Message from an epidemicScientists in Winnipeg are using live foot-and-mouth virus to defend North America against an outbreak
Margaret Munro National Post
Monday, March 17, 2003
The virus that causes foot-and-mouth disease, which has not been seen -- or allowed -- in Canada for more than 50 years, is replicating in a Manitoba laboratory.
The tiny microbe, responsible for the national disaster in the United Kingdom that saw millions of animals slaughtered in 2001, has been imported from Britain by scientists at the National Centre for Foreign Animal Disease, a federal facility located in Winnipeg.
The scientists are growing several different strains of the virus in the centre's lab and using them to infect animals for research and to give veterinarians a first-hand look at the disease.
Officials and scientists say they are confident the highly infectious virus can be contained at the Manitoba facility, which they describe as one of the most secure labs on the planet.
Only one U.S. lab is allowed to work with the foot-and-mouth virus, and it is located on Plum Island, 10 kilometres off the Connecticut coast. U.S. rules forbid use of the virus at high-level biohazard labs on the U.S. mainland.
The Canadian government gave scientists approval to import the virus to the Winnipeg lab after consultations with American authorities and livestock officials.
"The last thing we wanted was a trade embargo," says Dr. Paul Kitching, the centre's director.
Officials say they consider work on the virus an "essential" aspect of emergency preparedness.
"At the end of the day, Canada is the largest exporter of pigs and pig products in the world and the third-largest exporter of cattle and cattle products," say Dr. Kitching. "That would stop overnight if there were an outbreak of food-and-mouth disease. It would cost billions."
Several vials of the virus, carefully tucked iin a crash-proof canister, touched down at Winnipeg International Airport last year in a cargo aircraft and were whisked to the federal lab near the city centre.
There, the viruses joined a collection of nasty pathogens including the microbes that cause Ebola and Lassa fever, deadly human diseases, and hog cholera and lumpy skin disease, which afflict animals.
Even in microbial company of that kind, the virus for food-and-mouth disease stands out, largely because it is so contagious and could have such a devastating economic impact if it ever got loose.
The virus has escaped from labs in the past. Italian scientists accidentally turned it loose in farm yards in the 1980s when they inadvertently produced vaccines that contained live, instead of dead, virus.
But Dr. Kitching and his colleagues are adamant that is not going to happen at their new high-security lab, located within blocks of a residential area near downtown Winnipeg.
"Once you walk in the door, any concerns you have evaporate," says Dr. Kitching, who has toured hundreds of livestock producers and U.S. officials through the gleaming new facility. "If it is going be safe anywhere, it is going to be safe here."
For Dr. Kitching, the virus is an old foe. He spent close to 20 years studying the tiny microbe -- and its incredible ability to spread -- at Pirbright Laboratory in Britain before joining the Winnipeg centre in 2001. While no threat to human beings and rarely fatal to animals, the virus is highly contagious. It produces blisters on hooves and mouths that weaken and debilitate the infected creatures.
Dr. Kitching has seen the virus unleash its cellular destruction on animals from Asia to Africa. He has tracked it as it was wafting out of barnyards full of infected pigs. And he watched in dismay as the virus -- and the panic it created -- took hold in the United Kingdom in 2001.
The outbreak was devastating both to British agriculture and tourism, as more than four million animals were slaughtered and heaped into piles and burned. The cost was said to exceed $30-billion.
It turned out that as many as two million healthy animals were needlessly slaughtered because the British government was given bad advice from computer modellers who said the cull had to continue long after the virus had stopped spreading, says Dr. Kitching, who hopes North America will learn from the British disaster.
Bringing the virus to Winnipeg is meant to speed up the learning curve.
Dr. Kitching has imported seven different types of the virus -- some more virulent and contagious than others. They are being used for several research projects, and to produce reagents and tests that would be needed in the event of an outbreak.
Select groups of veterinarians are also being given a first-hand look at a disease caused by the virus that has not been seen in Canada since an outbreak in Saskatchewan in 1952.
Dr. Jim Goltz, a provincial veterinarian in New Brunswick, was among 25 animal disease specialists who were in Winnipeg last month for the first course featuring animals that had been infected with foot-and-mouth disease.
"It was incredible," says Dr. Goltz. The 12-day crash course also included Newcastle Disease and Avian Influenza (highly contagious poultry diseases), Blue Tongue (a viral disease in cattle and sheep) and Pseudo-rabies.
He says about 40 animals were infected with the different microbes and the vets watched the diseases and their symptoms progress. The animals were confined to cubicles in the biohazard lab once they had been infected. The vets had to change into lab clothes -- including government-issue boots and underwear -- for their daily sessions with the animals. On the way out they had to strip down and take two showers -- each one a mandatory three minutes -- before they could leave the building. They were also required to blow their noses, and soak their glasses in disinfectant for 20 minutes as part of the decontamination routine.
Dr. Goltz says it is unfortunate animals have to be infected. But he, like Dr. Kitching, says it is the only way to get experience with the diseases short of travelling round the world to see outbreaks as they occur. "It was an invaluable experience," he says.
