Influenza Virus Net is the web resource for anyone interested in influenza and flu pandemics. The objectives of Influenza Virus Net are to be the public and professional information resource for influenza and to serve as a network in the exchange of information and news related to influenza.

Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses), that affects humans, birds and other mammals. The virus spreads easily from person to person. Influenza circulates worldwide and can affect anybody in any age group. Influenza causes annual epidemics that peak during winter in temperate regions. Influenza is a serious public health problem that causes severe illnesses and deaths for higher risk populations. The most common symptoms of the disease are chills, fever, sore throat, muscle pains, severe headache, coughing, weakness/fatigue and general discomfort. Sore throat, fever and coughs are the most frequent symptoms. In more serious cases, influenza causes pneumonia, which can be fatal, particularly for the young and the elderly. An influenza epidemic can take an economic toll through lost workforce productivity, and strain health services. Vaccination is the most effective way to prevent infection.

• Avian Flu Scan for Apr 23, 2014 - CIDRAP
  Thu, 24 Apr 2014 00:11:
• Another swine flu case in Ahmedabad - Times of India
  Wed, 23 Apr 2014 23:23:
• Second wave of flu hits; Northeast region hardest hit by influenza B strain - Washington Post
  Wed, 23 Apr 2014 22:44:
• Alachua students' flu immunization sets record - Gainesville Sun
  Wed, 23 Apr 2014 22:42:
• BC health-care worker fired for not getting flu shot or wearing mask - Prince George Citizen
  Wed, 23 Apr 2014 22:25:
• Football: Flu keeps Bale on bench for Bayern clash - Channel News Asia
  Wed, 23 Apr 2014 18:12:
• Bird flu found in Stanislaus County - The Turlock Journal
  Wed, 23 Apr 2014 22:16:
• Flu kills five more in London area - London Community News
  Wed, 23 Apr 2014 17:54:
• Bird Flu Found on California Farm Spurs Export Bans - Bloomberg
  Wed, 23 Apr 2014 19:03:
• Flu remains in full bloom this spring - WNYT
  Wed, 23 Apr 2014 21:45:

• Baicalin inhibits TLR7/MYD88 signaling pathway activation to suppress lung inflammation in mice infected with influenza A virus.
  Wan Q, Wang H, Han X, et al. Baicalin inhibits TLR7/MYD88 signaling pathway activation to suppress lung inflammation in mice infected with influenza A virus. [JOURNAL ARTICLE]Biomed Rep 2014 May; 2(3):437-441.The present study aimed to investigate the protective effects and underlying mechanisms of baicalin on imprinting control region mice infected with influenza A/FM/1/47 (H1N1) virus. Oral administration of baicalin into mice infected with H1N1 prevented death, increased the mean time to death and inhibited lung index and lung consolidation. Subsequently, fluorescence quantitative polymerase chain reaction was used to assess the mRNA expression of toll-like receptor 7 (TLR7) and myeloid differentiation primary response gene 88 (MYD88), and western blot analysis was used to determine the expression of phosphorylated nuclear factor κB (NF-κB)-P65 and c-jun/activator protein 1 (AP-1). An enzyme-linked immunosorbent assay was applied to test for the inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1β and IL-6, in the lung tissue. The findings indicated that baicalin downregulated the mRNA expression of TLR7 and MYD88, significantly downregulated the protein expression of NF-κB-P65 and AP-1 and also inhibited the secretion of TNF-α, IL-1β and IL-6. In conclusion, baicalin effectively reduced the pathological damage and inflammation of the lungs by downregulating the TLR7/MYD88-mediated signaling pathway.


