Researchers recently found Powassan virus infected ticks in Bridgeport and Branford, Connecticut [1, 5-6]. Although the virus had already been reported in neighboring states -- New York, New Jersey, Massachusetts and Maine -- it had not yet been found in Connecticut . There have been no reported human infections of Powassan virus in Connecticut, but Dr. Theodore Andreadis from the Connecticut Agricultural Experiment Station, warns that human cases will soon follow . Dr. Andreadis and his team are currently conducting a study of ticks to determine the prevalence of the virus within the state .
What is Powassan Virus & Why the Alarm?
Powassan Virus is an emerging infectious disease related to the West Nile virus. Its life cycle requires transmission between certain rodents and specific species of ticks . The virus can be transmitted to humans through the bite of an infected tick [1-6]. Similar to West Nile Virus, humans are a dead-end host for the disease . This means that if an uninfected tick bites an infected human, the tick will not become infected. This is because the concentrations of the virus in the human’s bloodstream are not high enough for a feeding tick to become infected. The incubation period is highly variable, spanning from one week to one month [1,2]. Although not all infected individuals show signs of infection, common symptoms include headache, fever, vomiting, confusion, seizures, and memory loss [1,2]. Powassan virus can also infect the central nervous system, resulting in serious neurological diseases such as encephalitis (inflammation of the brain) and meningitis (inflammation of the brain and spinal cord membranes) [2,5-6].
So why are health authorities worried after discovering virus-infected ticks in Connecticut?
Apart from the fact that the disease had never been seen in Connecticut, people are worried because there is no available vaccine and no medical cure for the Powassan virus [1-6]. Furthermore, unlike Lyme disease where the infected tick needs to feed for at least 24 hours before infection can occur, with Powassan virus, the tick only needs to feed for one to two hours for the virus to be transmitted [2,6]. Health officials are also concerned because roughly 10% of Powassan virus encephalitis cases end in death and approximately 50% of infected individuals will have permanent neurological symptoms [2,6]. These include recurrent headaches, muscle wasting, and memory loss [1-2]. Lastly, although the disease is rare, there has been an increase in reported cases within the Untied States over the past few years [2,6].
In the United States, Powassan Virus is primarily found in the northeastern states and the Great Lakes region . Since the disease is spread by ticks, cases occur in late spring and early summer, when ticks are most active . Therefore Connecticut residents and visitors should be extra cautious of tick bites during the warmer months of April through September.
Prevention methods are similar to those for mosquito-borne diseases. This includes avoiding contact with ticks, wearing protective clothing (long sleeves and pants), using repellents, and conducting thorough tick-checks following outdoor activities [2,5]. The CDC provides detailed instructions on how to properly remove an embedded tick .