[West Nile virus meningomyeloencephalitis--value of interferon assays in primary encephalitis].

A 68 year-old woman contracted West Nile fever after a stay of one month in Israel. Mild encephalitis and severe myelitis, resembling the "polio syndrome", developed, with important sequelae. Specific antibodies against West Nile fever virus progressively increased in the patient's serum. Epidemiological and clinical data about neurologic aspects of this infection are reviewed. Meningoencephalitis is not unusual, but only one previous case of acute anterior myelitis has been described in humans although this pathology is well known in experimental and veterinary diseases. Very few studies concern interferon and arbovirus infections in humans. Interferon assays in our patient's serum and cerebrospinal fluid showed its presence and persistence: this is in relation with the replication of the virus in the central nervous system, as it has been demonstrated in other primary viral encephalitis.