• Utilizing Syndromic Surveillance Data for Estimating Levels of Influenza Circulation.
  Patterson-Lomba O, Van Noort S, Cowling BJ, et al. Utilizing Syndromic Surveillance Data for Estimating Levels of Influenza Circulation. [JOURNAL ARTICLE]Am J Epidemiol 2014 Apr 18.AbstractPublisher Full TextThe availability of weekly Web-based participatory surveillance data on self-reported influenza-like illness (ILI), defined here as self-reported fever and cough/sore throat, over several influenza seasons allows for estimation of the incidence of influenza infection in population cohorts. We demonstrate this using syndromic data reported through the Influenzanet surveillance platform in the Netherlands. We used the 2011-2012 influenza season, a low-incidence season that began late, to assess the baseline rates of self-reported ILI during periods of low influenza circulation, and we used ILI rates above that baseline level from the 2012-1013 season, a major influenza season, to estimate influenza attack rates for that period. The latter conversion required estimates of age-specific probabilities of self-reported ILI given influenza (Flu) infection (P(ILI | Flu)), which were obtained from separate data (extracted from Hong Kong, China, household studies). For the 2012-2013 influenza season in the Netherlands, we estimated combined influenza A/B attack rates of 29.2% (95% credible interval (CI): 21.6, 37.9) among survey participants aged 20-49 years, 28.3% (95% CI: 20.7, 36.8) among participants aged 50-60 years, and 5.9% (95% CI: 0.4, 11.8) among participants aged ≥61 years. Estimates of influenza attack rates can be obtained in other settings using analogous, multiseason surveillance data on self-reported ILI together with separate, context-specific estimates of P(ILI | Flu).


• Comparing clinical characteristics between hospitalized adults with laboratory-confirmed influenza A and B virus infection.
  Su S, Chaves SS, Perez A, et al. Comparing clinical characteristics between hospitalized adults with laboratory-confirmed influenza A and B virus infection. [JOURNAL ARTICLE]Clin Infect Dis 2014 Apr 18.AbstractPublisher Full TextWe challenge the notion that influenza B virus infection is milder than influenza A virus infection by finding similar clinical characteristics and outcomes between adults hospitalized with these two types of influenza. Among patients treated with oseltamivir, length of stay and mortality did not differ by type of virus infection.


• Causes of non-malarial fever in Laos: a prospective study.
  Mayxay M, Castonguay-Vanier J, Chansamouth V, et al. Causes of non-malarial fever in Laos: a prospective study. [JOURNAL ARTICLE]Lancet Glob Health 2013 Jul; 1(3):e46-e54.AbstractPublisher Full TextBecause of reductions in the incidence of Plasmodium falciparum malaria in Laos, identification of the causes of fever in people without malaria, and discussion of the best empirical treatment options, are urgently needed. We aimed to identify the causes of non-malarial acute fever in patients in rural Laos.For this prospective study, we recruited 1938 febrile patients, between May, 2008, and December, 2010, at Luang Namtha provincial hospital in northwest Laos (n=1390), and between September, 2008, and December, 2010, at Salavan provincial hospital in southern Laos (n=548). Eligible participants were aged 5-49 years with fever (≥38°C) lasting 8 days or less and were eligible for malaria testing by national guidelines.With conservative definitions of cause, we assigned 799 (41%) patients a diagnosis. With exclusion of influenza, the top five diagnoses when only one aetiological agent per patient was identified were dengue (156 [8%] of 1927 patients), scrub typhus (122 [7%] of 1871), Japanese encephalitis virus (112 [6%] of 1924), leptospirosis (109 [6%] of 1934), and bacteraemia (43 [2%] of 1938). 115 (32%) of 358 patients at Luang Namtha hospital tested influenza PCR-positive between June and December, 2010, of which influenza B was the most frequently detected strain (n=121 [87%]). Disease frequency differed significantly between the two sites: Japanese encephalitis virus infection (p=0·04), typhoid (p=0·006), and leptospirosis (p=0·001) were more common at Luang Namtha, whereas dengue and malaria were more common at Salavan (all p<0·0001). With use of evidence from southeast Asia when possible, we estimated that azithromycin, doxycycline, ceftriaxone, and ofloxacin would have had significant efficacy for 258 (13%), 240 (12%), 154 (8%), and 41 (2%) of patients, respectively.Our findings suggest that a wide range of treatable or preventable pathogens are implicated in non-malarial febrile illness in Laos. Empirical treatment with doxycycline for patients with undifferentiated fever and negative rapid diagnostic tests for malaria and dengue could be an appropriate strategy for rural health workers in Laos.Wellcome Trust, WHO-Western Pacific Region, Foundation for Innovative New Diagnostics, US Centers for Disease Control and Prevention.


