The experiments with mice infected with the 1918 influenza virus are important but not surprising ("The Bad Fight: Immune systems harmed 1918 flu patients," SN: 9/30/06, p. 211). John Barry's The Great Influenza: The Epic Story of the Deadliest Plague in History (2004, Viking) explains that many, perhaps most, of the victims were killed by the overreaction of their immune systems. This may be why most of the victims were young, with strong, young immune systems.
San Diego, Calif.
I was surprised you didn't mention the effect of salinity in ocean water ("Mystery of the Missing Heat: Upper ocean has cooled slightly in recent years, despite warming climate," SN: 9/30/06, p.213). Warming climate has melted much of the glaciers, bringing fresh water into the North Atlantic. That water isn't dense enough to sink