Local officials in Massachusetts have issued warnings about mosquitoes carrying eastern equine encephalitis (EEE), and, in one case, placed restrictions on the use of public fields at night, prompting backlash from some residents.

Public health experts, and others, are also concerned that such mosquito-borne viruses could become more common in the United States because of the climate crisis.

Some Massachusetts residents are particularly worried about a potential repeat of the Covid-19 pandemic restrictions – like limits on outdoor youth sports – which were also implemented during a 2019 outbreak of EEE.

“This fall season is so important because we are coming off of Covid restrictions and everyone not being able to play and participate, and finally feeling safe enough to be together in large crowds,” said Jennifer Voas, an Oxford, Massachusetts, resident and mother of two who started a petition urging the local health department not to adopt certain restrictions.

“It was very important that we could work with the town to maintain safety of all of our participants and our spectators and our parents, while also trying to maintain a season.”

EEE is a rare virus that spreads to people through mosquito bites. In the United States, the virus is more common in eastern and Gulf coast states, but only a few cases are reported each year, according to the Centers for Disease Control and Prevention.

About 30% of people who contract the virus die, and survivors often face ongoing neurological issues. There are no vaccines against mosquito-borne viruses, so the best way to protect against them is by avoiding bites.

“We don’t have vaccines for humans for any of these viruses, and we basically rely on vector control, monitoring mosquitoes, putting insecticide on and telling people not to go out after dusk and to wear Deet, but it’s not a perfect solution,” said Dr Arthur Reingold, epidemiology professor at the University of California, Berkeley School of Public Health.

There were 12 human cases of EEE in Massachusetts and six deaths in 2019. Oxford officials responded to the outbreak by canceling all outdoor activities on municipal properties from 6pm to 6am, the time when there is the greatest mosquito activity. Freetown, another Massachusetts town, also closed public spaces from dusk to dawn, according to CNN.

This year, a number of states, including Massachusetts, New Hampshire, New Jersey and Vermont have reported cases of EEE. On Tuesday, the New Hampshire public health department reported that an adult who was hospitalized with the virus had died.

A family member of a person reported to have EEE in Massachusetts contacted the city of Oxford to share his identity – as he was well known locally – because of concern “that people might not take it as seriously as they should”, said Jennifer Callahan, Oxford town manager. (That person is out of the critical phase of the infection but has “a long road to recovery”, she said.)

Voas, an Oxford resident for nine years, created the petition in opposition to rumored restrictions before an 21 August health board meeting.

“This is not a safety concern or issue, as EEE can be mitigated to a safe level. This is about our ability to continue playing on the fields,” Voas wrote in the petition, which received almost 900 signatures.

Callahan, the town manager, then issued a public letter informing residents that the health board was considering limiting access to outdoor recreation facilities and requiring private leagues to file an indemnification form and proof of “adequate insurance” should they continue to use public properties and not follow the health department’s recommendations.

More than 70 people attended the board’s meeting 21 August to express their concerns about potential restrictions. The local government ultimately approved a measure to require leagues to sign the waiver to use the fields after 6pm.

The health departments in Oxford and three surrounding towns also issued an advisory recommending that residents wear insect repellent and long sleeves and pants and end outdoor activities before 6pm through 30 September and before 5pm starting 1 October.

Local leagues instead wanted to be able to use the fields until 30 minutes before dusk, Voas said, which at this time of year, would mean shutting down around 7.30pm.

The extra time is important because families have work and school and practices often don’t start until 5.30 or 5.45pm, she added.

“It’s just not feasible. It would ruin our season,” said Voas, whose son plays football.

The leagues are negotiating with the local government to revise the indemnification form to ensure it’s “fair to all parties”, Voas said. In the meantime, teams are continuing to practice until 7.30pm.

Callahan said the city is just trying to educate people about the threat posed by the virus, urge them “take precautions as best as possible” and ensure they have filed the proper paperwork.

“No one has ever said we’re banning anything, anything, and we’re not curfewing anyone,” said Callahan.

Voas said that while some people at the public meeting and online have become really upset, she thinks the health board does have good intentions.

“Obviously you don’t want anyone to get this. This is a very deadly disease,” she said.

Both the youth sports league leaders and health officials are now considering what the future could hold for outdoor events should mosquito-borne viruses become more common. The climate crisis and warmer temperatures could “accelerate mosquito development, biting rates, and the incubation of the disease within a mosquito”, the Environmental Protection Agency reports.

“The entire infectious diseases community has been thinking about this,” said William Schaffner, an infectious diseases expert at Vanderbilt University school of medicine. “The occurrence this summer is, of course, a bit of a surprise, but I think many of my colleagues and I are probably saying, ‘Aha, here it comes.’”

Despite that threat, Reingold, the Berkeley epidemiologist, said it would be difficult to develop and implement a vaccine because the diseases remain rare, so conducting a trial to see if they are effective would be hard. Additionally, some people have lingering concerns about vaccine safety in the wake of the pandemic, so it’s not clear how many of them would get a vaccine.

Relying on pesticides and mosquito controls in the United States is “probably a pretty reasonable strategy”, Reingold said.

Leaders of local leagues have started to discuss what changes they might need to make, including potentially moving some sports indoors.

“I don’t think this is just going to go away,” Voas said. “We’re not angry; we’re not here with pitchforks and axes. We’re just human beings at the end of the day trying to do what’s best for our community and our children.”