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Clinical Microbiology Reviews Apr 2012The menu of diagnostic tools that can be utilized to establish a diagnosis of influenza is extensive and includes classic virology techniques as well as new and emerging... (Review)
Review
The menu of diagnostic tools that can be utilized to establish a diagnosis of influenza is extensive and includes classic virology techniques as well as new and emerging methods. This review of how the various existing diagnostic methods have been utilized, first in the context of a rapidly evolving outbreak of novel influenza virus and then during the different subsequent phases and waves of the pandemic, demonstrates the unique roles, advantages, and limitations of each of these methods. Rapid antigen tests were used extensively throughout the pandemic. Recognition of the low negative predictive values of these tests is important. Private laboratories with preexisting expertise, infrastructure, and resources for rapid development, validation, and implementation of laboratory-developed assays played an unprecedented role in helping to meet the diagnostic demands during the pandemic. FDA-cleared assays remain an important element of the diagnostic armamentarium during a pandemic, and a process must be developed with the FDA to allow manufacturers to modify these assays for detection of novel strains in a timely fashion. The need and role for subtyping of influenza viruses and antiviral susceptibility testing will likely depend on qualitative (circulating subtypes and their resistance patterns) and quantitative (relative prevalence) characterization of influenza viruses circulating during future epidemics and pandemics.
Topics: Clinical Laboratory Techniques; Humans; Influenza A Virus, H1N1 Subtype; Influenza, Human; Orthomyxoviridae; Virology
PubMed: 22491775
DOI: 10.1128/CMR.05016-11 -
Expert Review of Respiratory Medicine Feb 2015Besides its pandemic potential, seasonal influenza infection is associated with an estimated 250,000 to 500,000 deaths worldwide every year. Part of this virulence of...
Besides its pandemic potential, seasonal influenza infection is associated with an estimated 250,000 to 500,000 deaths worldwide every year. Part of this virulence of influenza virus can be attributed to its ability to evade the host innate immune response. Here, we discuss the possibility of using a recently described mechanism of boosting the innate immunity by oligoadenylate synthetase-like protein, to combat influenza infections.
Topics: 2',5'-Oligoadenylate Synthetase; Animals; Antiviral Agents; Genetic Therapy; Host-Pathogen Interactions; Humans; Immunity, Innate; Influenza, Human; Orthomyxoviridae; RNA, Viral
PubMed: 25544107
DOI: 10.1586/17476348.2015.994608 -
PLoS Pathogens Sep 2018
Review
Topics: Animals; Coinfection; Genome, Viral; Humans; Orthomyxoviridae; Reassortant Viruses; Recombination, Genetic; Virus Diseases
PubMed: 30212586
DOI: 10.1371/journal.ppat.1007200 -
Journal of Virology Nov 2009Arboviral infections are an important cause of emerging infections due to the movements of humans, animals, and hematophagous arthropods. Quaranfil virus (QRFV) is an...
Arboviral infections are an important cause of emerging infections due to the movements of humans, animals, and hematophagous arthropods. Quaranfil virus (QRFV) is an unclassified arbovirus originally isolated from children with mild febrile illness in Quaranfil, Egypt, in 1953. It has subsequently been isolated in multiple geographic areas from ticks and birds. We used high-throughput sequencing to classify QRFV as a novel orthomyxovirus. The genome of this virus is comprised of multiple RNA segments; five were completely sequenced. Proteins with limited amino acid similarity to conserved domains in polymerase (PA, PB1, and PB2) and hemagglutinin (HA) genes from known orthomyxoviruses were predicted to be present in four of the segments. The fifth sequenced segment shared no detectable similarity to any protein and is of uncertain function. The end-terminal sequences of QRFV are conserved between segments and are different from those of the known orthomyxovirus genera. QRFV is known to cross-react serologically with two other unclassified viruses, Johnston Atoll virus (JAV) and Lake Chad virus (LKCV). The complete open reading frames of PB1 and HA were sequenced for JAV, while a fragment of PB1 of LKCV was identified by mass sequencing. QRFV and JAV PB1 and HA shared 80% and 70% amino acid identity to each other, respectively; the LKCV PB1 fragment shared 83% amino acid identity with the corresponding region of QRFV PB1. Based on phylogenetic analyses, virion ultrastructural features, and the unique end-terminal sequences identified, we propose that QRFV, JAV, and LKCV comprise a novel genus of the family Orthomyxoviridae.
