Throughout history influenzas have consistently qualified as one of the top killers amongst common infectious diseases and it continues today to afflict millions in spite of our vast efforts to curb its effects. The World Health Organization (WHO) notes annual deaths of between 250,000 to 500,000 due to influenza. Alternative medicines have been traditionally used to treat this illness in the past, and have begun to experience an increase in popularity these days as a complementary supplement to improve treatment of influenza’s symptoms. The use of such natural extracts as Echinacea, ascorbic acid, and “Kan Jang” aim to mitigate symptoms and increase the efficiency of the healing process. Their use, however, has been scrutinized and somewhat controversial when looking at their effectiveness. Having such wide-spread use of these treatments, it is important to understand just how beneficial these alternative routes are when treating infectious diseases like influenza. The objective of this literature review is to assess the use of these traditional medicines in the treatment of influenza and influenza-like-illnesses (ILI). In order to do this, randomized controlled trials were studied to establish any benefits these medicines might provide in the treatment of symptoms and the prevention of influenza. Treatment groups with the three different alternative medicines were respectively compared to control groups without any treatment through singular symptoms and duration of these symptoms, as well as prevention of multiple infections. / published_or_final_version / Public Health / Master / Master of Public Health

Influenza viruses exploit sophisticated host cell machinery to replicate, causing both seasonal epidemics and unpredictable pandemics. Studying the host cellular factors interacting with conserved domains of viral proteins will help us to identify key host proteins for the virus infection. This will not only strengthen our understanding of the precise mechanisms of the virus life cycle, but also pave new avenues for anti-viral development. The cytoplasmic tail of M2 ion channel (M2/CT) is one of these highly conserved domains. It is fully accessible to the host cell machinery after fusion of the virus envelope with the endosomal membrane and during the trafficking, assembly, and budding processes. I hypothesized that recruitment of host cellular factors by M2/CT may regulate the M2-dependent stages of the virus life cycle. Through a large scale yeast two-hybrid (Y2H) screen with the M2/CT used as bait, the human annexin A6 was identified as a novel host cell interactant and this interaction was further confirmed by both GST pull-down assay on purified proteins and co-immunoprecipitation assay on virus infected cells. A functional characterization of this novel interaction demonstrated that depletion of annexin A6 could enhance the virus production, while its overexpression could reduce the virus propagation, which indicates that annexin A6 is a negative regulator of the virus infection. However, I found that the virus infection could not induce any changes of annexin A6 expression. Therefore, the annexin A6-mediated regulation may depend on the subcellular localization where the interaction with M2/CT occurs. To decipher which step of the virus replication is regulated, we dissected the virus life cycle and found that modulation of annexin A6 expression had no effect on the early stages of the virus life cycle or on viral RNA replication but impaired the release of progeny virus, as suggested by delayed or defective budding events observed at the plasma membrane of virus-infected and annexin A6-overexpressing cells during a transmission electron microscopy study. To further decipher the underlying molecular mechanisms, the contribution of annexin A6-mediated plasma membrane lipid rafts reorganization through cholesterol homeostasis modulation and cortical actin cytoskeleton remodeling was also investigated. In conclusion, here I have identified the human annexin A6 as a novel host cell interactant of M2/CT that negatively modulate the influenza virus infection by impairing the virus budding and release. This work further supports the idea that M2 is a multifunctional protein and is also consistent with the discovery by Rossman et al. that M2/CT mediates the virus budding process (Rossman et al., 2010). This study further emphasizes the importance of host cell interactants of M2/CT in this process. Regarding the biology of annexins, this study also adds a new member of this protein family in the list of regulators of influenza virus infection. / published_or_final_version / Public Health / Doctoral / Doctor of Philosophy

