- Swine Flu: Knowledge, Attitude, and Practices Survey of Medical and Dental Students of Karachi. [Journal Article]
- CCureus 2018 Jan 09; 10(1):e2048
- Introduction Pakistan is extremely susceptible to an influenza outbreak, as it shares borders with the most affected countries, namely China and India. The medical and dental students come into direc...
Introduction Pakistan is extremely susceptible to an influenza outbreak, as it shares borders with the most affected countries, namely China and India. The medical and dental students come into direct contact with the affected population and should be aware of the risk factors and signs and symptoms pertaining to swine influenza virus (SIV). Hence, this survey was conducted to assess the knowledge, perceptions and self-care practices of the medical and dental students with regards to this pandemic. Methods A descriptive, cross-sectional study was conducted to evaluate the swine flu-related knowledge, attitudes and practices of the medical and dental students at various institutions in Karachi, Pakistan. We approached 613 students that were available on the dates of this survey, keeping a medical to dental student ratio of 75:25. All students from first to final year comprised of the study population, and no internists or medical personnel were included. The questionnaire was divided into three sections, namely knowledge, attitudes and, practices. All questions were based on a multiple choice format. The data were entered and interpreted using the IBM Statistical Package for the Social Sciences 23.0 (IBM Corp., Armonk, New York). Results The majority of the students were aware that the swine flu is a transmittable disease (n=485, 80.8%). Most students identified the signs and symptoms correctly; however, diarrhea (15.5%) and vomiting (32.2%) were the least correct answers (n=93, n=193 respectively). Most of the preventative measures were reported accurately by the participants. Despite this, only 15.5% students (n=93) reported the use of a facemask when suffering from fever, cough and a runny nose. Conclusion There is a dire need for the routine integration of the awareness and management programs in the medical and dental schools. There exists a gap between the policy and practice, and it is high time we bridge the divide. The students should also be vaccinated annually for influenza A.
- Antigenically diverse swine-origin H1N1 variant influenza viruses exhibit differential ferret pathogenesis and transmission phenotypes. [Journal Article]
- JVJ Virol 2018 Mar 14
- Influenza A(H1) viruses circulating in swine represent an emerging virus threat as zoonotic infections occur sporadically following exposure to swine. A fatal infection caused by an H1N1 variant (H1N...
Influenza A(H1) viruses circulating in swine represent an emerging virus threat as zoonotic infections occur sporadically following exposure to swine. A fatal infection caused by an H1N1 variant (H1N1v) virus was detected in a patient with reported exposure to swine and who presented with pneumonia, respiratory failure, and cardiac arrest. To understand the genetic and phenotypic characteristics of the virus, genome sequence analysis, antigenic characterization, and ferret pathogenesis and transmissibility experiments were performed. Antigenic analysis of the virus isolated from the fatal case, A/Ohio/09/2015, demonstrated significant antigenic drift away from classical swine H1N1 variant viruses and H1N1 pandemic 2009 viruses. A substitution in the H1 hemagglutinin (G155E) was identified that likely impacted antigenicity, and reverse genetics was employed to understand the molecular mechanism of antibody escape. Reversion of the substitution to 155G, in a reverse genetics A/Ohio/09/2015 virus, showed that this residue was central to the loss of hemagglutination inhibition by ferret antisera raised against a prototypical H1N1 pandemic 2009 virus (A/California/07/2009), as well as gamma lineage classical swine H1N1 viruses, demonstrating the importance of this residue for antibody recognition of this H1 lineage. When analyzed in the ferret model, A/Ohio/09/2015 and another H1N1v virus (A/Iowa/39/2015), as well as A/California/07/2009, replicated efficiently in the respiratory tract of ferrets. The two H1N1v viruses transmitted efficiently among cohoused ferrets, but respiratory droplet transmission studies showed that A/California/07/2009 transmitted through the air more efficiently. Pre-existing immunity to A/California/07/2009 did not fully protect ferrets from challenge with A/Ohio/09/2015.IMPORTANCEHuman infections with classical swine influenza A(H1N1) viruses that circulate in pigs continue to occur in the United States following exposure to swine. To understand the genetic and virologic characteristics of a virus (A/Ohio/09/2015) associated with a fatal infection and a virus associated with a non-fatal infection (A/Iowa/39/2015), we performed genome sequence analysis, antigenic testing, and pathogenicity and transmission studies in a ferret model. Reverse genetics was employed to identify a single antigenic site substitution (HA G155E) responsible for antigenic variation of A/Ohio/09/2015 compared to related classical swine influenza A(H1N1) viruses. Ferrets with pre-existing immunity to the pandemic A(H1N1) virus were challenged with A/Ohio/09/2015 demonstrating decreased protection. This data illustrates the potential for currently circulating swine influenza viruses to infect and cause illness in humans with pre-existing immunity to H1N1 pandemic 2009 viruses and a need for ongoing risk assessment and development of candidate vaccine viruses for improved pandemic preparedness.
