scholarly journals Molecular Characterization of Influenza C Viruses from Outbreaks in Hong Kong SAR, China

2020 ◽  
Vol 94 (21) ◽  
Author(s):  
Rodney S. Daniels ◽  
Herman Tse ◽  
Burcu Ermetal ◽  
Zheng Xiang ◽  
Deborah J. Jackson ◽  
...  
Keyword(s):  
Hong Kong ◽  
Virus Infection ◽  
Severe Disease ◽  
Gene Sequencing ◽  
Virus Evolution ◽  
Antigenic Drift ◽  
Genetic Lineages ◽  
Hong Kong Sar ◽  
Influenza C Virus ◽  
The Impact

ABSTRACT In 2014, the Centre for Health Protection in Hong Kong introduced screening for influenza C virus (ICV) as part of its routine surveillance for infectious agents in specimens collected from patients presenting with symptoms of respiratory viral infection, including influenza-like illness (ILI). A retrospective analysis of ICV detections up to week 26 of 2019 revealed persistent low-level circulation, with two outbreaks having occurred in the winters of 2015 to 2016 and 2017 to 2018. These outbreaks occurred at the same time as, and were dwarfed by, seasonal epidemics of influenza types A and B. Gene sequencing studies on stored ICV-positive clinical specimens from the two outbreaks have shown that the hemagglutinin-esterase (HE) genes of the viruses fall into two of the six recognized genetic lineages (represented by C/Kanagawa/1/76 and C/São Paulo/378/82), with there being significant genetic drift compared to earlier circulating viruses within both lineages. The location of a number of encoded amino acid substitutions in hemagglutinin-esterase fusion (HEF) glycoproteins suggests that antigenic drift may also have occurred. Observations of ICV outbreaks in other countries, with some of the infections being associated with severe disease, indicates that ICV infection has the potential to have significant clinical and health care impacts in humans. IMPORTANCE Influenza C virus infection of humans is common, and reinfection can occur throughout life. While symptoms are generally mild, severe disease cases have been reported, but knowledge of the virus is limited, as little systematic surveillance for influenza C virus is conducted and the virus cannot be studied by classical virologic methods because it cannot be readily isolated in laboratories. A combination of systematic surveillance in Hong Kong SAR, China, and new gene sequencing methods has been used in this study to assess influenza C virus evolution and provides evidence for a 2-year cycle of disease outbreaks. The results of studies like that reported here are key to developing an understanding of the impact of influenza C virus infection in humans and how virus evolution might be associated with epidemics.

scholarly journals Temporal and gene reassortment analysis of influenza C outbreaks in Hong Kong SAR, China

2021 ◽  
Author(s):  
Rodney S. Daniels ◽  
Monica Galiano ◽  
Burcu Ermetal ◽  
Jasmine Kwong ◽  
Chi S. Lau ◽  
...  
Keyword(s):  
Hong Kong ◽  
Severe Disease ◽  
Disease Outbreaks ◽  
Great Majority ◽  
Antigenic Drift ◽  
Similar Time ◽  
Hong Kong Sar ◽  
Influenza C Virus ◽  
Time Frames ◽  
The Impact

From 2014 to week 07/2020 the Centre for Health Protection in Hong Kong conducted screening for influenza C virus (ICV). A retrospective analysis of ICV detections to week 26/2019 revealed persistent low-level circulation with outbreaks occurring biennially in the winters of 2015-16 and 2017-18 (1). Here we report on an outbreak occurring in 2019-20, reinforcing the observation of biennial seasonality in Hong Kong. All three outbreaks occurred in similar time-frames, were subsequently dwarfed by seasonal epidemics of influenza types A and B, and were caused by similar proportions of C/Kanagawa/1/76 (K-)lineage and C/São Paulo/378/82 S1- and S2-sublineage viruses. Ongoing genetic drift was observed in all genes, with some evidence of amino acid substitution in the HEF glycoprotein possibly associated with antigenic drift. A total of 61 ICV genomes covering the three outbreaks were analysed for reassortment and nine different reassortant constellations were identified, one K-lineage, four S1-sublineage and four S2-sublineage, with six of these being identified first in the 2019-20 outbreak (two S2-lineage and four S1-lineage). The roles that virus interference/enhancement, ICV persistent infection, genome evolution and reassortment might play in the observed seasonality of ICV in Hong Kong are discussed. Importance Influenza C virus (ICV) infection of humans is common with the great majority of people being infected during childhood, though re-infection can occur throughout life. While infection normally results in ‘cold-like’ symptoms, severe disease cases have been reported in recent years. However, knowledge of ICV is limited due to poor systematic surveillance and an inability to propagate the virus in large amounts in the laboratory. Following recent systematic surveillance in Hong Kong SAR, China and direct ICV gene sequencing from clinical specimens a two-year cycle of disease outbreaks (epidemics) has been identified with gene mixing playing a significant role in ICV evolution. Studies like those reported here are key to developing an understanding of the impact of influenza C virus infection in humans, notably where comorbidities exist and severe respiratory disease can develop.

