Powassan virus, which can cause a potentially life-threatening infection, is transmitted by three types of infected tick, including the deer tick that transmits Lyme disease. Powassan virus cannot spread from person to person.
“The division has no confirmation that Powassan virus was the cause of death for any Sussex County resident,” said James R. McDonald III, division director and health officer for the county’s Department of Health and Human Services.
The symptoms caused by this neuroinvasive disease can include fever, headache, swelling of the brain (encephalitis), swelling of the membranes that surround the brain and spinal cord (meningitis), vomiting, weakness, confusion, loss of coordination, trouble speaking and memory loss. However, many infected people never develop symptoms.
Most US cases occur in the late spring, early summer and mid-fall, when ticks are most active. Warmer winters have led to an increased tick population, so experts predict rising tick-borne infections of many types.
No treatment for Powassan virus
There are no vaccines to prevent and no medicines to treat Powassan infection. McDonald noted that the tick must be attached, not just crawling on your skin, for illness to be transmitted.
“About 15% of patients who are infected and have symptoms are not going survive,” said Lyons, who is also an assistant professor of neurology at Harvard Medical School. “Of the survivors, at least 50% will have long-term neurological damage that is not going to resolve.”
Although most infected people will never show symptoms, those who become sick usually do so a few days to about a week after the tick bite, she said. Symptoms can begin as late as a month after a tick bite transmits the virus. The most common symptoms will be fever and headache. “You basically feel nonspecific flu-like stuff,” Lyons said, including “muscle aches and pains; maybe you have a little rash on your skin, but almost certainly, you’ll have a fever and the headache.”
The unlucky few who develop a more serious illness will do so “very quickly over the next couple of days,” she said. “You start to develop difficulties with maintaining your consciousness and your cognition. … You may develop seizures. You may develop inability to breathe on your own.”
People with severe Powassan virus disease often need to be hospitalized to receive support with breathing and swelling in and around the brain, according to the CDC.
If a person has other medical conditions, they are at greater risk for developing complications from the Powassan virus, the Sussex County health department warned: “It is important to seek medical attention if symptoms develop.”
Preventing tick-borne diseases
“Inspect yourself when outside, and shower immediately upon coming back in to find and remove ticks,” McDonald said.
The Powassan virus was first discovered in Ontario in 1958. “A kid came down with an unspecified encephalitis” or brain inflammation, Lyons explained. When the previously unseen virus was identified, the scientists called it Powassan after the town where the child lived. Only a couple of cases were seen each year from the 1950s to the early 2000s, when reports of cases in Canada and the United States started to rise.