Rats and other reservoir hosts can carry leptospirosis without illness, shedding bacteria into the environment while dogs and people become the visible victims of infection, explains Jane Sykes, BVSc, DACVIM (SAIM), PhD, MPH, MBA, FNAP.

How leptospirosis spreads silently

In this interview tied to her 2026 Veterinary Meeting & Expo session, Jane Sykes, BVSc (Hons), DACVIM (SAIM), PhD, MPH, MBA, FNAP, a professor at the University of California, Davis, breaks down how leptospirosis moves through animal and human populations. She explains how reservoir species, such as rats, can carry the bacteria without appearing ill while still shedding high concentrations into the environment. Incidental hosts, on the other hand, such as dogs and people, often develop acute and sometimes life-threatening disease but are not typically infectious to other incidental hosts.

Below is the video transcript, lightly edited for clarity.

My name is Jane Sykes. I'm a professor of small animal internal medicine at the University of California, Davis, and I study infectious diseases of public health significance.

Can you explain the difference between reservoir hosts and incidental hosts in the transmission of leptospirosis?

[Leptospirosis] is a really fascinating bug because it achieves either [a] reservoir host status with a host or an incidental host status. If the spirochete is well adapted to a particular reservoir host—for example, we think about 

 as being really well adapted to rats—then it sits in the renal tubules. It forms [a thick layer of] biofilm in the renal tubules…[which] allows it to be shed chronically in the urine in high concentrations without causing any clinical signs.

So that reservoir host status is this chronic, persistent, subclinical infection that promotes contamination of the environment and transmission to other hosts. Animals or people that are acting as incidental hosts have not established that degree of premunition, and they mount a strong inflammatory reaction to the particular strain of [leptospirosis] that's infecting them, and that inflammation causes multiorgan failure and illness. That's when there's not that state of adaptation. So you see a very sick dog or a very sick human that has acute kidney injury and maybe dysfunction of other organs because [leptospirosis] doesn't actually cause liver failure—it causes hepatic dysfunction, and that's cholestatic—so that multiorgan illness is what is characteristic of the incidental host state.

Typically, incidental hosts don't shed very many organisms in their urine, and it's very hard for an incidental host to transmit infection to another incidental host. So we don't see one dog with [leptospirosis] transmitting [leptospirosis] and causing illness in a person [or another dog] very often.

That might have been a little different in the Los Angeles, [California], outbreak, but that's pretty typical in general for [leptospirosis]. It's mostly transmitted by reservoir hosts, which shed these large numbers of organisms in their urine without showing signs.

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Rats and other reservoir hosts can carry leptospirosis without illness, shedding bacteria into the environment while dogs and people become the visible victims of infection, explains Jane Sykes, BVSc (Hons), DACVIM (SAIM), PhD, MPH, MBA, FNAP.

How leptospirosis can spread silently

A team from the Penn Vet Working Dog Center tested whether highly trained detection dogs could identify an odor signature associated with canine hemangiosarcoma. The work is a controlled, proof-of-concept laboratory study that used automated olfactometer line-ups and double blinding to reduce bias. Serum came from dogs with histologically confirmed hemangiosarcoma, from dogs with other diseases, and from healthy controls. In total, dogs completed 423 blinded trials.

Image Credit: © grafoto72 | stock.adobe.com

Five biodetection dogs performed the task. Across all 423 trials the dogs’ overall accuracy was 70.0%, with individual dog performance ranging from 57.1% to 78.6%. On initial exposure, mean accuracy was also 70.0%, with first-trial results ranging from 58.3% to 83.3%. Sensitivity and specificity calculated from first-trial encounters were both approximately 70%.

The dogs alerted to hemangiosarcoma samples far more often than to controls. They signaled for HSA samples in 73.4% of presentations, compared with 21.3% for diseased controls and 17.1% for healthy controls. Odds ratios indicated dogs were more than 10 times as likely to alert to HSA versus diseased controls, and more than 13 times as likely to alert to HSA versus healthy controls. All comparisons were statistically significant.

For clinicians, the study is important because it provides evidence that hemangiosarcoma is associated with a detectable volatile organic compound profile in blood. That is a biologic signal that could, in principle, be captured by an engineered sensor or a standardized volatile organic compound (VOC) assay. At the same time this is an early laboratory result and not a validated clinical screening test. Accuracy near 70% and a relatively small set of hemangiosarcoma samples limit immediate clinical application. The testing environment used highly trained dogs and controlled presentation methods that are not directly transferable to the busy clinic.

