Evidence the West Nile Virus is in Tyler. The Texas Department of Health says mosquitoes found in East Tyler tested positive for the virus. They were taken from the 2700 block of Tanglewood. Again, the health department says you should avoid contact with mosquitoes by practicing the four Ds. That means stay inside during dusk and dawn. That's when mosquitoes are most active. Also dress in long sleeves and pants when you're outside, use insect repellents with deet and drain standing water near your home, because that's where mosquitos breed.