Introduction With the emergence of the H5N1 virus in humans that was of entirely avian origin, a better understanding of potential receptors of the influenza A virus is needed. It is widely accepted that terminally sialylated glycoconjugates on the surface of the red blood cells are receptors to which the influenza A virus binds to and causes the agglutination of red blood cells. By isolating glycans found on red blood cells, perhaps it is possible to find potential receptors that influenza A virus has preferential binding to. There has been a general shift of using turkey red blood cells rather than chicken red blood cells for the haemagglutination of viruses over the past few decades. The influenza virus’s loss in ability to agglutinate chicken red blood cells but keep the ability to agglutinate turkey red blood cells a puzzling mystery. By comparing the differences, perhaps it is possible to elucidate structures influenza viruses prefer to bind to. Methods Mass spectrometricanalysis of purified glycans will allow us to narrow down the structures of the most abundant glycans found on the erythrocyte surface. Lectin staining with flow cytometry is used to identify the receptor specificity of the influenza viruses. Haemagglutination assay in conjunction with glycan binding array data from the CFG will allow us to pinpoint the possible structures that give the viruses the ability to bind using treatments with sialidases. Results The mass spectrometric data was good and the basic glycan structures were elucidated according to their mass to charge ratio. The proportion of the different glycans for each of the erythrocyte type was clearly shown. The lectin staining gave more accurate results have selecting a single cell population and it was clear that turkey red blood cells had more α2,3 and α2,6 linked glycans than the chicken red blood cells. The haemagglutination assay aided the identification of differentiating theα2,3 linked and α2,6 linked liking viruses. The glycan array binding data was obtained but some results were absent. Conclusion It is certain that turkey red blood cells are better than chicken red blood cells for use in the haemagglutination assays as they present some glycans that are present in human bronchial epithelials. The most abundant sialylated glycan are the α2,6 linked sialylated glycans. The most abundant glycans on chicken red blood cells are either absent or in low abundance on the HBEs. Though the turkey red blood cells have some glycans that are present on HBEs, the glycan profile is very different. To agglutinate red blood cells, viruses are likely to bind to the bisecting glycans and shorter antennae glycans. In methodology: for lectin staining experiments, one must take caution in the lectin used as it may affect results. Sialidase S treated RBCs are a good method to distinguish α2,3 linked glycans liking viruses. / published_or_final_version / Pathology / Master / Master of Medical Sciences

Macrophages have well-established roles in the primary response to pathogens and hold essential functions during innate and adaptive immunity. Under activation by different growth factors and cytokines, human monocytes have been shown to differentiate and polarize into two main types of macrophage, classically-activated macrophages (caMφ) and alternatively-activated macrophages (aaMφ), displaying distinct properties and phenotypes. For instance, caMφ secrete pro-inflammatory cytokines, whereas aaM secrete anti-inflammatory cytokines. Additionally, aaMφ displays stronger phagocytic ability and are equipped with different endosomal proteases. While it has been established that monocyte-derived macrophages can be infected by Influenza A virus, most studies utilized a macrophage population obtained by differentiation in the presence of autologous plasma. My research project aimed at systematically comparing susceptibility of the infection by Influenza A virus to the recently described caMφ and aaMφ. Here I show that monocytes cultured in presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon (IFN)-γ or in presence of macrophage colony-stimulating factor (M-CSF) and interleukin (IL)-4 or IL-10 can be differentiated into distinct populations. According to immunophenotyping results, a distinct expression profile was observed for Cluster of Differentiation (CD) 36, CD86, Mannose Receptor (MR or CD206), and Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN or CD209) among differentiated macrophages. Except for CD86 expression, my results were in accordance with previous reports and thus allowed me to classify all populations into caMφ (M1 macrophages), and aaMφ (M2a and M2c macrophages). I then assessed the susceptibility of the above mentioned macrophages to pandemic Influenza A/California/04/2009 H1N1 virus (CA04) infection. My results demonstrate a marked difference, caMφ showing low to moderate permissivity, whereas aaMφ – and in particular M2a macrophages – were consistently highly infected. In contrast, no difference was observed with Influenza A/WSN/1933 H1N1 virus (WSN/33) infection. Because sialic acids are regarded as the primary receptor for influenza virus, I investigated the cell surface distribution of sialic acids with α2-3 linkage (SAα-2,3) or α2-6 linkage (SAα-2,6) among the population of human macrophages. By using lectin staining with Maackia amurensis lectin (MAL) II and Sambucus nigra lectin (SNA), which bind sialic acids with α2-3 linkage (SAα-2,3) and α2-6 linkage (SAα-2,6) respectively, I found all the