. >> reporter: in fact they got worse for domingo via. after 11 days at the baylor medical center, he's home, but walking with a cane and he still has blurry vision. >> they said i will get better but it's going to take some time. >> reporter: dallas, which has most cases, has mounted an after dark aerial attack, small planes spraying insecticide deemed safe by the epa. >> we're passing out brochures about west nile virus. >> reporter: on the ground an information campaign. standing water has become public enemy number one. it's prime breeding ground for mosquitoes. >> what we have right now is a very serious outbreak here. what we need to do is interrupt the transmission cycle as quickly as we can to try to save lives. >> reporter: 80% of people infected will have no symptoms. dr. nancy snyderman says for others, the virus can progress quickly. >> symptoms occurring 10 to 14 days after a bite. they are usually mild. fever, rash, exhaustion. if there are neurologic problems, confusion, seizures, or if you're over the age of 70, that's whe