Warning:
Deadly Flu Epidemic Looming

BY RACHEL WILDAVSKY AND CLAUDIA CORNWALL

THE VIRUS first came to official attention in a bag -- a bag of dead chickens. In March 1997 a farmer from Hong Kong's New Territories carried the bag into the Agriculture and Fisheries Department laboratory. Something had caused their tissues to hemorrhage, resulting in a hideous, bloody mush. By the time inspectors reached his farm, every last bird was dead. Cultures of the chickens' organs revealed they had died of an avian, or bird, influenza, type H5N1.

       In April there were outbreaks at two more farms. Mortality was 100 percent.

       Then came more bad news. A three-year-old boy died of complications following influenza in a Hong Kong hospital. The virus was H5N1. Flus of the H5 subtype had never before been known to infect humans.

       In the next seven months, 18 residents of Hong Kong fell ill with H5N1. Five died. All had been healthy and in the prime of their lives.

       In December public-health officials took a drastic step, ordering the slaughter of every chicken in every farm and marketplace in Hong Kong. The H5N1 virus seemed to disappear -- but for how long?

The Spectre of 1918

FLU IS one of the most changeable diseases known to man. After we've been sick with one strain, it can mutate to infect us again because we are only immune to flus our bodies have seen before.

       A flu can also "jump species" to an animal it has never infected before. Once such a flu moves into humans, if it can "learn" to pass easily among them, it can spark a pandemic -- a global outbreak.

       Birds carry flu viruses in their intestines and excrete it in their feces. In all likelihood, people who got sick with H5 touched surfaces contaminated with chicken feces.

       Humans, however, carry flus in their respiratory tracts and usually spread them easily in a cough or sneeze. Flus that travel this way are highly contagious.

       The H5 virus in Hong Kong was different. It infected very few but killed more than a quarter of them. Most who got sick with H5 seemed to catch it directly from a bird they bought in a live-poultry market.

       After the Hong Kong outbreak, flu experts fear one prospect more than any other: that H5 might learn to move readily among humans. Dr. John Spika, director of the Laboratory Centre for Disease Control in Ottawa and one of Canada's leading experts on infectious diseases, says: "If the Hong Kong virus had developed the ability to spread efficiently among people, we would have faced a crisis along the lines of the 1918 pandemic."

       That was the peak year of the greatest pandemic in recorded history, which in less than two years took at least 21 million lives. Three waves of the "Spanish flu" -- so named because it was erroneously thought to have started in Spain -- swept the globe. Virtually everyone was infected, and up to three percent died.

       In Canada the toll was frightful. In Quebec, for example, 13,800 died. At the peak of the epidemic in Montreal, a trolley car was adapted to carry coffins to the cemetery because city hearses could not keep up with the volume of dead bodies.

       In Toronto 1,682 people died from the flu between October 9 and November 2, and Toronto's chief medical officer compared the epidemic to a cyclone because of its swift progress through the city. Some perished in less than two days, their lungs filled with fluid and blood, their bodies blackened from lack of oxygen. Others expired within hours of infection.

       On September 30, 1918, three infected soldiers returning from the war arrived at the Winnipeg train station. They were quarantined, but not before a railway worker contracted the virus. Three days later two of the soldiers and the railway worker were dead. The disease spread through the city and by January, 824 Winnipeggers had died.

       Geographic isolation was no protection. In northern Labrador, villages like Okak and Hebron were nearly wiped out. One third of the Inuit people on the Labrador coast died. All told, at least 50,000 Canadians perished.

It Could Happen Again

ORIGINALLY, the virus that became the Spanish flu came from a bird. Many experts used to believe that this virus did not make the leap directly from birds to humans. They thought that the virus first evolved to affect swine. Dr. Danuta Skowronksi, an epidemiologist at the British Columbia Centre for Disease Control, explains: "Swine can be affected by both human and bird virus strains. They can act as a kind of 'mixing vessel' in which the bird virus can pick up the genes that allow it to infect humans."

       But Spika says that our experience with the H5N1 virus in Hong Kong gives us a new perspective. He asks, "Could humans be a 'mixing vessel'?" Perhaps the 1918 virus evolved to affect humans and then developed the ability to pass quickly from person to person in a simple cough or sneeze without any sojourn in a pig host.

       Either way, the Great Pandemic sheds a terrifying light on what might have been in Hong Kong, and what might still be. The first wave of the Spanish flu traversed the globe in months. Today, a flight leaving Hong Kong International Airport takes just 11 hours to reach Vancouver. An average of 225 international flights take off from HKIA daily, each carrying as many as 450 passengers to as many as 120 locations around the world.

       "We can expect another pandemic in the next five to ten years," Spika says emphatically. And we are nowhere near being able to produce enough vaccine to immunize 30 million Canadians quickly.

       To avoid being caught by surprise and quickly overwhelmed by another pandemic, here are three measures all nations need to take:

Better Surveillance

WHEN A pandemic starts, every day will count. But we can't start fighting a pandemic until we know we have one and what type it is. Thus it is critical to monitor flu activity around the world.

       Since 1996, a national FluWatch program has compiled a weekly report on influenza outbreaks among Canadians by relying on provincial laboratory reports and information from 200 sentinel physicians. The reports give data both on the geographic distribution of the disease and its intensity. "We must improve our sentinel system by increasing the number of physicians in the program -- especially in the major cities," Spika says. At present, sentinel physicians are distributed one per census tract, which means that heavily populated city tracts are proportionally underrepresented. Some census tracts don't even have sentinel physicians yet.

