Companion Animal Parasite Council Annual Forecast Is Released - Heartworm and Lyme Disease Are on the Rise

SALEM, ORE. (April 1, 2020) —The Companion Animal Parasite Council (CAPC), the leading source on parasitic diseases that threaten the health of pets and people, today released its annual 2020 parasite forecast and corresponding 30-day forecast maps to alert pet owners of impending outbreaks. CAPC predicts that heartworm will be higher than average, especially along the Atlantic coast and Mississipi river; the forecast for Lyme disease is for a continued spread in the Atlantic Coast and upper Midwest.

“We started providing our annual forecasts over nine years ago because of the dynamic and ever changing nature of parasites,” says Dr. Christopher Carpenter, DVM and Chief Executive Officer of CAPC. “Over the years, we have seen these diseases continue to move. Our annual forecast is critical to alert pet owners to the risks this year and remind them that all pets need to be tested and protected year-round.”

Pet owners who want to monitor the activity in their county throughout the year now have access to 30-Day Parasite Forecast Maps at These maps, developed exclusively by CAPC, provide a local forecast for every county in the continental United States on a monthly basis. This free service helps to remind pet owners of the continuous risk in their area and the importance of annual parasite testing and year-round protection.

According to CAPC, the risk of acquiring heartworm disease in 2020 is very real due to the expansive nature of the disease. Mosquitoes are responsible for the transmission of the parasite that causes heartworm disease. Heartworm disease can be deadly to pets. This increase in heartworm prevalence can be attributed to weather and the transportation of companion animals from one area of the country to another. Those areas most at risk for infection with heartworm reside along the Mississippi River throughout the southern portions of the Midwest, and the Atlantic Coast north into Virginia.

Heartworm isn’t the only threat pet owners will need to be watchful for. CAPC also predicts that Lyme disease is expanding quickly from the northeastern and mid-Atlantic states, the upper Midwestern states, and throughout Canada. Lyme disease is transmitted by ticks and is spreading as the white-tailed deer population grows and migratory birds carry ticks to new areas. Veterinarians and pet owners should test annually and use tick preventative/acaricidal treatment year-round. High-risk patients for vector-borne disease should be tested and consider a vaccination for Lyme disease.

The forecasts support CAPC’s recommendation for annual testing and having pets on preventative treatment year-round. For 2020, CAPC predicts the following risk areas for parasite-related diseases:

  • Infection with heartworm, which causes a potentially fatal disease is expected to be higher than average along the Mississippi River throughout the southern portions of the Midwest, and the Atlantic Coast north into Virginia. In addition, areas with historically lower prevalences of heartworm should particularly take note of predicted higher prevalence, including Indiana, northern Illinois, southern Iowa, and southern Wisconsin. Very few regions are expected to have lower than average prevalence. These include areas around Baton Rouge in Louisiana, Atlanta, Georgia, and Nashville, Tennessee, and along the southwestern border of Texas. Pet owners should take extra care to limit their pets’ exposure to mosquitoes, test their pets annually for heartworm diseases, and use heartworm preventatives year-round.
  • Lyme disease is a high threat and is expanding its range from the northeastern and mid-Atlantic states (Maine all the way south to North Carolina and Tennessee), the upper Midwestern states (Indiana, Michigan, Illinois, and Iowa), and throughout Canada. There is a higher than average seroprevalence predicted throughout the Midwest, with a hotspot expected in northwestern Minnesota. Pets living in or traveling to these states are considered at high risk; pet owners should talk to their veterinarian about a Lyme vaccination in addition to testing for the disease and protecting year-round against ticks.
  • Ehrlichiosis is expected to be above normal for the majority of the United States, particularly in Oklahoma, Arkansas, Missouri, Mississippi, Alabama, Georgia, Tennessee, and Kentucky. There are several small areas scattered throughout the US forecasted for lower than average seroprevalence including Arkansas, far western Tennessee, and the western coastal region of North Carolina.
  • Transmission of the agents of anaplasmosis is again forecasted to be average for much of the United States. However, anaplasmosis is expected to be higher than average throughout the New England states. The rise in exposure to Anaplasma spp. has been also seen in humans, with an increase in anaplasmosis cases being reported in Maine.

For more information about the Companion Animal Parasite Council visit, and to view local 30-Day Parasite Forecast Maps visit

How the forecasts are created:

The Parasite Forecasts are a collaborative effort from parasitologists and statisticians in leading academic institutions across the United States 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.

About the Companion Animal Parasite Council

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.