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Volume 32, Number 4—April 2026

CME ACTIVITY - Synopsis

Pediatric Meningoencephalitis Cluster Caused by Snowshoe Hare Virus, Whistler, British Columbia, Canada, 2024

Faisal Ali, Miguel Imperial, Muhammad Morshed, David M. Goldfarb, Jonathan B. Gubbay, Catherine A. Hogan, Rohit Vijh, Ellie N. Andres, Marta Jaeckel, Jaskiran Sajan, Heidi Wood, Alyssia Robinson, and Jennifer TamComments to Author 
Author affiliation: University of British Columbia, Vancouver, British Columbia, Canada (F. Ali, M. Imperial, M. Morshed, D.M. Goldfarb, J.B. Gubbay, C.A. Hogan, R. Vijh, J. Tam); Children’s & Women’s Health Centre of British Columbia, Vancouver (F. Ali, M. Imperial, D.M. Goldfarb, J.B. Gubbay, J. Tam); British Columbia Centre for Disease Control, Vancouver (M. Morshed, C.A. Hogan); Vancouver Coastal Health Public Health Surveillance Unit, Vancouver (R. Vijh, E.N. Andres, M. Jaeckel, J. Sajan); National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada (H. Wood, A. Robinson)

Main Article

Table

Clinical and demographic characteristics of patients in cluster of pediatric meningoencephalitis cases caused by snowshoe hare virus, Whistler, British Columbia, Canada, 2024*

Characteristics
 Case 1
 Case 2
 Case 3
Patient age, y/sex
 12/F
 3/F
 2/M
Clinical manifestations
 5-d history of headaches, neck stiffness, photophobia, and emesis; afebrile
 4-d history of fever and decreased energy; multiple hemiclonic focal seizures and subsequent Todd’s paresis on day 4 of illness
 5-d history of fever, lethargy, and vomiting; bradycardia at admission
Medical history
 No underlying conditions
 History of mild hypoxic ischemic encephalopathy and previous seizure
 Premature birth at 29 weeks’ gestation
Acute CSGV serology 8 d after symptom onset 5 d after symptom onset 13 d after symptom onset
IgM immunoassay
SSHV Reactive Reactive Reactive
JCV Reactive Nonreactive Reactive
PRNT
SSHV 1:1,280 1:80 1:2,560
JCV
 1:640
 1:40
 1:640
Convalescent CSGV serology 6 wks after acute serology 4 wks after acute serology 2 wks after acute serology
IgM immunoassay
SSHV Reactive Reactive Reactive
JCV Reactive Reactive Reactive
PRNT
SSHV 1:640 1:2,560 1:1,280
JCV
 1:320
 1:640
 1:640
CSF testing† 6 d after symptom onset 11 d after symptom onset 6 d after symptom onset
NCC, × 106 cells/L (% lymphocytes) 250 (74) 12 (74) 112 (38); 51% neutrophils‡
Glucose, mmol/L 4.0 3.0 3.6
Protein, g/L
 0.66
 0.31
 0.36
Head and brain imaging
CT Unremarkable ND Unremarkable
MRI Unremarkable Abnormal signal in the right perirolandic cortex, right insular cortex and bilateral thalami, with scattered areas of sulcal enhancement ND

*CSF, cerebrospinal fluid; CSGV, California serogroup virus; CT, computed tomography; JCF, Jamestown Canyon virus; MRI, magnetic resonance imaging; NCC, nucleated cell count; ND, not done; PRNT, plaque reduction neutralization test; SSHV, snowshoe hare virus. †Reference ranges: NCC <10 × 106 cells/L; glucose 2.8–4.4 mmol/L; protein 0.14–0.42 g/L. ‡Reference <6%.

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Page created: February 20, 2026
Page updated: April 10, 2026
Page reviewed: April 10, 2026
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