Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Balish AL[original query] |
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Influenza: propagation, quantification, and storage
Balish AL , Katz JM , Klimov AI . Curr Protoc Microbiol 2013 Chapter 15 Unit15G 1 Influenza viruses are negative-sense, single-stranded, enveloped RNA viruses belonging to the family Orthomyxoviridae. Three types exist, influenza A, B, and C. All infect humans, but only A and B are major human pathogens. Influenza type A viruses are divided into subtypes based on genetic and antigenic differences in the two surface spike proteins, hemagglutinin (HA) and neuraminidase (NA). The appropriate cell lines to be used for isolation of influenza A or B viruses depend on the clinical information and the host of origin. MDCK cells are the preferred cell line for isolation of human influenza viruses from clinical specimens. (Curr. Protoc. Microbiol. 29:15G.1.1-15G.1.24. (c) 2013 by John Wiley & Sons, Inc.) |
Microevolution of highly pathogenic avian influenza A(H5N1) viruses isolated from humans, Egypt, 2007-2011
Younan M , Poh MK , Elassal E , Davis T , Rivailler P , Balish AL , Simpson N , Jones J , Deyde V , Loughlin R , Perry I , Gubareva L , Elbadry MA , Truelove S , Gaynor AM , Mohareb E , Amin M , Cornelius C , Pimentel G , Earhart K , Naguib A , Abdelghani AS , Refaey S , Klimov AI , Donis RO , Kandeel A . Emerg Infect Dis 2013 19 (1) 43-50 We analyzed highly pathogenic avian influenza A(H5N1) viruses isolated from humans infected in Egypt during 2007-2011. All analyzed viruses evolved from the lineage of subtype H5N1 viruses introduced into Egypt in 2006; we found minimal evidence of reassortment and no exotic introductions. The hemagglutinin genes of the viruses from 2011 formed a monophyletic group within clade 2.2.1 that also included human viruses from 2009 and 2010 and contemporary viruses from poultry; this finding is consistent with zoonotic transmission. Although molecular markers suggestive of decreased susceptibility to antiviral drugs were detected sporadically in the neuraminidase and matrix 2 proteins, functional neuraminidase inhibition assays did not identify resistant viruses. No other mutations suggesting a change in the threat to public health were detected in the viral proteomes. However, a comparison of representative subtype H5N1 viruses from 2011 with older subtype H5N1 viruses from Egypt revealed substantial antigenic drift. |
Prevalence of 2009 pandemic influenza A (H1N1) virus antibodies, Tampa Bay Florida - November-December, 2009
Cox CM , Goodin K , Fisher E , Dawood FS , Hamilton JJ , Leparc GF , Gray M , Nelson L , Borse RH , Singleton JA , Reed C , Balish AL , Katz JM , Hopkins RS , Fry AM . PLoS One 2011 6 (12) e29301 BACKGROUND: In 2009, a novel influenza virus (2009 pandemic influenza A (H1N1) virus (pH1N1)) caused significant disease in the United States. Most states, including Florida, experienced a large fall wave of disease from September through November, after which disease activity decreased substantially. We determined the prevalence of antibodies due to the pH1N1 virus in Florida after influenza activity had peaked and estimated the proportion of the population infected with pH1N1 virus during the pandemic. METHODS: During November-December 2009, we collected leftover serum from a blood bank, a pediatric children's hospital and a pediatric outpatient clinic in Tampa Bay Florida. Serum was tested for pH1N1 virus antibodies using the hemagglutination-inhibition (HI) assay. HI titers ≥40 were considered seropositive. We adjusted seroprevalence results to account for previously established HI assay specificity and sensitivity and employed a simple statistical model to estimate the proportion of seropositivity due to pH1N1 virus infection and vaccination. RESULTS: During the study time period, the overall seroprevalence in Tampa Bay, Florida was 25%, increasing to 30% after adjusting for HI assay sensitivity and specificity. We estimated that 5.9% of the population had vaccine-induced seropositivity while 25% had seropositivity secondary to pH1N1 virus infection. The highest cumulative incidence of pH1N1 virus infection was among children aged 5-17 years (53%) and young adults aged 18-24 years (47%), while adults aged ≥50 years had the lowest cumulative incidence (11-13%) of pH1N1 virus infection. CONCLUSIONS: After the peak of the fall wave of the pandemic, an estimated one quarter of the Tampa Bay population had been infected with the pH1N1 virus. Consistent with epidemiologic trends observed during the pandemic, the highest burdens of disease were among school-aged children and young adults. |
Antigenic and genetic diversity of highly pathogenic avian influenza A (H5N1) viruses isolated in Egypt
Balish AL , Davis CT , Saad MD , El-Sayed N , Esmat H , Tjaden JA , Earhart KC , Ahmed LE , El-Halem MA , Ali AHM , Nassif SA , El-Ebiary EA , Taha M , Mona MA , Arafa A , O'Neill E , Xu XY , Cox NJ , Donis RO , Klimov AI . Avian Dis 2010 54 329-334 Highly pathogenic avian influenza A virus (H5N1) has diverged antigenically and genetically since its initial detection in Asia in 1997. Viruses belonging to clade 2.2 in particular have been reported in numerous countries with the majority occurring in Egypt. Previous reports identified antigenic similarities between viruses belonging to clade 2.2. However, poultry and human viruses isolated in northern Egypt during 2007 and 2008 were found to be antigenically distinct from other clade 2.2 viruses from this country. Genetic analysis of the hemagglutinin revealed a high degree of nucleotide and amino acid divergence. The antigenic changes in Egyptian viruses isolated during 2007-08 necessitated that two of these strains be considered as potential H5N1 pre-pandemic vaccine candidates. |
Detection and characterization of clade 7 high pathogenicity avian influenza H5N1 viruses in chickens seized at ports of entry and live poultry markets in Vietnam
Davis CT , Balish AL , O'Neill E , Nguyen CV , Cox NJ , Xu XY , Klimov A , Tung N , Donis RO . Avian Dis 2010 54 307-312 High pathogenicity avian influenza H5N1 has become an endemic poultry disease in several Asian countries, including Vietnam. Recently, clade 7 H5N1 viruses of the Eurasian lineage were isolated from chickens seized at ports of entry in Lang Son Province, Vietnam. Extensive nucleotide and amino acid divergence across the hemagglutinin (HA) protein gene of these isolates in comparison to previously described clade 7 viruses was identified. Clade 7 viruses are antigenically distinct from contemporary strains of H5N1 known to circulate in Vietnamese poultry (clade 1 and clade 2.3.4). Subsequent surveillance of sick poultry in live poultry markets in Hai Duong Province identified additional clade 7 isolates with HA genes very similar to the group B virus cluster detected previously at the Lang Son Province border. Antigenic analysis of the isolates from the live bird markets revealed significant cross-reactivity only between those clade 7 viruses belonging to the same subgroups. To meet pandemic response preparedness objectives, we have developed a reassortant virus from A/chicken/Vietnam/NCVD-016/2008, which could be used as a new prepandemic vaccine candidate for veterinary or human vaccination, should the need arise. Findings from these studies indicate that viruses with clade 7 HA have continued to evolve in Southeast Asian poultry, leading to significant antigenic drift relative to other H5N1 viruses currently circulating in Vietnam. |
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