Incidence of dengue and chikungunya viruses in mosquitoes and human patients in border provinces of Vietnam.

Background: Dengue virus remains a major threat in Vietnam, while chikungunya virus is expected to become one. Surveillance was conducted from 2012 to 2014 in Vietnam to assess the presence of dengue and chikungunya viruses in patients hospitalized with acute fever in five Vietnam provinces neighboring Lao PDR and Cambodia. Surveillance was extended to mosquitoes present in the vicinity of the patients' households.

Surveillance of dengue and chikungunya infection in Dong Thap, Vietnam: A 13-month study.

Objective: To establish a surveillance in Dong Thap, at the border with Cambodia by assessing the presence of DENV serotypes and CHIKV among patients hospitalized at Dong Thap general hospital.

Methods: Cross-sectional descriptive analysis was conducted on a cohort of 131 patients hospitalized with acute fever and symptoms compatible with dengue or chikungunya. The study was conducted from January 2012 to February 2013.

Role of Aedes aegypti and Aedes albopictus during the 2011 dengue fever epidemics in Hanoi, Vietnam.

Objective: To record the human cases of dengue fever (DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics.

Methods: 24 different outbreak points were recorded in 8 districts between August and December 2011.

Results: 140 patients were hospitalized following dengue diagnostic with a predominance of males (59.

A cluster randomised trial of cloth masks compared with medical masks in healthcare workers.

Objective: The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks.

Setting: 14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam.

Current practices and barriers to the use of facemasks and respirators among hospital-based health care workers in Vietnam.

Background: This study aimed to examine the knowledge, attitudes, and practices towards the use of facemasks among hospital-based health care workers (HCWs) in Hanoi, Vietnam.

Methods: A qualitative study incorporating 20 focus groups was conducted between August 2010 and May 2011. HCWs from 7 hospitals in Vietnam were invited to participate.

A new nidovirus (NamDinh virus NDiV): Its ultrastructural characterization in the C6/36 mosquito cell line.

We describe the ultrastructure of the NamDinh virus (NDiV), a new member of the order Nidovirales grown in the C6/36 mosquito cell line. Uninfected and NDiV-infected cells were investigated by electron microscopy 24-48 h after infection. The results show that the viral nucleocapsid-like particles form clusters concentrated in the vacuoles, the endoplasmic reticulum, and are scattered in the cytoplasm.

The footprint of genome architecture in the largest genome expansion in RNA viruses.

The small size of RNA virus genomes (2-to-32 kb) has been attributed to high mutation rates during replication, which is thought to lack proof-reading. This paradigm is being revisited owing to the discovery of a 3'-to-5' exoribonuclease (ExoN) in nidoviruses, a monophyletic group of positive-stranded RNA viruses with a conserved genome architecture. ExoN, a homolog of canonical DNA proof-reading enzymes, is exclusively encoded by nidoviruses with genomes larger than 20 kb.

Surveillance of Japanese encephalitis virus infection in mosquitoes in Vietnam from 2006 to 2008.

Japanese encephalitis virus (JEV) infection in mosquitoes was monitored in Vietnam from 2006 to 2008. A total of 15,225 mosquitoes, identified as 26 species in five genera were collected and 12,621 were grouped into 447 pools for examination of JEV infection by assays for cytopathic effects in C6/36 cells and by RT-PCR to detect flavivirus RNA. Three JEV strains were isolated from Culex tritaeniorhynchus Giles collected in northern and southern Vietnam and two JEV strains were isolated from Culex vishnui Theobald collected in the highlands of Vietnam.

Litchi-associated acute encephalitis in children, Northern Vietnam, 2004-2009.

Since the end of the 1990s, unexplained outbreaks of acute encephalitis in children coinciding with litchi harvesting (May-July) have been documented in the Bac Giang Province in northern Vietnam. A retrospective ecologic analysis of data for 2004-2009 involving environmental, agronomic, and climatic factors was conducted to investigate the suspected association between the outbreaks and litchi harvesting. The clinical, biological, and immunologic characteristics of the patients suggested a viral etiology.

