Input (grade 8): Although Allen Steere realized Lyme disease was a tick-borne disease in 1978, the cause of the disease remained a mystery until 1981, when B. burgdorferi was identified by Willy Burgdorfer.
Output (grade 11): Although Allen Steere realized in 1978 that Lyme disease was a tick-borne disease, the cause of the disease remained a mystery until 1982.