By Michelle Evason (BSc, DVM, DACVIM (SAIM), MRCVS) Director, Veterinary Education & Outreach at Antech • Antech Veterinary practitioners across North America are seeing more ticks, and dogs and cats with disease caused by tick-borne infections. These are occurring beyond the regions (and during seasons!) where veterinarians have traditionally detected them. Diseases like anaplasmosis, and dogs who test positive for exposure, are growing increasingly common. For anaplasmosis, this is due to the pervasiveness of the Ixodes scapularis deer tick. This tick vectors Anaplasma phagocytophilum, along with Borrelia burgdorferi (the agent of Lyme disease), in endemic and now emerging regions—this is happening even in my own area in Canada, where more than five years ago, we veterinarians just never thought about it being a problem.1 Meanwhile, other vector-borne disease (VBD) like Chagas (caused by transmission of Trypanosoma cruzi from kissing bugs to dogs or humans), and cytauxzoonosis in cats (transmitted by ticks), are moving out of areas in the U.S. we used to think of as focal hotspots, like Texas and Tennessee respectively, and emerging in new states and regions, such as Indiana, Illinois, and California.2,3 Both Chagas and cytauxzoonosis are two of several vector-borne diseases that can be devastating for pets if not diagnosed promptly. In its 2025 pet parasite forecasts and regional maps, the Companion Animal Parasite Council (CAPC) affirmed what veterinarians have been witnessing on the front lines: more pets testing positive for VBD pathogens. These numbers are expanding geographically in the U.S. and Canada, driven largely by increasing vector numbers and shifting, expanding, populations. Importantly, these numbers don’t account for the estimated millions of dogs that are not receiving advised veterinary screening for even the most common VBD. Unsurprisingly, human VBD cases have been trending up also. The Center for Disease Control and Prevention (CDC) reports that diagnosis of VBD in humans has increased significantly since 2004, with more than one million cases of VBD reported between 2001 and 2023, and annual cases more than doubling. In 2024, data presented by the World Health Organization (WHO) reported that VBD account for more than 17% of all human infectious diseases and causes more than 700,000 deaths annually. In dogs, heartworm, Lyme borreliosis, anaplasmosis, and ehrlichiosis remain the four VBD most commonly diagnosed by veterinarians. However, increased geographical spread of ticks that vector Rocky Mountain Spotted Fever (Rickettsia Spotted Fever group), babesiosis, cytauxzoonosis, and other vectors like kissing bugs and fleas, that transmit other dog and cat diseases, has led to rising cases in dogs and cats, and demands for wider flexibility and options for timely testing. As veterinary professionals, we’re sometimes only afforded the opportunity to manage disease concerns instead of absolutely diagnose, fix and cure the clinical signs caused by many diseases. However, most infectious diseases cause illness that we can actually fix, and completely cure, much of the time—once they’ve been definitely diagnosed—especially when we have access to testing that can detect them. We can then use that information to target treatment for pets quickly and effectively. Even better, we can prevent many vector-borne infectious disease concerns in dogs and cats from occurring at all, or catch them early on, through effective prevention strategies combined with annual screening. Over the past two decades, I’ve talked a lot with veterinarians about how to work towards detecting, diagnosing, and treating infectious diseases. I’m excited about the comprehensive, and contextualized, diagnostic options Antech now has available for VBD screening. Not only that, I feel proud that these options are supported with clinical algorithms that step practitioners through in-the-moment decision-making on what tests to run, in which pets, why, and provide information on what treatment and prevention strategies to use, along with helping veterinarians in pet owner communication and One Health conversations. Whether it’s a screening to identify exposure to tick-borne pathogens, like Anaplasma and Ehrlichia spp., and B. burgdorferi, or a broad molecular diagnostic panel to help with acute disease detection or confirm the presence of genetic material, like Antech’s new Vector-Borne Disease PCR (polymerase chain reaction) Panel, these options empower veterinary teams, guide treatment, and support antimicrobial stewardship. Our Shared Responsibility as Veterinary Care Providers With the proliferation of infectious diseases in today’s world, having the ability to quickly and easily test for disease (particularly when presented with acutely ill patients), identify disease exposure, pinpoint exactly what's going on to accurately diagnose, and then proceed to targeted treatment is critically important. Not only for our four-legged patients, but for their human families, the broader community, and environment as well. There are numerous cases of dogs, and even cats, acting as that proverbial ‘canary in the coal mine’ for their human caregiver. We know that many of these infectious agents that cause illness in pets have human health impacts. However, human care providers often don’t ask about family pet/animal health; dogs that are sick and diagnosed by their veterinarians with a VBD of concern are sometimes not included as part of human medical histories. Sadly, this lack of awareness around pets’ ability to act as sentinels of disease risk for people has led to human deaths, which may have been avoided if identified early. This makes increased understanding of VBD pathogen risk and provision of options for timely testing more important than ever before. One Health is a way of looking at the connections, and intersections, between people, animals, and the environment, and recognizing that we