18. West Nile Fever
West Nile fever can be hard to diagnose because it presents symptoms that are incredibly similar to other viral infections. You may get a headache, but that can also indicate meningitis, encephalitis, and polio. Flu-like symptoms are common with West Nile fever.
Within 3 to 6 days after symptoms begin to show, the West Nile Fever will take effect. You may feel sweaty, cold, weak, drowsy, and feverish. People with West Nile fever may also experience joint pain and gastrointestinal issues like nausea, loss of appetite, vomiting, and diarrhea. Nearly one-third of West Nile fever patients get a rash as well.