The Adams County SPCA says a first round of tests for a highly contagious virus has come back negative for every dog and puppy in its facility.
The dogs will be tested again next week for canine parvovirus, a disease that is spread from dog to dog and is often fatal to the animals, especially in puppies.
The shelter was quarantined this week for the first time in its 35-year history following the death of a pit bull brought in last month as a stray.
The dog was vaccinated when he arrived and showed no signs of being sick, but died 16 days later and tested positive for canine parvovirus.
Other dogs at the shelter are kennel-bound and stray dogs cannot be brought to the facility while the quarantine is in place.