Field Notes: April 2026

Droughts, heartworm, rare urinary stones, and more!

Dear Readers,

They say “April showers bring May flowers,” but so far, this spring in Tampa has been exceptionally dry—we are in the most severe drought in decades. In fact, we’ve received about an entire foot less rain than we would have in a typical year! There is a rather large pond on the golf course near us where we walk our dogs, and it is completely drained and bone dry for the first time I can remember living here.

Let’s hope we get some much needed rain soon 🤞 Even if we don’t, in a few weeks we will be moving to (literally) greener pastures in upstate New York. The spring bloom should be amazing to see, many towns near us celebrate with an annual tulip festival.

In this month’s edition of Field Notes, we have several articles of interest to vets and pet owners alike. First, I discuss how the range of heartworm infections is expanding. Then, I talk about a new type of urinary stones that might be associated with certain trendy diets. Finally, I provide details about an upcoming lecture I’ll be giving at the AVMA conference in July along with some stray links to other stories.

I hope you’re enjoying the start of spring and find this roundup useful!

—Eric

Heartworm “hot spots” expanding

Canine heartworm is a serious disease that can lead to heart failure and is caused by the nematode Dirofilaria immitis. Luckily, it is easily prevented with a number of topical and oral medications you can get from your family vet. To monitor this disease, the American Heartworm Society collects antigen test results from practices nationwide and publishes the results every three years. This April, they released 2025 data from >1,000 practices and animal shelters.

Here’s a quick summary of their findings:

• Data based on more than a million tests

• Most practices (59%) reported stable rates of infection, while roughly even numbers of practices reported increases and decreases in positive tests

• Some of the usual “hot spots” (defined as >100 cases/clinic) like Florida and Texas were joined by the Carolinas and southern Illinois

• The incidence in the top state, Texas, increased from 2.97% in 2022 to 3.78%

• New areas with “moderate” infection rates (6-25 cases/clinic) included expansions into southern California, southwest Colorado, east-central Wisconsin, and parts of Maine and Virginia

• There were ZERO heartworm-free states

In related news, the geographic ranges for ticks and the rickettsial diseases they carry is also expanding.

Why are these parasites spreading all over the map? One reason is probably the same as the Florida drought issue: Climate change. Warmer weather results in predictable increases in the ticks and mosquitos that carry these diseases, especially after floods and hurricanes. Urban development displaces wildlife that can carry these infections and increases contact with our pets. Finally, people moving across the country with dogs who are not on preventatives contributes to the expansion.

The clear implication is to make sure your pets are on appropriate heartworm and parasite prevention year-round, even in areas that “don’t have heartworm,” because that is becoming increasingly untrue anywhere in the US. Fortunately, these infections can be successfully treated, although the cost is much higher than prevention, and there can be side effects. When we adopted Kali from the Bahamas, she was infected with both heartworm and Ehrlichia, but today she is parasite-free and living her best life snuggled on the couch with our cats!

Bert and Kali went from enemies to BFFs in a very short period of time ❤️

Rare type of urinary stones on the rise

One of the veterinary institutions that has the most experience with bladder and kidney stones is the University of Minnesota Urolith Center. They accept samples of these stones when they are removed at surgery and analyze them chemically for research purposes and to make recommendations on management with food and medications. A recent story in VIN News highlights a rare type of stone that is suddenly being diagnosed at much higher rates: calcium tartrate tetrahydrate (CTT).

According to VIN News: “In the early 2020s, the Minnesota center tallied no more than 10 such stones in dogs each year. In 2023, the number rose to 11. Then, in 2024, to 28.” By 2025, it had surged to almost 200. While other types of stones like calcium oxalate dihydrate and magnesium ammonium phosphate (aka struvite) are far more common overall, CTT increased almost an order of magnitude in prevalence from 0.02% to 0.2% of cases over a very short period of time.

Researchers at the University of Minnesota were curious about what might be driving this increase and queried owners of dogs with this unusual stone about diet and medications. For those who responded, they found a source of tartaric acid in 76% of cases, and virtually all (96%) were associated with choline bitartrate, an additive to certain fresh pet foods and homemade diets. Three brands that were identified in multiple cases included Just Food for Dogs, The Farmer's Dog and Nom Nom.

