JACKSON (WNE) — Yellowstone National Park staff are reportedly clear of COVID-19. The park had 43 employees who regularly interact with visitors tested for the virus on May 28 and 29. Every employee’s test result was returned negative, according to a park press release on Thursday.

It was the first round in a series of “surveillance” testing that will carry on through the summer, as per the reopening plan implemented by the park. The testing is aimed at slowing the spread of the virus through efforts to recognize and quickly isolate any affected individuals who only have mild symptoms or are asymptomatic carriers.

Yellowstone will be running another 100 tests this week. The press release stated that they will continue giving public updates on the surveillance testing results.

Both Wyoming and Montana are giving assistance to the park’s testing program, as are Park County, Wyoming, and Park County, Montana.

Yellowstone Superintendent Cam Sholly said that within the national park system, their testing practices are the most aggressive undertaken so far.

“Information gained from this program will inform management decisions,” Sholly said in the press release.

The press release also stated that the park’s vehicle traffic at the open Wyoming gates has been 70% of 2019 vehicle traffic at those same gates. Overall, vehicle traffic in the park is only 20% of last year’s.