CAPC releases 2025 Pet Parasite Forecast

The Companion Animal Parasite Council (CAPC), a nonprofit that is the leading authority on vector-borne-diseases that impact the lives of pets and people, shared its 2025 Pet Parasite Forecast with a warning that Lyme, heartworm, anaplasmosis, and ehrlichiosis diseases are still spreading through the United States. According to an organizational release, the reports use over 10 million diagnostic tests that are reported every year for its annual forecast to help veterinarians and clients assess the risks of disease in their communities.

“The CAPC maps are an invaluable resource for veterinarians and pet owners,” said Brian Herrin, DVM, PhD, CAPC board president, in the release.¹ “These forecasts provide critical insights for both pet and public health, as pets and their owners live and play in the same places. It’s also important to remember that low risk doesn’t mean no risk, so year-round prevention is essential to keeping pets safe from these potentially fatal diseases.”

Graphics courtesy of the Companion Animal Parasite Council

Since 2012, CAPC has been precise with its forecasting of parasitic diseases with 94% accuracy in predicting the true prevalence of the 4 diseases across the US. In this year’s forecast, CAPC highlighted the continued expansion of pet and human vector-borne diseases geographically, primarily with shifting populations of mosquitoes and ticks.

Within the findings, CAPC stated that tick-borne diseases Lyme and anaplasmosis continue to expand south and west in the US, and the upper Midwest and northeast continue to be more high-risk areas. Ehrlichiosis, which is also spread by ticks, is high still in the southeast, with expansion moving northward in the upper Midwest and New England region.

The forecast also showed that mosquitoes are increasingly spreading heartworm diseases throughout the southeastern US, with highest risks found along the Atlantic coast and northward along the Mississippi River. Because of this spreading, from Kansas to Maryland is now at a heightened risk for heartworm infections, with New Mexico, Colorado, Wyoming, Montana, North Dakota, and Northern California now growing areas of increased risk.

“CAPC’s annual forecasts for Lyme, heartworm, anaplasmosis and ehrlichiosis should serve as a call to action for veterinarians and pet owners,” explained Rick Marrinson, DVM, Board member/past president for CAPC and practitioner in Longwood, Florida. “In historically endemic regions, these maps reinforce the importance of continued vigilance in testing and prevention. Meanwhile, in areas where these diseases are emerging, veterinarians should adapt new protocols to address the real and growing threats facing pets and people in their communities.”

The CAPC stated that because of the increasing threats in both endemic and emerging regions, it is crucial to administer preventatives year rounds to pets. Veterinarians are urged to reinforce the prevention of tick and mosquito exposure, assess their pet's risk based on their lifestyle and travel, and utilize vaccination and testing to help mitigate the spread of these diseases.¹

Besides providing this information to veterinary practices, the forecast also underscores the larger public health implications of vector-borne diseases after a CAPC study confirmed dogs are sentinels for human health, which provides insight into where humans face the greatest risk of Lyme disease.²

How is the forecast created?

Each year, the forecast is created by parasitologists and statisticians in academic institutes across the US who conduct ongoing data interpretation and research to collaborate on the creation of the annual forecasts. Through the forecast, those who participate in its creation hope to assist veterinary professionals and pet owners to better understand and monitor vector-borne diseases agent transmission and parasites' changing life cycles.

The CAPC Forecasts have a comprehensive analysis of multiple factors such as temperature, precipitation, and population density to ensure its strongly rooted in evidence.

“Because dog health helps us predict human health, our monthly, county-by-county forecasts are a crucial health tool for communities,” said Christopher Carpenter, DVM, MBA, chief executive officer, CAPC.¹

“Each year, we see a growing need for education and preventive care to curb the spread of these diseases. By leveraging the power of our extensive canine surveillance data, we help veterinarians and pet owners take proactive steps to safeguard animal and human health. We hope our forecasts spark meaningful conversations about how we can collectively lower disease risk,” he concluded.

References

1. Companion Animal Parasite Council 2025 Pet Parasite Forecast Warns Parasitic Diseases Affecting Pets and People Continue to Spread. News release. Companion Animal Parasite Council. April 14, 2025. Accessed April 14, 2025.
2. Liu Y, Nordone SK, Yabsley MJ, Lund RB, McMahan CS, Gettings JR. Quantifying the relationship between human Lyme disease and Borrelia burgdorferi exposure in domestic dogs. Geospatial Health. 2019;14(1). doi:https://doi.org/10.4081/gh.2019.750