Limitations noted by the authors and apparent from the methods include the modest number of HSA-positive samples and the need for external validation in larger, independent clinical cohorts. Future work should focus on identifying the specific VOCs responsible for the signal, standardizing sample handling, and developing objective sensor technology that can reproduce canine olfaction under clinical conditions.

For now this study is best read as a rigorous proof of concept. It supports further research into VOC-based diagnostics for hemangiosarcoma and other cancers, but it does not change diagnostic or screening recommendations at this time. Clinicians should monitor follow-up studies that report external validation and assay development.

Wilson C, Holden S, King J, et al. Trained dogs can detect the odor of hemangiosarcoma in canine blood samples. 

. Published online November 29, 2025. doi:10.1016/j.tvjl.2025.106522

Articles

In a blinded laboratory trial, trained biodetection dogs distinguished serum from dogs with hemangiosarcoma from control samples with about 70% accuracy, supporting the idea that the tumor produces a volatile organic compound signature that might be translated into a future diagnostic.

Dogs can sniff out hemangiosarcoma in blood samples, early study shows

Naomi Hoyer, DVM, DAVDC, provided insight about oral inflammation in a dvm360 interview at VMX 2026.

Reading the clinical signs of stomatitis

Oral inflammatory disease, such as stomatitis, is common in dogs and cats. Stomatitis is often painful in its early stages and can present clinical signs.

 Naomi Hoyer, DVM, DAVDC, an associate professor of dentistry and oral surgery at Colorado State University in Fort Collins, provided insight about stomatitis, in a continuing education (CE) session at the 2026 Veterinary Meeting & Expo (VMX) in Orlando, Florida. In an interview with 

at VMX, Hoyer discussed the common clinical signs of stomatitis in dogs and cats.

Using a full set of dental radiology images

The following is a transcript of the video, lightly edited for clarity:

What are common clinical signs of stomatitis?

: Stomatitis, unlike a lot of other dental diseases, often dogs and cats will actually show up, telling us that they're painful. And when I say that, I mean things like bloody drool or difficulty eating, changes in food behavior. So ‘I always used to eat dry food, and now I only want to eat canned food,’ shying away from having the face touched, sometimes even changes in behavior like development of aggression—all can be signs of oral pain. In those situations, I would want to rule out stomatitis. 

In cats, one of the most common [clinical signs] is actually decreased grooming. Cats will stop grooming because it hurts to stick their tongue out because of where the inflammation is.

Hoyer N. Stomatitis in cats and dogs: Tackling the inflammation! Presented at: Veterinary Meeting & Expo; Orlando, FL. January 17-21, 2026.

For more industry news and coverage of VMX, visit 

Allie Donaldson, DVM, discusses the Honey Bee Veterinary Consortium, in a dvm360 interview.

Networking with honey bee veterinarians

Allie Donaldson, DVM, is a past president of the Honey Bee Veterinary Consortium (HBVC), who attended the Honey Bee Symposium at the 2026 Veterinary Meeting & Expo (VMX) in Orlando, Florida, hosted by the North American Veterinary Community. Donaldson shared information with VMX attendees about the HBVC and how it can be used as a resource for the practice of honeybee medicine. In this video, Donaldson explains the goals of the HBVC and the opportunities it offers to the veterinary community.

The following is a transcript of the video:

The…HBVC was formed back in 2017 when bees were included [with]…food-producing animals. That meant that if beekeepers wanted to get antibiotics, they now needed to call a veterinarian. We formed this consortium to help support veterinarians in learning about bees, learning about honeybee medicine, and how we as veterinarians can support beekeepers, support the beekeeping community, and…bring our expertise with science, medicine, and herd medicine, specifically—those sorts of things—into beekeeping.

With HBVC, we have yearly conferences where we train brand-new beekeepers, veterinarians, [and] brand-new veterinarians who are interested in becoming honeybee veterinarians, as well as those veterinarians who are experienced beekeepers, [on] how to utilize our skills and…help beekeepers through veterinary medicine.

We also have a certification program. This is a program that is self-paced, but there are multiple modules to teach us how to really utilize the knowledge we have as veterinarians to help support the beekeeping community’s health, to reduce the diseases in hives, [and] how to train beekeepers on the management style we learn about in veterinary school with all of the other species. The certification program is really a great way to have our members be more confident when they go out and do their first hive inspection, when they take that first step out and pull out that first frame of bees, and interact with that beekeeper on what disease processes might be affecting their hive and how we might go about treating those.

