Why the West Nile virus is also receiving increasing attention in Europe

The West Nile virus belongs to the Flavivirus family and is primarily transmitted by mosquitoes. Wild birds serve as the primary natural reservoir, among which the virus is transmitted via mosquitoes. Humans and horses can also become infected but are considered “accidental hosts.” This means they generally do not spread the virus further.

The virus was first identified in Uganda in 1937 and is now widespread in many regions of the world. In recent years, infected birds, horses, and, in isolated cases, humans have also been detected in several European countries—including Germany and Austria. 

Transmission occurs through the bite of an infected mosquito. The mosquito first picks up the virus while feeding on the blood of an infected bird and can then transmit it to other animals or humans. Direct person-to-person transmission is not possible under normal circumstances. Only in very rare cases can the virus be transmitted, for example, through blood transfusions, organ transplants, or during pregnancy.

Since mosquitoes are primarily active during the warmer months, infections occur mainly between summer and early fall. 

About 80 percent of all infected people do not develop any symptoms. About one in five people affected develop mild, flu-like symptoms, a condition also known as West Nile fever.

Possible symptoms include:

• Fever
• Headache and body aches
• Fatigue
• Muscle aches
• Skin rash
• Swollen lymph nodes
• Nausea

Symptoms usually subside within a few days or weeks. In rare cases, the virus attacks the central nervous system and can cause meningitis, encephalitis, or inflammation of the spinal cord. Symptoms include severe headaches, neck stiffness, confusion, seizures, or paralysis.

Such complications constitute a medical emergency. 

Severe cases of the disease are rare overall. However, older adults, people with weakened immune systems, and those with chronic conditions such as diabetes, cardiovascular disease, or kidney disease are at particularly high risk. For healthy adults and children, an infection is usually mild or even goes completely unnoticed. 

If an infection with the West Nile virus is suspected, a medical examination is conducted first. Special blood tests can detect antibodies or components of the virus. If involvement of the nervous system is suspected, a cerebrospinal fluid analysis may also be necessary.

There is currently no specific antiviral treatment for the West Nile virus. Treatment is therefore based on the symptoms. Mild cases are treated symptomatically, for example, with adequate fluid intake, rest, and fever-reducing or pain-relieving medications.

Severe cases usually require hospitalization. How can you protect yourself from the West Nile virus?

Recommendations include:

• Insect repellent on exposed skin
• long, light-colored clothing
• Window screens
• Mosquito nets in high-risk areas
• Avoiding standing water in the garden, as mosquitoes breed there

These protective measures should be consistently followed, especially in the evening and at night when many mosquitoes are active. 

The West Nile virus has also reached Europe and is increasingly being detected during the summer months. Although most infections are mild, serious neurological complications can occur in rare cases. Those who consistently protect themselves against mosquito bites and seek medical advice if they experience persistent fever or neurological symptoms after a mosquito bite can significantly reduce the risk of severe illness. Staying vigilant rather than panicking is the best protection.