnam Veterinary Institute | Tada C.,Tohoku University | Nakai Y.,Tohoku University
Tropical Animal Health and Production | Year: 2016

Little information is available on the epidemiology of Giardia duodenalis in beef cattle from Vietnam. This study was performed to determine the prevalence and genotypes/assemblages of G. duodenalis in native beef calves younger than 6 months in the region. A total of 412 calf fecal samples, randomly selected from 99 small-scale farms located in DacLac and KhanhHoa provinces, central Vietnam, were screened for the presence of G. duodenalis cysts using the zinc-sulfate flotation method followed by iodine staining. The overall prevalence on the sample and herd levels were 13.8 % (57/412) and 42.4 % (42/99), respectively. Molecular analysis in the β-giardin and triosephosphate isomerase genes demonstrated the presence of only G. duodenalis assemblage E in the animals. Since assemblage E has been rarely reported in humans, the zoonotic risk in beef calves in the region appears to be minimal. © 2016, Springer Science+Business Media Dordrecht.


Vu-Khac H.,Central Vietnam Veterinary Institute | Duong V.Q.B.,Central Vietnam Veterinary Institute | Chen S.-C.,National Pingtung University of Science and Technology | Pham T.H.,Central Vietnam Veterinary Institute | And 2 more authors.
Diseases of Aquatic Organisms | Year: 2016

A total of 480 cage-cultured fish were collected from 4 coastal provinces in central Vietnam to investigate the causative agent of nocardiosis. Fish displayed unique characteristics such as paleness and lethargy and exhibited haemorrhages and ulcers on the skin. Prominent white nodules varying in size were observed in the spleen, kidney, and liver. Furthermore, histopathological sections showed typical granulomatous lesions in these organs. Using the Ziehl-Neelsen staining method, isolated bacteria exhibited acid-fast, bead-like filament morphology when cultured in brain-heart infusion medium or Ogawa medium. Phylogenetic analysis of 16S rDNA confirmed that the isolated bacterium was Nocardia seriolae. This study demonstrates for the first time an outbreak of N. seriolae in snubnose pompano in central Vietnam. © Inter-Research 2016.


Nguyen S.T.,Tohoku University | Nguyen S.T.,Central Vietnam Veterinary Institute | Fukuda Y.,Tohoku University | Tada C.,Tohoku University | And 4 more authors.
Parasitology Research | Year: 2012

The aims of this study were to investigate the prevalence of Cryptosporidium and to characterize the genotype distribution of Cryptosporidium isolates in native beef calves 2-6 months old in Dac Lac province, central Vietnam. The presence of Cryptosporidium oocysts was determined using the modified Ziehl-Neelsen staining method. The overall prevalence on the sample and herd levels were 18.9 % (44/232) and 50 % (20/40), respectively. Genotyping based on PCR and sequence analysis of the 18 S rRNA gene revealed occurrence of the two nonzoonotic species Cryptosporidium ryanae and Cryptosporidium bovis, with the former as a dominant species in the animals. The absence of the zoonotic species Cryptosporidium parvum in calves examined suggests that the native beef calves 2-6 months old in the study area are unlikely to contribute to human cryptosporidiosis transmission. ©Springer-Verlag 2012.


Nguyen S.T.,Tohoku University | Nguyen S.T.,Central Vietnam Veterinary Institute | Fukuda Y.,Tohoku University | Tada C.,Tohoku University | And 4 more authors.
Parasitology Research | Year: 2013

Little information is available on the epidemiology of Cryptosporidium in pigs in central Vietnam. The aims of this study were to investigate the prevalence and to characterize the genotype distribution of Cryptosporidium isolates in pigs in this region. A total of 193 pig fecal samples were screened for the presence of Cryptosporidium oocysts using the modified Ziehl-Neelsen staining method, and 28 (overall prevalence 14.5 %) were identified as positive by microscopic observation. Positive samples were further analyzed by polymerase chain reaction amplification and sequencing. Genetic identification based on the 18S ribosomal RNA and 70 kDa heat shock protein genes revealed that pigs in Vietnam are infected with two species/genotypes (Cryptosporidium suis and Cryptosporidium pig genotype II). This study is the first molecular characterization of Cryptosporidium in pigs in Vietnam. The presence of these host-adapted species/genotypes suggests that pigs may not pose a significant public health risk in this area. More extensive studies are necessary to ascertain the zoonotic potential of Cryptosporidium in porcine hosts in Vietnam. © 2012 Springer-Verlag.


Nguyen D.T.,Central Vietnam Veterinary Institute | Bilic I.,University of Veterinary Medicine Vienna | Jaskulska B.,University of Veterinary Medicine Vienna | Hess M.,University of Veterinary Medicine Vienna | And 6 more authors.
Avian Diseases | Year: 2015

This study was performed to investigate the prevalence and to characterize the genetic diversity of Histomonas meleagridis isolates in chickens in southern Vietnam. A total of 194 chickens, randomly selected from 18 backyard and 18 commercial flocks, were screened for H. meleagridis infection using both macroscopic diagnosis and an 18S rRNA gene-based PCR method. Overall, 12.9% of birds, representing 19 flocks, showed gross lesions typical for histomonosis whereas 25.3% of the birds from 29 flocks were positive by PCR assay. Following initial diagnostic approaches, H. meleagridis-positive samples were further analyzed by sequencing three different genomic loci; the 18S rRNA, alpha-actinin1, and rpb1. Thirteen samples from 12 flocks were genetically identified as H. meleagridis, demonstrating a flock and sample prevalence of 33.3% and 6.7%, respectively. There was no significant difference in prevalence between different farm types, age groups, and seasonality. Genetic analysis demonstrated minor heterogeneity of Vietnamese isolates with 99% homology to H. meleagridis sequences from the database. This is the first survey of the prevalence and genetic characterization of H. meleagridis in chickens in Vietnam. © 2015 American Association of Avian Pathologists.

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