monocyte-derived macrophages exhibited a comparable expression of SAα-2,3 and SAα-2,6, which unlikely explain the differential susceptibility to infection by CA04. In addition to sialic acids, C-type lectins were also proposed to mediate entry of influenza viruses into macrophages. All macrophages expressed CD206 but only M2a expressed CD209. However assay aiming at interfering with CD209 binding (MAb blocking assay or EGTA treatment) did not inhibit pdmH1N1 infection. Surprisingly, infection in presence of EGTA, which is believed to reduce the functional ability of C-type lectins, exacerbated susceptibility of the macrophages. Altogether my results show that susceptibility to Influenza A virus infection of in vitro differentiated primary human macrophages is unlikely to rely on the sialic acid expression profile and is dependent on viral strain. Further studies are needed to understand what difference from caMφ and aaMφ – either phenotypic and/or biochemical – confer them distinct susceptibilities to some viral subtype/strain of Influenza A. / published_or_final_version / Pathology / Master / Master of Philosophy

Neuraminidase (NA) inhibitors are one of two classes of antiviral compounds available for the control of influenza infections. The H275Y NA mutation confers resistance to the NA inhibitor oseltamivir carboxylate among the N1 influenza subtype and has been identified from resistant variants with distinct epidemiological outcomes in human. Specifically, dominance of oseltamivir-resistant variant of the A/Brisbane/59/2007-like viruses was reported during the 2008 to 2009 influenza season, until it was replaced by the 2009 pandemic H1N1 virus [A(H1N1)pdm09]. Since the emergence of the 2009 pandemic, the fitness and transmission potential of oseltamivir-resistant A(H1N1)pdm09 variants carrying the H275Y mutation has been a concern. This project aims to systematically evaluate the fitness of viruses carrying the H275Y mutation for A(H1N1)pdm09 and seasonal H1N1 viruses. A panel of recombinant viruses with their NA gene derived from the A(H1N1)pdm09 A/California/04/09 (CA04), seasonal H1N1 A/New Caledonia/20/1999 (NewCal) or A/Brisbane/59/2007 (Brisbane) was generated in the genetic background of CA04. The H275Y mutation in all three viruses led to a reduced affinity for 3’-sialylactose (3’SL) or 6’-sialylactose (6’SL). Similarly, lowered enzyme activity was observed across H275Y-carrying viruses in 3’SL and 6’SL, with the exception of RG-CA04NA-H275Y at catalyzing 3’SL. Differential 3’SL and 6’SL substrate usage was observed between the NA of seasonal H1N1 and A(H1N1)pdm09 viruses. Reduced infectivity was also observed for recombinant CA04 viruses carrying the H275Y mutation with decreased infectivity in mucin-secreting primary human airway epithelial cells when compared to their oseltamivir-sensitive counterparts. In the ferret model, the pathogenicity of RG-CA04NA-H275Y and RG-CA04BrisbaneNA-H275Y viruses was attenuated albeit the transmissibility was minimally affected when compared to RG-CA04 wild-type virus. In parallel, recombinant seasonal H1N1 viruses encoding the surface glycoproteins of NewCal and Brisbane were tested in ferrets. Results indicated that NewCal and Brisbane viruses carrying the H275Y mutation displayed comparable transmission efficiencies to the wild-type NewCal virus via direct-contact and respiratory-droplet settings. These results suggest that the H275Y NA mutation only leads to a minor reduction in viral fitness, with its transmission potential being minimally affected in the naïve ferret model. / published_or_final_version / Public Health / Master / Master of Philosophy

The seasonal Influenza A viruses are respiratory pathogens causing epidemics annually with mild illnesses, while sporadically, novel influenza viruses emerge and trigger pandemics associated with more widespread and sometimes severe disease. The biological basis for severity of influenza disease remains unclear though it is recognized that the interplay between the influenza viruses and the host immune responses both contribute to viral pathogenesis. As macrophages are key sentinels of the innate immune response and play a crucial role in being the “first responders” as well as contributing to shaping the subsequent (pathogen‐specific) adaptive immune response, the objective of this research was to bring insights on the outcomes of the interactions of influenza viruses with the macrophages. The occurrence of Antibody‐Dependent Enhancement (ADE) of Influenza infection in macrophages was investigated. ADE occurs when non‐neutralized virus‐antibody complexes find alternative entry routes into host cells, mainly through the Fc‐receptor pathway and has been demonstrated predominantly in macrophages. Addition of human serum from some individuals to influenza A virus (either H5 pseudoparticles or pandemic (H1N1) virus) led to enhanced infection of murine macrophage‐like cells as illustrated by a two to five fold increase in detection of influenza M‐gene copies. Immunofluorescence microscopy indicated that serum‐mediated pandemic (H1N1) infection