Topics: Amino Acid Sequence; Animals; Arboviruses; Base Sequence; Cell Line; Chlorocebus aethiops; Cryoelectron Microscopy; Humans; Mice; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Molecular Sequence Data; Orthomyxoviridae; Phylogeny; Sequence Alignment; Vero Cells
PubMed: 19726499
DOI: 10.1128/JVI.00677-09 -
MBio 2011Novel pandemic influenza viruses enter the human population with some regularity and can cause disease that is severe and widespread. The emergence of novel viruses,... (Review)
Review
Novel pandemic influenza viruses enter the human population with some regularity and can cause disease that is severe and widespread. The emergence of novel viruses, historically, has often been coupled with the disappearance of existing seasonal virus strains. Here, we propose that the elimination of seasonal strains during virus pandemics is a process mediated, at the population level, by humoral immunity. Specifically, we suggest that infection with a novel virus strain, in people previously exposed to influenza viruses, can elicit a memory B cell response against conserved hemagglutinin stalk epitopes and/or neuraminidase epitopes. The anti-stalk and/or anti-neuraminidase antibodies then act to diminish the clinical severity of disease caused by novel influenza viruses and to eliminate seasonal virus strains.
Topics: Antibodies, Viral; Biological Evolution; Extinction, Biological; Hemagglutinin Glycoproteins, Influenza Virus; Humans; Influenza, Human; Orthomyxoviridae; Selection, Genetic
PubMed: 21878571
DOI: 10.1128/mBio.00150-11 -
Microbiological Reviews Jun 1980
Review
Topics: Adult; Animals; Bacterial Infections; Cells, Cultured; Female; Ferrets; Fetal Diseases; Humans; Infant, Newborn; Infant, Newborn, Diseases; Influenza, Human; Male; Mice; Mucous Membrane; Organ Specificity; Orthomyxoviridae; Pregnancy; Recombination, Genetic; Respiratory System; Virulence; Virus Replication
PubMed: 6991901
DOI: 10.1128/mr.44.2.303-330.1980 -
Virus Research Dec 2013The tropism of influenza viruses for the human respiratory tract is a key determinant of host-range, and consequently, of pathogenesis and transmission. Insights can be... (Review)
Review
Use of ex vivo and in vitro cultures of the human respiratory tract to study the tropism and host responses of highly pathogenic avian influenza A (H5N1) and other influenza viruses.
The tropism of influenza viruses for the human respiratory tract is a key determinant of host-range, and consequently, of pathogenesis and transmission. Insights can be obtained from clinical and autopsy studies of human disease and relevant animal models. Ex vivo cultures of the human respiratory tract and in vitro cultures of primary human cells can provide complementary information provided they are physiologically comparable in relevant characteristics to human tissues in vivo, e.g. virus receptor distribution, state of differentiation. We review different experimental models for their physiological relevance and summarize available data using these cultures in relation to highly pathogenic avian influenza H5N1, in comparison where relevant, with other influenza viruses. Transformed continuous cell-lines often differ in important ways to the corresponding tissues in vivo. The state of differentiation of primary human cells (respiratory epithelium, macrophages) can markedly affect virus tropism and host responses. Ex vivo cultures of human respiratory tissues provide a close resemblance to tissues in vivo and may be used to risk assess animal viruses for pandemic threat. Physiological factors (age, inflammation) can markedly affect virus receptor expression and virus tropism. Taken together with data from clinical studies on infected humans and relevant animal models, data from ex vivo and in vitro cultures of human tissues and cells can provide insights into virus transmission and pathogenesis and may provide understanding that leads to novel therapeutic interventions.