- Appearance of reassortant European avian-origin H1 influenza A viruses of swine in Vietnam. [Journal Article]
- TETransbound Emerg Dis 2018 Mar 06
- Three subtypes-H1N1, H1N2 and H3N2-of influenza A viruses of swine (IAVs-S) are currently endemic in swine worldwide, but there is considerable genotypic diversity among each subtype and limited geog...
Three subtypes-H1N1, H1N2 and H3N2-of influenza A viruses of swine (IAVs-S) are currently endemic in swine worldwide, but there is considerable genotypic diversity among each subtype and limited geographical distribution. Through IAVs-S monitoring in Vietnam, two H1N2 influenza A viruses were isolated from healthy pigs in Ba Ria-Vung Tau Province, Southern Vietnam, on 2 December 2016. BLAST and phylogenetic analyses revealed that their HA and NA genes were derived from those of European avian-like H1N2 IAVs-S that contained avian-origin H1 and human-like N2 genes, and were particularly closely related to those of IAVs-S circulating in the Netherlands, Germany or Denmark. In addition, the internal genes of these Vietnamese isolates were derived from human A(H1N1)pdm09 viruses, suggesting that the Vietnamese H1N2 IAVs-S are reassortants between European H1N2 IAVs-S and human A(H1N1)pdm09v. The appearance of European avian-like H1N2 IAVs-S in Vietnam marks their first transmission outside Europe. Our results and statistical analyses of the number of live pigs imported into Vietnam suggest that the European avian-like H1N2 IAVs-S may have been introduced into Vietnam with their hosts through international trade. These findings highlight the importance of quarantining imported pigs to impede the introduction of new IAVs-S.
- Molecular evolution of H1N1 swine influenza in Guangdong, China, 2016-2017. [Journal Article]
- IGInfect Genet Evol 2018 Feb 26; 60:103-108
- Swine are the main host of the H1N1 swine influenza virus (SIV), however, H1N1 can also infect humans and occasionally cause serious respiratory disease. To trace the evolution of the SIV in Guangdon...
Swine are the main host of the H1N1 swine influenza virus (SIV), however, H1N1 can also infect humans and occasionally cause serious respiratory disease. To trace the evolution of the SIV in Guangdong, China, we performed an epidemic investigation during the period of 2016-2017. Nine H1N1 influenza viruses were isolated from swine nasal swabs. Antigenic analysis revealed that these viruses belonged to two distinct antigenic groups, represented by A/Swine/Guangdong/101/2016 and A/Swine/Guangdong/52/2017. Additionally, three genotypes, known as GD52/17-like, GD493/17-like and GD101/16-like, were identified by phylogenetic analysis. Importantly, the genotypes including a minimum of 4 pdm/09-origin internal genes have become prevalent in China in recent years. A total of 2966 swine serum samples were used to perform hemagglutination inhibition (HI) tests, and the results showed that the seroprevalence values of SW/GD/101/16 (32.2% in 2016, 32.1% in 2017) were significantly higher than the seroprevalence values of SW/GD/52/17 (18.0% in 2016, 16.7% in 2017). Our study showed that the three reassortant genotypes of H1N1 SIV currently circulating in China are stable, but H1N1pdm09 poses challenges to human health by the introduction of internal genes into these reassortant genotypes. Strengthening SIV surveillance is therefore critical for SIV control and minimizing its potential threat to public health.
- Synonymous Mutations at the Beginning of the Influenza A Virus Hemagglutinin Gene Impact Experimental Fitness. [Journal Article]
- JMJ Mol Biol 2018 Feb 18
- The fitness effects of synonymous mutations can provide insights into biological and evolutionary mechanisms. We analyzed the experimental fitness effects of all single-nucleotide mutations, includin...
The fitness effects of synonymous mutations can provide insights into biological and evolutionary mechanisms. We analyzed the experimental fitness effects of all single-nucleotide mutations, including synonymous substitutions, at the beginning of the influenza A virus hemagglutinin (HA) gene. Many synonymous substitutions were deleterious both in bulk competition and for individually isolated clones. Investigating protein and RNA levels of a subset of individually expressed HA variants revealed that multiple biochemical properties contribute to the observed experimental fitness effects. Our results indicate that a structural element in the HA segment viral RNA may influence fitness. Examination of naturally evolved sequences in human hosts indicates a preference for the unfolded state of this structural element compared to that found in swine hosts. Our overall results reveal that synonymous mutations may have greater fitness consequences than indicated by simple models of sequence conservation, and we discuss the implications of this finding for commonly used evolutionary tests and analyses.
