Scientists say there are signs of massive flu outbreak soon

HAMILTON - Which infectious disease should scare us most?

SARS.

Monkey pox.

Ebola.

Influenza.

The answer is little old influenza, not any of the new exotic scourges.

"The flu" is not taken seriously in many circles. Upset stomachs get called "the flu" in excuses made to the office. But real influenza, the knock-down, drag-out, high-fever-and-misery illness, is one of the oldest human enemies.

"It's just another example that nature is the best bioterrorist," said Marshall Bloom, associate director of Rocky Mountain Laboratories in Hamilton, where influenza experts talked to the public in a symposium Wednesday evening.

Influenza kills about 40,000 people each year in the United States. But that's in normal years. Every so often, three to five times a century, influenza erupts in a pandemic. While epidemics spread through a limited population, pandemics spread throughout the globe, making everybody at risk of illness.

The Spanish flu pandemic of 1918 and 1919 killed nearly 50 million people and caused illness in 20 to 40 percent of the world's population.

"It was one of the worst outbreaks in human history," said Herbert Swick, a physician who is director of the Institute of Medicine and Humanities in Missoula.

In some camps of soldiers fighting in World War I, 90 percent of the people got sick. Influenza struck the German troops who were mounting an offensive in France and may very well have turned the tide of the war, Swick said.

At home in New York, 851 people died in one day in October. The San Francisco streetcar authorities required masks for all passengers.

That was the last real pandemic. Many scientists and physicians think we're due for another one - maybe this year. And many look to the "bird flus" of recent years in the Eastern hemisphere as the possible source.

"Could the avian flu, which has struck Asia in recent months, be the next pandemic?" asked Swick.

It very well could, said physician Kanta Subbarao of the Laboratory of Infectious Diseases at the National Institute of Allergy and Infectious Diseases in Bethesda, Md. Subbarao, who traveled to Montana for the symposium, is a leading expert on vaccine development for SARS and influenza pandemics.

Here's how it works: The influenza virus is pretty smart in its tactics, which has kept it around for a long time - Hippocrates described it in 412 B.C. and Charlemagne in 876. The two types of virus responsible for the death and mayhem through the centuries are Type A and Type B.

Influenza A is divided into subtypes based on the two main proteins on the surface of the virus. One, hemagglutinin, has 15 subtypes. The other, neuraminidase, has nine. Wild birds are the reservoir for all the subtypes. Some of the types make people sick, some make domestic birds sick - the avian flus - and all of them infect pigs.

Flu viruses change a bit each year as people develop immunities to specific types. They can also change dramatically through resassortment, in which a previously circulating human virus and a new bird virus mix. Humans are caught off guard, unprepared with a vaccine to match that virus. That process caused the epidemics of 1957 and 1968. The Asian flu pandemic of 1957 killed about 70,000 people. The 1968 Hong Kong flu outbreak, which the Department of Health and Human Services calls the most recent pandemic, killed 34,000 people in the United States.

The new threat, Subbarao said, came in recent years with massive outbreaks of bird flu in domestic poultry.

"Suddenly, in the last 10 years we've had many, many outbreaks," she said. "Millions of birds had to be killed to control the outbreak."

In 1997, a bird flu broke the bird-human barrier and made people sick in Hong Kong. Of 18 cases, six people died. This year, there have been 39 cases; 28 people have died.

"That's a very, very high mortality rate of 70 percent," Subbarao said.

Now we know that bird flu viruses can jump directly to humans without a middle step where they combine with a human virus. They haven't learned to do it very well, Subbarao said, but they could learn. The worry?

"We only have vaccines for the human types," she said.

Every year, surveillance by the World Health Organization's WHO Influenza Program gathers information on the flu strains circulating at 110 national centers in 83 countries. That information is used to make an educated guess about which three strains to include in the fall flu vaccine. The surprise of a brand-new type or an avian flu in humans could leave people unprotected.

Subbarao's lab is working to develop all possible vaccines as a hedge against a pandemic.

"We need to generate a library of vaccines that are available," she said.

Health departments and first responders down to the county level are testing their pandemic response skills this fall. On Oct. 28, the Walk-in Ravalli County Flu Clinic will test the area's vaccine capacity, giving shots from 1:30 to 4 p.m. at Hamilton Middle School. The clinic is aimed at high-risk individuals. Questions? Call 375-6259.

Reporter Ginny Merriam can be reached at 523-5251 or at gmerriam@missoulian.com

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