• The updated phylogenies of the phasianidae based on combined data of nuclear and mitochondrial DNA.
  Shen YY, Dai K, Cao X, et al. The updated phylogenies of the phasianidae based on combined data of nuclear and mitochondrial DNA. [Journal Article]PLoS One 2014; 9(4):e95786.AbstractPublisher Full TextThe phylogenetic relationships of species in the Phasianidae, Order Galliformes, are the object of intensive study. However, convergent morphological evolution and rapid species radiation result in much ambiguity in the group. Further, matrilineal (mtDNA) genealogies conflict with trees based on nuclear DNA retrotransposable elements. Herein, we analyze 39 nearly complete mitochondrial genomes (three new) and up to seven nuclear DNA segments. We combine these multiple unlinked, more informative genetic markers to infer historical relationships of the major groups of phasianids. The nuclear DNA tree is largely congruent with the tree derived from mt genomes. However, branching orders of mt/nuclear trees largely conflict with those based on retrotransposons. For example, Gallus/Bambusicola/Francolinus forms the sister-group of Coturnix/Alectoris in the nuclear/mtDNA trees, yet the tree based on retrotransposable elements roots the former at the base of the tree and not with the latter. Further, while peafowls cluster with Gallus/Coturnix in the mt tree, they root at the base of the phasianids following Gallus in the tree based on retrotransposable elements. The conflicting branch orders in nuclear/mtDNA and retrotransposons-based trees in our study reveal the complex topology of the Phasianidae.


• Molecular characterization and phylogenetic analysis of H3 subtype avian influenza viruses isolated from domestic ducks in Zhejiang Province in China.
  Wu H, Wu N, Peng X, et al. Molecular characterization and phylogenetic analysis of H3 subtype avian influenza viruses isolated from domestic ducks in Zhejiang Province in China. [JOURNAL ARTICLE]Virus Genes 2014 Apr 20.AbstractPublisher Full TextIn 2013, 15 avian influenza viruses (AIVs), H3N2 (n = 7), H3N3 (n = 3), H3N6 (n = 3), and H3N8 (n = 2), were isolated from domestic ducks in Zhejiang Province in China. These strains were characterized by whole genome sequencing with subsequent phylogenetic analysis and genetic comparison. Phylogenetic analysis of all eight viral genes showed that these strains clustered in the AIV Eurasian lineage. Analysis of the neuraminidase (NA) gene indicates that a re-assortment event between H3 and H9N2 AIV occurred in these ducks. The molecular markers analyzed over the genome of all viruses indicated that these strains were low-pathogenic AIVs. Although there was no evidence of re-assortment in subtype H3 AIVs among the avian species' and mammalian hosts in this study, continued surveillance is needed considering the important role of domestic ducks in AIV re-assortment.


• Continuing evolution of equine influenza virus in Central Asia, 2007-2012.
  Karamendin K, Kydyrmanov A, Kasymbekov Y, et al. Continuing evolution of equine influenza virus in Central Asia, 2007-2012. [JOURNAL ARTICLE]Arch Virol 2014 Apr 20.AbstractPublisher Full TextEquine influenza (EI) continues to be an important respiratory pathogen of horses worldwide. Since 2007 several outbreaks of EI have occurred in Central Asian countries, including Kazakhstan, western Mongolia, India and western China. Phylogenetic analysis showed that two H3N8 equine influenza virus (EIV) isolates from Kazakhstan, A/equine/Almaty/26/2007 and A/equine/South Kazakhstan/236/12, were related to Florida sublineage 2, with high similarity to EIVs circulating in the same period in neighbouring countries. New outbreaks of EI during 2011 and 2012 in Kazakhstan and other Central Asian countries were caused by viruses of the same lineage. Genetic characterization of the viruses showed formation of a small EIV cluster with specific genetic signatures and continued evolution of this lineage in Central Asia between 2007 and 2012. The main genetic changes were observed in hemagglutinin gene without any antigenic drift. Although no vaccination policy was carried out in Kazakhstan, application of Florida clade 2-based vaccines is recommended.


