Evolution of H5N1 avian influenza viruses in Asia.
An outbreak of highly pathogenic avian influenza avian influenza: see influenza. A (H5N1) has recently spread to poultry in 9 Asian countries. H5N1 infections have caused [greater than or equal to] 52 human deaths in Vietnam, Thailand, and Cambodia from January 2004 to April 2005. Genomic analyses of H5N1 isolates from birds and humans showed 2 distinct clades with a nonoverlapping geographic distribution. All the viral genes were of avian influenza origin, which indicates absence of reassortment with human influenza viruses. All human H5N1 isolates tested belonged to a single clade clade Cladus, subtype Genetics A branch of biological taxa or species that share features inherited from a common ancestor; a single phylogenetic group or line. See Inheritance, Species. and were resistant to the adamantane drugs but sensitive to neuraminidase inhibitors. Most H5N1 isolates from humans were antigenically homogeneous and distinct from avian viruses circulating before the end of 2003. Some 2005 isolates showed evidence of antigenic drift antigenic drift (an´tējen´ik),
n the ability of viruses to alter their genetic makeup, thereby creating mutant antigens and bypassing the antibody barrier of the host. . An updated nonpathogenic H5N1 reference virus, lacking the polybasic polybasic /poly·ba·sic/ (-ba´sik) having several replaceable hydrogen atoms.
adj. cleavage site cleavage site
See restriction site. in the hemagglutinin hemagglutinin /he·mag·glu·ti·nin/ (-gloo´ti-nin) an antibody that causes agglutination of erythrocytes.
cold hemagglutinin one which acts only at temperatures near 4° C. gene, was produced by reverse genetics reverse genetics
methods such as antisense nucleic acids and site-directed mutagenesis that are used to selectively study gene function. Contrasts with classical genetics which depends on the isolation and analysis of cells (animals) with random mutations that can be identified. in anticipation of the possible need to vaccinate vac·ci·nate
To inoculate with a vaccine in order to produce immunity to an infectious disease such as diphtheria or typhus.
Highly pathogenic avian influenza viruses of the H5N 1 subtype (programming) subtype - If S is a subtype of T then an expression of type S may be used anywhere that one of type T can and an implicit type conversion will be applied to convert it to type T. are circulating in eastern Asia with unprecedented epizootic ep·i·zo·ot·ic
Affecting a large number of animals at the same time within a particular region or geographic area. Used of a disease.
ep and epidemic effects (1). Nine Asian countries reported H5N1 outbreaks in poultry in 2004: Cambodia, China, Indonesia, Japan, Laos, Malaysia, South Korea, Thailand, and Vietnam (1). Between 2004 and the first 3 months of 2005, a total of 89 laboratory-confirmed human infections, 52 of which were fatal, were reported to the World Health Organization (WHO) by public health authorities in Vietnam, Thailand, and Cambodia. These records indicate that this outbreak of human H5N1 infections is the largest documented since its emergence in humans in 1997 (2). Efficient viral transmission among poultry caused the virus to spread regionally, leading to the loss of >100 million birds from disease and culling. In contrast, human-to-human transmission of the virus is exceptional but has been described, most recently in a family cluster family cluster Epidemiology A grouping of disorders found in ≥ 2 members of a family in Thailand (3).
The 3 viral envelope viral envelope
The outer structure that encloses the nucleocapsids of some viruses. proteins of influenza A influenza A
Influenza caused by infection with a strain of influenza virus type A.
influenza A Infectious disease An avian virus, especially of ducks–which in China live near the pig reservoir and 'vector'; virus are most medically relevant. The hemagglutinin (HA), neuraminidase neuraminidase /neu·ra·min·i·dase/ (-ah-min´i-das) an enzyme of the surface coat of myxoviruses that destroys the neuraminic acid of the cell surface during attachment, thereby preventing hemagglutination. (NA), and M2 are essential viral proteins targeted by host antibodies or antiviral drugs Antiviral Drugs Definition
Antiviral drugs are medicines that cure or control virus infections.
Antivirals are used to treat infections caused by viruses. such as oseltamivir and rimantadine (4-6). The HA glycoprotein glycoprotein (glī'kōprō`tēn), organic compound composed of both a protein and a carbohydrate joined together in covalent chemical linkage. forms spikes at the surface of virions, mediating attachment to host cell sialoside receptors and subsequent entry by membrane fusion. The NA forms knoblike structures on the surface of virus particles and catalyzes their release from infected cells, allowing virus spread. The M2 is a transmembrane protein that forms an ion channel ion channel
See channel. required for the uncoating process that precedes viral gene expression.
