Highly pathogenic avian H5N1 influenza A viruses have spread throughout Asia, Europe, and Africa, raising serious worldwide concern about their pandemic potential. Although more than 250 people have ...been infected with these viruses, with a consequent high rate of mortality, the molecular mechanisms responsible for the efficient transmission of H5N1 viruses among humans remain elusive. We used a mouse model to examine the role of the amino acid at position 627 of the PB2 viral protein in efficient replication of H5N1 viruses in the mammalian respiratory tract. Viruses possessing Lys at position 627 of PB2 replicated efficiently in lungs and nasal turbinates, as well as in cells, even at the lower temperature of 33 degrees C. Those viruses possessing Glu at this position replicated less well in nasal turbinates than in lungs, and less well in cells at the lower temperature. These results suggest that Lys at PB2-627 confers to avian H5N1 viruses the advantage of efficient growth in the upper and lower respiratory tracts of mammals. Therefore, efficient viral growth in the upper respiratory tract may provide a platform for the adaptation of avian H5N1 influenza viruses to humans and for efficient person-to-person virus transmission, in the context of changes in other viral properties including specificity for human (sialic acid alpha-2,6-galactose containing) receptors.
Migratory birds have been implicated in the long-range spread of highly pathogenic avian influenza (HPAI) A virus (H5N1) from Asia to Europe and Africa. Although sampling of healthy wild birds ...representing a large number of species has not identified possible carriers of influenza virus (H5N1) into Europe, surveillance of dead and sick birds has demonstrated mute (Cygnus olor) and whooper (C. cygnus) swans as potential sentinels. Because of concerns that migratory birds could spread H5N1 subtype to the Western Hemisphere and lead to its establishment within free-living avian populations, experimental studies have addressed the susceptibility of several indigenous North American duck and gull species. We examined the susceptibility of Canada geese (Branta canadensis) to HPAI virus (H5N1). Large populations of this species can be found in periagricultural and periurban settings and thus may be of potential epidemiologic importance if H5N1 subtype were to establish itself in North American wild bird populations.
► This is a survey for avian influenza viruses among poultry in northern Vietnam in the year 2009. ► We isolated 21 H6N1 viruses and one H9N2 virus from domestic ducks. ► Phylogenetic analysis ...identified that they were related to those of the Eurasian origins. ► Monitoring on avian influenza in an area where different subtypes are in circulation is important.
We report the genetic characterization of low pathogenic avian influenza (LPAI) viruses isolated from domestic ducks in northern Vietnam in 2009. In total, 22 influenza A viruses consisting of 21 H6N1 subtypes and one H9N2 subtype were isolated from 1488 ducks collected in February, March, and April 2009, accounting the overall virus isolation rate for 1.5%. No H5N1 strain was isolated in this study. Phylogenetic analysis indicated that all the eight genes of the H6N1 and H9N2 subtypes analyzed in this study were similar to those isolated in Korea, southeast China and northern Japan, and wild birds which migrate along the coastal East Asian Flyway are estimated to transmit these viruses. There was no evidence that the H6N1 and H9N2 subtypes share the gene segments with H5N1 subtypes. However, it is important to monitor the prevalence and genetical backgrounds of LPAI viruses among poultry in an area where several different influenza A subtypes are in circulation.
Highly pathogenic H5N1 avian influenza A viruses have been spreading among domestic poultry, wild aquatic birds, and humans in many Asian countries since 2003. The largest number of patients, to ...date, infected with the H5N1 viruses are in Vietnam, where these viruses continue to cause outbreaks in domestic poultry. Here, we molecularly characterized the hemagglutinin and neuraminidase genes of nine H5N1 viruses isolated between January 2004 and August 2005 from domestic poultry in Vietnam. We found that several groups of highly pathogenic H5N1 avian influenza viruses are circulating among these birds, which suggests that H5N1 viruses of different lineages have been introduced into Vietnam multiple times.
Since late 2003, highly pathogenic H5N1 influenza A viruses have spread among poultry and wild aquatic birds in Asian countries. Transmission of these viruses to humans can be lethal. Most human ...cases of infection with H5N1 viruses have occurred in Vietnam. Therefore, to understand the pathogenicity in mammals of these H5N1 viruses, we took viruses isolated from poultry (5 strains) and humans (2 strains) in Vietnam and tested their virulence in mice. The results showed that the H5N1 viruses from humans were pathogenic in mice and that one avian isolate was also pathogenic. These findings suggested that the H5N1 viruses circulating in poultry adapted during replication in humans or that strains pathogenic in mice were transmitted directly to humans.
Rice production in the Mekong River Delta of Vietnam (MRD) is endangered by sea-level rise and an associated increase in the incidence of salinity intrusion. This paper examines the diffusion of salt ...tolerant rice varieties in the MRD that were promoted through Consortium for Unfavorable Rice Environments (CURE) activities. Factors associated with adoption of CURE-related varieties are estimated using a random utilty model and a dataset of 800 farm households with rice fields in salinity prone areas of the MRD. Results suggest that there has been widespread adoption of CURE-related varieties in salinity-prone areas. Further, multivariate analysis reveals that environment and location characteristics, rather than household characteristics, are the most important determinants of adoption. In particular, CURE-related varieties are more likely to be adopted in high-salinity-risk areas that are not protected by salinity barrier gates. Neighbhors' adoption decisions also strongly influence household decisions to adopt CURE-related varieties. The contracting of mechanization, particularly for land preparation and harvest, requires the coordination of village households in timing of planting, harvest and varietal duration. This coordination appears to extend to choice of CURE-related varieties. Finally, CURE-related varieties and other varieties generate similar net revenues in a year with low salinity exposure, suggesting that CURE-related varieties are a low-cost insurance policy against salinity inundation in high risk areas. Combined, these results highlight the need to address complex factors beyond current economic profits, like environment, community choices, and risk mitigation, when designing technologies and policies that support farmer adaptation to climatic change.