• Essential role for autophagy in the maintenance of immunological memory against influenza infection.
  Chen M, Hong MJ, Sun H, et al. Essential role for autophagy in the maintenance of immunological memory against influenza infection. [JOURNAL ARTICLE]Nat Med 2014 Apr 20.AbstractPublisher Full TextVaccination has been the most widely used strategy to protect against viral infections for centuries. However, the molecular mechanisms governing the long-term persistence of immunological memory in response to vaccines remain unclear. Here we show that autophagy has a critical role in the maintenance of memory B cells that protect against influenza virus infection. Memory B cells displayed elevated levels of basal autophagy with increased expression of genes that regulate autophagy initiation or autophagosome maturation. Mice with B cell-specific deletion of Atg7 (B/Atg7(-/-) mice) showed normal primary antibody responses after immunization against influenza but failed to generate protective secondary antibody responses when challenged with influenza viruses, resulting in high viral loads, widespread lung destruction and increased fatality. Our results suggest that autophagy is essential for the survival of virus-specific memory B cells in mice and the maintenance of protective antibody responses required to combat infections.


• Clinical performance evaluation of the BD Veritor System Flu A+B assay.
  Nam MH, Jang JW, Lee JH, et al. Clinical performance evaluation of the BD Veritor System Flu A+B assay. [JOURNAL ARTICLE]J Virol Methods 2014 Apr 17.AbstractPublisher Full TextEarly identification of influenza is important for optimal patient management and infection control. Rapid influenza antigen tests have been used routinely in clinical settings to confirm clinical suspicion, despite their low sensitivity. To improve sensitivity, various influenza point-of-care test reader systems have been developed. This study evaluated the clinical performance of a digital readout rapid influenza diagnostic test (RIDT), the BD Veritor™ System Flu A+B assay (BD). Nasopharyngeal swabs taken from 250 patients (influenza A positive, n=75; influenza B positive, n=75; and influenza negative, n=100) were analyzed using the BinaxNOW® Influenza A/B antigen kit (BN), SD Influenza Ag A/B kit (SD), BD, real-time reverse transcriptase polymerase chain reaction (RT-PCR), and an influenza virus culture. Compared to RT-PCR, the sensitivities of BN, SD, and BD were 56.0%, 53.3%, and 72.0%, respectively, for influenza A and 57.3%, 65.3%, and 69.3%, respectively, for influenza B. No false-positive results were noted with the three rapid antigen tests. For influenza A, the average RT-PCR threshold cycle (Ct) for specimens that tested positive using BD was higher than that for specimens that tested positive using BN and SD. BD is a sensitive and easy method for the early detection of influenza A and B.


• Knowledge, Attitudes, and Practices of Nonpharmaceutical Interventions following School Dismissals during the 2009 Influenza A H1N1 Pandemic in Michigan, United States.
  Shi J, Njai R, Wells E, et al. Knowledge, Attitudes, and Practices of Nonpharmaceutical Interventions following School Dismissals during the 2009 Influenza A H1N1 Pandemic in Michigan, United States. [Journal Article]PLoS One 2014; 9(4):e94290.AbstractPublisher Full TextMany schools throughout the United States reported an increase in dismissals due to the 2009 influenza A H1N1 pandemic (pH1N1). During the fall months of 2009, more than 567 school dismissals were reported from the state of Michigan. In December 2009, the Michigan Department of Community Health, in collaboration with the United States Centers for Disease Control and Prevention, conducted a survey to describe the knowledge, attitudes, and practices (KAPs) of households with school-aged children and classroom teachers regarding the recommended use of nonpharmaceutical interventions (NPIs) to slow the spread of influenza.A random sample of eight elementary schools (kindergarten through 5th grade) was selected from each of the eight public health preparedness regions in the state. Within each selected school, a single classroom was randomly identified from each grade (K-5), and household caregivers of the classroom students and their respective teachers were asked to participate in the survey.In total, 26% (2,188/8,280) of household caregivers and 45% (163/360) of teachers from 48 schools (of the 64 sampled) responded to the survey. Of the 48 participating schools, 27% (13) experienced a school dismissal during the 2009 fall term. Eighty-seven percent (1,806/2,082) of caregivers and 80% (122/152) of teachers thought that the 2009 influenza A H1N1 pandemic was severe, and >90% of both groups indicated that they told their children/students to use NPIs, such as washing hands more often and covering coughs with tissues, to prevent infection with influenza.Knowledge and instruction on the use of NPIs appeared to be high among household caregivers and teachers responding to the survey. Nevertheless, public health officials should continue to explain the public health rationale for NPIs to reduce pandemic influenza. Ensuring this information is communicated to household caregivers and teachers through trusted sources is essential.