We report on phylogenetic phy·lo·ge·net·ic
1. Of or relating to phylogeny or phylogenetics.
2. Relating to or based on evolutionary development or history. , phenotypic, and antigenic analysis of H5NI viruses from the 2004-2005 outbreak, focusing on these 3 genes, to address questions relevant to the public health response to the outbreak: 1) What is the genetic diversity of H5N 1 viruses involved in human infections? 2) Can the relationship between human and avian H5N1 isolates help explain the source of infection? 3) Do genetic changes correlate with enhanced viral transmissibility trans·mis·si·ble
That can be transmitted: transmissible signals.
trans·mis in humans? 4) How sensitive are HhN1 isolates to antiviral drugs? 5) What is the antigenic similarity between human HhN1 viruses and current candidate vaccines? and 6) Can candidate vaccine reference stocks be developed in time for an effective public health response?
All work involving infectious H5N1 influenza was performed in government-approved biosafety level biosafety level Epidemiology A classification for the degree of caution required when working with specific groups of pathogens. See Maximum containment facility. 3-enhanced containment facilities with experimental protocols in compliance with applicable federal statutes and institutional guidelines. Influenza A (H5N1) viruses isolated in Asia and A/Puerto Rico/8/34 (PR8) (H1N1) were propagated in embryonated chicken eggs or in Madin-Darby canine kidney (MDCK MDCK Madin-Darby Canine Kidney Cells (virus tissue culture) ) cells. The African green monkey kidney Vero cell line was from a cell bank certified for human vaccine production.
Viral RNA RNA: see nucleic acid.
in full ribonucleic acid
One of the two main types of nucleic acid (the other being DNA), which functions in cellular protein synthesis in all living cells and replaces DNA as the carrier of genetic was extracted by using a commercial lysis lysis /ly·sis/ (li´sis)
1. destruction or decomposition, as of a cell or other substance, under influence of a specific agent.
2. mobilization of an organ by division of restraining adhesions.
3. solution and resin kit and amplified by reverse transcriptase-polymerase chain reaction with specific oligonucleotide primers. Nucleotide sequencing reactions were performed with a cycle sequencing kit and resolved on an ABl 3100 Genetic Analyzer (Applied Biosystems, Foster City, CA, USA). DNA sequence DNA sequence Genetics The precise order of bases–A,T,G,C–in a segment of DNA, gene, chromosome, or an entire genome. See Base pair, Base sequence analysis, Chromosome, Gene, Genome. analysis was performed by using version 10 of the GCG GCG Genetics Computer Group
GCG Good Corporate Governance
GCG Global Consumer Group
GCG Global Church of God
GCG Generalized Conjugate Gradient
GCG Global Change Game
GCG Geological Curators' Group
GCG Giant-Cell Granuloma sequence analysis package (7), and phylogeny was inferred by using a neighbor-joining tree reconstruction method implemented in the Phylip package (8).
Postinfection ferret antisera were prepared as previously described (9). Hemagglutination hemagglutination /he·mag·glu·ti·na·tion/ (he?mah-gloo-ti-na´shun) agglutination of erythrocytes.
n. inhibition (HI) testing was performed as previously described with turkey erythrocytes Erythrocytes
Red blood cells.
Mentioned in: Bartonellosis
n.pl red blood cells. (10).
Median inhibitory concentration ([IC.sub.50]) values for oseltamivir and zanamivir were determined by using NA-Star substrate and Light Emission Accelerator IITM IITM Indian Institute of Technology Madras (India)
IITM Indian Institute of Tropical Meteorology
IITM International Institute of Trading Mastery (Applied Biosystems, Bedford, MA, USA) as previously described (11). Biological susceptibility to rimantadine was determined by recording the yield of viral progeny in MDCK cells infected with the H5N1 strains of interest at a multiplicity of >10 median egg infectious doses in the absence or presence of 2 [micro]g/mL rimantadine.
