Apple and Google have announced they are teamed up to track spread of coronavirus cases.

Apple and Google announced a partnership on Friday in which the two companies will work together to provide tools that will help track the spread of coronavirus.

Apple said both companies will launch developer tools (called APIs) in May that will "enable interoperability between Android and iOS devices using apps from public health authorities." The apps will launch on the iTunes App Store and the Google Play Store.

Experts have started to call on the private sector to help follow the spread of coronavirus using so-called "syndromic surveillance," a technique that can be used to track pandemics. Tech companies are particularly well positioned to do it, since most people in the U.S. own a phone where apps can be installed. And because government funding for syndromic surveillance has dried up.

"Google and Apple are announcing a joint effort to enable the use of Bluetooth technology to help governments and health agencies reduce the spread of the virus, with user privacy and security central to the design," a press release announcing the partnership said.

Bluetooth can be used to track the location of a phone, often with smaller Bluetooth beacons that are able to provide a more accurate position than a cellular signal or GPS. The tools from Apple and Google will enable app makers to use Bluetooth to let people know when they've come into contact with someone who has been diagnosed with coronavirus, a process called contact tracing.

Both Android and iOS allow you to monitor which apps have access to your location using Bluetooth and let you turn off tracking.

"Second, in the coming months, Apple and Google will work to enable a broader Bluetooth-based contact tracing platform by building this functionality into the underlying platforms," Apple said in a press release.

Google's website explained how this will work.

If you have a phone and you cross paths with someone who ends up testing positive for coronavirus, you may be alerted that you've come in contact with coronavirus.

Google's site says the apps won't collect personally identifiable information or user location data and "people who test positive are not identified to other users Google or Apple." Apps will store location for about 14 days. The data will "only be used for contact tracing by public health authorities for COVID-19 pandemic management" Google says.