Ticks And Tick-Borne Disease

Hello Summarians!

Older patients carry more than their owners know. Often more than their bloodwork suggests.

Three studies this week circle that problem from different angles. Abdominal ultrasound found new comorbidities in 70% of geriatric dogs before TPLO surgery, compared to 14% with chest films. Tick-borne disease is expanding faster than our ability to manage it across species. And some Cushing's dogs simply will not respond to trilostane, and the markers for predicting which ones are now clearer.

Worth knowing before you start the conversation.

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Chest Rads Vs AUS Before TPLO

This retrospective study examined whether preoperative abdominal ultrasound or thoracic radiographs were more useful for identifying hidden health problems in older dogs undergoing tibial plateau leveling osteotomy (TPLO), a common surgery used to treat cranial cruciate ligament disease. Researchers reviewed medical records from 258 systemically healthy dogs over 8 years old treated at two specialty veterinary hospitals between 2019 and 2022. All dogs had normal physical examinations and routine bloodwork before surgery, and owners were offered optional preoperative imaging with thoracic radiographs, abdominal ultrasound, or both.  

Most owners chose some type of imaging before surgery, with 72.5% electing screening tests. Thoracic radiographs alone were performed in 116 dogs, abdominal ultrasound alone in 10 dogs, and both imaging methods in 61 dogs. The study found that abdominal ultrasound identified previously unknown comorbidities far more often than thoracic radiographs. New health conditions were detected in 70% of dogs receiving abdominal ultrasound compared to only 13.8% of dogs receiving thoracic radiographs. Dogs that underwent ultrasound were estimated to be 163 times more likely to have a new comorbidity identified. Common ultrasound findings included splenic nodules, hepatic nodules, splenic masses, and gallbladder mucoceles, while thoracic radiographs most commonly revealed cardiomegaly, pulmonary nodules, mediastinal masses, and other chest abnormalities.  

Age was strongly associated with the likelihood of finding additional disease. Dogs with newly diagnosed comorbidities had a median age of 12.2 years, compared with 10.7 years for dogs without abnormalities. Despite discovering these conditions, every owner still chose to proceed with TPLO surgery. The authors concluded that abdominal ultrasound may provide greater diagnostic value than thoracic radiographs for geriatric dogs preparing for elective orthopedic surgery, especially in dogs older than 12 years. 

Fuller, J., Harding, L., Kalamaras, A., Jackson, A., Laube, R., & Doyle, C. (2026). Abdominal ultrasound more commonly leads to the diagnosis of underlying comorbidities when compared to thoracic radiographs in dogs undergoing tibial plateau leveling osteotomy. American Journal of Veterinary Research, 87(5), Article ajvr.25.10.0372, ajvr.25.10.0372.  https://doi.org/10.2460/ajvr.25.10.0372 

Bottom line — It is useful to check for comorbidities.

One Health And Tick Disease

Tick-borne diseases are becoming more common in the United States, affecting humans, pets, livestock, and wildlife. This increase is linked to factors such as climate and environmental changes, expanding deer populations, land use changes, global travel, and closer contact between humans and wildlife. The article emphasizes a One Health approach, recognizing that human, animal, and environmental health are interconnected. It reviews major tick species of medical and veterinary importance, including black-legged ticks, lone star ticks, American dog ticks, Gulf Coast ticks, brown dog ticks, and the invasive longhorned tick.  

The review explains tick biology and life cycles, noting that many ticks require multiple hosts during development. Different stages feed on different animals, ranging from rodents and birds to deer, livestock, dogs, and humans. Tick activity depends heavily on temperature, humidity, and seasonal conditions. Several species have expanded their geographic ranges in recent decades, increasing opportunities for disease transmission.  

The article discusses major tick-borne diseases such as Lyme disease, spotted fever rickettsioses, babesiosis, anaplasmosis, and ehrlichiosis. Lyme disease, caused by Borrelia burgdorferi, is the most commonly reported vector-borne disease in the United States. Symptoms in humans include fever, fatigue, rash, and joint pain, while dogs and horses may experience lameness, fever, and behavioral changes. Other diseases can produce anemia, neurological problems, organ damage, and severe systemic illness in both people and animals.  

The review also outlines diagnostic and prevention strategies. Accurate diagnosis depends on combining clinical signs, exposure history, and laboratory testing. Prevention relies on integrated tick management, including habitat control, tick repellents, prompt tick removal, and the use of veterinary acaricides. Vaccines are available for canine Lyme disease, although recommendations vary. The authors conclude that effective control of tick-borne diseases requires coordinated efforts across veterinary medicine, public health, and environmental management. 

Poh, K. C., Owen, J., Williams, L., Claude, R., & Eleftheriou, A. (2026). Tick and tick-borne disease management requires an integrated One Health approach. Journal of the American Veterinary Medical Association https://doi.org/10.2460/javma.26.02.0153

Bottom line — Coordination is essential.

Trilostane Failure

This retrospective study evaluated factors linked to poor response to trilostane treatment in dogs with pituitary-dependent hypercortisolism (PDH), the most common form of naturally occurring Cushing’s disease in dogs. Researchers reviewed medical records from 23 dogs treated with trilostane for four to eight months and divided them into good responders and nonresponders based on improvement of clinical signs such as excessive drinking and urination, increased appetite, lethargy, panting, abdominal enlargement, and hair loss. Fifteen dogs responded well, while eight had persistent clinical signs despite dose increases and repeated monitoring.  

At diagnosis, nonresponders generally showed evidence of more severe disease. They had significantly higher alanine aminotransferase (ALT) activity, higher endogenous ACTH concentrations, and higher cortisol levels before ACTH stimulation testing. Bilateral adrenal enlargement and alopecia were also more common in dogs that responded poorly. Even after statistical correction for multiple comparisons, elevated ALT, increased ACTH, alopecia, and bilateral adrenomegaly remained significantly associated with poor treatment response.  

During follow-up, nonresponders required more frequent recheck visits and much higher trilostane doses than dogs that improved clinically. Despite these adjustments, many still had persistent polyuria, polydipsia, polyphagia, lethargy, or dermatologic abnormalities. In contrast, all good responders achieved complete clinical resolution within four months, most within the first month of therapy. The study suggests that dogs with more severe hormonal and adrenal abnormalities at diagnosis may be less likely to achieve adequate control with standard trilostane therapy alone.  

The authors emphasized that persistent clinical signs after four to eight months of treatment should prompt veterinarians to reassess the diagnosis, evaluate for concurrent disease or medication absorption problems, and consider alternative therapies such as mitotane, hypophysectomy, or radiation therapy. Although no single variable could perfectly predict outcome, the identified markers may help veterinarians better counsel owners about prognosis, expected costs, and treatment challenges early in the disease course. 

Stefania Golinelli, Federico Fracassi, Francesca del Baldo, Rodolfo Oliveira Leal, Pascaline Pey, Edward C Feldman, Evaluation of clinical, ultrasonographic, and clinicopathological findings in dogs with pituitary-dependent hypercortisolism and poor trilostane response, Journal of Veterinary Internal Medicine, Volume 40, Issue 3, May-June 2026, aalag096, https://doi.org/10.1093/jvimsj/aalag096 

Bottom line — Good info to help discuss treatment expectations.

Just putting things in perspective …