Delta Airlines announced this week that it would no longer allow "pit bull-type" dogs on flights as service and support animals.

The new policy goes into effect July 10. The policy also introduces a limit of one emotional support animal per customer per flight.

According to a Delta press release, the changes are in response to recent incidents in which several employees and passengers were bitten. The company also cites an increase in incidents of animals urinating and defecating on flights. The company gives no specifics about the breeds of the dogs involved.

"The safety and security of Delta people and our customers is always our top priority," said Gil West, chief operating officer, in that release. "We will always review and enhance our policies and procedures to ensure that Delta remains a leader in safety."

Delta flies about 700 service or support animals each day, according to the company. Customers have attempted to fly with snakes, spiders, turkeys and gliding possums as comfort animals.

"The rise in serious incidents involving animals in flight leads us to believe that the lack of regulation in both health and training screening for these animals is creating unsafe conditions across U.S. air travel," said John Laughter, Delta’s senior vice president of corporate safety, security and compliance, when updating the airline's policy in March. "As a leader in safety, we worked with our Advisory Board on Disability to find a solution that supports those customers with a legitimate need for these animals, while prioritizing a safe and consistent travel experience."

Defining service and emotional support animals

The idea of a "service" dog can be fuzzy. Many people use the term, but true service dogs are highly trained to perform specific tasks to help an individual with a disability.

Service dogs are different from emotional support animals, which provide comfort to their owners, but don't require training. The only animal that legally can go to any public place the handler goes is a service dog.

MNN's Jaymi Heimbuch has an in-depth explanation of all the differences and protections offered to service dogs versus emotional support animals.

As Heimbuch points out, there has been a backlash against people who try to pass off their pets as fake service dogs or even questionable emotional support animals. When these pets aren't well trained, incidents like the one Delta cited can occur.

In June, for example, a Delta passenger was severely bitten by a 50-pound emotional support dog, described as a "chocolate Lab-pointer mix."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.