Plasmids with full-length cDNA from the 6 internal genes (PB1, PB2, PA, NP, M, NS) of influenza virus PR8 strain (12), flanked by human RNA polymerase I RNA polymerase I (also called Pol I) transcribes DNA to synthesize rRNA (Ribosomal RNA). Pol I consists of a 12 protein subunits (polypeptide). Pol I conducts 80% of all transcription in the cell. All 12 subunits have identical or related counterparts in Pol II and Pol III. (Poll) promoter and polyadenylation site at the 3' end and a Poll terminator as well as a PolII promoter at the 5' end, were generated as described previously (12-14). The cDNA of N1 NA or H5 HA genes of VN/1203/2004 or VN/1194/2004 (VN/04-1ike) were inserted into plasmids as described above. The 4 basic amino acid amino acid (əmē`nō), any one of a class of simple organic compounds containing carbon, hydrogen, oxygen, nitrogen, and in certain cases sulfur. These compounds are the building blocks of proteins. codons from the cleavage site of HA were deleted by overlap extension PCR PCR polymerase chain reaction.
polymerase chain reaction
Polymerase chain reaction (PCR) , as described previously (sequences available upon request) (13,15-17).
PR8 reassortant viruses with HA and NA from VN/04-like viruses were generated by plasmid DNA-based reverse genetics in Vero cell under good laboratory practice conditions appropriate for future human use. Candidate vaccine reference reagent reassortant viruses were generated at the National Institute of Biological Standards and Control (NIBSC NIBSC National Institute for Biological Standards and Control (UK) ), South Mimms, United Kingdom; Saint Jude Children's Research Hospital (SJCRH SJCRH St. Jude Children's Research Hospital (Memphis, TN) ), Memphis, Tennessee, USA; and Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. (CDC See Control Data, century date change and Back Orifice.
CDC - Control Data Corporation ), Atlanta, Georgia, USA. For brevity, the reverse genetics derivation method described represents a consensus of the institutions; minor unpublished protocol details unique to each laboratory were not described and are available upon request. The VN/04x/PR8 reassortant virus was recovered in embryonated eggs and identified in the allantoic allantoic /al·lan·to·ic/ (al?an-to´ik) pertaining to the allantois.
pertaining to the allantois.
see fetal fluids. fluid by HA assay. The genetic and antigenic properties of the resulting reassortant virus were determined as described previously (15,18-20). Candidate vaccine stocks were subjected to virulence studies in avian, murine murine /mu·rine/ (mur´en) pertaining to, derived from, or characteristic of mice or rats.
adj. , and ferret models to establish their safety (19).
Analysis of HA, NA, and M2 Genes from H5N1 Viruses
Phylogenetic analyses of the H5 HA genes from the 2004 and 2005 outbreak showed 2 different lineages of HA genes, termed clades 1 and 2. Viruses in each of these clades are distributed in nonoverlapping geographic regions of Asia (Figure 1). The H5N1 viruses from the Indochina peninsula are tightly clustered within clade 1, whereas H5N 1 isolates from several surrounding countries are distinct from clade 1 isolates and belong in the more divergent clade 2. Clade 1 H5N1 viruses were isolated from humans and birds in Vietnam, Thailand, and Cambodia but only from birds in Laos and Malaysia. The clade 2 viruses were found in viruses isolated exclusively from birds in China, Indonesia, Japan, and South Korea. Viruses isolated from birds and humans in Hong Kong in 2003 and 1997 made up clades 1' and 3, respectively.
[FIGURE 1 OMITTED]
The HA genes from H5N 1 viruses isolated from human specimens were closely related to HA genes from H5NI viruses of avian origin; human HA gene sequences differ from the nearest gene from avian isolates from the same year in 2-14 nucleotides (<1% divergence). These findings are consistent with the epidemiologic data that suggest that humans acquired their infections by direct or indirect contact with poultry or poultry products (21).
Analysis of the amino acid sequences showed that both clades of H5 HAs from the 2004-2005 outbreak have a multiple basic amino acid motif at the cleavage site, a defining feature of highly pathogenic avian influenza viruses. Among all H5N1 isolates collected in east Asia since 1997, only those in clades 1, 1', and 3 appear to be associated with fatal human infections (22,23). We compared amino acid sequences of HA from contemporary isolates (clades 1 and 2) with those of the fatal H5N1 infections in Hong Kong in 1997 and 2003 to identify changes that may correlate with patterns of human infection (Table 1). Thirteen polymorphic sites were identified when the HA1 from the 4 consensus sequences were compared. One change in the 2004-2005 viruses is serine serine (sĕr`ēn), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. 129 to leucine leucine (l`sēn), organic compund, one of the 20 amino acids commonly found in animal proteins. (S129L). This change affects receptor binding because S 129 makes atomic contact with cellular sialoside receptors (24). A second structural change in HA was the A156T substitution, which resulted in glycosylation of asparagine asparagine (əspâr`əjēn), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer participates in the biosynthesis of mammalian proteins. 154 and is predicted to reduce its affinity for sialosides. This change is commonly associated with viral adaptation to terrestrial poultry and increased virulence for these birds (25-27).
