Although most people with West Nile virus remain asymptomatic, approximately one in five people experiences West Nile fever, which is a mild infection marked by fever, body aches, headache, back pain and fatigue, according to Mayo Clinic. Other symptoms include swollen lymph glands, eye pain and skin rash.
Although rare, around 1 percent of people infected with West Nile virus experience a neurological infection, explains Mayo Clinic. This infection may cause encephalitis, which is inflammation of the brain. It can also cause meningoencephalitis, an infection of the brain and the membrane surrounding it. Meningitis, which is an infection of the spinal cord and the membranes surrounding the brain, may also occur. Rarely, West Nile poliomyelitis results from West Nile infection, causing weakness in the legs and arms and the muscles responsible for breathing.
These West-Nile-related diseases have common symptoms, including high fever, stiff neck, severe headache and confusion or disorientation, reports Mayo Clinic. Muscle jerking or tremors; coma or stupor; sudden muscle weakness; and partial paralysis are other symptoms. Additional symptoms include pain, convulsions and lack of coordination. The duration of West Nile fever is generally just a few days. However, the symptoms of the diseases related to West Nile may last much longer. Neurological effects may be permanent.