The vets stress that the animals are treated as humanely as possible. They were given painkillers if needed and put down if they started to suffer, Dr. Goltz says. At the end the course the animals were euthanized and the vets preformed necropsies to explore the damage the microbes had inflicted inside the animals, such things as the blisters and lesions the foot-and-mouth virus can generate all the way down animals' tongues.
While the virus produced plenty of blisters on the hooves and mouths of the four calves and pigs infected for the course, it had a much more subtle effect on two infected sheep, producing only one small blister on one animal. "It would be so easy to miss it in sheep," Dr. Goltz says The most obvious sign that the sheep were sick was that they developed fevers, a symptom common to many diseases.
Dr. Goltz hopes never to see the virus loose in Canada. But he, like many animal disease specialists, feels it may just be a matter of time. And having access to the live virus, they say, puts Canada is a much better position to respond.
"You need to get people working with the virus so they won't be frightened of the damn thing," says Dr. Kitching. Front-line workers, he says, "need to be able to work comfortably with the virus and be able to say, 'Yes, I can do the diagnosis and provide the diagnostic support for the agricultural community.' "
He says the work on the virus in Winnipeg will also make the country more independent and capable of reacting quickly to an outbreak. Until now Canada and the United States relied on a British lab to provide reagents used in tests to determine whether animals are infected.
Dr. Kitching's staff of close to 60 scientists are now making reagents for the seven different varieties of foot-and-mouth virus they imported from a British lab. This time-consuming process entails growing the viruses in tissue cultures, infecting rabbits and guinea pigs and then collecting the antibodies the animals' immune systems produce against the virus. The antibodies are used to make test kits that can, within 24 hours, tell if an animal is infected.
The scientists are also doing research on more rapid diagnostic tests, which Dr. Kitching says could be taken to farms and reveal within 15 minutes whether an animal is infected.
Time, he notes, is critical. A single pig infected with one of the more virulent strains of foot-and-mouth disease can spew out enough virus to infect about 30 million cattle in one day, Dr. Kitching says.
The virus is a small and simple organism. But it comes in many different guises. One strain found in southeast Asia infects only pigs. "Others are cattle-specific and don't like pigs," Dr. Kitching says.
Some travel easily by air: Plumes of aerosol from pig farms have been known to travel as far as 250 kilometres over water and 10 kilometres over land, while others do not.
One reason the disease spread widely in Britain before it was detected in 2001 is because of the different ways the virus behaves in different animals, especially the lack of symptoms exhibited in sheep.
Pigs are veritable virus factories. An infected animal will typically pump out 3,000 times more virus than cattle infected with the same microbe, Dr. Kitching says. No one knows why.
Nor can scientists explain why animals that have been vaccinated against foot-and-mouth disease can pick up and carry the live virus. These "carrier" animals do not get sick but there is evidence they can pass on the virus to other animals that do get sick, Dr. Kitching says. It is one of the mysteries his team hopes to explore in Winnipeg.
They are also collaborating with U.S. and Mexican veterinary services to maintain vaccine stocks that could be used in the event of an outbreak.
The British outbreak in 2001 is believed to have been caused by a virus that arrived on illegally imported pork products from Southeast Asia, some of which found its way into restaurants. Left-overs ended up in swill that a farmer fed to his pigs -- failing to boil it as required by law.
The farmer, who was eventually prosecuted, failed to report that his pigs were diseased for almost three weeks. The virus wafted on to nearby farms infecting pigs, cattle and sheep. Infected sheep, with no sign of disease, were shipped to market.
The resulting outbreak paralyzed not only farming but tourism, as authorities closed footpaths and restricted travel. The British government compounded the crisis by following bad advice on how to handle the outbreak, says Dr. Kitching, who at the time was head of the foot-and- mouth division at Pirbright Laboratory, the world's leading centre for research on the disease.
He and other vets at the lab, who had identified the strain of virus causing the outbreak, soon were confident it was under control. But the government, which was heading into an election, ignored their recommendations and decided to act on the computer modellers' dire predictions that the disease would run out of control for many months.
Dr. Kitching generated plenty of headlines in Britain before leaving to take up his new job in Winnipeg. (He had accepted the job before the outbreak.) He said the computer models were based on "a total suspension of common sense."
Dr. Kitching says computer models are only as good as the information fed into them, and notes the problem with the British models was that they were based on incorrect information about the type of virus circulating. It was not nearly as easily spread by infected herds as predicted.
Two years later, Dr. Kitching says there are many lessons to be learned from the British experience. Apart from not relying too heavily on "very fashionable" computer models, he stresses the need to respond quickly to an outbreak and have ready access to resources -- trained vets, tests and reagents -- to contain it.
Even though the virus has not been on the loose in Canada in more than half a century, he says it is important to remember that it could slip into the country. It is believed the 1952 outbreak in Saskatchewan started when someone tossed a sausage from Europe into a farmyard.
Though few Canadians have ever seen foot-and-mouth, Dr. Kitching says "people need to have the disease in the back of their minds."
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