Purdue project could help pets serve as disease watchdogs.

A national surveillance network that uses the medical records of companion animals could help prepare for a wide variety of emerging-disease threats to humans and animals, including avian influenza, according to veterinary scientists at Purdue University's School of Veterinary Medicine.

The National Companion Animal Surveillance Program was originally designed to alert people to potential anthrax or plague outbreaks. New findings on tests of the program are detailed in the current edition of Vector-Borne and Zoonotic Diseases.

"We discovered we can use analytical techniques to target specific geographic areas where vaccines need to be developed," said author Larry Glickman, professor of epidemiology. "This early warning will become critical to stopping the spread of avian flu virus and other diseases that might affect humans. The quicker we can identify the problem in the more than 150 million dogs, cats, or pet birds that live in approximately 40 percent of all households in the United States, the greater the probability we can contain a disease before it spreads to humans."

Glickman's co-authors were George E. Moore, Nita W. Glickman, and Richard J. Caldanaro of Purdue's School of Veterinary Medicine; David Aucoin of VCA Antech (a nationwide network of laboratories used by more than 18,000 private veterinary practices); and Hugh B. Lewis of Banfield, The Pet Hospital (a nationwide chain of veterinary hospitals).

Between 2002 and 2004, tests were conducted on more than 10 million pet records to determine how the database could be used to monitor disease outbreaks.

The research found patterns of interest in the following three areas:

* The data showed a clear pattern of association between flea and tick infestation in pets and the incidence of Lyme disease in humans, with a two-month lag and peak rates occurring during warmer months. This information allows veterinarians to anticipate unusual occurrences of diseases that are transmitted from animals to humans and design treatment methods. Public health officials also could be alerted so that they could provide timely information to the public and spray affected areas for ticks. In addition, specimens could be used for profiling other diseases that are potentially transmitted to humans by fleas and ticks, such as Rocky Mountain spotted fever.

* The data showed a 3.3 percent increase in the number of positive tests from 2002-2004 for a disease called canine leptospirosis. Leptospirosis can be transmitted from dogs to humans. The disease is currently the leading cause of acute kidney failure in dogs and can also damage the liver. Most animals and humans recover from leptospirosis if it is diagnosed early and treated with antibiotics. The Purdue project will help develop early-warning signs and aid in the development of vaccines that target emerging strains of leptospirosis. The data also document an increase in the disease over the past 10 years, probably related to increasing contact between dogs and wildlife such as raccoons, Glickman said.

* The data showed a correlation between the number of cases of influenza-like illness in cats and similar symptoms in humans in the Washington, D.C., area. This pattern suggested common environmental causes of influenza in cats and people. The finding also illustrates the ability of Purdue researchers to track diseases by geographic area and to detect statistical clusters of events in companion animals that could signal the introduction of new viruses into the United States, such as avian influenza virus due to bird migration or bioterrorism.

"We wanted to show that these animals could be used as sentinels for infectious agents and perhaps predict the occurrence of diseases in humans," Glickman said. "The long-term goal is to partner with other providers of companion-animal health care and animal laboratory data to create a comprehensive system. We think there is no comparable human-surveillance system in the country."

In ongoing work, the Purdue researchers are investigating ways to monitor cats for avian influenza. In collaboration with Banfield, they have developed an early-warning system for a canine influenza caused by a virus that appears to have jumped recently from horses to dogs. If a dog comes to a Banfield clinic with a predetermined set of clinical signs, the computer screen flashes in the hospital, and information appears that advises the practitioner what samples to collect from the dog for virus identification. A similar real-time surveillance system could be used to identify the avian-influenza virus in pet birds or cats, Glickman said.

The research was funded in part by the Centers for Disease Control and Prevention.