Enforcement of Hong Kong Sar Court Judgments in the People's Republic of China

2000 ◽  
Vol 49 (4) ◽  
pp. 867-875
Author(s):  
Qingjiang Kong
Keyword(s):  
Hong Kong ◽  
People’S Republic Of China ◽  
Special Administrative Region ◽  
People's Republic Of China ◽  
New Era ◽  
Republic Of China ◽  
Administrative Region ◽  
British Colony ◽  
Hong Kong Sar ◽  
The Impact

On 1 July 1997 Hong Kong entered a new era when it was transformed from a British colony into a Special Administrative Region (SAR) of the People's Republic of China (PRC). The impact of the handover of Hong Kong cannot be overstated but, for the time being perhaps, may lie more in the sphere of ideology than in institutions.

scholarly journals Genetic Lineage and Reassortment of Influenza C Viruses Circulating between 1947 and 2014

2016 ◽  
Vol 90 (18) ◽  
pp. 8251-8265 ◽  
Author(s):  
Yoko Matsuzaki ◽  
Kanetsu Sugawara ◽  
Yuki Furuse ◽  
Yoshitaka Shimotai ◽  
Seiji Hongo ◽  
...  
Keyword(s):  
Nucleotide Substitution ◽  
Herd Immunity ◽  
Respiratory Illness ◽  
Antigenic Drift ◽  
Genetic Lineage ◽  
M Gene ◽  
Genetic Lineages ◽  
Complete Genomes ◽  
Influenza C Virus ◽  
Reassortant Viruses

ABSTRACTSince influenza C virus was first isolated in 1947, the virus has been only occasionally isolated by cell culture; there are only four strains for which complete genome sequences are registered. Here, we analyzed a total of 106 complete genomes, ranging from the first isolate from 1947 to recent isolates from 2014, to determine the genetic lineages of influenza C virus, the reassortment events, and the rates of nucleotide substitution. The results showed that there are six lineages, named C/Taylor, C/Mississippi, C/Aichi, C/Yamagata, C/Kanagawa, and C/Sao Paulo. They contain both antigenic and genetic lineages of the hemagglutinin-esterase (HE) gene, and the internal genes PB2, PB1, P3, NP, M, and NS are divided into two major lineages, a C/Mississippi/80-related lineage and a C/Yamagata/81-related lineage. Reassortment events were found over the entire period of 68 years. Several outbreaks of influenza C virus between 1990 and 2014 in Japan consisted of reassortant viruses, suggesting that the genomic constellation is related to influenza C virus epidemics. The nucleotide sequences were highly homologous to each other. The minimum percent identity between viruses ranged from 91.1% for the HE gene to 96.1% for the M gene, and the rate of nucleotide substitution for the HE gene was the highest, at 5.20 × 10−4substitutions/site/year. These results indicate that reassortment is an important factor that increases the genetic diversity of influenza C virus, resulting in its ability to prevail in humans.IMPORTANCEInfluenza C virus is a pathogen that causes acute respiratory illness in children and results in hospitalization of infants. We previously demonstrated (Y. Matsuzaki et al., J Clin Virol 61:87–93, 2014,http://dx.doi.org/10.1016/j.jcv.2014.06.017) that periodic epidemics of this virus occurred in Japan between 1996 and 2014 and that replacement of the dominant antigenic group occurred every several years as a result of selection by herd immunity. However, the antigenicity of the HE glycoprotein is highly stable, and antigenic drift has not occurred for at least 30 years. Here, we analyzed a total of 106 complete genomes spanning 68 years for the first time, and we found that influenza C viruses are circulating worldwide while undergoing reassortment as well as selection by herd immunity, resulting in an increased ability to prevail in humans. The results presented in this study contribute to the understanding of the evolution, including reassortment events, underlying influenza C virus epidemics.

Impact of influenza virus during pregnancy: from disease severity to vaccine efficacy

2020 ◽  
Vol 15 (7) ◽  
pp. 441-453
Author(s):  
Ana Vazquez-Pagan ◽  
Rebekah Honce ◽  
Stacey Schultz-Cherry
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Immune Responses ◽  
Pregnant Women ◽  
Disease Severity ◽  
Influenza A ◽  
Antiviral Treatment ◽  
Influenza Virus Infection ◽  
Severe Influenza ◽  
The Impact

Pregnant women are among the individuals at the highest risk for severe influenza virus infection. Infection of the mother during pregnancy increases the probability of adverse fetal outcomes such as small for gestational age, preterm birth and fetal death. Animal models of syngeneic and allogeneic mating can recapitulate the increased disease severity observed in pregnant women and are used to define the mechanism(s) of that increased severity. This review focuses on influenza A virus pathogenesis, the unique immunological landscape during pregnancy, the impact of maternal influenza virus infection on the fetus and the immune responses at the maternal–fetal interface. Finally, we summarize the importance of immunization and antiviral treatment in this population and highlight issues that warrant further investigation.

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