Apart from a few flurries of residual poliovirus activity, usually in one of the world’s trouble spots, polio has reached its so-called endgame. That puts enterovirus 71 right up there as top neurovirulent enterovirus. Who has heard at street level of enterovirus 71? It’s not exactly a catchy name, is it? But in 1999 it caused an outbreak of infections in Western Australia. There were severe infections with neurological complications, but fortunately there were no fatalities.
The enteroviruses are a highly successful group of RNA viruses that cause the common cold, meningitis, paralysis, lower respiratory, cardiac and other infections, worldwide. The common cold viruses, or rhinoviruses, have recently been brought into this group, placing them alongside poliovirus and the coxsackie viruses.
Hand, foot and mouth disease is a relatively common cause of rash-forming infection in young children, which peaks in WA in July – December. It is transmitted by the faecal-oral route and is associated with a range of virus serotypes. In recent years nail-shedding has been observed in some HFMD cases, but this has not yet been a feature in WA.
The coxsackievirus capsid is icosahedral in shape (Swiss Institute of Bioinformatics). Its faces are pentamers, each made up of triangular protomers comprising three exposed proteins (VP1, VP2 & VP3) and a deeper VP4. The protomers each contain a central pit or canyon which some consider an effective method of protecting key viral antigens against antibody attack. This ‘canyon hypothesis‘ may explain why enteroviruses are so successful agents of human infection.
Subject matter, D Williams, PathWest breakfast meeting, 21-APR-11;
notes by the MicroGnome.