A pet dog has been confirmed dead after contracting pneumonic plague. The Colorado Department of Public Health and Environment said the bacteria disease is attributable for the demise of the dog. The Yersinia pestis bacterium is known to cause pneumonic plague.

The disease is rare, but very infectious. It causes serious infection in the lungs, and symptoms shown by the sufferer are fever, rapidly developing pneumonia and coughing of blood. After one suffers from the infection, it becomes very important to seek immediate treatment to prevent the chances of likely death.

The human plague was confirmed in three more people by Colorado health officials on June 18. They found that two of them had pneumonic plague, whereas one of them suffered from a milder form of the disease.

All these cases are believed to be associated with the dog owned by the first patient. The man is currently getting treatment in hospital, however, health officials have refused to comment on the current condition of the man. Scientists have ascertained that all the three men got infected with the disease as a result of coming into contact with the infected dog.

The dog must have become infected with the disease after getting exposed to plague-ridden fleas from a rabbit or prairie dog, said Jennifer House, public health veterinarian at the Colorado Department of Public Health and Environment. After conducting tests on flea samples collected from eastern Adams County, researchers found them positive for the plague bacteria.

"Contact your physician if you develop a high fever and other plague symptoms following a flea bite or direct contact with dead rodents, or exposure to a sick cat or dog that may have had contact with plague-infected rodents", advised the Colorado Department of Public Health and Environment.