New tick-borne illness is deadlier than Lyme disease

By John Murphy, MDLinx
Published June 27, 2019

Key Takeaways

Armand Desormeaux, of Hampton, NJ, was an active 80-year-old—until he developed a fever in early May 2019. Then he began to experience tremors and was unable to verbalize. Desormeaux died in the hospital 10 days later. What caused such a tragic condition in an otherwise healthy man? It was an uncommon virus from the bite of a tiny tick, the New Jersey Department of Health confirmed.

It’s a rare but deadly pathogen known as the Powassan virus, and it’s spread by the deer tick (Ixodes scapularis, aka the black-legged tick)—the same tick that infects people with Lyme disease. But unlike Lyme disease, there’s no effective treatment for the devastating Powassan virus. It’s fatal in 15% of people who are infected. Of those who survive, 50% end up with permanent neurological damage.

Incidence is increasing

Infections have been rare, but they’re becoming more common.

“There has been an important change in the ecology of Powassan virus in that the deer tick has recently become infected with the virus. Until a few decades ago, it was only transmitted by a tick species [Ixodes cookei, aka the groundhog tick] that does not commonly bite humans and human cases were extremely rare,” explained Durland Fish, PhD, professor emeritus of Epidemiology, Yale School of Public Health, New Haven, CT. “This recent change in the ecology of Powassan virus has caused concern within the public health community.”

Because deer ticks are now able to infect humans with the virus, more cases are being reported in areas where they haven’t occurred before. “As the geographic range of Lyme disease expands, so will Powassan,” Dr. Fish predicted.

Since 2008, the number of reported cases has averaged about 10 per year. But the numbers are rising, with 21 cases in 2016 and 32 cases in 2017 (the most recent year data are available).

Most US cases of Powassan virus have occurred in the Northeast and Great Lakes states, primarily in the late spring, early summer, and mid-fall when ticks are most active. From 2008 through 2017, cases have been reported in Minnesota (32), Wisconsin (22), Massachusetts (16), New York (16), New Jersey (7), Maine (6), Pennsylvania (5), New Hampshire (3), Rhode Island (3), Connecticut (1), North Carolina (1), North Dakota (1), and Virginia (1).

“There are currently no practical methods to control the spread of deer ticks or Lyme disease, and this is also true for Powassan virus,” Dr. Fish said. “Nothing can be done to prevent it from expanding into new areas, and human cases are expected to increase as more people become exposed to infected ticks.”

Signs and symptoms

Unlike Lyme disease, Powassan infection has no telltale bullseye rash at the site of the tick bite. Fortunately, most people who are infected never show any symptoms. But for those who do, the incubation period is quick, and symptoms usually develop within a few days to about a week or so after the tick bite.

The most common symptoms are fever and headache. Others include vomiting, weakness, confusion, loss of coordination, speech difficulties, and seizures. In more serious cases, Powassan can cause potentially fatal encephalitis and meningitis.

The virus cannot be transmitted from one human to another.

Healthcare workers are required to report all cases to the local health authority. (For more information on testing and reporting Powassan virus, see the CDC website.)

Treatment and prevention

There is no vaccine to prevent the virus and no specific remedy for it. Treatment is generally supportive and often involves hospitalization for serious cases.

Currently, the best “cure” is an ounce of prevention, according to the CDC. Simply put, stay away from ticks.

More specifically:

  • Avoid wooded and brushy areas with high grass and leaf litter.
  • Walk in the center of trails.
  • Prevent ticks on exposed skin using repellent that contains 20% or more DEET, picaridin, or IR3535, which provide several hours of protection.
  • On clothing, shoes, tents, and gear, use products that contain 0.5% permethrin. This remains protective through several washings.
  • Within 2 hours of being outdoors, bathe or shower to wash off and find ticks on your body.
  • Conduct a full-body tick check. Check children thoroughly, especially their hair. Also examine pets, clothing, and gear.

“As more ticks become infected with Powassan virus and more people become exposed to them, Powassan could become epidemic like Lyme disease,” Dr. Fish warned. “Because it can be a serious disease, causing fatalities, and [because] there is no treatment for it, Powassan has the potential to become a greater public health threat than Lyme disease.”

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