Powassan virus in the northeastern USA

On 21 August 2023, the Connecticut Department of Public Health reported 4 cases of Powassan virus infection. The Rhode Island Department of Health has also reported one death from Powassan virus infection in July 2023. The Centers for Disease Control and Prevention (CDC) has reported a further 11 cases in the north-eastern USA  as of 15 August 2023.  

Powassan virus is transmitted to humans through tick bites and occurs in the northern USA, Canada and Russia. Transmission is during the tick season which runs from late spring until autumn. Symptoms can include a mild or flu-like illness, and in some cases lead to more severe neurological disease.

Advice for Travellers

Travellers to endemic areas should be aware of the types of activities that increase tick exposure, such as walking, hiking, camping, cycling or fishing in forested areas during tick season and be advised to:

• avoid consuming unpasteurised dairy products
• avoid tick bites by use of insect repellents and appropriate clothing (e.g. long trousers tucked into socks, closed footwear)
• inspect their whole body for ticks daily after outdoor activities, and remove any ticks as early as possible

No vaccine against Powassan virus is available.

For further information, see the Insect Bite Avoidance page.