Polio-like motor paralysis associated with acute hemorrhagic conjunctivitis in an outbreak in 1981 in Bombay, India: clinical and serologic studies.

High and rising neutralizing antibody titers (NATs) to enterovirus type 70 (EV70) were detected in the serum and cerebrospinal fluid (CSF) of patients with polio-like motor paralysis accompanying acute hemorrhagic conjunctivitis (AHC) in an outbreak of AHC in 1981 in Bombay, India. Fifty-four (88.5%) of 61 patients with AHC with or without neurologic disease had serum NATs of greater than or equal to 1:16, and some paired sera from these patients showed significant increases in NAT. Serum from noninfected control subjects had no significant neutralizing antibody to EV70. Thirty-six (94.7%) of 38 CSF specimens from 30 patients with spinal or a combination of spinal and cranial motor paralysis associated with AHC had NATs ranging from 1:2 to 1:256. No neutralizing antibody was found in CSF specimens from patients with AHC alone or in those from non-infected control subjects, and a reduced ratio of serum NAT to CSF NAT was detected in patients with neurologic disease. Therefore, it is highly likely that intrathecal synthesis of antibody occurred in response to direct invasion of the central nervous system by EV70. The results represent strong laboratory evidence of the neurovirulence of EV70.