Because of the heightened alert due to H5N1 infections in Vietnam during the first months of 2005, we examined the HA sequences for evidence of shared amino acid changes. The HA of viruses isolated in the first 3 months of 2005 showed several amino acid changes relative to 2004 viruses (Table 1). None of the changes in the HA were common to all the 2005 viruses, which suggests that these variant viruses are cocirculating independently in poultry. The most commonly observed changes are located within short distances of the receptor-binding site. For example, positions D94, L175, and T188 may modulate the interaction of Y91, H179, and L190 with sialosides. One of the isolates from a fatal infection in 2005 showed a substitution of serine 223 to asparagine, which is predicted to facilitate binding of sialosides commonly found in mammalian species (Table 1).
The phylogenetic tree of the NA genes resembled that of the HA genes, which indicates coevolution co·ev·o·lu·tion
The evolution of two or more interdependent species, each adapting to changes in the other. It occurs, for example, between predators and prey and between insects and the flowers that they pollinate. of these 2 envelope genes (Figure 2). NA genes of isolates from Thailand seem to have diverged to form a group distinct from that of genes from Vietnam viruses. As reported previously, the NA of HK/213/03 did not co-evolve with the HA genes (28). NA genes from human and related avian H5N1 isolates from 2003-2005 as well as clade 3 isolates were characterized by deletions in the stalk region of the protein (positions 49-68 for clades 1-2 and 54 72 for clade 3) (29). Deletions in the stalk of the NA are thought to increase retention of virions at the plasma membrane plasma membrane
See cell membrane. (30) to balance weaker binding of sialic acid sialic acid: see glycoprotein. receptors by the HA with newly acquired N154 glycosylation.
[FIGURE 2 OMITTED]
Neuraminidase inhibitors are effective antiviral drugs against human influenza viruses, and preclinical studies preclinical studies,
n.pl a term used to describe research done before a clinical study. May be laboratory or epidemiologic research. suggest a similar effectiveness against avian influenza in humans (5,31). The [IC.sub.50] of oseltamivir for the clade 1 and 2 NA of 2004-2005 isolates was <10 nmol/L, as compared to [IC.sub.50] values of 85 and 1,600 nmol/L for resistant HIN1 or H3N2 mutants used as controls (Table 3). Thus, NA of H5N 1 isolates is sensitive to this class of antiviral agents.
The phylogenetic tree of the NA genes resembled that of the HA genes, indicating coevolution of these genes (results not shown). The amino acid sequence of the M2 protein of clade 1 viruses as well as of HK/213/03 indicated a serine-to-asparagine substitution at residue 31 (S31N), known to confer resistance to adamantanes (including amantadine amantadine /aman·ta·dine/ (ah-man´tah-den) an antiviral compound used as the hydrochloride salt to treat influenza A; also used as an antidyskinetic in the treatment of parkinsonism and drug-induced extrapyramidal reactions. and rimantadine) (6). Clade 1 isolates from 2004 and 2005 cultured in the presence of 2 [micro]g/mL rimantadine replicated as efficiently as in untreated cultures, whereas the replication of HK/483/97 was reduced to 1% of control values, indicating that all the currently circulating clade 1 isolates are resistant to adamantanes (data not shown).
Origin of Internal Genes of HfN1 Viruses from Asia
A complete genetic characterization of circulating H5N 1 viruses is critical to identify the possible incorporation of human influenza virus genes by reassortment. To this end, we analyzed the phylogeny of the internal protein coding genes. The PB2, PB1, and PA polymerase genes from 2003-2005 H5N1 isolates from humans constitute a single clade (data not shown) and have coevolved with the respective HA genes (Figure 1). No evidence of reassortment with polymerase genes from circulating H1N1 or H3N2 human influenza virus was found. The phylogenies of the NP and NS genes also supported the avian origin of these genes, indicating that all the genes from the human H5N1 isolates analyzed are of avian origin, which confirms the absence of reassortment with human influenza genes. Taken together, the phylogenies of the 8 genomic segments show that the H5N1 viruses from human infections and the closely related avian viruses isolated in 2004 and 2005 belong to a single genotype, often referred to as genotype Z (1).
