People sitting close together appear at greater risk of becoming infected.

It was not immediately clear how the two patients, a man and a woman, had become infected.

So far this year, 28 to 30 people have become infected.

As foreign material, they are at greater risk for becoming infected.

But none of the experts had any idea where he could have become infected.

In some day care centers more than half the children have become infected.

It was not immediately clear how they had become infected.

Since then, about 40 homosexual men a month have become infected.

Over the years, the eye became infected, got worse and eventually was lost.

Even among people who have close contact with a patient, 20 percent become infected.