Influenza Surveillance: 2014?2015 H1N1 ?Swine?-Derived Influenza Viruses from India
Kannan Tharakaraman, Ram Sasisekharan
DOI: http://dx.doi.org/10.1016/j.chom.2015.02.019
Summary
The 2014-15 H1N1 outbreak in India has reportedly led to 800 fatalities. The reported influenza hemagglutinin sequences from India indicate that these viruses contain amino acid changes linked to enhanced virulence and are potentially antigenically distinct from the current vaccine containing 2009 (Cal0709) H1N1 viral hemagglutinin.
? 2015 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
Full paper available here:
...
Although there are limited Indian-origin influenza sequences available in the public database to make any causal inference on the perceived increased fatalities in India, examination of the 2014 Indian H1N1 HA sequences shows traits with potential cause for concern. Amino acid changes in specific positions in the receptor binding site (RBS) of 2009pdmH1N1 have been shown to impact glycan RBS specificity and have been linked to increased virulence and disease severity. Among these changes, the Indian-origin strain A/India/6427/2014 contains amino acid changes T200A and D225N compared to the 2009pdmH1N1 pandemic strain. The T200A amino acid change has been shown to improve human glycan receptor-binding of 2009pdmH1N1 HA (Xu et al., 2012b). The D225N mutation has been linked to increased virulence and disease severity in patients infected by the 2009 pdm virus (Ruggiero et al., 2013). Importantly, a previous study showed that the D225N mutation in the context of H1 HA affected receptor binding and also decreased susceptibility to NA inhibitors (McKimm-Breschkin et al., 2013). It should be noted that the D225N mutation was previously linked to serious illness resulting in hospitalization or death (L?vov et al., 2010). The high population density in India, ease of person-to-person transmission, and lack of effective treatment options create ample opportunities for this variant to sustain and become dominant. It is unknown if the strain A/India/6427/2014 is still in circulation; however, the apparent severity of the current outbreak seems to suggest that it could be.
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Kannan Tharakaraman, Ram Sasisekharan
DOI: http://dx.doi.org/10.1016/j.chom.2015.02.019
Summary
The 2014-15 H1N1 outbreak in India has reportedly led to 800 fatalities. The reported influenza hemagglutinin sequences from India indicate that these viruses contain amino acid changes linked to enhanced virulence and are potentially antigenically distinct from the current vaccine containing 2009 (Cal0709) H1N1 viral hemagglutinin.
? 2015 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
Full paper available here:
...
Although there are limited Indian-origin influenza sequences available in the public database to make any causal inference on the perceived increased fatalities in India, examination of the 2014 Indian H1N1 HA sequences shows traits with potential cause for concern. Amino acid changes in specific positions in the receptor binding site (RBS) of 2009pdmH1N1 have been shown to impact glycan RBS specificity and have been linked to increased virulence and disease severity. Among these changes, the Indian-origin strain A/India/6427/2014 contains amino acid changes T200A and D225N compared to the 2009pdmH1N1 pandemic strain. The T200A amino acid change has been shown to improve human glycan receptor-binding of 2009pdmH1N1 HA (Xu et al., 2012b). The D225N mutation has been linked to increased virulence and disease severity in patients infected by the 2009 pdm virus (Ruggiero et al., 2013). Importantly, a previous study showed that the D225N mutation in the context of H1 HA affected receptor binding and also decreased susceptibility to NA inhibitors (McKimm-Breschkin et al., 2013). It should be noted that the D225N mutation was previously linked to serious illness resulting in hospitalization or death (L?vov et al., 2010). The high population density in India, ease of person-to-person transmission, and lack of effective treatment options create ample opportunities for this variant to sustain and become dominant. It is unknown if the strain A/India/6427/2014 is still in circulation; however, the apparent severity of the current outbreak seems to suggest that it could be.
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