JACKSON, Miss.—In 2002, Methodist Rehabilitation Center researchers were the first to report that West Nile virus can attack the motor cells of the spinal cord, causing fatigue, muscle weakness and a polio-like paralysis, and the first to confirm those findings through autopsy results.

Now they are collaborating with colleagues at the University College of London in the United Kingdom to learn more about the severity of neurological injury associated with West Nile virus infection.

“We’re taking samples of spinal fluid from people who suffered either from West Nile virus fever, meningo-encephalitis or polio-like paralysis and sending them to London for analysis,” said Dr. Dobrivoje Stokic, director of Methodist’s Center for Neuroscience and Neurological Recovery (CNNR). “Our focus is on the proteins released in the cerebral spinal fluid as a consequence of injury. These biomarkers reflect damage to different parts of the nervous tissue. By studying these biomarkers, we hope to determine whether they relate to the severity of both the initial and long-term neurological injury.”

This investigation comes on the heels of a CNNR study on 33 West Nile virus survivors that was funded by an $82,000 grant from the Mississippi State Department of Health and the Centers for Disease Control and Prevention. The study examined the outcome of two groups: patients who experienced muscle weakness during the acute stage of the illness and those who didn’t.

“We wanted to know what kind of recovery had taken place during the year after the initial infection so that we could compare it to their evaluation soon after they were infected,” Dr. Stokic said.

Stokic said preliminary results of the study reveal that lasting fatigue affected about half of the study participants. About 1 in 5 said fatigue was severe enough to impact their daily lives.

Overall, 20 to 30 percent of participants said that aftereffects of their West Nile virus infection were causing “big problems,” including limiting their outdoor activities and affecting their ability to fulfill family roles. On the positive side, muscle recovery was evident in almost all cases, and the majority of participants remained functionally independent.

CNNR senior scientist Dr. Art Leis said the study has helped identify a number of symptoms not previously associated with West Nile virus, including facial weakness, difficulty swallowing and vision problems.

Dr. Leis said that alerting other health care professionals to these more rare manifestations of the virus should help reduce what has been a common problem—doctors mistaking a patient's muscle weakness and paralysis for symptoms of stroke or Guillain Barre Syndrome.

“Treatments for those conditions are completely ineffective for West Nile virus and can cause injurious side effects,” Dr. Leis said.

Study results also have underscored the need for some West Nile patients to undergo a comprehensive battery of electro-diagnostic tests to determine the extent of neurological damage. “A complete neurological electromyography and nerve conduction studies are essential for a prognosis,” Dr. Leis said. “If the virus destroys a majority of cell bodies in the spinal cord, the patient will likely have permanent profound weakness.”