WHO: Deadly Strain of Bird Flu Starting to Show Signs of Mutating

The deadly H5N1 bird flu virus that has frightened people around the world and killed at least 148 people is getting stronger and more dangerous. A World Health Organization scientist said Thursday that the strain is now showing signs of being able to mutate and develop resistance to the anti-viral drugs that have proven somewhat effective in curtailing it. The strain is also likely to become resistant to any possible vaccines yet to be produced.

No vaccine for the H5N1 virus has been produced so far, but scientists are working hard to produce one and they are confident that they will be able to develop one in the future.

Dr. Mike Perdue, a team leader with WHO's influenza program, said that the H5N1 virus is splitting into to genetically different groups. Speaking at a two-day bird flu conference earlier this week sponsored by the United Nations health body, Perdue said that the virus has also been shown to mutate like seasonal flu viruses. New vaccines have to be developed each year for human influenza because of viral mutations, and the bird flu will be no exception.

"We are going to have to come to the realization that these viruses are genetically variable," Perdue said. "The vaccines that we have predicted to be protective today may not be protective a year from now." According to Perdue and other influenza experts, the two most effective and-viral drugs currently being used-Tamiflu and Amantadine-are also at risk of losing their potency. "We know from surveillance studies and from hospital clinical studies that resistance to the two primary anti-viral drugs, the Tamflu and Amantadine drugs, have already occurred," Perdue said.

In addition, Perdue said, the risk of the avian flu mutating to human form continues to increase. He also warned that there is a greater chance of mutation during the winter, adding that "the H5N1 strain of the virus does not sleep, and always constitutes a danger."

The latest WHO figures pertaining to the H5N1 strain have shown that there have been 251 cases of human avian flu since 2003, of which 148 people have died. The numbers are growing each year, and so far ten countries have been affected, with the worst being Indonesia and Vietnam.