Updated: 5:15 p.m.

The number of confirmed cases of coronavirus infections in Alabama increased to 517, as of 5:15 p.m. Thursday afternoon. That is up from 386 the evening before.

Also on Thursday, the state's second COVID-19 death was reported. Albert Johnson, 78, of Lauderdale County died from the disease, according to media reports and social media posts from his family.

There are now confirmed cases in 48 of Alabama's 67 counties. Jefferson County continues to lead the state in cases, with 159. In Montgomery, there are 17 confirmed cases. The number of cases in Autauga County rose to 6 Thursday. Lowndes County has its first reported case as well.

The Alabama Public Health Department switched to a new mode of reporting cases, using a graphic that will be updated in real time. The Montgomery Advertiser typically will report new case numbers twice a day.

The coronavirus COVID-19 causes flu- and pneumonia-like illnesses in those young and relatively healthy, though some experts caution it is still more dangerous and intense than the average flu for many patients.

But it can be deadly, particularly in those older than 60 or with pre-existing health conditions, and young people may be transmitting the virus without even knowing it, says Alabama Emergency Management Agency Director Brian Hastings.

On Thursday, Gov. Kay Ivey announced schools will remain closed for the remainder of the semester, and students will finish the year at home.

More:Alabama schools to stay shuttered amid the coronavirus pandemic

"This decision has not been made lightly. It's been made with a tremendous amount of concern and discussion," she said. "We must be serious about eliminating the spread of this virus. The public health orders are not suggestions. They have been put in place to save your life."

On Wednesday, the governor and state health officials confirmed the state's first death from the virus occurred in Jackson County, the far northeast corner of the state. The victim had underlying conditions, health officials said.

More:Alabama's first coronavirus death is in Jackson County, ADPH and governor say

Also on Wednesday, the number of reported cases rose by more than 100 between the morning and evening. After reporting 283 cases on Wednesday morning, the Alabama Department of Public Health reported 386 cases have been confirmed.

More:Confirmed Alabama coronavirus cases swell to 386

UAB Hospital announced its in-patient COVID-19 cases had tripled in a 24-hour period, with at least 60 people hospitalized by Wednesday evening. The majority of the patients were requiring ventilator care, though UAB said some patients had recovered.

"I want to be clear in what I'm saying about what this drastic and rapid increase means to our community," Dr. Sarah Nafziger said Tuesday. "This is a dangerous situation that our community needs to take seriously. Everyone has an important responsibility right now to save lives."

Alabama doctors and hospital leadership this week told the Advertiser that Alabama is not equipped to handle a large influx of cases all at once. Social distancing and isolation measures must be followed, experts say, to "flatten the curve" or spread out the number of infections over a longer period of time. If widespread infections happen too quickly, Alabama will run out of hospital beds and medical equipment.

More:'Absolute unknown territory': Alabama hospitals brace for coronavirus onslaught lacking resources

Alabama coronavirus cases by county:

Autauga (6)

Baldwin (5)

Blount (2)

Bullock (2)

Butler (1)

Calhoun (2)

Chambers (13)

Cherokee (1)

Chilton (4)

Choctaw (1)

Clay (1)

Cleburne (1)

Colbert (1)

Coosa (2)

Crenshaw (1)

Cullman (6)

Dallas (2)

DeKalb (1)

Elmore (10)

Etowah (4)

Franklin (3)

Houston (3)

Jackson (4)

Jefferson (159)

Lamar (1)

Lauderdale (9)

Lawrence (3)

Lee (47)

Limestone (13)

Lowndes (1)

Madison (43)

Marengo (1)

Marion (7)

Marshall (3)

Mobile (18)

Montgomery (17)

Morgan (9)

Pickens (1)

Pike (2)

Russell (1)

St. Clair (6)

Shelby (52)

Talladega (4)

Tallapoosa (4)

Tuscaloosa (19)

Walker (17)

Washington (2)

Wilcox (2)

Our Data Central page includes an interactive map that tracks confirmed COVID-19 cases, recoveries, and deaths from around the state, nation, and world.

The map is updated automatically and shows a closeup of each [state] county.

Or, zoom out to see numbers from around the nation and the world.