Tuesday, March 3, 2009
San Diego is in the midst of its annual flu season... and this year it's not very severe. But the next one may very much worse, and a worldwide flu pandemic is bound to happen. The only question is when. KPBS health reporter Tom Fudge reports on the threat of pandemic, and some exciting research that may lead to a cure for influenza.
All living things compete in the game we call evolution. But few seem as fit for survival as the flu virus. It's in a state of constant mutation, finding ways to elude new medications and fool the body's immune system. Wilma Wooten is the public health officer for San Diego county.
She says aside from using an antiviral medication like Tamiflu, health officials would have few options if a deadly flu pandemic came to San Diego. "The only measure or strategy we would have at our disposal would be the social distancing," she says. "We wouldn't have vaccinations. We would have medications but it could or could not be effective, depending on whether Tamiflu was resistant or not.
But inroads in the fight against the flu are being made in San Diego. Robert Luddington is director of the infectious disease program at the Burnham Institute of Medical research. He says the flu virus has several parts. The head of the virus constantly evolves because it's under constant attack by the immune system. But Luddington says he's found a way to aim at, and hit, a better target.
"We have been able to identify antibodies, that do not target the head region, as most antibodies do, but to target this very highly conserved region of the stalk," he says.
To say the stalk, also called the stem, is "conserved" means it does not mutate. The stem is the part of the virus that allows the virus's genetic material to enter a host cell. If that connection isn't made, then the person doesn't get the flu. And Luddington's antibody disables the stem.
So far he says it has neutralized many different strains of flu. Theoretically it will work against any flu virus
"There's a very real possibility that we could eradicate influenza, essentially altogether, certainly within North America," Luddington says.
Still, other scientists say targeting the viral stem could ultimately fail. A San Diego company called Nexbio is developing a medication it hopes will prevent human cells from receiving the flu. Dr. Fang Fang is the medical director of Nexbio.
She says the potential problem with trying to disable the stem, as Burnham has done, is that it could lead to a new kind of evolution within the flu virus. " It remains to be seen if the stem region would remain conserved in the presence of selection pressure," she says.
In other words, the stem could become elusive as well if it found itself under attack by a new medication.
This year, San Diego has been spared a tough flu season. Emergency rooms like this one, run by Kaisar Permanente, have seen flu-related illnesses drop to less than three percent of total admissions. But doctors point out if you've seen one flu season, you've seen…one flue season. The next one could be much worse.
And the nightmare scenario would be a pandemic spreading the avian flu. In the past ten years, this virus has been passed from birds to about 400 human beings. Sixty percent of those people have died. And the avian flu could mutate in a way that allowed it to be passed from one person to the next.
Even the seasonal flu kills about 30,000 American every year, and this year's flu virus is quite resistant to Tamiflu, the primary anti-viral treatment. Again, Robert Luddington.
"So if the vaccine doesn't work, and currently our primary anti-viral doesn't work either, you're left with chicken soup and bed rest if you're healthy," he says. "But obviously if you're weakened in any way, especially the very young and very old, it could be quite deadly."
Tom Fudge, KPBS News.