West Nile virus

Signs and symptoms

WNV is a neurotropic disease that attacks the central nervous system. The virus has an incubation time ranging from 3 to 15 days. Though the virus has shown to cause mortality among varied species of birds, it appears that it may only cause mild to moderate flu-like symptoms in humans that become infected. However, this excludes the elderly or those with weak immune systems, such as HIV or cancer, allowing the virus to more easily penetrate the blood-brain barrier and they therefore more often present with severe cases of the neurological disease.1 Other symptoms include nausea and vomiting, and may include swollen lymph glands and rashes around the torso.

Neurological symptoms may also include tremor (80% or more of patients), muscle weakness, neck stiffness, stupor, coma, vision loss, numbness and flacid paralysis. Neurological effects may be permanent. In the more serious cases, encephalitis and meningitis may occurr.