Pima County can expect a significant increase in COVID-19 cases within the next few weeks, according to Dr. Bob England, interim director for the Pima County Health Department. England's comments came hours after the third presumptive case was announced in the county, which he believes is the start of a communal spread of the virus.

"I suspect there are several intersections of people with mild illness, maybe people who don't even know they're sick at all, walking around in the community," Dr. England said. "That's why we're stressing so much about individual behavior about washing our hands and keeping our hands away from our face."

Today's case is the first in Arizona discovered by a commercial laboratory after Sonora Quest and LabCorp. were approved to begin screening for the virus in early March, said England. He hopeful the private labs will help give an accurate view as to how many COVID-19 cases the county is actually dealing with. Previously, testing was being done by state health officials, who have been working with narrow criteria for testing because for most of last week, they had only a few hundred test kits.

"Here's the point: The virus is probably circulating in the community already from person to person, causing illness that is mild enough that (don't meet the criteria for) getting tested," England said. "Having private labs available helps a lot because now it can be an individual's health care provider can decide whether or not you should be tested."

England said he does worry that even the third-party labs will eventually become overloaded due to the demand.

"I am worried that even with the private (lab's) aren't going to have the capacity to handle the demand if everybody wants to a whole lot of testing at once," England said.