Tick-Borne Powassan Virus Is On the Rise: What Your Patients Should Know

Chances are, when your patients think of tick-borne illnesses, they think of Lyme disease. This stands to reason, as Lyme disease is the most common and widespread tick-borne illness in the United States.¹

However, another illness spread by ticks is emerging: Powassan virus (POWV). Cases of POWV have increased from 2 in 2008 to 33 in 2017.² Recently, 2 cases were confirmed in New Jersey. One of the infected individuals has died, although it’s not clear whether POWV was directly responsible.³

Your patients may have questions about the tick-borne virus. Here’s what they should know.

Transmission

As is the case with Lyme disease, POWV is contracted through the bite of an infected tick.⁴ However, unlike in most cases of Lyme disease, the tick doesn’t attach to the body for 36 to 48 hours before the bacterium can be transmitted⁵; humans can become infected with POWV as soon as 15 minutes after the tick latches on.⁶

Management

Most people who are infected with POWV do not develop any symptoms. Those who do typically experience fever, vomiting, headache, weakness, loss of coordination, confusion, difficulty speaking, and/or seizures. The incubation period for POWV ranges from 1 week to 1 month.⁷

POWV affects the central nervous system and can cause encephalitis and meningitis. Approximately 1 in 10 cases is fatal. In some cases, patients experience permanent neurologic symptoms such as memory problems and recurrent headaches.⁷

There are no medications or vaccines available to treat or prevent POWV infection.⁷

Prevention

Like with Lyme disease and other tick-borne illnesses, the best way to prevent POWV infection is to avoid exposure to ticks. Advise your patients to avoid areas that harbor ticks and, if they do go in these areas, take preventive measures including⁸:

• Wearing long sleeves and long pants with socks pulled up over the bottom of the pant legs;
• Wearing light colors that make it easier to spot ticks on clothing;
• Using insect repellants; and
• Performing a tick check upon returning inside.

The Future

Although POWV is rare, the number of cases in the United States is slowly creeping up. Some researchers suggest this trend might continue as a result of changes in climate. “With the projected impact of climate change on tick populations, increases in the number of human cases are expected.”⁹

References

1. Tick-borne diseases. Centers for Disease Control and Prevention. Reviewed September 22, 2011. Accessed June 14, 2019.
2. Powassan virus: statistics & maps. Centers for Disease Control and Prevention. Reviewed December 4, 2018. Accessed June 14, 2019.
3. Officials: dead NJ man had rare illness spread by tick bite. CBS New York. June 11, 2019. Accessed June 14, 2019.
4. Powassan virus: transmission. Centers for Disease Control and Prevention. Reviewed December 4, 2018. Accessed June 14, 2019.
5. Lyme disease: transmission. Centers for Disease Control and Prevention. Reviewed February 6, 2019. Accessed June 14, 2019.
6. Powassan virus. Columbia University Irving Medical Center. Accessed June 14, 2019.
7. Powassan virus: symptoms & treatment. Centers for Disease Control and Prevention. Reviewed December 4, 2018. Accessed June 14, 2019.
8. Shiffer E. What is Powassan virus? This tick-borne illness can cause fatal swelling of the brain. Health. May 28, 2019. Accessed June 14, 2019.
9. Corrin T, Greig J, Harding S, Young I, Mascarenhas M, Waddell LA. Powassan virus, a scoping review of the global evidence [published online June 17, 2018]. Zoonoses Public Health. 2018. doi:10.1111/zph.12485