Первое сообщение об Auerbachia chakravartyi (Myxosporea: Bilvavulida) из желчного пузыря Megalaspis cordyla во Вьетнаме

В 2017 г. в Тонкинском заливе было исследовано 20 экз. Megalaspis cordyla. Морфологическими и молекулярно-биологическими методами было установлено наличие в желчном пузыре 7 из 20 рыб (35 %) спор Auerbachia chakravartyi Narasimhamurti, Kalavati, Anuradha, Padma, 1990. Это первая находка представителей рода Auerbachia в морских рыбах Вьетнама

Infection status and molecular identification of digenean cercariae in snails in Kim Son district, Ninh Binh Province and Ba Vi district, Ha Noi

In this study, the molecular method was used to identify digenean cercariae from freshwater snails in Kim Son District (Ninh Binh Province) and Ba Vi District Ha Noi. A total of 9 snail species were collected and examined for cercarial infection. Three snail species (Radix swinhoei, Angulyagra polyzonata and Pomacea canaliculata) were not infected, while the other 6 species (Austropeplea viridis, Gyraulus convexiusculus, Parafossarulus striatulus, Bithynia fuchsiana, Melanoides tuberculata and Tarebia granifera) were infected with digenean cercariae at low infection rates, ranging from 2.3% to 6.3%. Seven cercarial groups were identified: Echinostome, Monostome, Parapleurophocercaria, Xiphidiocercaria, Fucocercaria, Gymnocephalous and Megalurous. Snails M. tuberculata and P. striatulus were infected with 4 cercarial groups, A. viridis and G. convexiusculus snails were infected with 2 groups, 2 snail species B. fuchsiana and T. granifera were infected with one group of cercaria. The results of ITS2 sequences analyses of the cercarial groups identified the larvae of 9 trematode species, namely Echinostoma revolutum, Echinochasmus japonicus, Notocotylus intestinalis, Philophthalmus gralli, Haplorchis pumilio, Procerovum cheni, Fasciola gigantica, Australapatemon burti and Cyathocotyle prussica. Among them the last three species, P. cheni, A. burti and C. prussica, were found for the first time in Vietnam. In addition, the ITS-2 sequence of Gymnocephalous cercariae which was previously identified as Sphaeridiotrema monorchis, from P. striatulus snail was 97% similar to that of Sphaeridiotrema pseudoglobulus. Likewise, ITS-2 sequence of Echinostome cercaria from B. fuchsiana snail was 93% similar to that of E. japonicus and that of Xiphidiocercaria cercaria from M. tuberculata snail was 93% similar to Lecithodendrium spathulatum.

Gene diversity and genetic variation in lung flukes (genus Paragonimus)

Paragonimiasis caused by lung flukes (genus Paragonimus) is a neglected disease occurring in Asia, Africa and the Americas. The genus is species-rich, ancient and widespread. Genetic diversity is likely to be considerable, but investigation of this remains confined to a few populations of a few species. In recent years, studies of genetic diversity have moved from isoenzyme analysis to molecular phylogenetic analysis based on selected DNA sequences. The former offered better resolution of questions relating to allelic diversity and gene flow, whereas the latter is more suitable for questions relating to molecular taxonomy and phylogeny. A picture is emerging of a highly diverse taxon of parasites, with the greatest diversity found in eastern and southern Asia where ongoing speciation might be indicated by the presence of several species complexes. Diversity of lung flukes in Africa and the Americas is very poorly sampled. Functional molecules that might be of value for immunodiagnosis, or as targets for medical intervention, are of great interest. Characterisation of these from Paragonimus species has been ongoing for a number of years. However, the imminent release of genomic and transcriptomic data for several species of Paragonimus will dramatically increase the rate of discovery of such molecules, and illuminate their diversity within and between species

Determinants of Vietnam's Potential Trade: A Case Study of Agricultural Exports to the European Union

This study aims at quantifying the determinants of Vietnam’s potential exports to the EU, taking agricultural commodities as a case study. In order to achieve this, we employed a stochastic frontier analysis to estimate Vietnam’s potential agricultural exports, and a system GMM approach to analyze the determinants of the estimated potential agricultural exports of Vietnam. The results showed that Vietnam’s potential agricultural exports to the EU have been high and on an upward trend. In addition, factors such as financial market development, trade freedom, technological readiness, and labor freedom have positive impacts on Vietnam’s potential agricultural exports to the EU. Measures to improve the financial market development, remove trade barriers, increase technological capability, and promote labour freedom are strongly suggested in order to enable Vietnam’s agricultural exports to attain its maximum level

Determinants of Vietnam's Potential Trade: A Case Study of Agricultural Exports to the European Union