led to an increase in the number of infected cells than in controls. As the fold change in viral gene copies paralleled the fold increase of infected cells I concluded that ADE infection provide pandemic (H1N1) virus with increased opportunity to infect cells rather than simply increase the viral load per cell. In order to strengthen our results, and make them more physiologically relevant, experiments were then performed with human primary cells with clinical sera. However, ADE was not demonstrated in primary human macrophages, suggesting that ADE may be cell type or host specific. The second research question investigated was whether the different state of human primary macrophage differentiation or activation in vitro determined the susceptibility to influenza infection. Recently, work by others has shown a diverse range of macrophage phenotypes that arise by differences in macrophage differentiation and activation. In addition to the classical activation pathway (caMΦ), new mechanisms of activation, designated as alternative activation (aaMΦ), have been reported. Classically and alternatively activated macrophages display different phenotypes and properties, such as molecule expression patterns, cytokine secretion, and gene signatures. This study constitutes the first systematic comparison of Influenza A virus infection of these different subsets of human primary monocyte‐derived macrophages. When assessed for their permissiveness to different influenza A viruses, aaMΦΦshowed greater susceptibility to influenza A infection than caMΦ. This work also documents the receptor patterns and the gene expression profile of these macrophages in response to influenza virus infection in vitro. The results point to differences in susceptibility of the classically and alternatively activated human macrophages to pandemic H1N1 and other influenza A viruses and reveal intrinsic differences between these macrophage subtypes. Further investigations are needed to define the cellular and molecular determinants that define susceptibility of different macrophage subsets to influenza A infection. / published_or_final_version / Public Health / Doctoral / Doctor of Philosophy

Influenza B virus contributes to a significant portion of influenza disease burden in men. It is structurally similar and replicates in the same manner as the influenza A virus, leading to a comparable clinical presentation between the two viral species. Since 1977, influenza B has caused seasonal epidemics around the world together with A/H1N1 and A/H3N2 subtypes, and has a strong affinity to affect children of school age and young adults. In the 1980s, two antigenically distinct lineages of influenza B virus emerged, one being the B/Yamagata lineage and the other known as B/Victoria lineage. The most significant antigenic difference between the two is located in the HA1 domain of the viral hemagglutinin. Host immunity is not shared between the two viral lineages. Therefore, the global prevalence of the two influenza B lineages is closely monitored by the World Health Organization in order to decide which viral lineage to include in the annual trivalent influenza vaccines. Surprisingly, the current methods used in influenza B viral surveillance and lineage discrimination have not seen much technical advancement in nearly 25 years since the emergence of two viral lineages. The current study presents a novel, asymmetric real-time PCR assay which is able to determine the viral lineage in addition to detecting the presence of influenza B virus in clinical specimens. Asymmetric PCR is performed by deliberately limiting the amount of primers in one side of a PCR reaction. This significantly affects the replication efficiency and sensitivity of the PCR reaction, but at the same time facilitates target sequence detection by hybridization probes, due to an increased number of single stranded products in the reaction. Nevertheless, the use of asymmetric PCR has been avoided in the past. The recent introduction of linear-after-the-exponential (LATE) PCR refines the method by adjusting melting temperature of PCR primers so that TmLimiting – TmExcess ≥ 0°C. The modification is shown to raise the efficiency of asymmetric PCR to those of symmetric PCR, as well as allowing more relaxed criteria for PCR primer and probe design. In the current asymmetric assay, pan-influenza B primers and probes targeting Victoria and Yamagata linage specific regions of the influenza B HA were evaluated against a similar symmetric influenza B assay published by the World Health Organization. HA plasmid standards and 155 clinical specimens were tested by both assays, in which the two had intra-assay CV% of less than 5%. Albeit the efficiency and sensitivity of WHO published assay was slightly higher, LATE-PCR based assay performed influenza B detection and genotyping simultaneously with the use of hydrolysis probes. The overall sensitivity/ specificity of the genotyping assay are 96.81%/100% while the WHO recommended assay is at 98.94%/100% for influenza B detection. The LATE-PCR based genotyping assay also successfully genotyped 89 out of 94 clinical specimens. In conclusion, the influenza B genotyping assay evaluated in this study performed favorably and could serve as an alternative to cumbersome viral culture methods to aid in high-throughput global influenza surveillance. / published_or_final_version / Microbiology / Master / Master of Medical Sciences

