Research, monkeys, and influenza

In 1918 there was an outbreak of influenza. That's not unusual. Most winters see a flu going around. That's been true ever since British trading ships began circulating from China back to Europe and the Americas in the late 1700s. You see, birds are the main reservoir for the flu virus and since many birds are migratory, seasonal patterns of flu transmission occur. Many of the flus we experience have their root in shallow Siberian lakes where ducks spend their summer. When the weather turns cold, the ducks migrate to China and infect people with the flu virus, which in turn is transmitted to British sailors and then those sailors would bring it back to Europe with them. Year after year.

Most years not many people died but occasionally the virus would be particularly deadly and hundreds of thousands would die in a pandemic, sometimes, like in 1889, over a million would die. But never in human history has there been as deadly a pandemic as the 1918 flu, often called the Spanish Flu. Estimates of the dead vary from 50 million to 100 million before the virus disappeared. That was 5% of the world population so 1 in every 20 people alive in 1918 was destined to die from this flu. Further, it's estimated that 20% of the population was infected so not much was getting done since so many people were sick.

The reason I bring all this up is that I recently read an article in the January 18, 2007 issue of NATURE about the 1918 flu pandemic. The article outlines the risks and benefits of recent research into the way that the H1N1 subtype (the specific mutation of influenza that caused the 1918 outbreak) spreads from species to species and individual to individual. Apparently the huge change in action from the H1N1 subtype was due to just changes in either one or two amino acids. Just that small a mutation is what killed 100 million people.

Work has been done recently in macaque monkeys--which can catch this type of flu just as humans do--which has demonstrated how the H1N1 subtype does its damage. Most flus are dangerous mostly to the very young and old--people who tend to have immune systems that don't work as well. An average of 36,000 people die each year of flu in the USA, and most of those people are either small children or elderly. H1N1, on the other hand, was most deadly with healthy adults who presumbly have healthy immune systems. The macaque research has shown that the Spanish Flu kills by overstimulating the immune system in what is called a cytokine storm. As a result of this knowledge, a method of treatment using drugs that target over zealous immune response can be implemented if H1N1, or a similar behaving variant, ever breaks out again. This is the opposite treatment as would usually be implemented in flu treatment since you usually want to push the immune system, not suppress it. Which means that typical flu treatment would actually make a case of Spanish Flu worse.

Food for thought...