Topics: Animals; Cell Culture Techniques; Humans; Influenza A Virus, H5N1 Subtype; Influenza, Human; Orthomyxoviridae; Respiratory System; Viral Tropism
PubMed: 23684848
DOI: 10.1016/j.virusres.2013.03.003 -
Viruses Mar 2014Seasonal influenza A viruses (IAV) originate from pandemic IAV and have undergone changes in antigenic structure, including addition of glycans to the hemagglutinin (HA)... (Review)
Review
Seasonal influenza A viruses (IAV) originate from pandemic IAV and have undergone changes in antigenic structure, including addition of glycans to the hemagglutinin (HA) glycoprotein. The viral HA is the major target recognized by neutralizing antibodies and glycans have been proposed to shield antigenic sites on HA, thereby promoting virus survival in the face of widespread vaccination and/or infection. However, addition of glycans can also interfere with the receptor binding properties of HA and this must be compensated for by additional mutations, creating a fitness barrier to accumulation of glycosylation sites. In addition, glycans on HA are also recognized by phylogenetically ancient lectins of the innate immune system and the benefit provided by evasion of humoral immunity is balanced by attenuation of infection. Therefore, a fine balance must exist regarding the optimal pattern of HA glycosylation to offset competing pressures associated with recognition by innate defenses, evasion of humoral immunity and maintenance of virus fitness. In this review, we examine HA glycosylation patterns of IAV associated with pandemic and seasonal influenza and discuss recent advancements in our understanding of interactions between IAV glycans and components of innate and adaptive immunity.
Topics: Adaptive Immunity; Glycosylation; Hemagglutinin Glycoproteins, Influenza Virus; Host-Pathogen Interactions; Humans; Immunity, Innate; Orthomyxoviridae; Virus Attachment
PubMed: 24638204
DOI: 10.3390/v6031294 -
Viruses Mar 2022Antibodies to influenza D virus (IDV) have been detected in horses, but no evidence of disease in the field has been reported. To determine whether IDV is infectious,...
Antibodies to influenza D virus (IDV) have been detected in horses, but no evidence of disease in the field has been reported. To determine whether IDV is infectious, immunogenic, and pathogenic in horses, four 2-year-old horses seronegative for both influenza A (H3N8) and D viruses were intranasally inoculated with 6.25 × 10 TCID/animal of D/bovine/California/0363/2019 (D/CA2019) virus, using a portable equine nebulizer system. Horses were observed daily for clinical signs including rectal temperature, nasal discharge, coughing, lung sounds, tachycardia, and tachypnea. No horses exhibited clinical signs of disease. Nasopharyngeal swabs collected from 1-8 days post-infection demonstrated virus shedding by qRT-PCR. The horses showed evidence of seroconversion as early as 13 days post-infection (dpi) and the geometric mean of the antibody titers (GMT) of all four horses ranged from 16.82-160 as demonstrated by the microneutralization assay. Further, deep RNA sequencing of the virus isolated in embryonated chicken eggs revealed no adaptive mutations indicating that IDV can replicate in horses, suggesting the possibility of interspecies transmission of IDV with bovine reservoir into equids in nature.
Topics: Animals; Antibodies, Viral; Cattle; Horse Diseases; Horses; Influenza A Virus, H3N8 Subtype; Orthomyxoviridae; Orthomyxoviridae Infections; Thogotovirus
PubMed: 35458390
DOI: 10.3390/v14040661 -
Viruses Oct 2019This report describes and characterizes three novel RNA viruses isolated from dead birds collected during West Nile virus surveillance in Harris County, TX, USA (the...
This report describes and characterizes three novel RNA viruses isolated from dead birds collected during West Nile virus surveillance in Harris County, TX, USA (the Houston metropolitan area). The novel viruses are identified as members of the families , , and and have been designated as San Jacinto virus, Mason Creek virus, and Buffalo Bayou virus, respectively. Their potential public health and/or veterinary importance are still unknown.
Topics: Animals; Bird Diseases; Birds; Mice; Orthomyxoviridae; Phylogeny; RNA Viruses; RNA, Viral; Texas
PubMed: 31658646
DOI: 10.3390/v11100927