Loose dogs are a problem in San Antonio, especially for letter carriers who have to deal with them daily.

"Clearly if it's a problem for the carriers, you're putting citizens at risk, you are putting anyone who walks down the sidewalk at risk for getting bites," Animal Care Services Field Operations Manager Aimee Decontreras said.

The City of San Antonio wants everyone including letter carriers to be as safe as possible around aggressive dogs.

"We give them weekly safety talks and we've partnered with animal control for the city of San Antonio which has helped," San Antonio Post Office Customer Service Relations Coordinator Becky Hernandez said.

In the U.S., the CDC says 4.5 million Americans are bitten by dogs annually. Last year, USPS says 6,755 letter carriers were attacked by dogs. That's up 206 from the previous year and the highest in three decades.

"We have had 24 dog bites so far this year," said Hernandez. That's in the past six months across San Antonio. Six of those in the 78201 zip code, and six in 78204. Hernandez added, "Those are the higher areas where we have had more dog bites than any other location in the city."

The Postal Service ranked dog attacks by city for 2016. Los Angeles was number one with 80 attacks. Houston came in second with 62. San Antonio made the list at number 11 with 42 attacks.

In the area near the 2700 block of Ruiz Street, carriers are warned of dogs in advance by GPS.

"When we get to a house it beeps and alerts us that there is a dog coming up," Martinez said.

"There have been some roaming dogs and the mail has been stopped in that block for Ruiz street," Hernandez said.

When a letter carrier feels threatened by a dog, a homeowner gets a written notice.

"If they don't heed that warning and we find the dogs roaming around, we can discontinue mail to the whole block," Hernandez said. "Then their neighbors will have to come to the post office and pick up their mail."

"Maybe somebody on the corner is not getting their mail because somebody in the middle of the block is letting their dog run free," Decontrares said.

It's not just an inconvenience, but an aggressive loose dog that attacks, in a worst case scenario, can cause death.

"It's tragic. It's so preventable. It's literally keeping your dogs contained and being a responsible pet owner," said Decontreras.