CONCORD, N.H. (AP) — Hospitals across the country recommended hepatitis C testing for about 7,900 patients last summer after a traveling medical worker was accused of stealing drugs and infecting patients with tainted syringes in New Hampshire. But five months later, nearly half of those who were possibly exposed to the liver-destroying disease in other states have yet to be tested.

Described by prosecutors as a “serial infector,” David Kwiatkowski is accused of stealing syringes of the powerful painkiller fentanyl from the cardiac catheterization lab at New Hampshire’s Exeter Hospital and replacing them with saline-filled syringes tainted with his own blood. In jail since his arrest in July, he pleaded not guilty to 14 federal drug charges earlier this month and is expected to go to trial next fall.