Heartworm disease and Lyme disease are forecasted to be highly problematic in 2017

by Michael J Yabsley MS, PhD, FRES

The 2017 forecasts are in, and CAPC is forecasting an active year for heartworm disease and Lyme disease. Based on analysis of multiple environmental drivers of disease, CAPC is predicting heartworm disease and Lyme disease will increase well beyond their established endemic boundaries, leading to higher than average caseloads. The 2017 forecasts for Ehrlichia and Anaplasma are less volatile in comparison, requiring ongoing surveillance in regions of endemic disease.  One exception is the Ohio River Valley, which is experiencing convergence of Ehrlichia from the south and Lyme disease from the Central Midwest and Northeastern US.

Heartworm disease forecast

The United States as a whole experienced above average precipitation and seasonal temperatures in 2016, leading to perfect conditions for breeding the mosquitoes that transmit heartworm disease. Last year's forecasted heartworm outbreak in Northern California unfortunately came to fruition. Given the ongoing trend toward above average temperatures and rainfall, CAPC is forecasting high levels of heartworm disease activity in 2017 for most of the country, with an especially active year for the Western United States. Of great concern is the ongoing precipitation that the West is currently seeing this winter, leading to the prediction that heartworm disease will continue to increase even farther beyond its endemic range in 2017.

Overall, CAPC is forecasting above average heartworm disease activity nationwide. Key areas of concern include:

  • The Lower Mississippi Valley, where heartworm disease is rampant, is expected to observe greater cases loads than normal.
  • Locations in the Rockies and westward, where heartworm disease may not be foremost on the veterinarian's mind, are forecasted to be problematic in 2017.
  • New England, the Ohio River Valley, the Upper Midwest, and the Atlantic Coast States are predicted to see above normal heartworm disease activity.
  • Western Texas from Amarillo to Laredo may observe static to lower than average burden of heartworm disease in 2017.

CAPC recommends that all dogs be tested annually for both heartworm antigens and microfilariae, even if they are on year-round preventives.

20170410 Capc Forecast Maps Display V4 Heartworm

Lyme disease

Nationwide, Lyme disease continues to emerge beyond accepted endemic boundaries. Veterinarians practicing on the edges of Lyme disease endemic areas (The Dakotas, Iowa, Missouri, Southern Illinois, Ohio, Kentucky, Tennessee, North Carolina) should be aware of disease encroachment and remain vigilant about testing and protecting patients and educating clients about this zoonotic disease.

  • Western Pennsylvania, and Pittsburgh are of elevated concern: Lyme disease is now endemic in these regions and is forecasted to be even more problematic this year.
  • New York State, North-western Wisconsin and Northern Minnesota, already endemic for Lyme disease, are expected to observe higher caseloads than in previous years.
  • Lyme disease along the Atlantic seaboard (I-95 corridor) from Washington DC to Boston is forecasted to remain static this year. 
20170410 Capc Forecast Maps Display V4 Lyme

Ehrlichiosis and Anaplasmosis

View the Ehrlichia spp. and Anaplasma spp. forecast and learn more about the CAPC guidelines for prevention and treatment of ehrlichiosis and anaplasmosis.             

2017 Anaplasma spp. forecast 

2017 Ehrlichia spp. forecast


Year-round protection, annual testing

The best way to protect your patients is to advise owners of the importance of year-round prevention, even during the winter months. You can use the CAPC Parasite Prevalence Maps to support your recommendation by underscoring the risks in your area and in regions of the country your clients may travel with their pets. It’s also critical to emphasize the importance of compliance and using products according to label. The use of CAPC Parasite Prevalence maps and Forecast maps are a validated tool for increasing client willingness to engage in parasite prevention. Sign up for local alerts today by visiting the CAPC Parasite Prevalence Maps and selecting "Get Updates".

The Science behind the Forecasts

Vector-borne disease is dynamic and ever changing, driven by multiple factors that affect the development of arthropod vectors and the pathogens they carry. Leading parasitologists work in collaboration with a team of statisticians to identify regions of the country that may experience higher parasite incidence in the months ahead. Numerous factors are analyzed, including the number of positive disease tests and the influence of weather patterns, vegetation indices, the changing distribution of wildlife that may harbor the parasite, and human population density. Using this multi-disciplinary approach, we are leveraging everyone’s expertise to focus on a single common interest: forecasting parasitic disease. While these forecasts predict the potential risk of a dog testing positive, they do not necessarily reflect the occurrence of clinical disease.

To learn more about the science behind the maps, full access to our manuscripts describing the methodology and fidelity of our forecasts can be found here.