Elevated risk of heartworm disease and Lyme disease continues in 2018

For the fourth year in a row, the Companion Animal Parasite Council (CAPC) forecasts heartworm infection prevalence to be above normal across virtually the entire United States. Unfortunately, 2017’s above normal forecast panned out. This increase was partially attributed to the hot and wet weather that occurred in 2016, (mosquitoes like these conditions), and in 2017 weather was again hot and wet. Moreover, infected dogs act as “reservoirs of infection”, increasing the number of infected mosquitoes and ultimately spreading the parasite to other dogs. CAPC is concerned with this annual increase in numbers of cases. Nationally, prevalence rates have risen each of the last five years and are now up 20% from 2013 levels.

In addition to concerns related to heartworm, there is an increasing number of dogs being detected with infections with the bacteria that causes Lyme disease. Given this, it is natural that our national forecasts voice concern for many areas of the country.

Heartworm Disease Forecast

20180412 Capc Forecast Maps Heartworm

Overall, CAPC is forecasting above average activity nationwide.

  • The Lower Mississippi Valley, an area where heartworm is rampant, is again forecasted to be more active than normal in 2018.
  • Locations in the Northern tier states --- from Washington State to Vermont --- are forecasted to see more cases in 2018.
  • North and South Carolina coastal areas: you are also predicted to see above normal activity.
  • The Pacific Coast states west of the Sierras are expected to see above normal prevalence.
  • Congratulations Alpena, Michigan: you are virtually the only area in the country forecasted to see below normal activity in 2018.

The increase in heartworm activity supports CAPC’s recommendation that all dogs be given heartworm preventatives year-round, and tested annually for both heartworm antigens and microfilariae.

Lyme Disease Forecast

20180412 Capc Forecast Maps Lyme

Nationwide, dogs exposed to the agent of Lyme disease are continuing to be discovered in areas outside recognized endemic regions. The savvy veterinarian living close to the borders of these regions (The Dakotas, Iowa, Illinois, Ohio, Kentucky, Tennessee, and North Carolina) needs to be vigilant.

  • Western Pennsylvania, Eastern Ohio, West Virginia, and the Appalachian region in Virginia: prepare for an active year.
  • Northwestern Wisconsin and Northern Minnesota are expected to see much higher than normal activity in 2018.
  • Washington DC to Philadelphia, PA and eastward (including the Delmarva area) and the Boston/Cape Cod area: congratulations, you are expected to see a little relief this year.

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.

2018 Anaplasma spp. forecast

2018 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".

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.