Antigenic Analysis of H5N1 Viruses from Asia
Influenza vaccines whose HA are antigenically similar to circulating strains provide the highest level of protection from infection (32). H5N1 isolates collected in 2004 and 2005 analyzed by the HI test showed reactivity patterns that correlated with the 3 main clades of recent isolates identified in the HA gene phylogeny (Table 2 and Figure 1). Viruses from humans and birds in clade 1, represented by VN/1203/04, were found to constitute a relatively homogeneous and distinct antigenic group characterized by poor inhibition by ferret antisera to isolates from other clades (Table 2), in particular by the ferret antiserum antiserum /an·ti·se·rum/ (an´ti-se?rum) a serum containing antibody(ies), obtained from an animal immunized either by injection of antigen or by infection with microorganisms containing antigen. raised to HK/213/03 (64-fold reduction compared to the homologous titer titer /ti·ter/ (ti´ter) the quantity of a substance required to react with or to correspond to a given amount of another substance. ). The latter isolate was previously used to develop a vaccine reference strain in response to 2 confirmed H5N1 human infections in February 2003 (15). These HI results provided the motivation for the development of an updated H5N1 vaccine that would be antigenically similar to 2004 2005 human isolates. The antigenic similarity of VN/1203/04 and the closely related VN/1194/04 to the contemporaneous H5N1 isolates from humans (data not shown) prompted their selection for vaccine reference stock development.
Antigenic analysis of human isolates from 2005 provided evidence of antigenic drift among the most recently circulating H5N1 strains (Table 2). For example, VN/JPHN30321/05 showed a reduced HI titer against VN/1203/04 reference serum. This antigenic difference is correlated with 7 amino acid differences between the HA1 domain VN/1203/04 and VN/JPHN30321/05: R53K, N84D, D94N, K140R, L175M, K189R, and V219I (Table 1 and online Appendix Table).
Development of Candidate H5N1 Vaccine Reference Stocks
Mass vaccination is the most effective approach to reduce illness and death from pandemic pandemic /pan·dem·ic/ (pan-dem´ik)
1. a widespread epidemic of a disease.
2. widely epidemic.
Epidemic over a wide geographic area.
n. influenza. Inactivated inactivated
rendered inactive; the activity is destroyed.
treated so that they are no longer able to produce evidence of growth or damaging effect on tissue. influenza vaccines are manufactured from reassortant viruses obtained by transferring the HA and NA genes with the desired antigenic properties into a high-growth strain such as PR8 (33). However, reassortants with H5-derived HA with a polybasic cleavage site are potentially hazardous for animal health. Because the high pathogenicity of the H5N1 viruses in poultry, mice, and ferrets depends primarily on the polybasic cleavage site in the HA molecule, a derivative with a deletion of this motif was engineered in cloned HA cDNAs. Three high-growth reassortant influenza viruses were developed: NIBRG-14 (NIBSC), VN/04xPR8-rg (SJCRH), and VNH VNH Very Nice Hand (online card games)
VNH Virtual Naval Hospital
VNH Visiting Nurse Hospice 5N1-PR8/CDC-rg (CDC). These candidate vaccine strains, bearing mutant H5 HA, intact NA, and the internal genes from PR8, were generated by a reverse genetics approach (12,13,20,34) using Vero cells and laboratory protocols compatible with eventual use of the vaccine in human subjects (15,18). These 3 vaccine candidates were characterized genetically (nucleotide sequencing of HA and NA) and antigenically in HI assays to confirm that their antigenicity remained unchanged relative to the wildtype virus (Table 2). The candidate reference stocks had molecular and antigenic properties equivalent to parental H5N1 donor strains and lacked virulence in chicken, mouse, and ferret models.
The growing H5N1 epizootic in eastern Asia could expand the environmental load of virus and cause more infections in mammals (35), which would increase the probability that a highly transmissible transmissible /trans·mis·si·ble/ (trans-mis´i-b'l) capable of being transmitted.