- Major histocompatibility complex I of swine respiratory cells presents conserved regions of influenza proteins. [Journal Article]
- JGJ Gen Virol 2018; 99(3):303-308
- Influenza A virus in swine (IAV-S) is a prevalent respiratory pathogen in pigs that has deleterious consequences to animal and human health. Pigs represent an important reservoir for influenza and po...
Influenza A virus in swine (IAV-S) is a prevalent respiratory pathogen in pigs that has deleterious consequences to animal and human health. Pigs represent an important reservoir for influenza and potential mixing vessel for novel gene reassortments. Despite the central role of pigs in recent influenza outbreaks, much remains unknown about the impact of swine immunity on IAV-S transmission, pathogenesis, and evolution. An incomplete understanding of interactions between the porcine immune system and IAV-S has hindered development of new diagnostic tools and vaccines. In order to address this gap in knowledge, we identified swine leukocyte antigen (SLA) restricted IAV-S peptides presented by porcine airway epithelial cells using an immunoproteomics approach. The majority of MHC-associated peptides belonged to matrix 1, nucleoprotein and nonstructural 1 proteins. Future investigation of the potential cross-reactive nature of these peptides is needed to confirm antigen recognition by cytotoxic T lymphocytes and their utility as vaccine candidates.
- Defective RNA sensing by RIG-I in severe influenza virus infection. [Journal Article]
- CEClin Exp Immunol 2018 Feb 17
- Influenza virus infection causes worldwide seasonal epidemics. Although influenza usually is a mild disease, a minority of patients experience very severe fulminating disease courses. Previous studie...
Influenza virus infection causes worldwide seasonal epidemics. Although influenza usually is a mild disease, a minority of patients experience very severe fulminating disease courses. Previous studies have demonstrated a role for type I interferon (IFN) in antiviral responses during influenza. However, IFN regulatory factor (IRF)7 deficiency is so far the only genetic cause of severe influenza described in humans. In this study we present a patient with severe influenza A virus (IAV) H1N1 infection during the 2009 Swine Flu pandemic. By whole exome sequencing we identified two variants, p.R71H and p.P885S, located in the CARD and RNA binding domains, respectively, of DDX58 encoding the RNA sensor RIG-I. These variants significantly impair the signaling activity of RIG-I. Similarly, patient cells demonstrate decreased antiviral responses to RIG-I ligands as well as increased pro-inflammatory responses to IAV, suggesting dysregulation of the innate immune response with increased immunopathology. We suggest that these RIG-I variants may have contributed to severe influenza in this patient and advocate that RIG-I variants should be sought for in future studies of genetic factors influencing single-stranded RNA virus infections. This article is protected by copyright. All rights reserved.
- Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States. [Journal Article]
- VVirology 2018 Feb 13; 518:45-54
- Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evoluti...
Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-β (1A.2), H1pdm (1A.3.3.2), H1-γ (1A.3.3.3), H1-δ1 (1B.2.2), and H1-δ2 (1B.2.1) currently circulating in pigs in the United States. The δ1-viruses diversified into two new genetic clades, H1-δ1a (1B.2.2.1) and H1-δ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-δ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission.
- Evidence for Cross-species Influenza A Virus Transmission Within Swine Farms, China: A One Health, Prospective Cohort Study. [Journal Article]
- CIClin Infect Dis 2018 Feb 01; 66(4):533-540
- CONCLUSIONS: There was considerable evidence of A(H1N1)pdm09-like, swine-lineage H1N1, and swine-lineage H3N2 viruses circulating, likely reassorting, and likely crossing species within the pig farms. These data suggest that stronger surveillance for novel influenza virus emergence within swine farms is imperative.
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- Challenges of influenza A viruses in humans and animals and current animal vaccines as an effective control measure. [Review]
- CEClin Exp Vaccine Res 2018; 7(1):1-15
- Influenza A viruses (IAVs) are genetically diverse and variable pathogens that share various hosts including human, swine, and domestic poultry. Interspecies and intercontinental viral spreads make t...
Influenza A viruses (IAVs) are genetically diverse and variable pathogens that share various hosts including human, swine, and domestic poultry. Interspecies and intercontinental viral spreads make the ecology of IAV more complex. Beside endemic IAV infections, human has been exposed to pandemic and zoonotic threats from avian and swine influenza viruses. Animal health also has been threatened by high pathogenic avian influenza viruses (in domestic poultry) and reverse zoonosis (in swine). Considering its dynamic interplay between species, prevention and control against IAV should be conducted effectively in both humans and animal sectors. Vaccination is one of the most efficient tools against IAV. Numerous vaccines against animal IAVs have been developed by a variety of vaccine technologies and some of them are currently commercially available. We summarize several challenges in control of IAVs faced by human and animals and discuss IAV vaccines for animal use with those application in susceptible populations.