Human enterovirus 71 (EV71) is the major etiologic agent of hand, foot, and mouth disease (HFMD). EV71 outbreaks have been reported in Dak Lak in recent years, however, the genotypes/subgenotypes information and phylogeny of circulating EV71 strains are limited. The objectives of this study were to determine the genotypes/subgenotypes and investigate the phylogeny of EV71 isolates in Dak Lak over a 6-year period. Viruses were isolated from clinical samples from patients with HFMD. In total, 43 EV71 isolates circulated in Dak Lak during 2011-2016 were used for the phylogenetic analysis using complete VP1 gene. The phylogenetic analysis of the VP1 gene revealed that two major genotypes, B and C, were found. Among the 43 EV71 strains, 29 belonged to subgenotype C4, 2 belonged to subgenotype C5, and 12 belonged to subgenotype B5. Of these, the subgenotype C4 was predominant in 2011-2013 and this was later replaced by the subgenotype B5 in 2014. The subgenotype B5 was dominant between 2014 and 2015, and then C4 recirculated in 2016. Our study also indicated that the subgenotypes C4 and B5 emerged into Dak Lak were closely related to variants causing epidemics of HFMD in the southern and central region of Vietnam and Thailand. Sequence analysis showed that nine amino acid mutations were detected in the VP1 region. Our results identified two significant amino acid substitutions (D31N and E145G/Q) associated with enhancing EV71 virulence.

Background Reports of pregnant women infected with avian influenza are rare. Studies showed that A/H5N1 virus can penetrate the placental barrier and infect the fetus. Of six documented cases, four died and two survivors had a spontaneous abortion. Objectives We report a clinical, outcome and epidemiological characteristics of a 36‐week pregnant woman infected with A/H5N1 and her newborn in Soc Trang province of Vietnam in 2012. Methods Epidemiological and laboratory investigations were conducted. Clinical manifestations, progress, treatment and outcome of the case‐patient and her newborn were collected. Human tracheal aspirate, throat swab and serum specimens were tested for influenza A/H5N1, A/H3N1, A/H1N1pdm09 and B by real‐time RT ‐ PCR and genome sequencing. Poultry throat and rectal swabs were tested by PCR and virus isolation. Results Case‐patient hospitalized with high fever and cough, and died after onset 6 days. She continuously slaughtered sick poultry 5 days before illness onset. Clinical manifestation showed rapid progressive severe pneumonia. Her tracheal aspirate sample was positive influenza A/H5N1 virus. Her new‐born was delivered by caesarean section with low birth weight and early onset pneumonia, however fully recovered after 16 days treatment. Neonate's throat swabs and paired serum samples tested negative for influenza A/H5N1. Clade 1.1 A/H5N1 virus was detected in poultry samples, was same clade and highly homogenous with the virus was detected in the mother. Conclusions This was the first documented a live birth from a pregnant woman infected with influenza A/H5N1 virus. Intensive studies are needed to better understand mother‐to‐child transmission of influenza A/H5N1 virus.

Dengue fever is perhaps the most important viral re-emergent disease especially in tropical and sub-tropical countries, affecting about 50 million people around the world every year. In the Central Highlands regions of Vietnam, dengue fever still remains as a major public health issue. Although four viral serotypes have been currently identified, dengue virus type 2 (DENV-2) was involved in the most important outbreaks during 2010-2012, especially, 2010 when the fatality rate highly increased. Detection of genotype of DENV-2 provided information on origin, distribution and genotype of the virus. In this study, DEN-2 isolated from dengue patients during the 2010-2012 epidemics was amplified and sequenced with E gene. The consensus sequences were aligned with reference E gene sequences of globally available Genbank. Phylogenetic analysis was performed using Neighbor-joining and Kimura 2-parameter model to construct phylogenetic tree. A total of 15 isolates (seven from 2010; one from 2011 and seven from 2012) were obtained from human serum samples. Phylogenetic analysis revealed that Asian genotype 1 is currently circulating locally in Central Highlands region. Isolates of this genotype were closely related to viruses from Thailand, Laos, and Cambodia. It indicated that these epidemics maybe imported into the Central Highlands region from South-East Asia neighbor countries. The study results would help in planning for prevention and control of dengue virus in Vietnam. Continuous monitoring of DENV genotypes is necessary to confirm the current findings and detect possible genotype shifts within the dengue viruses in the future. Rev. Biol. Trop. 65 (2): 819-826. Epub 2017 June 01.

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