Health departments around the U.S. that are using contact tracers to contain coronavirus outbreaks are scrambling to bolster their ranks amid a surge of cases and resistance to cooperation from those infected or exposed. With too few trained contact tracers to handle soaring caseloads, one hard-hit Arizona county is relying on National Guard members to pitch in. In Louisiana, people who have tested positive typically wait more than two days to respond to health officials -- giving the disease crucial time to spread. Many tracers are finding it hard to break through suspicion and apathy to convince people that compliance is crucial. Contact tracing -- tracking people who test positive and anyone they've come in contact with -- was challenging even when stay-at-home orders were in place.