Vancouver: Encephalitis cluster reported in the Whistler area due to Jamestown Canyon/Snowshoe Hare Virus
Vancouver: Encephalitis cluster reported in the Whistler area due to Jamestown Canyon/Snowshoe Hare Virus
Vancouver Coastal Health (VCH) reported recently to Physicians and Nurse Practitioners, a cluster of three pediatric cases of encephalitis with onset of symptoms in August 2024.
The three patients tested positive for Jamestown Canyon/Snowshoe Hare Virus and are residents of Whistler, British Columbia (BC).
Jamestown Canyon virus (JCV) and Snowshoe Hare Virus (SSHV) are mosquito-borne viruses that belong to the California serogroup in the Bunyaviridae family. They have a similar life cycle and clinical presentation to West Nile Virus.
JCV/SSHV have been identified in BC and across Canada for decades, but reports of human illness are rare. Prior to this cluster, ten cases of JCV/SSHV had been reported in BC since 2009, two in the VCH region.
Most infections with JCV/SSH are asymptomatic. Symptoms can range from fever, headache and vomiting to more severe presentations with high fever, meningeal symptoms, tremors, and occasionally seizures (especially in children). Neuroinvasive presentations are clinically indistinguishable from other viral causes of aseptic meningitis and encephalitis. Rarely, acute flaccid paralysis can occur. Severe infections may result in various sequelae such as behavior changes, learning disabilities, and cognitive deficits. Neuroinvasive presentations in adults are more commonly from JCV virus and in children from SSHV.