The tick vector of Borrelia burgdorferi, an agent of Lyme disease in dogs, is expanding its range from the northeastern and mid-Atlantic states, the upper Midwestern states, and throughout Canada. These ticks are bringing their associated pathogens along for the ride. These include Anaplasma phagocytophilum, Babesia spp., Borrelia miyamotoi, Ehrlichia muris eauclarensis, and possibly Bartonella spp. among others.

  • The seroprevalence of B. burgdorferi is predicted to be higher in three areas this year. Most notably throughout the Appalachian region. Veterinarians in eastern Pennsylvania, West Virginia, western Virginia and North Carolina, and eastern Ohio and Kentucky should reinforce their recommendations on the use of tick preventatives and may consider vaccination for high-risk patients.
  • Second, a hotspot of higher than average seroprevalence is expected to be seen in northwestern Minnesota.
  • Third, although small, areas in Indiana are expected to see higher than average seroprevalence. This is not a historically endemic state, so veterinarians should educate themselves and their clients about the risks of tick-borne disease.
  • The Atlantic coast, New England states, central Wisconsin, and southeastern Minnesota are all expected to see lower than average seroprevalence in 2019.

Preventing exposure to ticks is the best way to prevent infection with tick-borne pathogens. The areas highlighted above expected to see lower than average seroprevalence are endemic for Borrelia burgdorferi and risk for exposure is high!

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.

2019 Anaplasma spp. forecast

2019 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 is 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”.

Veterinary professionals and pet owners who want to monitor the activity in their county throughout the year, can also access 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.

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 tests and the influence of weather patterns, vegetation indices, and human population density. Using this multi-disciplinary approach, we are leveraging everyone’s expertise to focus on a single common interest: forecasting the risk of exposure to vector-borne pathogens. 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.

We are committed to publishing our scientific studies in open-access journals so they are freely available to researchers, veterinarians, and the general public. For those interested in learning more about the science of these forecasts or to see additional graphics, we encourage you to view them here:


Bowman DD, Liu Y, McMahan CS, Nordone SK, Yabsley MJ, Lund RB. Forecasting United States heartworm Dirofilaria immitisprevalence in dogs. Parasit Vectors. 2016 Oct 10;9(1):540.

Wang D, Bowman DD, Brown HE, Harrington LC, Kaufman PE, McKay T, Nelson CT, Sharp JL, Lund R. Factors influencing U.S. canine heartworm (Dirofilaria immitis) prevalence. Parasit Vectors. 2014 Jun 6;7:264

Brown HE, Harrington LC, Kaufman PE, McKay T, Bowman DD, Nelson CT, Wang D, Lund R. Key factors influencing canine heartworm, Dirofilaria immitis, in the United States. Parasit Vectors. 2012 Oct 30;5:245.

Tick-borne pathogens:

Stich RW, Blagburn BL, Bowman DD, Carpenter C, Cortinas MR, Ewing SA, Foley D, Foley JE, Gaff H, Hickling GJ, Lash RR, Little SE, Lund C, Lund R, Mather TN, Needham GR, Nicholson WL, Sharp J, Varela-Stokes A, Wang D. Quantitative factors proposed to influence the prevalence of canine tick-borne disease agents in the United States. Parasit Vectors. 2014 Sep 4;7:417.

Watson SC, Liu Y, Lund RB, Gettings JR, Nordone SK, McMahan CS, Yabsley MJ. A Bayesian spatio-temporal model for forecasting the prevalence of antibodies to Borrelia burgdorferi, causative agent of Lyme disease, in domestic dogs within the contiguous United States. PLoS One. 2017 May 4;12(5):e0174428.

Liu Y, Lund RB, Nordone SK, Yabsley MJ, McMahan CS. A Bayesian spatio-temporal model for forecasting the prevalence of antibodies to Ehrlichiaspecies in domestic dogs within the contiguous United States. Parasit Vectors. 2017 Mar 9;10(1):138.

McMahan CS, Wang D, Beall MJ, Bowman DD, Little SE, Pithua PO, Sharp JL, Stich RW, Yabsley MJ, Lund RB. Factors associated with Anaplasmaspp. seroprevalence among dogs in the United States. Parasit Vectors. 2016 Mar 22;9:169.

Liu Y, Watson SC, Gettings JR, Lund RB, Nordone SK, Yabsley MJ, McMahan CS. A Bayesian spatio-temporal model for forecasting Anaplasmaspecies seroprevalence in domestic dogs within the contiguous United States. PLoS One. 2017 Jul 24;12(7):e0182028.



We shall see if Wisconsin truly has lower seroprevalence.  I’m not buying it.