Republican state leaders in Wisconsin on Tuesday filed a lawsuit against the Democratic governor Tony Evers, challenging his stay-at-home order to contain the coronavirus outbreak.

The issue of when to re-open state economies has on occasion put Donald Trump at odds with his own top public health officials and federal guidelines.

Trump has pressed for a swift lifting of restrictions put on social and business activities across the US and last week spoke of rightwing backed protesters against stay-home orders as “responsible people”, in a highly unusual move to encourage civil disobedience in violation of government guidelines amid a national emergency.

The lawsuit asks the Wisconsin supreme court to issue a temporary injunction on the state’s order that was extended until 26 May by the Wisconsin department of health services secretary last week at the direction of the governor.

Meanwhile, health officials in Wisconsin said they have identified at least seven people who may have contracted the coronavirus from participating in the 7 April primary and supreme court seat election in the state.

These are the first such cases following Wisconsin’s controversial decision to go ahead with in-person voting amid a pandemic, despite widespread concern about the public health risks.

The infections involve six voters and one poll worker in Milwaukee, where difficulty finding poll workers forced the city to pare nearly 200 voting locations back to just five, and where voters – some in masks, some with no protection – were forced to wait in long lines for hours.

It is not certain that the seven people contracted the virus at the polls. The possible connection was made because local health officials are now asking newly infected people whether they participated in the election.

“It means they were at the polls, which is a potential exposure, but [we] can’t say they definitely got it at the polls,” said Darren Rauch, the health officer/director for suburban Greenfield, and one of the health officials helping with the coronavirus response in the Milwaukee area.

Milwaukee officials are still gathering information from about 70% of people who have tested positive since the election.

The election, which included a presidential primary as well as a state supreme court race and local offices, took place after a legal struggle between Democrats and Republicans.

Thousands of Wisconsin voters stayed home, unwilling to risk their health and unable to be counted because requested absentee ballots never arrived.

Democrats and voting rights groups have filed lawsuits to expand mail and absentee voting options, and pushed for an extra $2bn to help states adjust their election systems. National Republicans are fighting those efforts, while Donald Trump claims without evidence that mail-in voting is vulnerable to fraud.