Capable of being conveyed from one person to another. virus will emerge in mammals. We therefore analyzed the medically relevant genes from viruses isolated from the beginning of the outbreak until March 2005 to evaluate parameters relevant to public health.
The origin of the HA genes of the 2004 2005 outbreak as well as an earlier isolate from a fatal human infection in Hong Kong in 2003 (clade 1') can be traced back to viruses isolated in 1997 in Hong Kong (clade 3) and from geese in China (goose/Guangdong/96) (Figure 1A). The phylogeny also shows that viruses with HK/97-like HA may have circulated in avian hosts continuously after 1997, without causing any reported human infections until the 2 confirmed cases in Hong Kong in February 2003 (28).
The 2004 2005 H5N1 isolates are sensitive to 2 neuraminidase inhibitors that are recommended for prophylactic or therapeutic intervention against human infections with recent H5N1 strains. Rapidly testing potentially pandemic influenza viruses for their susceptibility to licensed drugs is essential to establish appropriate control measures.
An effective H5N1 vaccine is a public health priority and the cornerstone for pandemic prevention and control. Reverse genetics approaches allow the rapid production of high-growth PR8 reassortant viruses by engineering a virus with a homologous HA gene lacking the polybasic amino acids associated with high virulence. These candidate H5N1 pandemic vaccine viruses have been made available to vaccine manufacturers to produce pilot lots for clinical trials and are available for possible large-scale manufacturing should the need arise.
Genetic and antigenic analyses have shown that, compared to previous H5N1 isolates, 2004 2005 isolates share several amino acid changes that modulate antigenicity and perhaps other biological functions. Furthermore, our molecular analysis of the HA from isolates collected in 2005 suggests that several amino acids located near the receptor-binding site are undergoing change, some of which may affect antigenicity or transmissibility. For example, an isolate (VN/JP12-2/05) showed a change from serine to asparagine at position 223 of the HA1 (S223N) that may affect receptor-binding specificity (36). The VN/30321/05 isolate demonstrated considerable antigenic drift from VN/04-like isolates, which have been selected as the candidate vaccine antigens. Further surveillance to determine the prevalence of such variants in poultry will be critical to determine if these variants compromise the efficacy of the candidate vaccine or increase the efficiency of transmission.
The phylogenies of the 8 genomic segments from the clade 1 and 2 isolates from 2004 2005 showed that all genes are of avian origin. All H5N1 isolates from both clades belong to 1 of the genotypes recently circulating in Eastern and Southern Asia, e.g., genotypes V and Z (1,37). The influenza virus genome has remarkable plasticity because of a high mutation rate and its segmentation into 8 separate RNA molecules. This segmentation allows frequent genetic exchange by segment reassortment in hosts co-infected with 2 different influenza viruses. No evidence has been seen that the 2004-2005 H5N1 isolates have acquired nonavian influenza genes by reassortment. However, continued surveillance is important because genetic reassortment may facilitate the evolution of viruses with increased virulence or expanded host range.
The currently circulating H5N1 viruses were reported to infect domestic or wild captive felids felids
cats. , such as tigers, feeding on infected bird carcasses, and the infected cats can transmit H5N1 to pen mates (38). Furthermore, circumstantial evidence circumstantial evidence
In law, evidence that is drawn not from direct observation of a fact at issue but from events or circumstances that surround it. If a witness arrives at a crime scene seconds after hearing a gunshot to find someone standing over a corpse and holding a indicates that tiger-to-tiger transmission of H5N1 has occurred at a zoo in Thailand (39). Recent evidence of person-to-person transmission and the clustering of H5N1 cases raise the level of concern for a pandemic of H5N1 influenza (3). Therefore, sustained and aggressive efforts to control H5N1 circulation in poultry are mandatory to avoid possible catastrophic public health consequences.
We thank Ruben O. Donis for drafting the manuscript on behalf of the WHO team, Michael Shaw for phylogenetic analyses, WHO Geneva Geneva, canton and city, Switzerland
Geneva (jənē`və), Fr. Genève, canton (1990 pop. 373,019), 109 sq mi (282 sq km), SW Switzerland, surrounding the southwest tip of the Lake of Geneva. for coordinating access to specimens, and Catherine Macken for providing access to the Influenza Sequence Database. The WHO Global Influenza Surveillance Network would like to thank WHO regional offices for Southeast Asia and the Western Pacific and WHO country offices for their generous and valuable support in sharing viruses and specimens between affected countries and WHO.
