The outbreak has been particularly fatal for the state’s black residents, who make up 41% of Michigan’s reported deaths but only 14% of the state’s total population, according to state and federal data. White people make up another 28% of the state’s reported deaths, while the racial identities of another 26% weren’t reported.

Virus-related deaths in the Detroit area have quickly outpaced everywhere else in the country but New York and New Jersey, according to data from the Covid Tracking Project.

“I can tell you without a doubt, it’s going to get worse before it gets better,” said Denise Fair, the city’s chief public health officer.

To prepare, the city’s massive convention center—long home to the Detroit auto show, which was recently canceled for June—is being converted into a 1,000-bed field hospital for virus- stricken patients.

The Spirit of Detroit statue is seen wearing a mask, with the GM Renaissance Center in the background in downtown Detroit on Monday.

With many in the city lacking health insurance and access to health care, the prevalence of underlying health conditions, such as diabetes, asthma and heart problems, are much higher here than elsewhere in the country. That makes for a population more vulnerable to getting sicker from the virus, doctors and public health officials say.

The city recently said it would start using new tests that deliver results within 15 minutes. It is also participating in a treatment experiment that aims to use hydroxychloroquine, an antimalarial drug, to prevent infections among first responders, Mayor Mike Duggan said.

“There is no evidence that this spreads more quickly among the poor than the wealthy,” he said, pushing back against the idea that the city’s poverty is exacerbating the virus.

“It seems like the situation just blew up all of sudden,” said J. Drew Sheard, a minister in Detroit, whose elderly parents have been hospitalized after testing positive for the virus. His brother also is sick but recovering well at home, he said.

Central City Integrated Health, a primary-care clinic near downtown, has struggled to provide protective gear for staff, with suppliers focusing on orders from larger hospitals. The dearth has left the clinic to treat most patients virtually. The problem is that not all patients have regular access to phones and computers, said Dr. Kimberly Farrow, chief executive of Central City Integrated Health. “We’ve had a major breakdown of our system.”

A U.S. Army Corps of Engineers arrived Monday to transform the TCF Center, formally known as Cobo Hall, into an emergency field hospital.

For instance, she had one asthmatic patient go to the hospital complaining of symptoms but was turned away because her case wasn’t deemed severe enough for a hospital bed. When Dr. Farrow tried to help her patient by phone, the woman’s prepaid cellphone minutes had run out.

Steve Ware, a social worker at Central City, said many of his clients want to stay home, but lack the savings to stock up on days’ worth of food, forcing them to venture out. Most lack the car necessary for the city’s drive-through test site, though the city is looking to coordinate rides for those without transportation.

The clinic is working hard to transform into a test site, but a lack of resources and a spike of new cases is hampering the attempts to move quickly, Mr. Ware said.

“We’re setting it up as quickly as it can be set up, but the disease is obviously much faster than us,” he said.