The danger of humans getting infected by vector-borne illnesses, such as Lyme disease, is massively underrecognized, particularly in areas that are not traditionally seen as endemic. That’s where canine mapping comes in. Dogs spend a lot of time outdoors in the company of their owners, meaning both canines and humans are exposed to similar environments and risk factors.
According to Dr. Michael Yabsley, who created a forecast map in 2017 showing Lyme disease infections in dogs across the U.S. at a county level, “Dogs really are the canary in the coal mine for human infection. Our research team has evidence that the relationship between canine disease and human disease is strong.” (1)
Canines also serve as effective sentinel indicators for human infections because of differences in how dogs and people are diagnosed. Many veterinarians recommend that dogs get tested annually for tick-borne diseases (e.g., the popular IDEXX 4Dx blood test can detect antibodies to Lyme disease bacteria, Anaplasma, Ehrlichia, and heartworms), as well as after a tick bite. (2) This contrasts sharply with people, who are generally only tested if they happen to notice a tick bite or after they have suffered years of increasingly severe symptoms. (Not to mention, many dogs are on tick preventatives year-round to reduce the likelihood of getting bitten in the first place.) As a result of these testing differences, more data is widely available on the prevalence of tick-borne diseases in canines, and research demonstrates how this information can be used to predict the dangers faced by humans.
Canine maps can give the public more information about the spread of ticks and the infections they carry, like Lyme disease, into areas not generally considered endemic. Take the state of Texas, for instance, which is generally not considered high risk for tick-borne diseases. This 2021 study provided evidence that self-reported tick bites from Texas residents overlapped with individuals who had CDC-positive Lyme tests as well as canine-positive Lyme, Anaplasma, and Ehrlichia tests. (3) It also identified county hotspots where the threat of tick-borne illness was high for both dogs and people.
Even in places considered endemic, the risk of contracting Lyme disease or another tick-borne illness can vary greatly depending on the particulars of the region. For example, a 2023 study examined IDEXX 4Dx blood tests from 3,750 dogs living in shelters in 19 states in the Eastern United States. The results found that 8.9% of the canines had Lyme disease bacteria, 2.4% had Anaplasma, and 8% had Ehrlichia. Furthermore, almost 5% of the shelter dogs were suffering from multiple infections. Based on the geographical distribution of these tick-borne infections, researchers will be able to determine better the risks to humans residing in the same areas.
It’s not uncommon for patients seeking answers to their mysterious symptoms to hear some variation of: “It can’t be Lyme disease. Lyme doesn’t exist here.” However, canine maps clearly illustrate that Lyme disease and other tick-borne infections have spread across the United States. Studies like this one out of Germany (4) reveal similar patterns in human and canine infections, suggesting that if a dog can get exposed to Lyme and other tick-borne infections, then so can the people living in the same geographical region, even if they are non-pet owners.
For U.S. residents who are wondering about their level of risk, a nonprofit called the Companion Animal Parasite Council (CAPC) has been collecting data and putting together parasite prevalence maps for various vector-borne diseases, including Lyme, Anaplasmosis, and Ehrlichiosis, since 2012. In 2022, for instance, the CAPC reported 424,025 positive cases for canine Lyme disease; essentially, 1 out of every 30 dogs tested positive. (5) The numbers for canine Anaplasmosis and Ehrlichia cases for 2022 were similar, at 425,391 and 295,061 respectively. Compare this to the CDC data, which reports approximately 30,000 human Lyme disease cases per year despite estimating that the true statistics is closer to half a million. (6)
Based on the canine data, it’s clear that tick-borne infections in humans are going underreported and very likely misdiagnosed. Awareness of the prevalence of Lyme disease and other tick-borne illnesses in our canine companions can improve our understanding of how these infections are affecting the human population.
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After losing the role of a lifetime, an aspiring actor retreats to his hometown. When he encounters a woman who has Lyme disease, an unexpected friendship develops, forcing them both to make life altering decisions.
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The International Lyme and Associated Diseases Society (ILADS) hosted its 2024 Annual Scientific Conference from November 7–10, 2024, at the Grand Hyatt San Antonio River Walk in San Antonio, Texas. This highly rated conference focuses on the theme "Redefining Lyme Disease: The Fusion of Science and Practice," bringing together healthcare professionals, researchers, and advocates to advance the understanding and treatment of Lyme and other tick-borne illnesses.
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When someone in a child’s life has Lyme disease — whether it is a parent, a sibling, a friend, or they themselves — they are bound to have questions. They may experience a range of feelings, including stress, worry, fear, or even anger. Parents and other caring adults can help by providing age-appropriate answers and being present and supportive.
