Dallas is ticketing people for standing water, which can become a breeding ground for mosquitoes, on their property in its aggressive fight against West Nile virus.

The Dallas City Marshal's Office is looking for violations of the city ordinance that requires tires to be under a roof structure, which prevents water from building up inside the tires.

Since late April, the office has issued 48 citations. Last year, it issued 132.

"We are seeing a lot more compliance," Chief Deputy Marshal Paul Hansen said. "We don't see as many violations reported."

"We look at that as a good thing, the enforcement that we are doing is making a difference as far as West Nile virus," he said.

This year, Dallas is starting its fight against West Nile virus early. The city has been setting out 90 mosquito traps per week since the beginning of May.

"We are seeing some areas with large population of mosquitoes, but in all tests we've done ... we've seen no positive results," said Michael Sanders, city environmental specialist.

Learn more about mosquitoes and how to control their population with this interactive learning tool: Mosquito Safari