Spotting How Bird Flu Pops Into People

Every now and then a new, nasty version of the influenza virus sweeps across the world. Health experts have known for a long time that these worldwide outbreaks of fatal disease start in birds. Now scientists are uncovering for the first time the secrets of the viruses which can make the jump from birds to humans, according to research to be presented tomorrow, Tuesday 30 March 2004, at the Society for General Microbiology’s meeting in Bath.

“Most bird flu viruses cannot normally infect people and other warm blooded animals”, says Ms Angie Lackenby from the Institute for Animal Health at Compton, near Newbury. “The reason some viruses can jump from one species to another and the changes needed in the virus to make this possible are not clear”.

The scientists at the Institute for Animal Health, working with colleagues from the University of Reading, developed a system that would let them identify which genes from chickens were vital for the viruses to grow. They used cells from hamsters with genetic information from chickens inserted to spot the essential genes.

“At the same time we also investigated what changes in bird flu virus were needed to improve its growth in mammal cells”, says Ms Lackenby. “By altering virus genes and measuring their effect on the virus reproduction in cells we were able to see which ones were the most significant”.

By drawing together these two lines of investigation the researchers can show how influenza viruses interact with humans and other mammals to cause such dangerous outbreaks of disease. Knowing how the systems work will enable health workers to spot potentially fatal viruses circulating in wild waterfowl and put safety measures in place in advance of any human infection.

Eventually, a better understanding of the way bird viruses from the wild infect humans will lead to safer and more effective vaccines, making officials better prepared for outbreaks in the future.