Research at St. Jude Hospital was supported in part by grant A195357 from the National Institutes of Health.
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(27.) Perdue Perdue may refer to:
(28.) Guan Y, Poon poon
Any of several trees of the genus Calophyllum, of southern Asia, having light hard wood used for masts and spars.
[Sinhalese p LL, Cheung CY, Ellis TM, Lim W, Lipatov AS, et al. H5N1 influenza: a protean pro·te·an
Readily taking on varied shapes, forms, or meanings.
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Pharmacologic class: Viral neuroaminidase inhibitor
Therapeutic class: Antiviral
Pregnancy risk category C
Action) is efficacious against A/Hong Kong/156/97 (H5N1) and A/Hong Kong/ 1074/99 (H9N2) influenza viruses. Antiviral antiviral /an·ti·vi·ral/ (-vi´ral) destroying viruses or suppressing their replication, or an agent that so acts.
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(38.) Kuiken T, Rimmelzwaan G, van Riel ri·el
See Table at currency.
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The World Health Organization Global Influenza Program Surveillance Network * (1)
* World Health Organization, Geneva, Switzerland
(1) Members of the World Health Organization Global Influenza Program and collaborating laboratories: Jean-Thierry Aubin, Saliha Azebi, Amanda Balish, Jill Banks, Niranjan Bhat, Rick A. Bright, Ian Brown, Philippe Buchy, Ana-Maria Burguiere, Hua-lan Chen, Peter Cheng, Nancy J. Cox, Alice Crosier crosier
bishop’s staff signifying his ruling power. [Christian Symbolism: Appleton, 21]
See : Authority , Aaron Curns, Frederique Cuvelier, Guohua Deng, Julia Desheva, Stephanie Desvaux, Nguyen Hong Diep, Ruben O. Donis, Alan Douglas, Scott F. Dowell, Nguyen Tien Dung, Lindsay Edwards, Keiji Fukuda, Rebecca Garten, Elena Govorkova, Victoria Gregory, Alan Hampson, Nguyen Thi Hong Hanh, Scott Harper, Alan Hay, Erich Hoffmann, Diane Hulse, Masaki Imai, Shigeyuki Itamura, Samadhan Jadhao, Patricia Jeannin, Chun Kang, Jackie Katz, Jae-Hong Kim, Alexander Klimov, Yong-kuk Kwon, Chang-Won Lee, Phuong Song Lien, Yanbing Li, Wilina Lim, Yi Pu Lin, Stephen Lindstom, LaMorris Loftin, Jan Mabry, Le Quynh Mai, Taronna Maines, Jean-Claude Manuguerra, Masaji Mase, Yumi Matsuoka, Margaret McCarron, Marie-Jo Medina, Doan Nguyen, Ai Ninomiya, Masatsugu Obuchi, Takato Odagiri, Malik Peiris, Michael L. Perdue, Jean-Marc Reynes, James Robertson, Claudine Rousseaux, Takehiko Saito, Somchai Sangkitporn, Michael Shaw, James M. Simmerman, M. Slomka, Catherine Smith, San Sore, Erica Spackman, Klaus Stohr, David L. Suarez, Haan Woo Sung, David E Swayne, Maryse Tardy-Panit, Masato Tashiro, Pranee Thawatsupha, Terrence Tumpey, Timothy Uyeki, Phan Van Tu, Sylvie van der Weft, Sirenda Vong, Richard Webby, Robert Webster, John Wood, Xiyan Xu, Guan Yi, and Wenqing Zhang; for a list of affiliations, see online footnote at http://www.cdc.gov/ncidod/EID/vol11no10/05-0644_fnote.pdf
Address for correspondence: Ruben O. Donis, Influenza Branch, DVRD DVRD Division of Viral and Rickettsial Diseases (CDC) , NCID NCID National Center for Infectious Diseases (US CDC)
NCID Non-Cooperative Identification
NCID Net-Centric Implementation Document (US DoD) , Centers for Disease Control and Prevention, Mailstop G16, 1600 Clifton Rd, Atlanta, GA 30333, USA; fax: 404-639-2334; email: rdonis@ cdc.gov
