In South Korea, government agencies are harnessing surveillance-camera footage, smartphone location data and credit card purchase records to help trace the recent movements of coronavirus patients and establish virus transmission chains.

In Lombardy, Italy, the authorities are analyzing location data transmitted by citizens’ mobile phones to determine how many people are obeying a government lockdown order and the typical distances they move every day. About 40 percent are moving around “too much,” an official recently said.

In Israel, the country’s internal security agency is poised to start using a cache of mobile phone location data — originally intended for counterterrorism operations — to try to pinpoint citizens who may have been exposed to the virus.

As countries around the world race to contain the pandemic, many are deploying digital surveillance tools as a means to exert social control, even turning security agency technologies on their own civilians. Health and law enforcement authorities are understandably eager to employ every tool at their disposal to try to hinder the virus — even as the surveillance efforts threaten to alter the precarious balance between public safety and personal privacy on a global scale.