August 19, 2008

Long-Term Prognosis After West Nile Good

The long-term prognosis of recovery from West Nile virus, a central nervous system infection spread by mosquitoes, is good, Canadian researchers said.

Study author Dr. Mark of McMaster University in Hamilton said that many people infected by West Nile virus never get sick, so the disease can be difficult to diagnose. However, approximately 20 percent have symptoms that range from mild flu-like illness to neurological problems such as meningoencephalitis, encephalitis and acute flaccid paralysis.

Loeb and colleagues tracked 156 patients infected with West Nile from 2003 to 2007 to record patterns of physical disease and mental effects. Researchers anticipated greater severity and a longer course of depression and fatigue in participants with neurological problems.

However, the study, published in the Annals of Internal Medicine, found symptoms and recovery times to be similar to those in participants without neurological consequences of infection.

However, pre-existing health conditions were an important factor in long-term prognosis. Patients who were healthy at the time of infection returned to normal health more quickly on average than those who had pre-existing conditions.