State officials said four Connecticut residents tested positive for the tick-borne Powassan virus (POWV).

The four cases, two men from Middlesex and Litchfield counties and two women from Windham and Litchfield counties, are the first “POWV-associated illness” identified in the state this year. All patients are 50+ years old.

All four patients were hospitalized with central nervous system problems, but have been discharged and are recovering.

Health officials say Powassan virus is spread via “the bite of an infected black-legged, or deer tick.” It takes up to a month after being bitten to develop symptoms of POWV, and the virus can be transmitted in as little as 15 minutes after the tick attaches.

Health officials said many people infected with POWV don’t experience symptoms that are any more than mild, but some will develop severe issues that hit the nervous system. They say one in 10 severe cases are fatal, while half who survive the severe cases experience long-term problems.

Severe case symptoms might include fever, vomiting, headache or weakness, which can then lead to confusion, coordination loss and seizures.

From 2016 through 2022, 19 POWV cases were reported, including six last year. Two people died from POWV illness in 2022.