Double Trouble: Doug’s Wellness Screening Revealed Unexpected Duo of Vector-Borne Diseases

Overview

Conducting routine wellness lab work on a pet that presents as healthy can not only set a baseline for the rest of their lives, but also potentially uncover important information regarding exposure or disease before they reach the clinical threshold. That’s exactly what happened with Doug, a rescue dog who moved with his family from Alabama to their new home in Pennsylvania shortly after he was adopted.

Case Details and History

Doug was adopted from a rescue group by a young couple living in Alabama and was deemed healthy by the rescue group. Shortly after he was adopted, Doug and his new family moved to Pennsylvania. After eight months in Pennsylvania, Doug’s owners brought him into the veterinary hospital for his annual exam and vaccinations. He appeared clinically healthy at home and his owners had no concerns.

Physical Examination

• No abnormalities were detected during Doug’s physical wellness exam.
• The clinician spoke with Doug’s owners about the importance of preventive care and compliance with expert- and evidence-based guidelines for infectious disease and screening.
• Additionally, the clinician discussed expanding that testing to include a complete minimum database to establish a baseline of health that can be trended at his annual visits moving forward.
• After discussion with the owners about the risks and the costs, together they decided to move forward with comprehensive wellness testing.

Diagnostic Process

• The clinician recommended screening for infectious diseases of the GI tract with fecal testing via Antech’s KeyScreen™ GI Parasite PCR. As the most comprehensive fecal GI parasite screening, KeyScreen identifies common hookworms, roundworms, whipworms, tapeworms, protozoa species like cryptosporidium that oftentimes are missed during flotations. Importantly, KeyScreen also tested Doug’s sample for drug-resistant hookworms and Giardia, including Giardia strains with the potential to infect people.
  • Key Diagnostic Finding: Doug’s KeyScreen results came back clear—no GI parasites were noted.
• Doug was also screened for vector-borne diseases via a blood test. The Accuplex™ vector-borne disease screening looked for heartworm disease as well as tick-borne disease exposure.
  • Key Diagnostic Findings: Doug’s Accuplex panel, performed at the Antech Reference Lab, came back positive for antibodies to Borrelia burgdorferi, the causative agent of Lyme disease. In compliance with expert-based guidelines, Accuplex identifies the antibodies to the C6 peptide which indicates natural exposure/infection to Lyme causing bacteria without cross-reactivity to vaccinal antibodies. Doug also came back as heartworm positive; per the American Heartworm Society guidelines, the team needed to then do confirmatory testing to know whether or not to treat Doug for an active infection.
• Doug’s wellness profile included CBC, chemistry, and urinalysis.

Diagnosis and Treatment

• Diagnosing and Treating Borrelia burgdorferi:
  • In Doug’s case the team looked to Antech’s clinical decision-making algorithms, coupled with the ACVIM consensus statement on Lyme borreliosis in dogs and cats, to guide a full assessment of Doug.
  • With positive C6 antibodies in a patient that’s non-clinical, the recommended next step is to assess for proteinuria. In an asymptomatic dog, antibiotics may not be warranted, but a small percentage of dogs develop protein-losing nephropathy, or glomerulonephritis, if the immune system overreacts. Screening for early detection of proteinuria provides an opportunity to intervene early for better clinical outcomes.
    • Doug’s labwork, as part of his minimum database, showed that his kidneys were functional. His urine specific gravity was highly concentrated, and he had no protein in his urine.
      • If increased protein had been detected, and in the absence of an active sediment, a urine protein:creatinine ratio (UPC) is recommended to assess the significance of the proteinuria and concern for kidney damage.
    • With no sign of glomerulonephritis for Doug, the veterinarian discussed improving tick prevention protocols and plans for routine, quarterly screening for proteinuria, as long as he remains Lyme antibody positive.

• Diagnosing and Treating Heartworm:
  • The CAPC parasite prevalence maps show a much higher prevalence for heartworm in Alabama where Doug came from than in his current home in Pennsylvania. As such, it was suspected he had acquired his infection when in the Southern US. Though the rescue had screened Doug as healthy before he was adopted, heartworm antigen likely occurred early in the life cycle of a heartworm infection before antigen from a mature gravid female worm could be detected.
  • Doug’s care team ran a confirmatory test, identifying circulating microfilaria.
  • Though Doug’s CBC showed no signs of anemia or thrombocytopenia (which could support active Lyme infection), he did have an eosinophilia, which may have been a reflection of the parasitic heartworm infection, and the team planned to recheck after treatment.
  • Fortunately, everything on Doug’s chemistry profile fell nicely right in the middle of the reference interval, supporting healthy organ function and metabolic processes. This meant the team could reassure Doug’s owners that—even given exposure to (or potential infection with) Lyme disease alongside a known heartworm infection—he otherwise appeared healthy and should be a good candidate for pharmaceutical treatment of his heartworm infection..

Case Impact

It’s easy to get compliance on diagnostic lab work when you have an owner coming in with a beloved pet that is appearing “off” or presenting with signs of illness. But when that patient is wagging their tail and just coming in for a wellness appointment — it can be tricky to communicate the value of diagnostic lab work as part of their preventive care plan.

An American Animal Hospital Association (AAHA) published study found that one in seven seemingly healthy adult-aged animals had clinically significant lab abnormalities that warranted further intervention or further diagnostics. AAHA recommends comprehensive lab work to obtain a baseline of health sometime in a pet’s young adult years, conducting annual testing as they get to mature adult years, and testing more frequently in their senior years to catch abnormalities or disease early during periods of clinical health. Care teams must remember the importance of explaining the difference between exposure and disease, and how regular wellness labs provide a foundation to monitor health moving forward.

Doug’s case highlights the importance not only of wellness testing, but also of taking history into account and casting a wide net in testing/screening. Vector-borne diseases observed in our pet population — particularly Lyme, Anaplasma, or Ehrlichia — are the proverbial canary in the coal mine. An increased prevalence of Lyme in an area means that, by default, the humans living in that area are at an increased risk over time for exposure to those diseases as well. This means veterinarians have an important educational role to play in our communities when it comes to public health, and to ensure the health of our pets, and their humans, it’s important to explain the value and importance of year-round compliance on prevention, as well as the potential impact on human health.