A 56-year-old man with the coronavirus attending a single church service in Ohio led to the infection's spread to at least 91 other people across five counties.
"It spread like wildfire," the governor said at a news conference Tuesday where the graphic was displayed. "Very, very scary."
"We have been very careful throughout this pandemic to exempt religious services from any regulations," the governor said. "The only exception to that is that we are now asking people who attend church to wear a mask."
He noted on his Facebook page that while this case of community transmission stems from a church, it can happen anywhere.
"All it takes is one person to cause tremendous #COVID19 spread," he wrote.
After the man with the coronavirus went to the church service in Ohio County in June, 53 others who had been at the same service became infected, according to the graphic shared by DeWine.
Eighteen of the these 53 spread the virus to at least one other person, the graphic shows. The man's wife, a son and a daughter also got sick.
All 91 others infected after the service showed symptoms of COVID-19, the disease caused by the coronavirus, the governor said.
DeWine in a series of tweets on Tuesday also provided other examples of the virus' spread within family and friend groups.
In one case, a son living with his father who was in hospice care developed a cough and believed he had bronchitis. Family members came to visit to pay respects to his father. Five family members later tested positive for the virus, including a great-nephew, the governor said.
Separately, a man who had COVID-19 symptoms attended his brother's wedding and reception. Now, 15 people are sick, including the bride, groom and one of their grandfathers.
And in another outbreak, a person who tested positive for the virus attended a bridal shower, leading to others becoming infected. "There are now six confirmed cases and six households impacted by this outbreak," DeWine said.
"None of us want to stay away from our families and of course, it's natural to want to show affection when you see them," he tweeted Tuesday. But this virus is "lurking," he wrote. "Please try to remember that you are showing love by protecting them."
Rachel Feeley, a spokeswoman for the Ohio Department of Health, declined on Thursday to release the name of the church where the virus spread or any details on the other cases. "We are not releasing additional information about these examples to the general public, in order to protect private health information," she said.
Feeley said that anyone who may have come into contact with people who had tested positive in these examples were notified through normal contact-tracing protocol.
On Thursday, DeWine's office said in a statement that he had tested positive for the coronavirus, but later said a second test, a PCR test, came back negative. The governor will be tested again Saturday.