The Department of Health and Senior Services is testing people meeting criteria established collegially with the federal Centers for Disease Control and Prevention (CDC). Those criteria include testing blood and/or spinal fluid samples from people with a fever greater than 100 degrees and with altered mental status and with elevated levels of protein in their spinal fluid and/or with muscle weakness. Together, these symptoms are compatible with encephalitis, which can be caused by a number of viruses, including West Nile. Only a West Nile test can confirm or rule out West Nile virus infection. One should not assume that just because someone is being tested for West Nile they have the virus.