Canada has recorded its first case of Tamiflu-resistant H1N1 virus, in a Quebec man who had been given the drug to prevent infection.
The 60-year-old man was given the antiviral medication after his son fell ill with the pandemic virus. But he managed to come down with the flu anyway.
He recovered quickly and did not require hospital treatment. There is no evidence he transmitted the resistant virus to anyone else.
Meanwhile, Japan revealed Tuesday it had found a second such case of Tamiflu resistance.
The cases are the fourth and fifth globally since the new H1N1 virus was discovered in April.
Jirina Vlk, spokesperson for the Public Health Agency of Canada, says the Quebec man's case appears to be an isolated one of Tamiflu resistance, adding her agency continues to be vigilant for similar cases.
Vlk said the agency recommends using Tamiflu for treatment only, not for prophylaxis to try to prevent illness.
Infectious disease expert Dr. Neil Rau says there has been evidence that giving Tamiflu to those who have been exposed to the virus can prevent infection. "But the downside to that is exactly what we're seeing here in Quebec," he told CTV News Channel.
"I think this may be a lesson not give people this drug in this fashion."
Dr. Allison McGeer, an influenza expert at Toronto's Mount Sinai University, says using Tamiflu to prevent infection has been seen, on occasion in the past, to give rise to resistant viruses.
"We know that it was going to happen and it's not good news that it's happening," McGeer told The Canadian Press.
She said that given the amount of Tamiflu being used in the world right now, such cases were bound to arise. It remains to be seen whether such cases will arise only sporadically or whether there will be widespread Tamiflu resistance.
Other cases of Tamiflu resistance in H1N1 cases have been reported in Denmark, Japan and Hong Kong.
The newest Japan case was in a person who had been given the antiviral drug after being exposed to the pandemic virus. The person recovered after being successfully treated with Relenza, a second drug in the same class as Tamiflu. It appears there was no further spread of the resistant virus.
Three of the four cases arose in people who had been taking the drug prophylactically. The other was in a San Francisco girl who travelled to Hong Kong and was discovered to be ill there. She hadn't taken the drug ahead of her infection, suggesting the virus that caused her infection was already resistant.
U.S. officials have intensified surveillance for resistant viruses in the San Francisco area but say they have not found other cases.
Flu survivor thought he would die
A Toronto area man who had one of the first cases of H1N1 says the illness put him into intensive care and had him wondering if he was going to survive.
Santini Gale says thought when he first became ill in late April that he had a simple cold.
"At the time that I got it, it was really the early stages of swine flu. So there was no information out there about it," he told Canada AM Wednesday.
He suspected he had bronchitis and went to a walk-in clinic for a prescription for antibiotics. But after seven days of treatment, he was still sick. "If anything, I was even worse," he says.
His symptoms continued to intensify to include dizziness, nausea and intense fever. He developed pain in his chest, crushing headaches and realized he needed to get to hospital.
"It literally immobilized me... this was something where I couldn't get out of bed. I became dehydrated. I hadn't eaten in days. I was sleeping for days on end. It was like my body was completely shutting down," he recounted
The hospital treated him for dehydration, gave him more antibiotics, morphine for the pain, and put him on Tamiflu. After two nights in intensive care, he recovered and was sent home on May 8.
Gale says he has no idea why he developed a severe case of H1N1, but says that while health authorities say the virus causes mostly mild disease, that was certainly not his experience.
"In my case, it was far from mild. It was beyond severe," he said.
With files from The Canadian Press
