Cold Season

"I woke today and found the frost perched on the town
it hovered in a frozen sky, and gobbled summer down."
-Joni Mitchell

Rostock has its first real frost this morning. In anticipation of this event, the first bad cold of the year has been going around. I think about half the Institute has gotten it so far. I have been sick to varying degrees for a week now. Without having actually looked at the relevant research, my understanding is that we get so many more colds when it gets colder because the airborne viruses break down much more slowly when the areas cold and dry and sunlight is weak. I've also heard somewhere that the cold air makes mucous membranes more susceptible to viruses. This all makes sense, and helps explain why that other common airborne virus that spreads every year, the flu, also concentrates in winter, but it leaves me wondering this: is the pattern the same in species that are adapted to highly seasonal climates? Humans are basically a tropical species that construct tropic-like microclimates for ourselves wherever we go. Our ancestors a few thousand generations ago would not have experienced the yearly cold season as we do today. Moose on the other hand have been living in cold climates forever. Their bodies should expect high virus conditions every winter and prepare accordingly. I speculate that the immune systems of such animals are seasonal, being better at fighting airborne viruses in the winter, and perhaps skin fungus is in the summer. I wouldn't personally want to do the experiments to find out, but I would read the paper if somebody else wrote it.