HLTH341 Lecture Notes - Lecture 2: Flu Season, Influenzavirus C, Neuraminidase
31 Dec 2015
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Document Summary
Classes: nomenclature (a/b/c) from host species, geographical site, serial number, year) Influenza a causes seasonal flu epidemics the natural host is wild birds its the most common. Influenza b causes seasonal flu epidemics natural host is humans less common and severe than influenza a. Influenza c doesn"t cause seasonal flu epidemics natural host is humans and pigs rare and causes mild illness. Major surface antigen on the virus: 16 different ha antigens. Facilitates interaction with cellular targets and fusion of the virion. One base substitution occurs in the ha gene per virus generation. Along with ha it confers genetic variability of the virus. Avian cells express specific receptors that allow for infection with avian influenza. Likewise, human cells express receptors for human influenza. Mainly large /small droplets secretions of infected people. At risk targets young children and elderly and high-risk groups has the highest morbidity and mortality.
