What are the symptoms of West Nile virus?
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Symptoms of West Nile Virus: A Comprehensive Overview
Common Symptoms of West Nile Virus Infection
West Nile virus (WNV) is a mosquito-borne flavivirus that can cause a range of symptoms in humans. Most infections are asymptomatic, but when symptoms do occur, they can vary widely in severity. The majority of symptomatic cases present with a self-limited febrile illness known as West Nile fever. Common symptoms include fever, headache, muscle pain, fatigue, and rash . Other frequently reported symptoms are nausea, vomiting, eye pain, and loss of appetite .
Severe Manifestations: Neuroinvasive Disease
In more severe cases, WNV can lead to neuroinvasive disease, which includes conditions such as meningitis, encephalitis, and acute flaccid paralysis. These severe manifestations are more common in older adults and individuals with weakened immune systems . Symptoms of neuroinvasive disease often include high fever, severe headache, neck stiffness, altered mental status, and muscle weakness . In some cases, patients may experience gastrointestinal symptoms such as nausea and vomiting, as well as back pain and rash .
Persistent and Long-term Symptoms
A significant number of individuals who recover from WNV infection report persistent symptoms that can last for months. Common long-term symptoms include fatigue, muscle aches, difficulty concentrating, and memory problems . These persistent symptoms are more likely to occur in individuals who had neuroinvasive disease, as well as those with underlying conditions such as hypertension and diabetes.
Demographic and Clinical Factors
Certain demographic and clinical factors are associated with the severity and persistence of WNV symptoms. Older age and immunosuppression are significant risk factors for developing severe neuroinvasive disease . Additionally, sex differences have been observed, with females reporting more symptoms than males, despite similar initial viral loads.
Conclusion
West Nile virus infection can range from asymptomatic to severe, life-threatening illness. While most symptomatic cases involve mild, flu-like symptoms, a subset of patients may develop severe neuroinvasive disease, particularly older adults and those with compromised immune systems. Persistent symptoms are common and can significantly impact quality of life. Understanding the full spectrum of WNV symptoms and associated risk factors is crucial for effective diagnosis, treatment, and management of the disease.
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