Nonprofit Companion Animal Parasite Council (CAPC) Warns Parasitic Pet Diseases Will Spread Further in 2024

CAPC Forecasts Expansion of Lyme, Heartworm and Other Tick-Borne Diseases in Pets

SALEM, ORE. (April 2, 2024) — The nonprofit Companion Animal Parasite Council (CAPC), the nation’s leading authority on parasitic diseases that threaten the health of pets and people, today warned of the continued expansion of heartworm, Lyme Disease and other tick-borne diseases throughout the United States in 2024. Pet owners can learn more about higher-than-average parasitic disease risks CAPC predicts in its 2024 Pet Parasite Forecast released today, as well as in its corresponding monthly prevalence maps at

CAPC has been accurately forecasting parasitic diseases of pets for more than 12 years. When compared to reported laboratory results from U.S. companion animals, CAPC’s annual forecasts have demonstrated an almost-perfect correlation between forecasted values and actual readings for the year.

“What was true before may not be true today when it comes to the local threat of parasites to our pets and families,” said Heather Walden, MS, PhD, president of CAPC Board and associate professor at the University of Florida College of Veterinary Medicine. “Over the past 12 years, we have seen the movement of parasitic diseases and the vectors that carry them expand to new areas, signaling the need for pet owners to test their pets every year and protect them year-round.”

In its 2024 Pet Parasite Forecast, CAPC reports ticks and mosquitoes remain the principal transmitters of pet and human vector-borne diseases. Specifically, tick-borne diseases Lyme, anaplasmosis and ehrlichiosis are advancing into places like North Carolina, Kentucky, and California, respectively. Mosquitoes are spreading heartworm disease throughout the mid-Atlantic region and pushing northward into densely populated areas.

The risks of contracting Lyme, anaplasmosis, ehrlichiosis and heartworm diseases are increasing due to many factors, including:

  • Rehoming of pets across the country
  • Land use, urbanization and human population growth
  • Changes in wildlife host and vector (mosquito and tick) densities
  • Recently discovered vectors, such as the invasive Asian long-horned tick in the eastern U.S.
  • Short- and long-term changes in climatic conditions
  • Increasing international trade and travel

CAPC Pet Disease Alerts 30-Day Forecasts

In addition to its annual forecasts, CAPC also posts corresponding prevalence maps updated every month to highlight geographic areas where veterinarians and pet owners should be extra vigilant. Both the annual forecast and the 30-Day Pet Parasite Forecast Maps are designed to alert pet owners of impending outbreaks.

“While our nationwide annual forecasts help us track progression of diseases, our monthly forecasts help pet owners understand immediate threats in their neighborhoods,” said Dr. Christopher Carpenter, DVM, MBA and Chief Executive Officer of CAPC. “Every county ecosystem and weather pattern is different. To get a sense of the parasitic disease risks to your pet and family, we urge pet owners to check our monthly, county-by-country forecasts, and discuss them with their veterinarian.”

Pet owners have free access to the CAPC 30-Day Pet Parasite Forecast Maps at Developed exclusively by CAPC and updated every 30 days, they provide local outlooks for every county in the continental United States on a monthly basis. These highly accurate forecasts are provided as a public service to remind pet owners of the risk of parasitic disease in their area, as well as the importance of annual parasite testing and year-round protection.

Testing and Prevention Strategies

Supported by ongoing research by parasitologists and statisticians at leading U.S. academic institutions, the 2024 CAPC forecast highlights areas where more should be done to lower the risk of companion animal exposure to disease vectors like ticks and mosquitoes. At the foundation of these prevention strategies are CAPC’s recommendations that veterinarians and pet owners test their pets annually for disease, use products that kill and/or repel mosquitoes and ticks, and administer preventatives year-round as well as applicable approved vaccines.

Parasite infections can be harmful and even deadly to pets and people. According to the Centers for Disease Control (CDC), mosquito-borne and tick-borne human disease incidence in the United States tripled between 2004 and 2016, with much of this increase due to tick-borne pathogens that were reported in higher numbers and across a larger geographic area. CAPC’s pet parasite forecast maps paralleled the CDC’s findings, showing increased prevalence of mosquito-borne and tick-borne diseases in companion animals throughout the U.S.

“The zoonotic potential of parasites to transmit diseases between animals and humans underscores the importance of CAPC’s annual and 30-day forecasts to alert communities of the risk they pose to people and pets locally,” said Dr. Carpenter.

How CAPC Forecasts are Created

The annual CAPC Pet Parasite Forecasts are a collaborative effort between parasitologists and statisticians in leading academic institutions across the United States who conduct ongoing research and data interpretation. Their goal is to better understand and monitor vector-borne disease agent transmission, as well as changing life cycles of parasites.

The forecasts are based on many factors, including temperature, precipitation and population density. More than 12 peer-reviewed articles about these forecasts have demonstrated a consistent, weighted correlation of 0.9 and higher to actual laboratory results, illustrating that CAPC Forecasts are highly accurate.

About the Companion Animal Parasite Council

The Companion Animal Parasite Council ( is an independent not-for-profit organization comprised of parasitologists, veterinarians, as well as medical, public health and other professionals, who provide information for the optimal control of internal and external parasites that threaten the health of pets and people. Formed in 2002, 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 disease transmission.