Allie Donaldson, DVM, discusses the Honey Bee Veterinary Consortium in a dvm360 interview.

Networking with honeybee veterinarians

The FDA is alerting pet owners of potential health risks linked to certain Raaw Energy frozen dog food products after testing by state agriculture officials in Connecticut and New Jersey revealed multiple pathogenic bacteria in 8 unopened product samples. According to the FDA, the findings stemmed from a consumer complaint submitted to the Connecticut Department of Agriculture about a dog illness, prompting follow-up testing.

Laboratory results revealed contamination with 

in all 8 samples tested. Additional testing detected 

 O157:H7, which, the FDA warns, “may be harmful.”

The federal agency says it advised Raaw Energy to issue a recall on the 8 lots. Still, the company has yet to initiate an adequate recall.

The affected products are sold as frozen raw diets in 2-lb or 5-lb clear plastic tubes sealed at both ends with a metal clip, packaged in brown cardboard boxes. The products are distributed through online ordering with in-person pickup.

The manufacturer does not use conventional lot numbering, so affected batches can be identified by a date code (date of manufacture) printed on white stickers on the plastic tubes and the brown cardboard box. The stickers also contain the product flavor and ingredients.

The FDA is warning consumers who have purchased Raaw Energy dog food to check the packaging for affected date codes before feeding it to their pets. Owners should monitor pets for signs of illness and seek veterinary care if symptoms develop following exposure.

“Consumers who have had the recalled products in their homes should clean and disinfect all pet supplies, including all storage containers, bowls, utensils, food prep surfaces, pet bedding, litter boxes, toys, floors, and any other surfaces that the food or pet may have had contact with, including your refrigerator or freezer,” the FDA said in its announcement.

“Clean up the pet’s feces in places where people or other animals may become exposed. Consumers should thoroughly wash their hands after handling the product or cleaning up potentially contaminated items and surfaces.”

Why bacterial contamination in pet food matters

Pathogenic bacteria in pet food pose a One Health concern. Dogs and cats exposed to contaminated diets may develop gastrointestinal illness, fever, or lethargy, but may also be asymptomatic. Still, pets with no clinical signs can shed bacteria through saliva or feces, posing a contamination risk to the household environment, including other animals and, in some cases, people.

Public health officials have linked contaminated pet foods to 

 outbreaks of illness in both pets and humans.

 The risk is greatest for young children, older adults, pregnant individuals, and people with compromised immune systems who are more susceptible to severe infection.

According to the FDA, freezing or refrigeration does not kill pathogens such as 

 making prevention and sanitation important when contamination occurs. Veterinary professionals can play a key role in educating clients about proper hygiene, including proper disposal of pet waste, thorough handwashing after handling pet food or cleaning feeding areas, and disinfecting surfaces that may have come into contact with contaminated products.

Clinical signs in pets vary by pathogen but can include vomiting, diarrhea (including bloody diarrhea), decreased appetite, fever, and lethargy. More severe symptoms, such as dehydration or systemic illness, may develop in young, older, or immunocompromised animals.

FDA advisory: do not feed eight lots of Raaw Energy dog food due to contamination with harmful bacteria. FDA. January 23, 2026. Accessed January 26, 2026. 

https://www.fda.gov/animal-veterinary/outbreaks-and-advisories/fda-advisory-do-not-feed-eight-lots-raaw-energy-dog-food-due-contamination-harmful-bacteria?utm_medium=email&utm_source=govdelivery

Bautista-Alejandre A. FDA warns of contaminated dog food linked to serious infection in child. 

. July 30, 2025. Accessed January 26, 2026. 

https://www.dvm360.com/view/fda-warns-of-contaminated-dog-food-linked-to-serious-infection-in-child

The FDA has issued a warning that multiple lots of Raaw Energy frozen dog food have tested positive for Listeria, Salmonella, Escherichia coli O157, and Campylobacter jejuni.

FDA flags Raaw Energy dog food after multistate testing finds pathogenic bacteria in samples

Busy clinicians don’t have time to doomscroll through the headlines. You need quick, reliable information that tells you what actually matters for the exam room, the hospital floor, and the bottom line. That’s exactly why we put together 

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This format is built for speed. Instead of long analysis, you get a single place, updated monthly, with the pieces our editors judged highest in clinical interest or urgency and the links to dig deeper if you choose. It’s designed so you can skim in 60 seconds and decide whether to click through.

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