Up to 1% of infected dogs are microfilaria-positive and antigen-negative.

He says that vaccines don't always work, it would be a disaster for even one infected dog to get into this country.

Biologists suspect that it was introduced to Yellowstone by a tourist's infected dog or a coyote.

During the fight, one of the infected dogs bites Sam.

The worms are prolific egg layers and an infected dog may pass millions of eggs daily for several weeks.

Hookworm eggs are found in the stool of infected dogs and cats.

Normally a practice would deal with just one infected dog a year.

When the investigators place one of the worms into the infected dog, it recovers.

It is also possible for dogs to become infected through a blood transfusion from an infected dog.