Island boards of health reported one new case of Covid-19 on Monday, bringing the Vineyard’s total coronavirus caseload to 96 as Nantucket continued to see a spike in case numbers, particularly among landscape workers.

The new Covid-19 patient tested positive off-Island, according to Tisbury health agent Maura Valley — at least the fourth individual so far to do so.

“The new positive case is an individual tested off-island reported positive on Friday,” Ms Valley wrote in an email.

There are now likely four active cases on the Island, including three from last week. A fourth case reported last week was transferred to an off-Island board of health and has since been completed, according to Ms. Valley.

A total of 72 individuals have now tested positive for the virus via laboratory testing; 27 male and 45 female. The new positive individual is a male in his 20s, according to a daily demographic report from the boards of health.

Another 24 individuals have tested positive for viral antibodies or been symptomatically diagnosed with the virus, bringing the total Covid caseload to 96.

In the update, the boards of health reported that TestMV, which continues to test asymptomatic patients for the virus, has tested 13,511 patients since the pandemic began, with 26 tests coming back positive and 502 still pending.

The Martha’s Vineyard Hospital, which is testing symptomatic patients and their close contacts for the virus, has now tested 4,481 patients for the virus, with seven tests pending.

Meanwhile, across the Muskeget Channel, Nantucket’s precipitous rise in case numbers continued Monday, with the Nantucket Cottage Hospital reporting five more positive cases over the weekend. The island has now had 30 people test positive in the last six days, prompting officials to move schools to all remote learning and close some public parks.

At an emergency board of health meeting held Monday morning, Nantucket health agent Roberto Santamaria termed the rise in cases a “September surge” and indicated that most of the new cases came from workers in the landscaping, cleaning services and construction fields. He said the individuals likely spread the virus over Labor Day weekend, leading to the large case numbers this week.

“We now know that there were spreader events that happened over Labor Day,” Mr. Santamaria told the board of health. “We knew we would see an uptick in cases caused by Labor Day, that was expected. But in this case a lot more people presented than expected.”

Both the Vineyard and Nantucket instituted temporary construction moratoriums back in April when case numbers peaked in Boston. Mr. Santamaria said Nantucket would be increasing its public awareness and mask enforcement, and would consider further measures if case numbers continued to increase.

He said none of the cases were in the food, retail, hotel or movie theater businesses. The Vineyard has thus far not reported any sustained outbreaks among certain employment groups.

No individuals are currently hospitalized with the virus on either Nantucket or Martha’s Vineyard, according to the two hospital websites. While Vineyard hospital officials have stated that they have approximately five to seven available ventilators, Nantucket only has three. Both Islands have had to transfer sick Covid-19 patients to Boston earlier in the year.

“When we look at enforcement, we want to reach out to the landscaping community, which is the primary hit community, as well as cleaning and construction closely behind that,” Mr. Santamaria said. “We’re going to see more cases . . . we’re just trying to slow down the onslaught.”