Data Reveal Cats Need Better Protection Against Roundworm and Heartworm

Lack of compliance in use of preventives cited as No. 1 reason for more infected felines.

BEL AIR, Md. (June 21, 2011) – Extensive data collected by laboratories for IDEXX, ANTECH, and Banfield Pet Hospitals in 2010 reveal that cats need better protection from heartworms and roundworms, according to the Companion Animal Parasite Council (CAPC). The comprehensive results of the combined national sample data can be found on interactive maps on the CAPC website, and a,llows the viewer to search for canine or feline infection rate results by state, county and type of parasite. The interactive maps were commissioned by the board of directors and developed by Chuck Blier under the direction of Mike Paul, DVM, past executive director of CAPC.

Nationally for roundworms, 6 percent of 780,000 fecal samples from cared-for cats contained the eggs of the feline roundworm, Toxocara cati. For the 4 million cared-for canine fecal samples that were examined, the national average was 2.9 percent containing the eggs of Toxocara canis. There were only four states – Alaska, Arizona, California and Nevada – where a higher percentage of dogs were infected with roundworms than cats.

For heartworm, there was a higher percentage of cats positive for heartworms than dogs in every state except for Arkansas, Louisiana, Mississippi, Oklahoma and Texas. For the 250,000 feline samples and 5 million canine samples, the national averages were 2.7 percent of cats being positive and 1.2 percent of dogs testing positive. In general, three out of every 100 cats tested was positive for heartworm antigen, a good indicator that these positive cats have living heartworms in their lungs, according to the CAPC.

The numbers from these maps suggest that heartworm preventives with broad-spectrum internal parasite control are reducing the worm populations in dogs, but that cats are not receiving the same protection. These data strongly support the CAPC recommendation that all pets, both cats and dogs, be protected annually throughout the United States against heartworm, intestinal parasites and ectoparasites. According to the CAPC, every veterinary clinic’s parasite prevention motto should be every pet, all year long.

Additional information and frequently updated research on parasite infections of canines and felines can be found on the CAPC website at

The Companion Animal Parasite Council ( is an independent not-for-profit foundation comprised of parasitologists, veterinarians, medical, public health and other professionals that provides information for the optimal control of internal and external parasites that threaten the health of pets and people. Formed in 2002, the CAPC works to help veterinary professionals and pet owners develop the best practices in parasite management that protect pets from parasitic infections and reduce the risk of zoonotic parasite transmission.