Toronto has one of the largest groups of international travellers in the world who come back with a tropical disease, according to a new study

Elaine Carey:

Almost half are immigrants returning from visiting family and friends in Third World countries, says Dr. Jay Keystone, head of the tropical disease unit at Toronto General Hospital.

Such travellers don't believe they will be affected by diseases in their home country and also can't afford the cost of anti-malarial drugs and vaccines, Keystone said in an interview.

About 8 per cent of travellers to the developing world require medical care during or after their trip, according to the study of 17,000-plus of them, about a quarter from the Toronto clinic, published yesterday in the New England Journal of Medicine.

The travellers' destination determines what disease they're apt to get, the study, the first of its kind, concludes.

Fevers from the tropics were seen disproportionately in visitors returning from sub-Saharan Africa or Southeast Asia, and acute diarrhea noted among visitors to south-central Asia. Skin diseases were most apt to be picked up in the Caribbean or Central or South America.

Preventive drugs can cost over $1,000 for a family of four and are no longer covered by OHIP.

"I think that's ridiculous," Keystone said. "The (government's) attitude is, `If you can afford to travel, you can afford to pay.'"

The drugs were delisted about eight years ago as a cost-cutting measure "because they decided to cut out luxuries," he said. "The issue has always been preventative medicine doesn't pay."

OHIP also doesn't cover the cost of getting travel advice from a doctor before travelling to developing countries, Keystone said, and most travel agents never recommend seeing a doctor "because they don't want to mention travel and health in the same sentence."

Keystone's clinic, the largest in Canada, was one of 30 tropical medical clinics on six continents that took part in the study. Called GeoSentinel sites, they began sharing data five years ago as a way of quickly alerting the world to emerging diseases.

"It's an amazing network, one of the most effective surveillance networks for global infectious disease," he said. For example, the network tagged a malaria outbreak last year at a resort in Punta Cana, Dominican Republic. "Within two or three days, the world knew if you were going to Punta Cana, you needed anti-malarials."

The Toronto site was also vital in alerting the world to the SARS outbreak two years ago.

Returning immigrants are "a hugely important group of travellers" that tropical disease specialists have been unable to reach, he said. Toronto's huge multicultural population makes it one of the most vulnerable.

Keystone's clinic treats 700 returning travellers a year and "the study backs up what we as clinicians see," he said.

It will also help family doctors and infectious disease experts more quickly identify what patients have contracted, he said. But most doctors don't advise their patients to get preventive drugs before they travel because they don't get paid for it.

If a traveller returns from a developing country with hepatitis A, they will be off work for a month, 3 per cent will die and 1 per cent will have chronic liver disease, which costs the medical system far more than paying for prevention, Keystone said.

An editorial in the journal, accompanying the study, said less than half of travellers with high risk for illness seek pre-travel care and many physicians make errors in judgment about what they need to take.

Immigrants, especially, "often believe that they have little risk of contracting disease in a place that was once their home," Dr. David Hill, director of the National Travel Health Network in London, England, said in the editorial.

But other tourists are also vulnerable. Legionella outbreaks are common in hotels in the Mediterranean region as are noroviruses on cruise ships and diarrhea from water in swimming pools. Even travellers who do take precautions can get sick. Between 20 and 60 per cent of visitors to resource-poor regions will get diarrhea because of widespread contamination of food and drink, Hill wrote.

He called on the travel industry to inform customers of necessary health measures. Tropical disease specialists must publicize the benefits of pre-travel medical care, especially to immigrants, and to educate physicians in assessing the health risks of travel.

International travellers face burden of tropical disease

Toronto tuberculosis capital of Canada