During the first week in August 1938 an outbreak of equine encephalomyelitis causing the death of more than 200 horses occurred in southeastern Massachusetts and Rhode Island. August 12 a girl aged 12 years was referred to the Haynes Memorial Hospital with a diagnosis of epidemic cerebrospinal meningitis. On admission a provisional diagnosis of encephalitis was made. Seven hours after admission the patient suddenly died. At autopsy the diagnosis of encephalitis was confirmed. No virus studies were made on the brain. Seventeen days later, August 29, a boy aged 13 years was admitted from the same city, presenting much the same clinical picture. In view of the existing epidemic of equine encephalomyelitis in the same area, the spinal fluid obtained from the lumbar puncture was injected into mice but the results were inconclusive. Death occurred twenty hours after entry. Unfortunately permission for an autopsy was not granted.
Similar cases continued
WESSELHOEFT C, SMITH EC, BRANCH CF. HUMAN ENCEPHALITISEIGHT FATAL CASES, WITH FOUR DUE TO THE VIRUS OF EQUINE ENCEPHALOMYELITIS. JAMA. 1938;111(19):1735–1741. doi:10.1001/jama.1938.02790450017005