Heartworm and Lyme disease are on the march

The Companion Animal Parasite Council forecasts problem areas, blaming weather and the “ever-changing nature of parasites.”

Heartworm and Lyme disease are on the march

Pets living in or traveling to certain parts of the United States face a higher risk of contracting heartworm or Lyme disease this year, the Companion Animal Parasite Council reports.

The organization warned that mosquito-transmitted heartworm disease poses a bigger threat in the Southeastern United States because of weather that is predicted to be warmer and more humid than normal. Pet owners in the Appalachian region, Minnesota and the Atlantic Coast should be on high alert for Lyme disease, which is spread by ticks that quickly expand their range by catching rides on white-tailed deer and migratory birds.

“We started providing our annual forecasts over eight years ago because of the dynamic and ever-changing nature of parasites,” said Christopher Carpenter, DVM, the council’s executive director. “Over the years, we have seen these diseases continue to move.”

A key takeaway is that both diseases are preventable in pets. The council recommends regular testing, Lyme disease vaccinations and year-round use of heartworm preventives.

The annual forecast includes these diseases and risk areas:

  • Heartworm: Higher than average in the south-central and southeastern states. “The areas of greatest concern are those along the Mississippi River from northern Louisiana all the way into Illinois,” the council stated. “In addition, areas with historically lower prevalences of heartworm should particularly take note … including Indiana, Illinois and Iowa. Southern Louisiana and a small area along the Texas border are currently forecasted to be lower than average.”
  • Lyme: “Oozing into the entire Appalachian region, the Atlantic Coast and throughout Wisconsin and Minnesota.”
  • Anaplasmosis: “Average for much of the United States. However, northwestern Minnesota is forecasted to have an active year.”
  • Ehrlichiosis: “Higher throughout the southern central United States, particularly in Oklahoma, Arkansas and Missouri.”

The Companion Animal Parasite Council generates 30-day forecast maps to alert pet owners and veterinarians of pending outbreaks. The maps, broken down by county, are available at

CAPC heartworm

CAPC Lyme Protection Status