West Nile Virus Disease

West Nile virus (WNV) disease is a mosquito-borne illness that can cause fever, encephalitis (inflammation of the brain), and meningitis (inflammation of the lining around the brain and spinal cord). The virus is primarily transmitted through the bite of an infected mosquito.

Transmission

West Nile virus is mainly spread through the bite of an infected Culex mosquito, which becomes infected by feeding on birds that carry the virus. Humans can become infected when an infected mosquito bites them. The virus can also be transmitted through organ transplantation, blood transfusion, and from mother to child during pregnancy or breastfeeding.

Symptoms

The symptoms of West Nile virus disease can range from mild to severe. Mild symptoms include:

• Fever
• Headache
• Body aches
• Joint pain
• Rash
• Sore eyes
• Sore throat
• Diarrhea
• Vomiting

Severe symptoms include:

• High fever
• Stiff neck
• Stupor or disorientation
• Coma
• Tremors
• Muscle weakness
• Paralysis
• Seizures

Diagnosis

West Nile virus disease is diagnosed through a combination of physical examination, medical history, and laboratory tests. Laboratory tests include:

• Enzyme-linked immunosorbent assay (ELISA) to detect antibodies against WNV
• Polymerase chain reaction (PCR) to detect the genetic material of the virus
• Serum and cerebrospinal fluid tests to detect the presence of WNV antibodies or antigen

Treatment

There is no specific treatment for West Nile virus disease. Treatment focuses on relieving symptoms and supporting the patient's recovery. This may include:

• Fluid replacement to prevent dehydration
• Pain relief medication to manage headache, fever, and body aches
• Anticonvulsant medication to control seizures
• Supportive care in an intensive care unit for patients with severe symptoms

Prevention

To prevent West Nile virus disease, the following measures can be taken:

• Avoiding mosquito bites by using insect repellents, wearing protective clothing, and staying indoors during peak mosquito hours
• Eliminating standing water around homes to reduce mosquito breeding sites
• Using air conditioning or screens on windows and doors to keep mosquitoes out
• Avoiding outdoor activities during peak mosquito hours (dawn and dusk)

Complications

West Nile virus disease can lead to several complications, including:

• Encephalitis, which can cause permanent brain damage or death
• Meningitis, which can cause permanent neurological damage or death
• Acute flaccid paralysis, which can cause permanent muscle weakness or paralysis
• Death, especially in older adults and people with weakened immune systems

Epidemiology

West Nile virus disease is found worldwide, with outbreaks reported in Africa, Asia, Europe, and North America. The virus is typically transmitted during the summer and early fall months when mosquito activity is highest.