The turkeys found dead in Edgartown earlier this month have preliminarily tested positive for avian flu, marking the first cases known to be on the Island.

The Edgartown board of health on Friday said that MassWildlife has indicated that the samples taken from the flock were positive, prompting the samples to be sent to a federal lab for further testing.

Islanders have been on high alert for the pathogenic avian influenza since the 20 dead turkeys were found in the Smith Hollow neighborhood of Edgartown. Farmers especially have been concerned about their flocks.

It could take weeks to get results back from the federal testing labs for the Edgartown turkeys, which would officially confirm the disease. 

Since the first turkeys were found over the weekend starting Jan. 31, about 10 more turkeys in the same flock have been found dead, according to Brice Boutot, the Edgartown health agent. 

A blue jay in the area has also preliminarily tested positive, Mr. Boutot said. 

Martha’s Vineyard boards of health, along with the state Department of Public Health and Department of Agricultural Resources, are urging Islanders to take precautions for bird flu. 

They also emphasized that there are no human cases of avian flu reported in Massachusetts, and there is minimal risk of human infections for people who do not engage in direct contact with infected animals. 

Health officials recommend Islanders not feed wild birds and remove birdfeeders, birdbaths or anything else that encourage wild birds to congregate. 

Pets should also be kept away from sick or dead birds, and poultry flocks should be kept apart from wild birds. 

Sick and dead birds can be reported to mass.gov/reportbirds