Mesoniviridae: a proposed new family in the order Nidovirales formed by a single species of mosquito-borne viruses.

Recently, two independent surveillance studies in Côte d'Ivoire and Vietnam, respectively, led to the discovery of two mosquito-borne viruses, Cavally virus and Nam Dinh virus, with genome and proteome properties typical for viruses of the order Nidovirales. Using a state-of-the-art approach, we show that the two insect nidoviruses are (i) sufficiently different from other nidoviruses to represent a new virus family, and (ii) related to each other closely enough to be placed in the same virus species. We propose to name this new family Mesoniviridae.

A novel biosensor based on serum antibody immobilization for rapid detection of viral antigens.

In this paper, we represent a label-free biosensor based on immobilization of serum antibodies for rapid detection of viral antigens. Human serum containing specific antibodies against Japanese encephalitis virus (JEV) was immobilized on a silanized surface of an interdigitated sensor via protein A/glutaraldehyde for electrical detection of JEV antigens. The effective immobilization of serum antibodies on the sensor surface was verified by Fourier transform infrared spectrometry and fluorescence microscopy.

Discovery of the first insect nidovirus, a missing evolutionary link in the emergence of the largest RNA virus genomes.

Nidoviruses with large genomes (26.3-31.7 kb; 'large nidoviruses'), including Coronaviridae and Roniviridae, are the most complex positive-sense single-stranded RNA (ssRNA+) viruses.

Identification of a novel neuropathogenic Theiler's murine encephalomyelitis virus.

Theiler's murine encephalitis viruses (TMEV) are divided into two subgroups based on their neurovirulence. Persistent strains resemble Theiler's original viruses (referred to as the TO subgroup), which largely induce a subclinical polioencephalomyelitis during the acute phase of the disease and can persist in the spinal cord of susceptible animals, inducing a chronic demyelinating disease. In contrast, members of the neurovirulent subgroup cause an acute encephalitis characterized by the rapid onset of paralysis and death within days following intracranial inoculation.

Development of a rapid and comprehensive proteomics-based arboviruses detection system.

A rapid and comprehensive protocol, which combines simple purification and liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI/MS/MS), was developed for identification of arboviruses in infected culture fluid. Using this protocol, various arboviruses were detected including uncommon viruses that were described previously as Banna virus and Yunnan orbivirus. This approach is useful for the rapid screening of viral samples that cannot be identified by conventional gene amplification or immunological methods.

Evidence of frequent introductions of Japanese encephalitis virus from south-east Asia and continental east Asia to Japan.

The Japanese encephalitis virus (JEV) circulating in Japan consists of viruses with multiple phylogenetic origins. Phylogenetic analysis revealed that some JEV strains have recently migrated from south-east and continental east Asian countries. One phylogenetic subcluster of the JEV strains circulating in Japan was closely related to viruses isolated in Vietnam and China's inland region while other JEV subclusters were related to viruses isolated in Shanghai, China.

Isolation and molecular characterization of Banna virus from mosquitoes, Vietnam.

We isolated and characterized a Banna virus from mosquitoes in Vietnam; 5 strains were isolated from field-caught mosquitoes at various locations; Banna virus was previously isolated from encephalitis patients in Yunnan, China, in 1987. Together, these findings suggest widespread distribution of this virus throughout Southeast Asia.

Shift in Japanese encephalitis virus (JEV) genotype circulating in northern Vietnam: implications for frequent introductions of JEV from Southeast Asia to East Asia.

This study analyses the evolutionary relatedness of 16 Japanese encephalitis virus (JEV) isolates (nine from Vietnam and seven from Japan) to previously published JEV strains using E gene sequence data. Vietnamese and Japanese strains isolated between 1986 and 1990 were found to cluster in genotype 3. However, more recent Vietnamese and Japanese strains isolated between 1995 and 2002 grouped within genotype 1, now a dominant though previously unreported genotype in Vietnam.