WAUKESHA, Wis. (AP) -- A Waukesha humane society hopes to learn today what's caused seven dogs to die in 10 days and 10 others to show signs of illness.

The Humane Animal Welfare Society of Waukesha County says it's not accepting dogs while the disease is being investigated.

Executive director Lynn Olenik says that in 15 years in the business she's never seen something like this. She says the illness quickly turns dogs from healthy to lethargic and feverish, then invades the lungs.

Results of lab tests could be available Friday to identify the illness.

Olenik says the source of the infection hasn't been determined, although five dogs had been brought in from a Milwaukee County shelter and are among the dogs that have died.

The illness hasn't affected people or other types of animals.