You can read the UMN paper here:

Lulich, J., Koehler, L., Ulrich, L. and Furrow, E. (2025), Association of Diet and Calcium Tartrate Tetrahydrate Uroliths in Dogs. J Vet Intern Med, 39: e70093.

Image credit: University of Minnesota Urolith Center (link)

AVMA talk on medical misinformation

For anyone who is interested in attending the annual AVMA Convention or already registered, I will be delivering a continuing education talk for the Leadership & Professional Development track on Friday July 10th. The title of the lecture is “Speaking Out: How Veterinarians Can Lead in the Fight Against Medical Misinformation”. You can read the session description and objectives below:

Veterinarians are among the most trusted professionals in society, yet their voices are often absent from public conversations where science and medicine are most at risk of distortion. In today’s climate of medical misinformation, vaccine hesitancy, and politicized science, veterinarians have both an opportunity and a responsibility to lead. This session will introduce veterinarians, technicians, and animal health professionals to the essentials of science communication and advocacy, drawing from real-world lessons in social media, client interactions, and public discourse. We will explore the “credibility gap” that often separates scientific evidence from public understanding, and identify the red flags of misinformation—anecdotal claims, miracle cures, conspiratorial narratives—that undermine trust. The rising tide of veterinary vaccine hesitancy will be used as a case study in how misinformation can have real-world consequences for both animal and public health. Beyond simply correcting falsehoods, attendees will learn how to frame scientific information clearly, empathetically, and persuasively for diverse audiences. We will discuss practical strategies for using communication platforms such as Substack, Facebook, LinkedIn, and TikTok effectively, while avoiding common pitfalls that erode credibility. Finally, we will consider the broader moral imperative of advocacy: like canaries in the coal mine, veterinarians can serve as early-warning voices for society, speaking out not only for animal health but for the principles of science and public trust. By the end of this session, participants will leave with concrete tools to identify misinformation, engage confidently in public dialogue, and take greater ownership of their role as trusted advocates for science, health, and societal well-being.

Objectives:

1. Identify common red flags of pseudoscience and misinformation in veterinary and public health claims

2. Apply effective strategies for communicating scientific information clearly and credibly to non-expert audiences.

3. Analyze the case example of vaccine hesitancy to develop empathetic and evidence-based responses

4. Design social media or public messaging to advocate for evidence-based veterinary medical practices

I’m really looking forward to this session and hope to see some of you there in person!

Odds & Ends

Here are a few other things I’ve been checking out recently:

• Rethinking antibiotics for subclinical UTIs - This is a link to a Worms and Germs blog post by Dr. J. Scott Weese discussing a recent study that evaluated the outcomes of cats with chronic kidney disease and asymptomatic bacteria in their urine when treated with antibiotics vs benign neglect. They found that there was no difference in survival or CKD progression. Dr. Weese provides thoughtful commentary on the specific study as well as new guidelines that aim to reduce the unnecessary use of antibiotics in our patients.

• OpenAI vs Elon Musk - This might be the Silicon Valley trial of the century, and the results could have a huge impact on the market for LLM chatbots. I don’t have a lot of sympathy for either party here, and have previously written about the damage Musk did to the federal government through DOGE. That said, it’s hard not to agree with his core premise that OAI gained a lot of investment and recruiting advantages by promising to be a benevolent non-profit for society’s benefit and then totally reneged. If only there was a way both parties could lose!

• Man who sequenced human genome died - J. Craig Venter (79) passed away on Wednesday after complications of cancer treatment. He was a colorful scientist, entrepreneur and philanthropist most famous for racing the NIH’s Human Genome Project when he deemed progress too slow. His “shotgun sequencing” approach was faster than the clone-by-clone technique used at the NIH, and his rapid results arguably sped up both teams’ results. The winner of the “race” was ultimately declared a tie, and the two groups published their independent results within 24 hours of each other in Science and Nature.

Author’s Note: The commentary above represents my personal opinion and does not necessarily reflect the viewpoints of any current or previous employers.