The classic mistake of patients taking virtually any medicine is assuming their diseases have been cured because they no longer feel the symptoms. Against all evidence, the United States and other wealthy countries have adopted this flawed, and often fatal, line of reasoning in their response to the growing AIDS crisis spinning out of control in other parts of the world.

An international conference on AIDS treatment and prevention began yesterday in the shadow of a recent U.N. report predicting 45 million new HIV infections in the next eight years, accompanied by 68 million deaths within the next two decades. These millions will be added to the 20 million AIDS deaths and 40 million HIV infections recorded in the previous 20 years.

The numbers alone qualify AIDS as the largest epidemic in human history. But even more alarming is the disease’s spread throughout Africa, Asia, the Caribbean and Eastern Europe. With the disease comes not only death but also disrupted societies and economic stagnation.

Yet the United States and other powers remain comfortably shielded by well-developed public health systems and treatments. In Western countries last year, 25,000 people died of AIDS, but 500,000 received treatments. In Africa, six million people need antiretroviral drugs but only 230,000 receive the treatments, and 2.2 million died of the disease last year. A U.N. campaign to raise a relatively paltry $10 billion drew only $500 million from the United States.

The AIDS catastrophe is one of the most significant threats to economic development, cultural integration and political stability in the world’s less-developed countries. It deserves a response proportionate to this threat.