       Most countries don't start tracking avian influenza unless an epidemic kills their chickens. In Canada, according to Bruce Hunter, an avian pathologist at the Ontario Veterinary College, provincial veterinary laboratories and the Canadian Co-operative Wildlife Health Centre investigate when birds have died with flulike symptoms. He says, "This surveillance is far from perfect." No analysis is done unless dead birds are turned in to the labs.

       Elsewhere, too, the coverage is not good enough, says Dr. W. Paul Glezen of the Baylor College of Medicine's Influenza Research Branch in Houston. He names Africa and South America as areas where the World Health Organization (WHO) net is incomplete. "We need surveillance at enough sites to detect a dangerous new strain early."

       In no place is greater surveillance more urgently needed than in China. Mainland China is believed to be where most new flu strains emerge, because species that carry different flus -- people, pigs, chickens, ducks and geese -- live close together there, sometimes under the same roof.

       The Chinese accept WHO monitoring of human influenza but balk at disclosing anything about their poultry. Says Dennis Senne of the avian virus section of the U.S. Department of Agriculture's National Veterinary Services Labs: "I think they're increasing their monitoring, but they don't share much."

       Nevertheless, they must. China has received assistance to set up its own influenza surveillance network. This spring the Centres for Disease Control funded a WHO team that trained Chinese laboratory personnel in advanced monitoring techniques. The information the Chinese will gather is a matter of life and death.

More Vaccines and Flu Shots

Related Links For more information, visit these web sites. If you think you may have a health problem, see your doctor. INFLUENZA PANDEMIC: Influenza revealed American researchers have come closer to unravelling the mystery behind the pandemic of 1918 by sequencing the gene responsible. Avian Influenza Detailed veterinary virology information. Science News Online A Doughboy's Lungs Yield 1918 Flu Virus. Health Canada National Advisory Committee on Immunization STATEMENT ON INFLUENZA VACCINATION FOR THE 1999-2000 SEASON. Vads Corner - Influenza A (H5N1) Site Comprehensive H5N1 news, information and links.

UNTIL Hong Kong, only three of the 15 known virus subtypes that can cause influenza pandemics -- H1, H2 and H3 -- had been found in people. Vaccines exist for each. H5 made a fourth, and an H5 vaccine is now being developed. Most experts agree with Dr. Spika, who says that if we developed a base vaccine for each of the other known subtypes as well, we would be able to create the specific variety we need more quickly.

       Base vaccines are updated each year to target whatever flu strains are circulating, and that would be true in a pandemic. Still, having the bases for all the influenza vaccines could be a lifesaver. In a pandemic we would still need to develop a targeted vaccine, but that would take less time.

       Health authorities also suggest that more people get flu shots. Canada's high-risk individuals and their contacts number 14 million. While we do have enough vaccine to immunize all of these people, and it is available to high-risk individuals at no charge, each year only about 4.5 million -- or 30 percent -- come forward to get their shots.

       Surprisingly, among health-care professionals who are part of this target group, the percentage who have annual immunization is even lower -- 15 percent. Vaccinating more Canadians would pay immediate health dividends. Each year at least 1,000 people die of influenza and its complications. Those deaths are largely preventable.

       Dr. Susan Tamblyn, medical officer of health for Perth County in Ontario, also advises high-risk Canadians, including seniors and anyone over the age of two with a chronic health problem, to get a pneumococcal vaccine. A single injection -- it does not need to be updated annually -- protects against pneumococcal pneumonia, one of the major complications of influenza. She says, "During a pandemic, medical personnel won't have time to give this vaccine."

       This vaccine is usually available free to people in certain high-risk categories. The cost for those who do not qualify for a free vaccine is around $20.

A Complete Pandemic Plan

H5 WASN'T the only influenza virus making waves recently. During the winter of 1998, the A Sydney flu put a strain on the health-care system in several parts of Canada. In British Columbia, flu outbreaks caused 62 long-term care facilities to shut their doors to new patients in an effort to contain the disease. Edmonton hospitals had to postpone elective surgery to free up beds for flu victims.

       In a serious pandemic, hospital beds won't be the only problem. A vaccine takes about three months to prepare. Meanwhile, antivirals can be used to treat flu before a vaccine is available. But, warns Dr. Allison McGeer, director of infection control at Mount Sinai Hospital in Toronto: "We now have only one antiviral drug, amantadine, licensed in Canada. So little is prescribed that stocks remain low and there isn't enough for a pandemic."

       A second antiviral drug, zanamivir, may soon be approved for use here.

       In Hong Kong the sick who survived required respirators. But there are only so many respirators available in Canada.

       During the Spanish flu pandemic, vital services were disrupted because of the many employees who were sick and unable to work. McGeer estimates that the next pandemic could strike ten million in this country alone. What will we do if we suffer shortages of police officers, utility workers or military personnel?

       The Hong Kong outbreak caused Canadian health authorities to re-examine our pandemic plans. One change: Health Canada, responsible for selecting our flu vaccine suppliers, plans to sign contracts with Canadian producers only.

       Elinor Caplan, former parliamentary secretary to Health Minister Allan Rock, said: "The concern is that other countries might place an embargo on exports of vaccine during a pandemic. It is important to build up the capacity of Canadian manufacturers."

       So, the good news about the Hong Kong scare is that it may serve as a wake-up call-and none too soon:

       In March of this year, Hong Kong's Agriculture and Fisheries Department announced that it had found H5N1 in goose excrement in a poultry stall. The virus was not identical to the 1997 version, and the next day it was nowhere to be found. But the two viruses were related. H5 was back.

       And a month later, the Hong Kong Department of Health announced that two girls, ages one and four, were recovering from an H9 flu virus found in pigs and poultry. H9 has never before been known to infect humans.