All Intensive Purposes

Paradoxically, the news that avian flu is growing less deadly is not good for those of us who fear a pandemic, since it makes transmission more likely.

If a disease quickly kills almost everyone it infects, it has little chance of spreading very far, according to international health experts. The less lethal bird flu becomes, they say, the more likely it is to develop into the global pandemic they fear, potentially killing tens of millions of people....

Health researchers believe that nearly all the 52 people known to have died of bird flu in Southeast Asia caught the virus from infected poultry. But with more clusters of cases among families reported in Vietnam this year ... experts say they are growing increasingly suspicious that the disease has begun passing from one human to another.

Also worrying is the discovery of at least five cases ... in which people tested positive for bird flu but showed no symptoms. This could make it more difficult to contain an epidemic because people could transmit the disease without anyone realizing it."