Companion Animal Parasite Council Annual Forecast Predicts Heartworm and Lyme Disease to Be More Problematic for Pets in 2018

SALEM, ORE. (April 18, 2018) —The Companion Animal Parasite Council (CAPC), the leading source on parasitic diseases that threaten the health of pets and people, has released its annual 2018 parasite forecasts. The big headline for pet owners is an increase in prevalence of two of the most problematic diseases for pets: heartworm and Lyme disease. Heartworm is predicted to continue to aggressively spread across the United States with the growth of Lyme disease focused east of the Rockies.

According to CAPC, the expansive nature of heartworm is partially attributed to the hot and wet weather over a two-year span. Shifting weather patterns have created ideal breeding conditions for mosquitoes across the country. Mosquitoes transmit the parasite that causes heartworm disease which can be deadly to pets. Another contributing factor is the relocation of many unknown heartworm positive dogs across the country, who survived these dangerous storms.

Heartworm isn’t the only parasite pet owners will need to be watchful for. CAPC also predicts the spread of Lyme disease into non-endemic areas including the Dakotas, Iowa, Missouri, southern Illinois, Ohio, Kentucky, Tennessee and North Carolina. A Lyme disease agent is transmitted by ticks and is spreading as the white-tailed deer population grows and migratory birds carry ticks to new areas.

“Our annual forecasts provide critical and important information to help veterinarians and pet owners understand parasites are a true risk to both pets and people,” said Dr. Dwight Bowman, CAPC board member and professor of parasitology at Cornell University College of Veterinary Medicine. “This year, there are significant shifts in prevalence, making our maps a critical educational tool for veterinary hospitals, and allowing veterinarians and pet owners to see that parasites are ever changing and widespread, sometimes surprisingly so.”

The forecasts support CAPC’s recommendation for annual testing and having pets on preventative treatment year-round. For 2018, CAPC predicts the following risk areas for parasite-related diseases:

  • Infection with heartworm,which causes a potentially fatal disease is expected to be above average nationwide. The forecast also predicts the hyper-endemic prevalence seen in the lower Mississippi River region will be even more active than normal. Veterinarians in the northern tier states from Washington State to Vermont should be on alert as this area may see a problematic rise in heartworm infections among their patients.
  • Lyme disease is a high threat again this year and is now seen to be “oozing” into non-endemic areas. Veterinarians living close to Lyme’s endemic boundary line (the Dakotas, Iowa, Missouri, Southern Illinois, Ohio, Kentucky, Tennessee and North Carolina) should be on high alert. Western Pennsylvania, eastern Ohio, West Virginia and the Appalachian region in Virginia need to prepare for an active year. As for Washington, DC to Philadelphia, PA and eastward (including the Delmarva area) and the Boston/Cape Cod area: congratulations, you are expected to see a little relief this year.
  • Transmission of the agents of anaplasmosis is forecasted to be average for much of the United States. However, northwestern Minnesota isforecasted to have an active year. Two bright spots are the Wisconsin/Minnesota border area as well as the Boston/Cape Cod region, which are expected to see less activity than normal.
  • Ehrlichiosis is always geographically challenging. The disease can be nonexistent to rampant within 200 miles. Southern Virginia and northern North Carolina are forecasted to be more active than normal. The rest of the United States is expected to see about normal prevalence in 2018.
  • CAPC offers prevalence data that localizes reported parasitic disease activity at the county level for veterinarians to use in their discussions about annual testing and year-round protection. This information is available for free at the CAPC website Pet owners can use these maps as a reminder of the importance of year-round protection.

The Parasite Forecasts represent the collective expert opinion of academic parasitologists who engage in ongoing research and data interpretation to better understand and monitor vector-borne disease agent transmission and changing life cycles of parasites. The annual CAPC Parasite Forecasts are based on many factors including temperature, precipitation and population density.

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.