The United States confirmed more than 71,000 new coronavirus infections Thursday — one of the worst daily tolls of the U.S. outbreak so far.

North Dakota has suspended contact tracing efforts as a backlog of cases overwhelmed National Guard soldiers assigned to track down the contacts of infected people. As of Thursday, North Dakota’s hospitals had just 14 intensive care unit beds available statewide. Data compiled by Johns Hopkins shows that if North Dakota were a nation, it would have the highest number of per capita COVID-19 cases in the world.

In Wisconsin, a massive field hospital outside Milwaukee admitted its first COVID-19 patient Thursday as Wisconsin’s infections continued to surge to record-high levels.

Utah Governor Gary Herbert warned Thursday that the state’s healthcare system is at or near its capacity.

In Massachusetts, Boston’s schools superintendent on Thursday canceled plans to resume in-person learning at public schools.

In Houston, Texas, teachers at dozens of schools staged “sick-out” protests Thursday demanding smaller class sizes, enforced social distancing and mask wearing, better classroom ventilation and other safety measures at schools.