CAPC forecast points to broader parasite risk in 2026

The 2026 Pet Parasite Forecast from the Companion Animal Parasite Council, or CAPC, is another sign that vector-borne disease risk in companion animals is no longer confined to familiar hot spots. This year’s outlook projects continued geographic expansion of canine Lyme disease, ehrlichiosis, anaplasmosis, and heartworm across the United States, including growth in places that many veterinary teams have historically treated as lower-risk markets. (prnewswire.com)

That shift has been building for years. CAPC says its annual forecasts draw on more than 10 million diagnostic test results per vector-borne disease each year, along with weather patterns, vegetation, and human population data, to model where dogs are likely to test positive. The council argues that surveillance has to be continuous and geographically broad because parasite risk is changing with tick and mosquito habitat, wildlife movement, climate pressures, and pet relocation. Auburn parasitologist and CAPC board member Kathryn Reif, the lead author on the 2026 forecasts, said the central trend is simple: ticks keep spreading, and the risk is increasingly year-round. (capcvet.org)

The disease-specific signals are practical for clinics. CAPC projects Lyme disease spreading beyond the traditional Northeast and Upper Midwest into parts of the Midwest, Appalachia, the Northern Plains, and portions of the Southeast. Heartworm remains highest in the Southeast, but the forecast points to continued northward spread along the Mississippi River corridor and Atlantic coast, plus emerging pockets in the Mountain West and Northern California. Ehrlichiosis risk stays high across the Southeast, Southwest, and south-central U.S., while anaplasmosis is rising both alongside Lyme expansion and in the Southwest, where CAPC says brown dog tick transmission may be a useful proxy for broader brown dog tick activity, including Rocky Mountain spotted fever risk. (prnewswire.com)

CAPC’s recommendations are correspondingly direct. The group advises year-round parasite prevention, annual testing, and closer use of county-level prevalence and forecast maps to tailor recommendations. It also says Lyme vaccination should remain risk-based, but veterinarians in endemic and increasing-risk areas should weigh it more actively as local exposure changes. CDC guidance aligns with that framing, noting that Lyme disease is the one tick-borne disease for which dogs may be vaccinated and advising veterinary consultation about local tick-borne risk. (capcvet.org)

Outside CAPC, the broader public health conversation is moving in the same direction. On May 29, 2026, HHS announced a federal initiative to strengthen the U.S. response to Lyme disease and other tick-borne illnesses, including a CDC-led pilot program focused on tick control, innovation funding, and additional work on alpha-gal syndrome. That announcement is aimed at human health, but it reinforces the One Health context around the parasite forecast: companion animal data are increasingly relevant to how public health agencies think about emerging vector risk. (hhs.gov)

Expert commentary around the forecast has emphasized that point. Reif said dogs are “wonderful sentinels” for human risk because they share many of the same exposure patterns as people. That’s consistent with CDC-backed literature showing canine serology can function as an adjunct to human Lyme surveillance, not because dogs transmit Lyme directly to people, but because positive dogs often reflect shared environmental exposure to infected ticks. FDA consumer guidance also notes that reducing tick exposure in dogs can lower the chance of infected ticks reaching people in the household. (vetmed.auburn.edu)

Why it matters: For veterinary teams, the operational takeaway is that “low-risk” may no longer be a stable category. Practices may need to revisit how they frame seasonality, whether they’re testing often enough, how they discuss travel and relocation risk, and when they introduce Lyme vaccination into preventive conversations. The forecast’s county-level granularity could be especially useful for client communication, since CAPC says the maps can support compliance and help practices show why year-round prevention matters even in winter or in markets where parasite risk once seemed sporadic. (capcvet.org)

What to watch: The next signal will be whether forecasted expansion shows up in local testing patterns over the 2026 season, and whether veterinary uptake of year-round prevention, annual screening, and more localized vaccine decision-making accelerates alongside new federal attention to tick-borne disease. (capcvet.org)