A Maynard resident was recently diagnosed with the Powassan virus, a deadly tick-borne illness, according to Town Administrator Greg Johnson and the Maynard Public Health Division.According to the Centers for Disease Control and Prevention, Powassan virus is rare but often severe. The virus can cause encephalitis, a potentially fatal swelling of the brain, or meningitis, inflammation of the membranes surrounding the brain and spinal cord that can be life-threatening. The number of reported cases of Powassan virus has increased in recent years. Massachusetts had 22 cases between 2009 and 2018, the third-highest total in the country."We haven't seen a lot of cases in the past, but over the past five years or so, especially Massachusetts and a few other states have been seeing an increasing number of cases," said Dr. Todd Ellerin, the director of infectious diseases at South Shore Health.The Maynard Board of Health did not release any information about the patient's condition. Most cases start with a fever, headache, vomiting and weakness."Most people who acquire Powassan actually remain asymptomatic," Ellerin said.The Powassan virus can only be spread to people by bites from infected ticks. But unlike other tick-borne diseases, it can be transmitted to a person in just 15 minutes. For comparison, it can take 36 to 48 hours for a tick to transmit Lyme disease to a person."There are very few medications that we have to treat viruses in general, and for Powassan virus specifically, we have no specific antidote," said Dr. Jennifer Lyons, of Brigham and Women's Hospital.Although tick bites can happen at any time of the year, they are especially prevalent from April to September.Public health officials say the best protection against the Powassan virus is prevention. Daily tick checks are recommended, as well as using bug repellent that contains at least 20% DEET when going outside.