(AP)—Health officials say a national wave of severe respiratory illnesses caused by an unusual virus is about to start looking a whole lot bigger, but that's because a new test will be speeding through a backlog of cases.

Starting Tuesday, the Centers for Disease Control and Prevention is using a new, faster test—which is expected to help the agency test four or five times more specimens per day that it has been.

The test checks for 68, which since August has been fingered as the cause of hundreds of severe, asthma-like illnesses in children—some so severe they needed a breathing machine. The virus is being investigated as a cause of at least 6 deaths.

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