The Centers for Disease Control and Prevention (CDC) has confirmed that at least 3,000 dogs are infected with the rabies virus.
The dogs tested positive for the virus on Friday.
The outbreak has affected the dogs of over 50,000 people, according to the CDC.
The agency said it was unable to share the details of how many dogs have been affected because of a federal law that restricts the release of the names of people who have been infected.
The CDC also announced Friday that a number of dogs had tested positive after they were released from quarantine.
The animals were released Thursday into their owners’ homes.
A total of 2,848 people have been tested so far, the CDC said.
The spread of the virus is not confined to the United States.
Dogs in Spain have been found infected with other strains of the disease.
The European Union on Thursday announced that a dog had tested negative for the rabys virus in Spain.
The Spanish government is urging the dog owners to get tested for the disease and report any new infections.