are all linked. Along with supporting antimicrobial stewardship, at Antech, One Health is part of the development of advanced diagnostic tests, clinical decision-making algorithms, and the communication and support given to veterinarians by the consultation services team. Antibody vs. PCR Testing: What to use for which pet, when, and why? In veterinary medicine, we’ve historically used serology (antibody testing) to look for both evidence of infectious disease and exposure, and these tests have an important role in screening for a pet’s immune response to infectious agents. For example, the presence of a positive test result on Accuplex™, or Antech’s in-house test option trūRapid FOUR™, confirms a dog has been exposed to the bacteria that can cause Lyme disease, anaplasmosis, and ehrlichiosis, and developed an antibody response. However, it’s important to recognize that most dogs and cats exposed to VBD pathogens like these do not develop clinical disease. Screening for antibodies provides the critical opportunity to inform conversations with pet-owners on prevention and cheer compliance with medications when negative. When VBD is suspected in acutely ill pets, PCR is often the better test choice, because antibody production by the body can take time to develop for many infectious disease agents, and serology testing will be negative, while PCR detects genetic material when an infectious agent is present. Here’s how PCR works: When a veterinarian obtains a blood sample from a pet, the PCR test works to amplify genetic material (e.g. DNA, RNA) in the sample. By amplifying with PCR, pathogen DNA or RNA can be utilized to pinpoint and detect infectious agents before the immune system has had a chance to mount an antibody response. A common example of test option decision-making, especially these days, is when an apparently healthy dog (i.e. no clinical signs) has a positive antibody result on an Anaplasma spp. or Ehrlichia spp. screening test, like Accuplex. This result tells us that the dog has had a tick bite—and the tick attached long enough to transmit the infection—and the dog mounted an antibody response which is picked up by the test. In these situations, it can be difficult for a veterinarian to know whether the patient is actively ill, might become sick, or has cleared the infection on their own. Consequently, determining the appropriate course of action (or if additional diagnostic testing is necessary) can be quite challenging. A PCR test detects the genetic material of an infectious agent (like Anaplasma or Ehrlichia spp.) and confirms the presence of active infection; this informs whether specific antimicrobial treatment is needed or not. This is important as we, as veterinarians, don’t want to be using antimicrobials when not needed, and we certainly want to make the correct recommendations on next-step diagnostics as well. Since many VBD, like anaplasmosis in dogs, frequently present with vague, non-specific clinical signs (e.g. reduced appetite, lethargy, generalized pain), and as antibodies are not usually present in acute onset of disease, PCR is often preferred to detect infection, clarify these complex cases, identify any co-infections, and help veterinarians target appropriate and timely treatment. The Most Comprehensive PCR Panels in the Industry This year, in concert with bringing Antech’s Vector-Borne Disease PCR Panel, the in-house trūRapid FOUR, and expanded Accuplex test options to market, multiple research abstracts on these diagnostic offerings were submitted, accepted, and presented at the 2025 ACVIM Forum. One of these studies reported that the Antech Vector-Borne Disease PCR Panel was at parity, in a head-to-head comparison with the PCR test currently considered the “gold standard” by many veterinarians, and detected a broader range of pathogens, plus contained an antimicrobial resistance marker (atovaquone drug) to assist veterinary teams with targeted treatment planning in dogs and cats. In addition to testing for the common VBD pathogens, Antech’s comprehensive Vector-Borne Disease PCR Panel includes emerging pathogens like Trypanosoma cruzi (Chagas), Cytauxzoon felis, Hepatozoon, and Rickettsia Spotted Fever Group, among others. The Vector-Borne Disease PCR Panel also detects the antimicrobial resistance marker for atovaquone, a growing concern in the treatment of Babesia and Cytauxzoon infections and is exclusively available through Antech. The Time to Detect is Now As cases of VBD, and evidence of VBD pathogen exposure, continue to rise in both endemic and emerging regions, veterinary professionals will increasingly become leaders in provision of care that considers the interconnectedness of human, animal, and environmental health—and are perfectly positioned to work across disciplines in order to detect, prevent, and control health threats. Antech’s VBD options ensure veterinarians have access to, and options for, the broadest range of contextualized infectious disease diagnostics on the market—exactly what our profession, pet patients, and their people need right now. References Jacob AE, Weese JS, Rosseau J, Clow KM. Spatial patterns of Borrelia burgdorferi, Borrelia miyamotoi and Anaplasma phagocytophilum detected in Ixodes spp. ticks from Canadian companion animals, 2019-2020. Zoonoses Public Health. 2022 Dec;69(8):944-955. Gavic EA, Achen SE, Fox PR, Benjamin EJ, Goodwin J, Gunasekaran T, Schober KE, Tjostheim SS, Vickers J, Ward JL, Russell DS, Rishniw M, Hamer SA, Saunders AB. Trypanosoma cruzi infection diagnosed in dogs in nonendemic areas and results from a survey suggest a need for increased Chagas disease awareness in North America. J Am Vet Med Assoc. 2023 Feb 2;261(5):705-712. Reichard MV, Cotey SR, Dangoudoubiyam S, Weerarathne P, Tussey K, Wilkes RP, Miller CA, Mehringer L, Burcham GN. Cytauxzoonosis in Indiana, USA: a case series of cats infected with Cytauxzoon felis (2018-2022). J Feline Med Surg. 2024 May;26(5)).
