Tests have determined that "strep zoo" was the illness that killed six dogs earlier this week at two city animal shelters.

The illness, Streptococcus zooepidemicus, had been believed to be canine influenza and prompted the quarantine of two shelters.

Kim Wolf, a spokeswoman for the PSPCA, which ran one of the shelters, said Wednesday that she did not know when the quarantines would be lifted.

Before the tests came back, another three dogs were euthanized after showing signs of the infection. Strep zoo is a bacterial infection that can be successfully treated with penicillin, Wolf said.