According to the Companion Animal Parasite Council (CAPC), 2024 Lyme seroprevalence data showed one in 20 pets, or 4.32 percent of patients throughout the U.S., tested positive for Lyme with 12,289,296 total tested (Figure 2). (Keep in mind this is only from commercial labs and reported test results and does not include those in-house tests not reported.) However, Pennsylvania has the highest Lyme prevalence, and the data suggests one in 10, or 9.55 percent—at minimum—of the population reported was positive. Given the numerous in-clinic tests and, thus, tests not counted, I guarantee this is a gross underestimate of the seroprevalence.
In 2019, CAPC suggested the data represented 30 percent of actual U.S. cases. This percentage has likely increased given the vector's spreading home range and the spread of clinical cases across the U.S. CAPC suspects true canine seropositivity well exceeds 1 million.
So, do we treat all 9.55 percent that test positive, even if they are asymptomatic and testing confirms exposure but cannot tell us which ones will, if ever, develop clinical signs? That is a lot of antibiotics to doll out for often asymptomatic patients. Sadly, because the disease is not reportable in animals, we have a much less clear picture of the true incidence of clinical cases than in human medicine, which also has significant underreporting concerns.
