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Immigrants face new screening for disease
Aim is to keep Canadians and newcomers healthy
Concerned about health risks to the Canadian public and excess demands on the medicare system, Ottawa is about to get tougher on who it lets into the country.
Or, rather, on what infectious diseases they may bring in with them.
Would-be immigrants, already barred if they have active tuberculosis or syphilis, will soon be routinely screened for HIV and hepatitis B. Those infected with either will be denied entry.
In addition, the 1,400 overseas doctors contracted by Ottawa to do immigrants' medical examinations and oversee laboratory screening tests are to be more stringently monitored.
Canada, the United States and Australia plan to start using the same designated doctors, says Dr. Ron St. John, director of Health Canada's office of health and security. If, in a spot check, one country finds irregularities or corruption - bribe-taking for fraudulently healthy results is not unknown - the doctor will lose the business of all three.
Refugees, who are allowed entry for humanitarian reasons even with an infectious disease, may also have their physical status more swiftly and fully assessed. A current pilot project in Montreal will determine if they should continue, as now, to be given a TB test within 60 days of arrival when making their refugee claim, or within the first five days.
A second study, also in Montreal, will decide whether point-of-entry testing of refugees for malaria is worth doing. Of a group of 223 central African refugees who landed in Montreal in August and who dispersed to sponsoring groups and families in Quebec after orientation, 13 subsequently came down with a virulent form of the disease.
A second group of 50 who arrived last month was tested within hours of landing and three found to be infected. Treatment was begun immediately.
The goal of increased pre-testing for immigrants isn't always ``to screen to keep out,'' emphasizes St. John, ``but to screen to let in, help newcomers be healthy.''
In an ideal world, new arrivals would be tested for everything from malaria to pregnancy to ensure they're quickly connected with appropriate health care, he says.
In the real world, however, immigrant-welcoming countries such as Canada must be wary of importing conditions that could wreak havoc among the general population. TB stands out among the rest, with a staggering one-third of the world's population now infected, and 1.5 million dying of it every year.
`The global TB situation is deteriorating and there isn't a barrier high enough to stop it. If we do intercept it (once it's here), we then have to cope with it.'
- Dr. Ron St. John, director of Health Canada's office of health and security
``The global TB situation is deteriorating and there isn't a barrier high enough to stop it,'' says St. John. ``If we do intercept it (once it's here), we then have to cope with it.''
The disease once was virtually eradicated in Canada, but there are now about 2,000 new active cases annually, one-quarter of them in Toronto. The city is the main entry point for half the country's immigrants and refugees, most of whom originate in countries where TB is endemic and drugs often not available to fight it.
But Canada is also on guard against HIV, the AIDS-causing virus, and hepatitis B, a sexually transmitted liver disease, whose incidence jumped alarmingly in the 1980s with the influx of immigrants from high-risk regions.
The introduction of immigrant screening for both diseases is the result of a unique computer-modeling program. It was devised four years ago by St. John's office at the Centre for Emergency Response to assess the public health risks of 47 communicable diseases.
So far, it has calculated the dangers of TB, syphilis, HIV, hepatitis B and C and Chagas' disease (a parasitical infection endemic in 21 countries in South and Central America), and made recommendations to the final arbiter, Immigration Canada.
It assessed the impact of each under three different immigration scenarios: 1) No medical screening and entry; 2) mandatory screening, treatment if the person is infected, then entry; and 3) screening and entry denied.
``To look at what happens if you do 1, 2 or 3 with each disease is a huge, time-consuming process,'' says St. John, explaining why it's taken so long to analyze the first six.
Screen and exclude was the recommendation on hepatitis B because Canada now draws many of its immigrants from southeast Asia and Africa where it is ``hyper-endemic,'' with up to 50 per cent of the population infected.
At present, with no screening, infected immigrants generate 15,000 new infections yearly in Canada, he says.
Screen and exclude was also the advice on HIV, after the computer model calculated that one in 1,000 immigrants arrive annually with the incurable virus and account for 37 ``spreads'' or transmissions to other people. The cost to the health-care system per HIV patient is between $150,000 and $260,000, says St. John.
Overseas doctors have had the discretion to screen for the virus, but by routinely testing for it, Canada now joins 50 other countries worldwide, including the United States, which has screened since 1987.
There was insufficient data to make a call on hepatitis C, says St. John, but it will be reviewed again. The advice on Chagas' disease was to screen and allow entry to infected immigrants, provided they're informed never to donate blood.
St. John's office recommended the status quo on syphilis: ``With 100 to 130 cases a year, it's not a huge problem, but our goal is to eliminate it entirely, so screen and exclude.''
Similarly with TB, the recommendation was to bar active cases, allow entry to the infected, then provide preventive drug treatment after arrival so the disease doesn't activate itself.
``If we cut off the infected, just about everybody would be excluded,'' says St. John. ``Canada's immigration would be reduced to a trickle.''
The key is to make sure preventive treatment actually takes place, says Dr. Neil Heywood, director of immigration and health policy at the selection branch of Immigration Canada. ``That's the critical part of our thrust. If we are to wipe out TB, we have to be vigilant.''
However, tracking and treating those with inactive TB is an obstacle-ridden job.
In theory it works like this: The overseas doctor finds evidence of infection in an applicant during the mandatory medical exam, the results of which are reviewed by one of 10 medical officers of health Immigration has stationed around the world.
The infection is encoded on the person's landing card, alerting officials at the point of entry that he is to undergo medical surveillance. He signs a form agreeing to report to a public health authority within 30 days and have a chest x-ray. His address is forwarded to a provincial health department, then on to the public health authority in the municipality where he'll be living.
