The deaths of three dogs from two animal shelters indicates that the often-deadly and highly contagious canine parvovirus is present in Pittsburgh.

At greatest risk are dogs that have not been vaccinated and puppies younger than 4 months old.

"Recently both the Animal Rescue League of Western Pennsylvania and the Western Pennsylvania Humane Society have seen an uptick in the number of cases in dogs coming into the shelters with this sickness," the Humane Society said on Tuesday.

One dog died at the Animal Rescue League shelter in Larimer. Two dogs that had recently been adopted from the Humane Society died in their new homes.

"Both shelters are performing aggressive sanitation tactics to make sure the disease does not spread throughout the canine populations housed at both open door shelters," the Humane Society said. Sick dogs have been separated from the general kennel population.

The Humane Society said the disease is highly infectious and is spread from dog to dog by direct or indirect contact with feces. It can be halted by vaccinating dogs against it, but there is no cure once a dog has it.

The main symptoms are vomiting and severe, often bloody, diarrhea that can cause rapid dehydration. Treatment at a veterinary clinic generally includes intravenous fluids to combat dehydration.

The Humane Society is offering a vaccination clinic from 9 a.m. to 2 p.m. Sunday at its shelter on Western Avenue on the North Side. The cost is $13 for a shot that will inoculate against parvovirus, distemper, hepatitis and parainfluenza. Canine and feline rabies vaccines will also be offered for $8.

Go to www.wpahumane.org cq or call 412-321-4625 for further information.