CNN 10 and I'm your anchor.

Carla Zeus.

Happy to have you watching this Wednesday in the ongoing fight against Cove in 19 nations around the world are increasingly turning to technology to track the disease.

This isn't just about testing to find out who's had it.

It's about finding out where someone who's tested positive has been whom he or she might have interacted with and then telling those people that they might have been exposed to the disease.

So let's say you go to a party and someone there later test positive for Corona virus.

You could get a call or text in the days afterwards, saying you might have been exposed and that you should stay home and socially distance yourself for 14 days.

The intent is that this could prevent you from spreading cove in 19 before you even know you have it.

This form of tracking is called contact Tracing.

It requires a lot of workers to do it, and the U.

S Centers for Disease Control says it's a key strategy for preventing the spread of Corona virus.

But those concerned about privacy say contact tracing could cause a lot of problems.

For one thing, your smartphone can be used without you being told about it.

Toe.

Learn a lot about the places you go, the time you spend there and the people you see based on their smartphone info.

Critics say anyone with access to this data could use illegally to track information people expect to be kept private.

They're not only concerned about the mass surveillance of Americans, they're also uneasy about the possibility of this data still being collected even after the threat of the Corona virus has passed.

So contact tracing, while useful, is controversial.

I spoke with this is unprecedented, especially for a respiratory.

California is busy building an army to find out who has Cove in 19 and to keep it from spreading further, along with robust testing capabilities.

These air key priorities under Governor Gavin Newsom's plan to fully reopen the state.

These air simply disease detectives that will be trained to support the existing workforce through a new program led by the University of California, San Francisco and U.

C.

L.

A.

The state is virtually training mostly current state and county employees as contact tracers tracer growing the force from 3000 to about 13,000 by the end of the month.

Once a positive test result is reported to the health department, that person can expect to get a call, can't be about your symptoms and then really go over in detail where you've been in the last five days, we're and interested in finding out.

With whom?

Have you been in contact for more than 10 minutes within six feet without a mask on?

How much information are these people being asked to share?

We need to know who they are, where they are, who their medical providers are, where they're gonna go into isolation.

We also want to know where they're working.

But this is also not only about managing the individuals but also trying to identify clusters of transmission, just as tracers did.

When someone in Pasadena decided to throw a birthday party recently, one person brought a gift no one wanted.

There was someone who was coughing, who attended the party, and, uh, there were subsequently five laboratory confirmed cases of Kobe 19 1 infectious person who led to five confirmed cases within the city, plus possibly five or six other partygoers who live outside of Pasadena.

And we're also beginning to show symptoms, all tracked down by talking to the person who initially tested positive for the virus to get the names and numbers of those they had been around.

What we're doing is for a particular reason not to be invasive or intrusive or to take away any of their freedoms.

Marie Plume normally works for the Pasadena Central Library.

For now, she's assisting the city's health department as a contact tracer.

After recall, she sends her notes to a public health nurse who does a secondary investigation.

They make a determination as to whether or not this person would be safe to go back to work, getting back to work the ultimate goal, not just for the recovered before California as well.

12th trivia.

Which of these animals has the widest wingspan?

Ostrich, manta ray stingray or wandering albatross?

Wingspan or disc size of a giant manta ray can measure more than 25 feet across.

Banta means cloak or blanket in Spanish, a fitting term for the world's largest rank giant.

Oceanic mantas can weigh up to £5300 significantly more than great white sharks.

But as far as people are concerned, mantas are gentle giants.

Thes cold blooded fish don't have the venomous barb on their tails that stingrays have.

Still, our friends at great Big Story tell us that people should never touch a manta ray in the wild unless maybe they're experts.

So next today we're joining one for a swim, both an expert and a manta.

Off the coast of the East African country of Mozambique, Batteries are very large.

They're one of the largest animals in the ocean, certainly either the largest of any of the race species they could get up to about 25 feet across.

When they come towards you and they're that size, they look like an alien spacecraft.

As they go overhead, they actually blight out the sun.

It's just so incredible to be that close to such a large animal, especially one that you don't have to fear.

My name's Andrea Marshall.

I'm a man trade researcher in a marine biologist.

I've been in love with the ocean all of my life ever since I could remember I wanted to be a marine biologist when I moved out of Africa with the intention of studying things like great white sharks actually shifted my focus over to match raise when I realized that no one had ever done a study on Manta rays before.

One of the things that makes mantra so special is that they're large, and sometimes people feel frightened by them just because of their sheer size.

But actually, they're one of the most gentle animals in the entire ocean.

Manta rays are very intelligent animal.

They actually have the largest brain of any marine fish.

But one of the things that surprises me the most is just the fact that they seek out encounters with humans.

So this is an enamel.

It swims away from you.

This is an animal that swims to you.

They recognize you almost as a friend.

Southern Mozambique is just an incredible location.

Look here for the last 15 years, and even though I traveled all over the world to do my work, I enjoy coming back here because this is such a wild place.

It's so exciting.

One of the reasons I began work on matches is because I knew that these animals were under threat recently, you know, within the last 15 to 20 years, they have started to be fished for Asian tonics, and as a result of this, we've seen manta populations crashing across the globe.

Even here in Mozambique, where we don't even have a very aggressive fishery, we've seen the population collapsed by up to about 98% over the last 15 years.

We're starting Teoh, lose them faster than we can study them.

So it's really important for me to get these messages across to people who don't have the opportunity to peek down into the underwater world.

You know, it's not every day you meet someone who's been playing video games for 39 years.

Then again, it's not every day you meet a 90 year old Youtuber Hama Komori holds the Guinness world record for being the oldest YouTube gamer.

She's known as gamer Grandma to more than 1/4 1,000,000 subscribers.

Back in the day when she started playing, and by that we mean 1981 years before the Nintendo entertainment system came out, she says.

She was surrounded by kids who played games and thought they shouldn't be the ones having all the fun.

The Japanese Nana Generi in started with a cassette vision console and never looked back.

So is it really all fun and games?

She says She's always game for playing but feels defeated whenever it's game over.

Of course, she's able to control and console herself.

Nen, 10.

Don't you know you get good at that?

After PS 40 years of a next boxing new games and constantly switching things up?

I'm Carla Zeus.

Last stop today is in Vietnam, where we're happy to see the students of the bilingual Canadian International School.

They're watching from HOA Thi Minh City, also known as Saigon, and they're commenting at youtube dot com slash CNN.