Searchers map the global spread of drug-resistant influenza

September 14, 2011 by Claudia Adrien

In the new movie "Contagion," fictional health experts scramble to get ahead of a flu-like pandemic as a drug-resistant virus quickly spreads, killing millions of people within days after they contract the illness.

Although the film isn't based entirely on reality, it's not exactly science fiction, either.

"Certain strains of are becoming resistant to common treatments," said Ira M. Longini, a professor of biostatistics in the University of Florida College of Public Health and Health Professions, the UF College of Medicine, and the UF Emerging Pathogens Institute. "We've been able to map out globally how this phenomenon is happening."

Longini is among a team of researchers who have published this month in the Royal Society journal Interface and explain how seasonal H1N1 influenza became resistant to , otherwise known as Tamiflu, the most widely used antiviral agent for treating and preventing flu. The scientists say that a combination of and through air travel can lead to the rapid global spread of drug-resistant strains.

"If you see in parts of the world where no one is taking , that's the smoking gun that the resistant strain must be transmitting," said Longini, who also worked on this research at the Fred Hutchinson Cancer Research Center in Seattle.

In some situations, drug-resistant bacteria and viruses can spread when drugs are overused. The scientists explored this theory using a mathematical model that simulates the spread of influenza across 321 cities connected by air travel. Using this model, they found that oseltamivir use had not been nearly widespread enough to promote the spread of antiviral resistance after it arose. However, the resistant strain probably originated in one person taking the drug.

"Oseltamivir is an important prophylactic, or preventative agent, against future , including a potential H5N1, or 'bird flu,' pandemic," said Dennis Chao, the lead author of the paper and a staff scientist at the Center for Statistics and Quantitative Infectious Diseases at the Fred Hutchinson Cancer Research Center.

However, influenza can mutate, making the drug less effective. It had been believed that this mutation would not spread because it makes the flu less transmissible in people not taking the drug.

"The fact that it spread so quickly in seasonal H1N1 between 2006 and 2008 took everyone by surprise," Chao said.

The researchers say that the mutation may have "hitchhiked" on one or more other mutations that made the drug-resistant influenza strain more transmissible. They suggest that because of influenza turn over so rapidly, there are many opportunities for these types of mutations to arise in an otherwise highly transmissible strain and become widespread, and it can become the dominant strain within a couple of years, making the drug useless.

"For the next pandemic, we should have all the available drugs at our disposal as a first line of defense to both prevent infection and to treat the most vulnerable," Longini said. "Or else, the chance that the next pandemic influenza strain is resistant goes up. We know something like 'Contagion' could happen for influenza."

Related Stories

Recommended for you

Antibody found that fight MERS coronavirus

July 28, 2015

(Medical Xpress)—An international team of researchers has found a MERS neutralizing antibody—a discovery that could perhaps lead to a treatment for people infected with the virus. In their paper published in Proceedings ...

Experimental MERS vaccine shows promise in animal studies

July 28, 2015

A two-step regimen of experimental vaccines against Middle East respiratory syndrome (MERS) prompted immune responses in mice and rhesus macaques, report National Institutes of Health scientists who designed the vaccines. ...

Can social isolation fuel epidemics?

July 21, 2015

Conventional wisdom has it that the more people stay within their own social groups and avoid others, the less likely it is small disease outbreaks turn into full-blown epidemics. But the conventional wisdom is wrong, according ...

Lack of knowledge on animal disease leaves humans at risk

July 20, 2015

Researchers from the University of Sydney have painted the most detailed picture to date of major infectious diseases shared between wildlife and livestock, and found a huge gap in knowledge about diseases which could spread ...

IBD genetically similar in Europeans and non-Europeans

July 20, 2015

The first genetic study of inflammatory bowel disease (IBD) to include individuals from diverse populations has shown that the regions of the genome underlying the disease are consistent around the world. This study, conducted ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.