Ottawa claims the goal of its screening program is healthy newcomers
With 53 per cent of the 250,000 annual immigrant intake heading to Toronto, says Heywood, about 3,000 to 4,000 surveillance notifications are sent out to the city.
``But that's not what's been happening,'' says Dr. Andrew Simor, a Toronto infectious disease specialist.
``I see people who immigrated five years ago and had been told by Immigration to have a TB test. But there's been no follow-up, they didn't have a test and now they have an active case.''
Some immigrants, through fear or confusion or lack of understanding that treatment is free, never report in to be checked. And by the time public health units are informed of their location, many have moved. Toronto loses track of about one-third of the notifications it receives from the province every year.
Jeff Bell, spokesperson for Ontario's health ministry, says, ``If there's a breakdown in the system, it's Ottawa's responsibility and they should be fixing it. People should be quickly checked.''
``It's the immigrants' responsibility,'' counters Heywood. ``They've been granted entry on the basis that they'll report.''
But yes, he's ``aware surveillance isn't as rigorous as it should be. Addresses are a problem. Public health authorities shouldn't have to go searching for them.''
With only 52 staff and $3.2 million from the city and province, Toronto's TB program doesn't have the resources to do so, says manager Sharron Pollock.
It can barely monitor the 400 individuals in the city with active TB. Only 25 to 30 per cent of them are being given DOT, directly observed therapy, in which they're watched each time they take their medication. ``We'd like to do DOT with all of them,'' she says, ``but we'd need double the staff.''
It's crucial that people take the full course of treatment, which can last from six months to two years. Last week, health officials in Montreal were so concerned about transmission that they sought a court order to temporarily imprison a man who has repeatedly refused to complete therapy.
In southern Ontario, a team of 11 public health officials is currently working to track down more than 1,000 people in Hamilton, Toronto and the regions of Peel, Halton and Haldimand-Norfolk who came into contact with two Hamilton residents diagnosed with a deadly strain of tuberculosis that resists ordinary treatment.
Drug resistance develops when a person stops medication too soon because he's feeling better, and then passes on the drug-resistant strain to someone else. About 12 per cent of cases are now resistant to one or more of the first-line drugs, but the number is increasing. Drug-resistant TB costs $250,000 to treat; the straightforward version $10,000.
But active cases are ``only the tip of the iceberg,'' warns Pollock.
Without treatment, 10 out of every 100 infected newcomers will develop the disease within five years because their immune systems have been weakened by the stress of immigrating or, as with many refugees, fleeing for their lives.
A 10-member outreach team was set up this summer to go into ethnic communities from high-risk countries to get the message out that the disease can be stopped from emerging, and fully cured if it does.
``It's difficult, because TB has an enormous stigma and people are afraid of it,'' she says. ``But if a skin test shows an infection, they can be given free preventive treatment.''
With Toronto the destination of almost half the country's 25,000 refugee claimants every year, TB testing absolutely should be done within five days of arrival, says Pollock, if not sooner.
In the U.S., refugees are given skin tests and digitalized x-rays on their first day in the country, says Roberta Lavin, deputy chief of operations at the U.S. immigration service.
``We use teleradiology - digital images of the chest that are sent via e-mail to the University of Maryland for diagnosis. We test them on day one and the results are back within four hours, not 48.''
Like Canada, the intent is not to turn anyone back, she stresses, but to start treatment if they have an active or latent form of the disease.
Dr. Barbara Yaffe, Toronto's director of communicable disease control, met last fall with Immigration Minister Elinor Caplan in an attempt to get federal money for TB control. New York city gets 60 per cent of its TB funding from Washington in recognition of its uniqueness as a major immigrant and refugee centre. Toronto, she argued, is in the same situation.
No luck, Yaffe says dryly. She has also repeatedly asked for Toronto to be included in federal-provincial public health talks, but it's not allowed in. ``All we want to do is quickly identify infected cases and be able to directly observe all treatment. Right now we can't.''
Health Canada is about to dispatch a 250-page set of TB guidelines mainly to family doctors who have little or no experience with the disease. They, not public health officials, are often the first to see infected individuals, says Dr. Howard Njoo of the TB prevention and control branch, ``and diagnosis can be hit and miss.''
That's precisely what Dr. Brian Ward, a tropical disease specialist at Montreal General Hospital, found this summer when faced with a malaria outbreak among 223 Africans who'd arrived on a humanitarian flight from refugee camps in Burundi.
Because there is no point-of-entry screening procedure for the disease, the 13 who were ill showed up days later at emergency departments, or went to local doctors who often failed to recognize the illness, he says. ``The system screwed up in a lot of ways, with missed diagnoses and wrong drugs being given. Refugees usually arrive in groups of five to 30. We were caught off guard with the number.''
A second group last month was screened almost immediately: ``We were ready this time.''
Ward is now heading a study examining the subsequent health condition of the first group to see if immediate screening would have benefited them - and protected the public. (A small risk of transmission exists in Canada during warm-weather months if a mosquito sucks the blood of an infected person then spreads it to a second person. Untreated malaria can kill.)
Some communicable disease experts have called for screening at the point of origin, not entry, when the country is known to be malarial. But in refugee camps, the expertise and equipment for proper testing is rarely available.
It makes no sense to screen before departure, says Immigration's Neil Heywood, because recent infections won't be picked up. ``A person could be bitten by a mosquito on the plane before it is sprayed.''
And that's the problem in a nutshell: ``People can now move faster than the incubation period of many diseases.''
Countries such as Canada are just starting to come to grips with the implications. It means continually finding a balance between protecting public health and living up to its genuine desire - and demographic need - to welcome in newcomers＜本文发表于: 相约加拿大:枫下论坛 www.rolia.net/f ＞
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