Half may develop a rash. Lymph nodes may be swollen and respiratory symptoms can occur. The West Nile virus is spread by mosquitoes that have bitten infected birds and then bite humans. It is not spread by direct contact from birds to people, or people to people. Because this is a viral illness, there is no specific treatment.
Care is entirely supportive and directed toward symptoms.
You are not running a greater risk by waiting to see what happens with your mild symptoms. If you have a severe, persistent headache, coupled with a very stiff neck, so that you cannot put your chin on your chest, then you should see a physician. If you are disoriented, cannot maintain your balance, or think properly, especially if you have a fever and a headache, then contact a physician right away. If you have mosquito bites, or have been in areas where you are likely to have been bitten, then your chance of exposure is higher. Mosquitoes are most likely to bite at dusk and after dark, so take particular precautions then.