West Nile virus is primarily spread to humans through mosquito bites.
About 80% of people who are infected with West Nile virus do not feel sick. For those who do feel sick, symptoms can include fever, headache, tiredness, nausea, vomiting, swollen lymph glands, and a rash on the chest, stomach, or back.
In rare cases, those infected can develop a severe illness affecting the central nervous system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). Symptoms can include high fever, headache, neck stiffness, disorientation, coma, and more.
In a very small number of cases, West Nile virus has been spread through exposure in a laboratory setting, through blood transfusion and organ donation, and from mother to baby during pregnancy, delivery, or breast feeding.
Read the original notice at Centers for Disease Control and Prevention (CDC)