This study aims at quantifying the determinants of Vietnam’s potential exports to the EU, taking agricultural commodities as a case study. In order to achieve this, we employed a stochastic frontier analysis to estimate Vietnam’s potential agricultural exports, and a system GMM approach to analyze the determinants of the estimated potential agricultural exports of Vietnam. The results showed that Vietnam’s potential agricultural exports to the EU have been high and on an upward trend. In addition, factors such as financial market development, trade freedom, technological readiness, and labor freedom have positive impacts on Vietnam’s potential agricultural exports to the EU. Measures to improve the financial market development, remove trade barriers, increase technological capability, and promote labour freedom are strongly suggested in order to enable Vietnam’s agricultural exports to attain its maximum level

Paragonimus

This chapter provides state-of-the-art overviews on foodborne diseases caused by Paragonimus in relation to their etiology, biology, epidemiology, clinical presentation, pathogenesis, diagnosis, treatment, and prevention. Lung flukes of the genus Paragonimus are zoonotic agents of paragonimiasis in animals and humans. Their life cycle requires at least three hosts: freshwater snails as the first and crustaceans as the second intermediate hosts. The full diversity of African Paragonimus species remains to be revealed and might be substantial. Based on the location of the worms, symptoms and pathogenicity of paragonimiasis can be divided into four categories: intestinal symptoms, pleural symptoms, parenchymal symptoms, and extrapulmonary paragonimiasis. Tegumental spines, subtegumental cells, morphology of intestine, and ypical egg sections are features to identify the worm as Paragonimus. The dot immunogold filtration assay (DIGFA) is considered to be better than ELISA because it is easier, faster, and cheaper but exhibits comparable sensitivity and specificity

Current status of fasciolosis in Vietnam: an update and perspectives

Vietnam is recognized as endemic for fasciolosis. However, most of the available publications have not been published in international journals. This review is based on national and international Vietnamese publications and highlights the current status of fasciolosis in Vietnam. It also provides some information available in neighboring countries. Updated data on responsible species, distribution, transmission and control aspects, are summarized. The Central region of Vietnam is reported as being highly endemic for fasciolosis with a high number of human patients (more than 20.000 in 2011). Fasciola gigantica is reported as the main species in Vietnam. However, hybrids between F. gigantica and F. hepatica were identified. Both human and animals are infected by the ingestion of raw vegetables and possibly contaminated drinking water. Three lymnaeid snail species (Austropeplea viridis, Radix auricularia, Radix rubiginosa) may act as intermediate host of Fasciola spp. However due to the likely misidentification of snail species and cercariae during the previous decade the critical analysis of published data is difficult. A better understanding of transmission aspects of fasciolosis would allow the implementation of preventive measures of this important neglected zoonotic disease.Epidemiological aspects of fasciolosis in North and Central Vietna

Impact of institutional and cultural distance on ASEAN’s trade efficiency

This paper aims to analyze the impact of institutional and cultural distance on ASEAN’s trade efficiency using bilateral trade data from 2006 to 2016. The authors first employ an improved version of the stochastic frontier model to control endogeneity in estimating efficiency scores and then apply a sys-GMM model to estimate the impact of various distances on trade efficiency. The major findings are summarized as follows: first, trade efficiency of ASEAN’s with the rest of the world is moderate, ranging from 0.48 to 0.60, and shows a downward trend. This indicates that considerable trade potential exists between ASEAN countries and the rest of the world. Second, institutional and cultural distance negatively affects ASEAN’s trade efficiency. Third, trade freedom is an important factor that positively influences ASEAN’s trade efficiency. Based on these findings, this study concludes that efforts to reduce differences in institutions and culture and to promote trade liberalization are strongly suggested as remedies for ASEAN countries to turn potential trade performance into actual trade performance. (Published in Special Issue Recent developments in international economics

Seasonal change of Lymnaeid snails intermediate host of Fasciola gigantica in North and Central Vietnam

Objective: The present study was undertaken to investigate the population dynamics of the intermediate hosts of Fasciola gigantica and the levels of infection in the snails. This would allow identifying the most important transmission periods and suggesting optimal snail control for the area. Methods: Lymnaeid snails were monthly collected by hand picking in Ha Noi (Northern Vietnam) during the period from March 2010 to December 2011 and in Binh Dinh province (Central Vietnam) during the period May and September 2012. Collected snails from different sites were identified based on morphology and the partial 16S rDNA sequence and ITS-2 sequence. Snails were examined for the presence of Fasciola larval by the crushing method and confirmation by multiplex PCR analyses with PCR primer for Fasciola gigantica cathepsin L in parallel with the snail rDNA species specific primer. Result: The density of Lymnaeid populations underwent great changes in relation to the geographical locations and seasons. In Central Vietnam, the Lymnaeid populations reached the peak in the dry/rainy season (May) and decreased sharply in rainy/dry season (September). In contrast, in Hanoi, it reached the peaks in 2 periods (February to April and August to November) of rice cultivation or early stage of growing of rice, and greatly deceased when the rice becomes fully developed. Transmission of fascioliasis in Ha Noi were high when rice cultivation is performed, while the permanent transmission can takes place through the year in Binh Dinh with peak transmission during the dry season