HIV escape review - N work to understand these issues, and...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
work to understand these issues, and there is no funding now,” she says. Breaking the species barrier Although scientists know that influenza viruses can jump the species barrier directly, such an event has been seen as a rarity. A review of the literature yields only 18 cases of pure swine in- fluenza directly crossing into people, says Olsen. But his work suggests that many cases of transmission may occur, then fizzle out. Olsen tested 74 swine farm owners, employees, their family members, and veterinari- ans in rural Wisconsin for anti- bodies to swine influenza and compared the results to those for 114 city folk in a study published last sum- mer in Emerging Infectious Disease . Seventeen of those routinely exposed to pigs tested positive for the antibodies, whereas only one urban dweller did so. Olsen and his colleagues have also found evidence that a novel H4N6 swine virus isolated in pigs in Ontario—which probably came from local ducks—has al- ready acquired genetic mutations that give it the potential to bind to human cell receptors. Such an event could be cata- strophic, as humans have no immunity to H4 viruses. But getting into humans is just the first step. To have pandemic po- tential, a new influenza virus must also be able to move easily from one person to the next. No new virus from swine or birds, nor any hybrid created in pigs, has been able to accomplish this since the 1968 pandemic. Even so, experts in both animal and hu- man health are beginning to call for in- creased surveillance to stop a new pan- demic before it starts. The World Health Organization (WHO) constantly scans the globe for new strains of human influenza, which are used to make annual recommen- dations for next year’s vaccines. But “there is no systematic monitoring of [human] populations where there may be inter- species transmission between humans, birds, and pigs,” says Carolyn Buxton Bridges, an epidemiologist at the U.S. Centers for Disease Control and Prevention in Atlanta. In addition, “we don’t have any official surveillance system for swine influenza,” says Sabrina Swenson, head of bovine and porcine viruses at the National Veterinary Services Laboratories in Ames, Iowa. “We have to bring the human-health people together with the veterinary-health people because of concern that the viruses can move to people. It would be nice to have something better defined, but it’s dependent on funding,” she says. Webster, who heads the WHO collabo- rating laboratory on animal influenza in Memphis, Tennessee, calls for the devel- opment of reagents to recognize every possible influenza subtype and for a global network for monitoring of ani- mal influenzas at the human- animal interface. “If some- thing strange pops up in Georgia or Washington state, do we have the reagents in place to move quickly from identification to making a hu- man vaccine?” he asks. Last month, at a WHO
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

HIV escape review - N work to understand these issues, and...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online