No abstract available.
Animals* ; Viruses*

Genotypes of hepatitis C virus are clinically relevant to epidemiology, prognosis and therapeutical management of HCV infection. Our study aims to compare different methods for HCV genotyping. Hepatitis C genotypes and subtypes of infected patients in Ho Chi Minh city was determined by serological typing using HCV serotyping 1-6 (Murex company), by molecular typing using Innolipa HCV II assay (Innogenetics NY) and direct sequencing of core and NS5b region. Our results show that the hepatitis C virus by analysing the sequences of the core and NS5b regions gave concordant results. The NS5b region is reliable for the identification of HCV subtype 6 circulating in Viet Nam.
Hepacivirus ; Viruses

Haemagglutination Inhibition Technique was applied to study conversion anti-Japanese encephalitis (JE) virus antibodies in pigs in Hoai Duc, Ha Tay, in 2002. The results showed that antibody conversion in pigs occurs year-round. Vero and C6/36 cells were used to isolate JE virus. From 83 mosquito pools and 30 pig blood samples, 7 JE viruses strains were isolated from mosquito pools, and 4 JE viruses strains were isolated from pig blood samples. These JE viruses strains were isolated either in the epidemic or in the non epidemic season. Sequencing of E gene region of JE virus strains that were isolated from mosquitoes and pigs, circulating of genotype I of JE virus in North Vietnam in 2002
Encephalitis Virus, Japanese ; Encephalitis Viruses ; Encephalitis ; Viruses

No abstract available.
Bronchiolitis* ; Respiratory Syncytial Viruses*

In 1998-1999, 124 human sera and 27 rodents' sera samples were examined for Hanta virus antibodies. The results showed that 4.03% of human sera samples and 3.37% of rodent sera samples were positive with Hanta virus.
Viruses ; Hantaan virus ; epidemiology

From 1991 to 1994, 203 poliovirus positive cases were identified among 559 patients with acute flaccid paralysis. Of these 207 isolates: 175 cases were caused by poliovirus type 1, 7 by type 2 and 11 type 3. Most of these isolates were intratypically differentiated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Of the studied 142 isolates: 107 were wild type 1 poliovirus strains, 7 were wild type 3 poliovirus strains, the remaining strains were Sabin vaccine-like strains. 107 wild type 1 poliovirus strains were divided into 7 groups by PCR-RFLP patterns and were also classified into 3 genomic groups by nucleotide sequencing and phylogenetic analysis. There were 3 unique wild poliovirus strains were circulating in Northern Vietnam during period 1991-1993. In 1994, no wild poliovirus was isolated
Poliovirus ; Viruses ; epidemiology

The nucleotide sequence from position 5966 to 6582 of the hepatitis E virus (HEV) genome was determined from a Vietnamese isolate obtained from the acute-phase sera of a sporadic case of acute hepatitis. This sequence was compared with the corresponding sequences of 17 HEV strains deposited in GenBank. This analysis revealed that the Vietnamese strain of HEV belongs to genotype 1 closely related to the Myanmar, India, and Nepal subtypes. Phylogenetic analysis demonstrated genotype-specific nucleotides and aminoacids within this region
Hepatitis E ; viruses

Composite recombinant antigens were constructed from diagnostically relevant antigenic regions derived from the hepatitis C virus (HCV) core, NS3, NS4 and NS5 proteins. Antigenic properties of each antigenic region included into these composite antigens were preliminary evaluated by testing recombinant proteins containing the HCV protein fragments of different sizes encoded by overlapping PCR fragments. Immunoreactive recombinant proteins were tested by EIA against a large panel of anti-HCV positive and negative serum specimens to identify the most immunoreactive and specific proteins. Three composite antigens were designed based on this analysis. The fist composite protein was composed of one antigenic region from core, NS3 and NS4. The second protein contained an additional NS4 region, while the third protein contained all immunodominant antigenic regions identified in this study. After EIA analysis for the detection of anti-HCV, each composite protein showed almost identical results compared to combining each of the corresponding individual proteins.
hepatitis C ; antigens ; viruses

The integrated cell culture-PCR (ICC-PCR) method has been suggested as an improved method for detection of viruses in water environments. We tested 57 source waters including finished water samples in Gyeonggi-do for enteric viral contamination using total culturable virus assay (TCVA) using BGMK cells and ICC-PCR. Nineteen of the 57 source water samples (33.3%) exhibited the cytopathic effect (CPE) on BGMK cells and no finished water did exhibited CPE. Nineteen samples (33.3%) of the 57 were positive for reoviruses. For the enteroviruses, only 3 samples (5.3%) of the 57 samples showed positive results. By using ICC-PCR method, 202 flasks from source water samples were positive for enteroviruses and reoviruses. Three samples from source water were positive for both viruses. However, any flasks tested was not co-infected with two types of viruses. While the enteric viral frequencies in TCVA and ICC-PCR were similar, the viral frequency for reoviruses at first passage in two type of method was higher in ICC-PCR (94.7%) than TCVA (56.9%).
Enterovirus ; Viruses ; Water

Natural killer (NK) cells play a pivotal role in early surveillance against virus infection and cellular transformation, and are also implicated in the control of inflammatory response through their effector functions of direct lysis of target cells and cytokine secretion. NK cell activation toward target cell is determined by the net balance of signals transmitted from diverse activating and inhibitory receptors. A distinct feature of NK cell activation is that stimulation of resting NK cells with single activating receptor on its own cannot mount natural cytotoxicity. Instead, specific pairs of co-activation receptors are required to unleash NK cell activation via synergy-dependent mechanism. Because each co-activation receptor uses distinct signaling modules, NK cell synergy relies on the integration of such disparate signals. This explains why the study of the mechanism underlying NK cell synergy is important and necessary. Recent studies revealed that NK cell synergy depends on the integration of complementary signals converged at a critical checkpoint element but not on simple amplification of the individual signaling to overcome intrinsic activation threshold. This review focuses on the signaling events during NK cells activation and recent advances in the study of NK cell synergy.
Killer Cells, Natural ; Viruses