Background The pandemic of influenza A (H1N1-2009) virus was particularly widespread among children. Children and young adults were more likely to be infected than older adults, and infection among infants tended to lead to a higher risk of severe complications than among older children and adults. Vaccination against the virus was thus recommended as an effective countermeasure to protect these susceptible age strata from influenza infection and subsequent complications. Parental perception, attitudes and beliefs would thus play a major role in mitigating the pandemic influenza because these factors underlie the degree of vaccination uptake among children. Objective The primary aim of this study is to understand factors that are associated with parental acceptance of pediatric vaccination against influenza (H1N1-2009). The secondary aim is to consider the effective future vaccination campaign in the event of a pandemic and to increase child vaccination coverage. Methods We conducted a systematic literature search of the electronic databases, PubMed and the Web of Science. We identified and examined published literatures associated with parental acceptance dating back to the beginning of the 2009 pandemic. We extracted key datasets from these literatures, summarized the evidence systematically and determined the relationship amongst the aforementioned parental characteristics and acceptance of pandemic influenza vaccines. Results We included a total of 14 studies in this review. Our systematic review indicates that parents were more willing to accept H1N1 pandemic influenza vaccination if 1) their children had previous experience with seasonal influenza; 2) they have had the pandemic influenza vaccine themselves; or 3) they intended to have their children vaccinated against seasonal influenza vaccine. We also founded that parental perceptions and attitudes towards both the influenza pandemic itself and the pandemic influenza vaccine are significantly associated with acceptance. Our study identified misperceptions and distrust in vaccine safety as the main reason for parents to refuse pandemic influenza vaccination for their children. In addition, we found that parents usually received negative appraisal on pediatric influenza vaccination from the media and tended to regard health care workers as the most reliable source of information on pediatric influenza vaccination. . Conclusions Parental perceptions are influential on pandemic influenza vaccine acceptance of their children. We affirm the importance of the role of health care workers in delivering appropriate information on influenza vaccines to parents in increasing pediatric vaccination uptake. We recommend public health officials to employ effective strategies for risk communication regarding pediatric influenza vaccines in order to increase the coverage and hence effectiveness of vaccination program against a future influenza pandemic. / published_or_final_version / Public Health / Master / Master of Public Health

Cigarette smoke displays both immunoactivating and immunosuppressive activities. Although the health risks of cigarette smoke are widely reported, the impact and mechanism of cigarette smoke exposure on inflammatory diseases are still unclear. Innate immune responses could be activated shortly after influenza A virus infection and then trigger inflammation in the lung. Until now, the effect of prior cigarette smoke on the inflammation caused by the following influenza A virus infection has not been fully understood and there is no study about the role of cigarette smoke in 2009 pandemic H1N1 (pdmH1N1) and avian H9N2 (H9N2/G1) infection. In this study, C57/B6N mice were whole body exposed to 4% cigarette smoke 4 hours per day for 21 days and then infected with pdmH1N1 or H9N2 virus. Some mice were exposed to room air in parallel as the control. Nicotine was also used to mimic the effect of the cigarette smoke. Human lung adenocarcinoma epithelial cell line A549 or human monocyte-derived macrophages were pre-treated with 10μM nicotine, and then infected with pdmH1N1 or H9N2 virus. The expression of cytokines and chemokines was examined in the supernatant. C57/B6N mice were treated with 24mg/kg/day nicotine or sterile water subcutaneously for 21 days and then infected with pdmH1N1 or H9N2 virus. Survival, body weight changes, lung viral loads, inflammatory responses and immune cells that infiltrated into the lung were analyzed. Cigarette smoke exposure alone significantly up-regulated the lung inflammation, confirmed by the dramatically decreased body weight gain and increased inflammatory response compared with the control mice. Such prior cigarette smoke exposure significantly reduced the disease severity induced by subsequent