Infectious diseases of the central nervous system (CNS) remain common and life-threatening, especially in developing countries. Knowledge of the aetiological agents responsible for these infections ...is essential to guide empiric therapy and develop a rational public health policy. To date most data has come from patients admitted to tertiary referral hospitals in Asia and there is limited aetiological data at the provincial hospital level where most patients are seen.
We conducted a prospective Provincial Hospital-based descriptive surveillance study in adults and children at thirteen hospitals in central and southern Viet Nam between August 2007-April 2010. The pathogens of CNS infection were confirmed in CSF and blood samples by using classical microbiology, molecular diagnostics and serology.
We recruited 1241 patients with clinically suspected infection of the CNS. An aetiological agent was identified in 640/1241 (52%) of the patients. The most common pathogens were Streptococcus suis serotype 2 in patients older than 14 years of age (147/617, 24%) and Japanese encephalitis virus in patients less than 14 years old (142/624, 23%). Mycobacterium tuberculosis was confirmed in 34/617 (6%) adult patients and 11/624 (2%) paediatric patients. The acute case fatality rate (CFR) during hospital admission was 73/617 (12%) in adults and to 42/624 (7%) in children.
Zoonotic bacterial and viral pathogens are the most common causes of CNS infection in adults and children in Viet Nam.
TD.HK01® consists of a Japanese traditional medicine: Nattokinase (derived from soybean) and three other natural components, namely dried Hirudo medicinalis, Semen Mucuna interrupta and Huperzia ...carinata.
TD.HK01® is potentially aimed to the preventive treatment of cardiovascular disease (CVD) in general, and myocardial infarction (MI) in particular.
In this study, a non-invasive method has been used to induce MI in rats, preceded by oral administration of TD.HK01® for 30 consecutive days to determine the potential cardiovascular effect of this pretreatment. Rats were divided into four groups: normal control group, ISO-induced group (isoproterenol (ISO), 150 mg/kg, s.c.) and two groups treated by TD.HK01® in different doses (0.31 and 0.92 g/kg, orally + ISO 150 mg/kg, s.c.).
TD.HK01® treated groups showed significant improvement as in abnormal electrocardiography (ECG) alteration ratio, in decreased biochemical specific markers troponin T and in decreased non-specific biochemical markers (LDH and AST) between each of TD.HK01® treated groups and ISO-induced group. The effect on vascular system was also evaluated through serum eNOS quantification and a notable increase in an anti-oxidative enzyme catalase. All three groups, except the normal control one, had pathological lesions in histopathology in different levels - modest injuries in treated groups and more severe in ISO-induced group.
It is concluded on the basis of the findings that isoproterenol induced MI in all three groups and TD.HK01® did have its potential protective effect in vivo on cardiovascular system.
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Blood cultures are commonly employed to identify bacterial pathogens causing sepsis. PCR assays to diagnose septicemia require extraction of bacterial DNA from blood samples and thus, delay the ...initiation of appropriate antimicrobial treatment. The presence of abundant human DNA may hamper the sensitivity of PCR in the detection of bacteria.
We used serial dilutions of E. Coli spiked pseudo-blood-sepsis samples to develop a simple method that combines the use of a polar detergent solvent and adjustment of the basic pH to remove human DNA. A 16S rRNA gene-based screening algorithm was established to differentiate Gram-positive and Gram-negative groups of bacteria and the family of Enterobacteriaceae. A stringent validation with appropriate controls was implemented. The method of human DNA removal was then applied on 194 sepsis blood samples and 44 cerebrospinal fluid (CSF) samples by real-time PCR.
This uncomplicated and straightforward approach allows to remove up to 98 % of human DNA from peripheral blood of septic patients. The inhibitory effect of human DNA is efficiently prevented and the detection limit of real-time PCR is increased to 10 E. Coli CFUs/ml. This sensitivity is 10 times higher compared to conventional real-time PCR assays. The classical blood culture detected 58/194 (30 %) of sepsis and 9/44 (21 %) of CSF samples. Out of the 194 blood samples tested, the conventional real-time PCR targeting 13 common sepsis causing pathogens correctly detected the bacterial DNA in 16/194 (8 %) only and 14/44 (32 %) in cerebrospinal fluid samples. Our newly established approach was able to provide correct diagnoses in 78 (40 %) of the 194 blood samples and in 14 (32 %) of the CSF samples. The combination of both blood cultures and our technique raised the rate of sepsis diagnoses to 112/194 (58 %). Of the total group tested positive, 46 (24 %) cases showed overlap with the classical methodology.
We report a simple optimized in-house protocol for removal of human DNA from blood sepsis samples as a pre-analytical tool to prepare DNA for subsequent PCR assays. With the detection increase of our in-house DNA removal approach, subsequent PCR assays can reach detection limits of 10 E. coli CFUs/ml and significantly improve the diagnostic rate in blood sepsis cases.
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