In the summer of 1991, when John was 6, his symptoms first appeared.

These symptoms usually appear over a few days to weeks.

The first symptoms appear between two and five years of age.

Symptoms can appear within the first 2 months of the baby's life.

In those cases, people can do nothing more than wait until middle age to see whether the symptoms of the disease appear.

Symptoms often don't appear until a person is 40 or older.

Symptoms may appear or change as a child gets older.

Contact with any form of water can cause symptoms to appear.

Eight hours after the symptoms appeared, the patient was dead.

It can help you see if an attack is coming, sometimes even before any symptoms appear.