Swine flu update: Europe and the bottom of the world

For those of you looking to follow new cases (most of them suspected at this point, not confirmed), a great resource is HealthMap. Reports are popping up of possible infections worldwide: Scotland, Spain, Australia, and New Zealand. Certainly additional possible cases will be showing up over the coming days as well.

One thing I’ve seen mentioned (including here in the comments) is a question about the unlikelihood of a flu outbreak in Mexico in late April. Isn’t influenza a cold-weather bug? Well, yes and no. Influenza circulates year-round at a low level, but it lasts longer in the environment in colder temperatures with lower humidity, meaning more people can potentially be infected by each infected person, leading to our seasonal outbreaks. However, recall that in 1918 the first cases began in winter/spring 1918, and then it came back with a vengeance beginning in August, and really taking off by October. Additionally, we essentially have no barriers to worldwide spread, and there are already potential cases in New Zealand and Australia (where winter is setting in).

Again, we don’t know right now whether this will die out or become the next pandemic, but the spring timing of this doesn’t necessarily limit the virus’ potential.