pdmH1N1 or H9N2 virus infection. For pdmH1N1 infection, cigarette smoke exposure group had a significantly lower mortality than the control group, which might be due to the lower inflammatory response at day 5 post virus infection. Similarly, after H9N2 virus infection, the mice in cigarette smoke exposure group displayed a significantly milder disease, as evidenced by less weight loss, weaker inflammatory response as well as lower number of immune cells infiltrating into the lung compared to the control group. There was no difference for the lung viral loads between the two groups upon both pdmH1N1 and H9N2 virus infection. Besides, pre-treating the A549 and primary human macrophages with nicotine decreased the expression of some cytokines and chemokines after pdmH1N1 or H9N2 virus infection. The mice treated with nicotine displayed significantly less weight loss and lower inflammatory response than control mice treated with sterile water upon pdmH1N1 or H9N2 virus infection. Collectively, our study demonstrated that the immunosuppressive effect of cigarette smoke was responsible for amelioration of pdmH1N1 and H9N2 pathogenicity by dampening the hyper-reaction of inflammatory response without any direct effect on viral replication. Nicotine, an anti-inflammatory factor, was the key component in cigarette smoke that was responsible for this immunosuppressive effect. Our study provided the first in vivo evidence that cigarette smoke, mostly due to nicotine, could protect against the pathogenicity of not only pdmH1N1, but also H9N2 virus. / published_or_final_version / Paediatrics and Adolescent Medicine / Doctoral / Doctor of Philosophy

Background Swine influenza virus (SIV) was first isolated in the United States in 1930 and was thereafter widely reported in many countries. Most SIVs that have been identified are influenza A viruses. There was no report of influenza B viruses isolated in swine. Seroepidemiological study in UK has shown a low seroprevalence of influenza B antibody in pigs. The primary serological test used to detect influenza antibody is the hemagglutination inhibition (HI)test. Enzyme-linked immunosorbent assay (ELISA) are also available commercially for detection of antibodies against influenza A viruses but not for the detection of influenza B antibodies. Objectives 1) To examine the prevalence of influenza B antibodies in pig sera sampled at the abattoir in Hong Kong. 2) To develop the cell-based ELISA assay for the detection of antibodies against influenza A and B viruses. 3) To compare the cell-based ELISA assays with three commercial ELISA kits, namely the IDVet ID Screen influenza A antibody competition ELISA, the IDEXX Influenza A Ab test and the IDEXX AI MultiS-Screen Ab test using swine sera. 4) To test swine sera using the influenza B cell-based ELISA assay to complement data on swine seroprevalence obtained with HI tests. Methods The first part of this study involved HI screening of 4643 pig sera from 2009 to 2012. These sera were tested for the presence of antibodies against B/Brisbane/60/2008 and B/Wisconsin/1/2010whichrepresent the B/Victoria and B/Yamagata lineages respectively. The second part of this study involved the development and performance evaluation of the cell-based ELISA assays. The cell-based ELISA assays were developed using influenza virus infected cells as the capture antigens and fluorescence-labelled anti-IgG antibody as the detection antibody. The viruses that were used to prepare the assays were A/California/04/2009, B/Brisbane/60/2008 and B/Wisconsin/1/2010. All three cell-based ELISA assays were tested with WHO reference sera and swine sera and the results were analyzed using paired t-test and receiver operating characteristic analysis. In addition, the results of the influenza A cell-based ELISA assay were compared with the commercial ELISA assay using Fisher’s exact two-tailed test, Pearson’s correlation analysis and Bland-Altman plot. Results A low prevalence (0.28%; 95%CI: 0.16%-0.47%) of influenza B antibody was observed inthe swine sera samples. The seroprevalence for B/Victoria was higher than that of B/Yamagatain 2010to2012. Co-existence of B/Victoria and B/Yamagata antibodies were found in the swine population during 2010 and 2011. The influenza A cell-based ELISA was found to have low sensitivity (64.1%;95%CI: 52.4%-74.4%) and high specificity (94.7%; 95%CI:80.9%-99.1%) when compared with the commercial ELISA assays. In contrast, using HI as the reference test influenza B cell-based ELISA prepared using B/Wisconsin/1/2010 infected cells were shown to have high sensitivity (92.31%; 95%CI:64.0%-99.8%) but low specificity (63.16%;95%CI:38.4%-83.7%) in detection of influenza B antibodies in swine sera. Conclusion Sporadic transmission of influenza B virus may occur in swine but there is no evidence for efficient and sustained transmission of the virus between them. Cell-based ELISA assay prepared with B/Wisconsin/1/2010 may be considered as an alternative screening testprior to HI subtyping. / published_or_final_version / Public Health / Master / Master of Public Health