An important line of defense against the coronavirus lies in contact tracing, tracking the steps of an infected individual and reaching out to others who may have been exposed with advice on testing, self-quarantine and available resources.

Training contact tracers to perform the grueling work in Orange County has been an uphill battle. On Thursday, healthcare officials reported another 348 new cases, bringing the county’s total to 42,171.

Though many more have been trained, Orange County Health Care Agency officials confirmed Thursday the agency has just 185 staff members dedicated to tracking coronavirus cases.

In low-income areas and communities of color such as Santa Ana and Anaheim — where rates of infection are 20 times higher than the countywide average — the challenges of contact tracing can also be exponentially higher.