There have been at least 30 new confirmed coronavirus cases in Carroll County since Wednesday, when the state expanded testing in the area.
The county's total was 48 on Monday morning, according to state data.
"Carroll County Public Health strongly recommends the use of masks in public," the department said Sunday in an online post. "You should assume the person next to you could possibly be infected ... take precautions seriously."
Starting on Wednesday, St. Anthony Regional Hospital gained access to hundreds more test kits from the state and is conducting drive-through testing of residents at its Carroll hospital on Mondays, Wednesdays and Fridays and at its Denison clinic on Tuesdays and Thursdays.
"It has been very busy," said Nicole Schwering, the county's public health director.
Many of the newly infected people do not know how they might have contracted the virus.
Sara Anderson, the emergency management coordinator for Carroll County, said about 500 tests had been done in the first four days of the expanded testing, and that she had to request 500 more from the state for tests this week.
Anderson is charged with guiding businesses, cities, schools and others about how to proceed in a way that stems the spread of the virus. A significant problem she has encountered repeatedly are people who don't self-quarantine for at least 10 days after being in contact with someone who was infected.
Those people are identified through contract tracing, an exhausting process that involves calling all the people who were in close contact with someone with a confirmed infection in the past several days.
"They get that call, they go get tested, and the test is negative," Anderson said. "They go back to work, then all of a sudden five days later they start feeling crappy. They get tested again, and it's positive. We have heard that time and time again."
On Sunday the county public health department reiterated the safety precautions that have been suggested for the past several months:
— Limit social gatherings.
— Stay home if ill.
— Have one person complete your shopping.
— Wash your hands.
— Do not touch your face.
— Cover coughs and sneezes.
— Practice social distancing.
— Wear a mask if you cannot maintain social distancing.
Anderson said many residents are not taking the new coronavirus as seriously as they should, and that's partly because western Iowa was shut down too early, before significant spread of the virus started here.
The majority of restrictions on businesses and social gatherings have been lifted in recent weeks, including those that forced restaurants to operate at half capacity for in-person dining. The most severe restrictions were effective while Carroll County had just a handful of confirmed cases.