1918 Flu Virus Limited The Immune System --WaPo

http://www.washingtonpost.com/wp-dyn/content/article/2007/01/17/AR2007011701113.html?referrer=email

1918 Flu Virus Limited The Immune System
Body's Effort to Fight Was Often Deadly

By David Brown
Washington Post Staff Writer
Thursday, January 18, 2007; A10

...Experiments in monkeys reveal that the 1918 virus came with the pre-packaged capacity to limit the immune system's ability to fight back in the first few days after infection. As the virus grows unchecked, the body attacks it with increasing quantities of highly toxic substances, which over time do as much harm to the host as to the invader. The result is often lethal damage to the lungs, where most influenza virus growth occurs.

The research provides further evidence that the 1918 virus had traits not found in other flu viruses and that it was the body's frantic effort to fight it that ultimately killed many victims...The virulence of the 1918 virus has always been a mystery. It was most lethal in young adults, the segment of the population usually most able to fight off severe infections. Many died a week or more after falling ill, with autopsies showing they had pneumonia caused by bacteria that had opportunistically infected virus-damaged lungs.

There were many reports, however, of people who died more quickly, occasionally even with a day of first symptoms. They presumably succumbed to the viral infection alone, and at autopsy their lungs were flooded with bloody fluid...While many of the victims of bacterial pneumonia would be saved today with antibiotics, which didn't exist in 1918, there are still few treatments for the overwhelming viral pneumonia seen in Spanish flu. Consequently, understanding how it occurs on a molecular level is a high priority. That is especially true now, because the H5N1 "bird flu" strain of virus circulating in Southeast Asia has killed some of its 267 victims with viral pneumonia reminiscent of Spanish flu.

The experiment was done in a Canadian biosafety Level 4 lab, where researchers work in the equivalent of space suits. Kawaoka's team does not have permission to experiment with the virus in the United States.
Because of its extreme hazard, only a single group of U.S. researchers, at the Centers for Disease Control and Prevention in Atlanta, is currently allowed to use whole, living reconstructed versions of the pathogen that killed at least 50 million people nearly a century ago.

In the new experiment, Darwyn Kobasa, a scientist in a Canadian government microbiology lab in Winnipeg, Manitoba, synthesized the 1918 virus from scratch and infected seven macaque monkeys with it. Three other animals were infected with a modern, far less virulent strain from the same large family of influenza A/H1N1 viruses...The monkeys infected with the 1918 virus were so sick within eight days that they had to be euthanized. "Profuse watery and bloody liquid" filled 60 to 90 percent of the their lung tissue, "greatly reducing lung function," the researchers reported.

Hope those scientists, janitors, etc., are honorable and security conscious. We wouldn't want Cheney's operatives to get their hands on this stuff...

The flu symptoms that resemble pnuemonic plague are caused by the body's immune system going nuts and releasing taxins that kill invader and bodily tissue together. That is why the age distribution of fatalities on a chart looks more like a W that a U. Usually those with the weakest immune systems, young children and the elderly are hit the hardest. For the 1918 flu, the hardest hit were those with the most robust immune systems at ages 16-30.

What this demonstrated is that the 1918 flu had a remarkably long prodromal stage during which people were infected and shedding virus, but the immune system was suppressed and delayed provoking the symptoms we associate with flu that show us the virus is being fought off.

By the time the immune system kicked in, the virus was present in an overwhelming amount. What is generally thought of as the misery of the flu, the aches, fever, coughing, and shedding of large quantities of mucus, were all stepped up enormously to deal with the huge virus load. These symptoms are all caused by the immune reaction and the expulsion of virus from the body, not the virus itself.

If the immune system hadn't kicked in at all, the person would have been dead through massive cell death in too many necessary organs. If the immune system did eventually kick in under these conditions, the person died of the immune response to a massive viral load.

This research explains how the 1918 flu killed so quickly, in a matter of hours between onset of symptoms and death. It doesn't explain why children and the elderly were largely spared.

who was 7 months pregnant at the time, died from the 1918 flu. A number of years later, my grandfather remarried - my grandmother - and they had one child, my dad. Odd to think that if it weren't for the epidemic I wouldn't be here.

that's for sure. I remember reading about a group of women playing cards until about 10 at night, then turning in. Three were dead of the flu by morning. That's how quickly it appeared to kill.

This research makes a lot of sense to me, demonstrating why the immune response to the flu happened so quickly and so severely, killing people who had been infected within hours.

In my case, if the Stonewall riots had happened a century sooner, I would not be here. Some people might say that's a good thing.

All patients had an immune response to the disease. Where it was inadequate such as in children and the elderly, the patient developed pneumonia and died. Where it was excessive, the patient developed acute respiratory distress syndrome (ARDS).

The symptoms you described are side effects of the immune response. The fever, the aching, coughing and generation of excessive mucus are damaging to the body and indicate an out-of-control immune response. True, viruses unchecked can kill. A slight elevation in temperature invigorates the immune response. A high fever, however, can be more dangerous than the virus. Likewise, sinus congestion and uncontrolled coughing inhibit healing.