Viruses prefer winter

By Ilkka Ahtiainen
     
      The stir around swine flu is gradually dying down. Presumably this is because the illness looks set not to develop into the feared pandemic after all.
      Besides, it seems that the H1N1 virus may well be lost among a plethora of other flu viruses.
      So, the early autumn’s topical question amidst the coughing, hacking and sneezing classes is: do I have swine flu, or something else?
      Professor of infectious diseases Olli Ruuskanen from the Turku University Hospital wrote recently on the Helsingin Sanomat opinion pages that in addition to the H1N1, or swine flu, there are a dozen or so other viruses going the rounds that typically cause flu-like symptoms.
     
The nasty rhinovirus, the notorious bocavirus, and the merciless adenovirus, among others, cause thousands and thousands of people to fall ill.
      These viruses, however, are left outside the present media frenzy, because they have already become yesterday’s news.
      Nevertheless, as sure as Santa Claus, they will turn up every winter.
      And then they'll disappear again.
     
But where do they disappear to? The researchers have discovered that the viruses always go somewhere where there is winter to be had.
      So, right now the rhinos, the bocas, etc, are on their migration route back to the north, but once we have cleared the winter up here, these pathogens set their sights again for the southern hemisphere.
      And, as reliably as a well-thrown boomerang, it will be the Australians’ turn to catch it and start coughing and spluttering.
     
The reasons for this viral migration are unknown. There are only assumptions, such as: viruses prefer the cold, or people are more susceptible to contracting illnesses when it is chilly.
      In the winter people also tend to stay cooped up indoors more than at other times of year, which increases the risk of passing viruses from one person to the next.
      Furthermore, it is also unclear why for example the respiratory syncytial virus (RSV) - another nasty piece of work that lays low children in particular - only makes landfall in Finland every second year.
      “Lord only knows”, professor Ruuskanen sighs over the telephone.
     
     
Helsingin Sanomat / First published in print 6.9.2009


Previously in HS International Edition:
  Swine flu outbreak at Espoo day care centre (7.9.2009)
  Swine flu may cause decreased intensive care availability (2.9.2009)
  Sweden reports first swine flu death (1.9.2009)
  Swine flu may reduce number of available child-minders in Helsinki area (18.8.2009)

Links:
  Human respiratory syncytial virus (Wikipedia)
  Ministry of Social Affairs and Health press release 22.7.2009: Finnish health care prepares for an extensive epidemic of influenza A (H1NI)
  Influenza A virus subtype H1N1 (Wikipedia)
  Rhinovirus (Wikipedia)
  Human bocavirus (Wikipedia)
  Adenoviridae (Wikipedia)