Table 1. Amino acid differences among H5 hemagglutinins (HA1) Clade 3 Clade 2 Clade 1' Clade 1 N45 * D D D S84 N N N A86 A A V N94 D D D (1) N124 D S S S129 S L L L138 Q Q Q S155 -- N155 -- T156 ([double dagger]) A A T L175 L L L (2) T188 T T T (3) K189 R R K E212 K K R S223 -- N223 ([section]) -(4) T263 A A T 325R ([paragraph]) Absent -- -- Clade 3 H3 No. Functional significance N45 * 54 ([dagger]) Antigenic site C S84 92 Antigenic site E A86 93 Antigenic site E N94 101 Near Y91; receptor binding? N124 129 Antigenic site B S129 133a Receptor binding L138 142 Antigenic site A S155 159 Antigenic site B T156 ([double dagger]) 160 N154 glycosylation motif L175 179 Near H179; receptor binding? T188 192 Near L190, receptor binding? K189 193 Adjacent to receptor binding, antigenic site B E212 216 Antigenic site D S223 227 Receptor binding T263 266 Antigenic site E 325R ([paragraph]) Absent HA cleavage efficiency * Amino acid residue in single-letter code and position in the mature H5 HA1. ([dagger]) Equivalent residue number in the mature H3 HA1 aligned with H5 amino acid sequence; --, no change from HK97 clade HA consensus. ([double dagger]) A156 or S156 were found in certain clade 3 Has; A156 was present in some HAs from clade 2. HA genes from [approximately equal to] 50% of isolates collected in 2005 had these substitutions present in only one isolate: 1) to N or V; 2) to M or I; 3) to A, V, or I; or 4) to N. ([section]) Change present exclusively in isolates from humans. ([paragraph]) Arginine at the start of the polybasic cleavage site, position 325. Table 2. Antigenic analysis of H5N1 isolates from Asia Reference ferret antisera * Virus antigen Clade HK156 NCVD8 HK213 VN1203 A/Hong Kong/156/97 3 1,280# 320 640 80 A/ck/Vietnam/NCVD8/03 -- 640 160# 80 80 A/Hong Kong/213/03 1' 1,280 1,280 2,660# 80 A/Vietnam/1203/04 1 40 20 < 10 640 A/Vietnam/1203/04xPR8-rg 1 80 < 10 10 640# A/Vietnam/1194/04 1 40 20 10 640 A/Vietnam/JP178/04 1 80 10 < 10 1,280 A/Vietnam/JP4207/05 1 160 40 40 1,280 A/Vietnam/JP14/05 1 20 < 10 10 640 A/Vietnam/JP30321/05 1 40 40 10 < 10 Reference ferret antisera * VN04xPR8- Virus antigen rg VN78 VN4207 VN14 VN32321 A/Hong Kong/156/97 320 40 80 80 80 A/ck/Vietnam/NCVD8/03 160 20 < 10 160 40 A/Hong Kong/213/03 640 160 160 640 640 A/Vietnam/1203/04 320 40 160 80 40 A/Vietnam/1203/04xPR8-rg 320 40 160 160 40 A/Vietnam/1194/04 320# 40 160 160 40 A/Vietnam/JP178/04 320 80# 160 160 80 A/Vietnam/JP4207/05 640 80 320# 160 80 A/Vietnam/JP14/05 80 20 40 80# 40 A/Vietnam/JP30321/05 40 10 < 10 40 160# * Homologous HI titers are in boldface. Note: Homologous HI titers is indicated with #. Table 3. Sensitivity of H5N1 influenza isolates to oseltamivir Virus Oseltamivir [IC.sub.50] * H1N1 (H274) ([dagger]) 0.69 H1N1 (Y274) ([dagger]) 85.92 H3N2 (R292) ([double dagger]) 1.99 H3N2 (K292) ([double dagger]) 1,600.00 Hong Kong/483/97 4.86 Hong Kong/213/03 5.07 Vietnam /1194/04 2.49 Vietnam/1203/04 7.68 Chicken/VN/NCVD1/04 5.87 Chicken/VN/NCVD8/03 9.90 * Median inhibitory concentration ([IC.sub.50]) of oseltamivir (nmol/L) for H5N1 influenza isolates and control H1N1 or H3N2 isolates (results for viruses shown are representatives of 31 isolates tested). ([dagger]) Wildtype (H274) and resistant mutant (Y274) influenza virus A/Texas/36/91 (H1N1). ([double dagger]) Wildtype (R292) and resistant mutant (K292) influenza virus A/Victoria/3/75 (H3N2).