This past month we are seeing more cases of West Nile Virus (WNV). In fact, there has been a record number of cases in Fresno since July. West Nile Virus is a member of the encephalitis virus antigenic complex, and can lead to a wide range of clinical symptoms from no symptoms at all to severe meningitis and encephalitis. Humans get WNV infection from infected mosquito bites. The symptoms start 2-15 days after a mosquito bite, and can last for several days. The elderly and patients with other medical conditions are more likely to have severe symptoms that require hospitalization.
When is WNV more prevalent? During the mosquito season, which is late summer and early Fall.
What kind of symptoms does it cause? The majority of patients have no symptoms at all. However 20-40% will experience a high fever, headache, weakness, back pain, muscle aches, and loss of appetite. A red rash may appear as well. A very small minority of patients can experience encephalitis, meningitis, or an acute asymmetric flaccid paralysis.
Are there any lingering symptoms after the infection? After the acute infection, many patients with WNV infection experience persistent symptoms, such as fatigue, memory impairment, weakness, headache, and balance problems.
How do I get tested? Contact your primary care doctor. If you have significant symptoms, you may likely be referred to your nearest emergency room.
How do I protect my family from WNV infection? Avoid mosquitoes by staying indoors during the night and early morning. If you are outside during the time mosquitoes are out, wear long sleeves and pants. You may also use insect repellent. Lemon-eucalyptus essential oil can keep mosquitoes away, as can commercially prepared mosquito repellents.
How do I protect my home? Mosquitoes live and lay their eggs in standing water. Get rid of standing water in bird baths, old tires, pot holes, and buckets. If you have a pond in your yard, get some mosquito fish to eat the mosquito eggs. You can get mosquito fish for free by calling the city at 559-268-6565.
How do I protect my pet? Animal can get WNV infection too, especially horses. Change the water in your pets dishes daily — avoid leaving standing water out for your furry friends. Contact your vet and ask about the WNV vaccine series.
How do I protect my community? Dead birds are a potential sign that WNV has infected animals in your neighborhood. If you see a dead bird, do not touch it with your bare hands. Call the West Nile Dead Bird Program at 1-877-968-2473. Swimming pools that are not maintained also breed mosquitoes, so report these green swamp-like pools to the Fresno Mosquito Control office at 559-268-6565.