Ask Dr. Paola - Yeast Infections, Heat Cycles & Norovirus (September 22, 2025)

Welcome to our "Ask Dr. Paola" series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our readers better understand their dog's health and well-being.

Whether you're a new pet parent or a seasoned dog lover, Dr. Paola is here to provide answers to your most pressing questions. From nutrition tips and preventive care to troubleshooting common behavioral issues, Dr. Paola is ready to offer insights that will keep your furry friend happy and healthy. Stay tuned for expert guidance on a range of topics that matter most to you and your dog, so you can make informed decisions and provide the best possible care for your canine companion. ‎Have‎ a ‎question? Send it in here!

Can I Use Brewers Yeast on My Dog?

"Does brewer’s yeast help dogs with yeast infection? "- Dan

Hi Dan,

Yeast infections in dogs can be frustrating, and it is natural to want to try supplements like brewer’s yeast to help. The important thing to know is that brewer’s yeast does not treat yeast infections. These infections, most often caused by Malassezia pachydermatis, happen when the normal balance of skin organisms is disrupted, often because of allergies, hormonal changes, or other underlying health issues. To clear the infection, the real cause needs to be addressed, along with antifungal treatment prescribed by a veterinarian. Depending on the case, this may involve medicated shampoos, wipes, or oral antifungal medication for more persistent problems.

Although brewer’s yeast is sometimes promoted as a source of B vitamins or even as a natural flea repellent, research does not support its use for yeast infections. In fact, for some dogs, it may cause digestive upset or sensitivities without offering any benefit. If your dog is showing signs like itchiness, odor, or skin irritation, the most effective step is a veterinary exam. This way, the underlying cause can be identified and treated, bringing true and lasting relief instead of temporary or incomplete improvement.

Kind regards,

- Dr. Paola

Help! My Spayed Dog Acts Like She is in Heat!

"Is it possible for my spayed dog (Lady Macbeth) to still have a cycle? Sometimes she seems like she is in heat (moody, humpy, lethargic)" - Betty

Hi Betty,

Once a dog has been spayed and both ovaries are completely removed, she should no longer go into heat. If Lady Macbeth is still showing signs that resemble a cycle, such as mood changes, mounting, or periods of low energy, one important possibility is ovarian remnant syndrome. This happens when a small piece of ovarian tissue is left behind during surgery. Even a tiny fragment can continue to release hormones, which makes the body behave as if it is still cycling.

To investigate this, your veterinarian may recommend blood tests to measure hormones like progesterone or Anti-Müllerian Hormone, ideally done when Lady Macbeth is showing these signs. Vaginal cytology may also be used, since the cells in the vaginal wall change in response to estrogen. If ovarian tissue is confirmed, the solution is a second surgery to remove the remnant, and this usually resolves the problem completely.

There are also other explanations worth considering. Contact with human estrogen creams, adrenal tumors that secrete hormones, or conditions like urinary tract infections or vaginitis can all mimic heat. Mounting and mood shifts can also be related to stress or social behavior rather than hormones, and lethargy may point to other health issues, such as thyroid disease. Because these possibilities overlap, a complete veterinary evaluation is the best way to uncover what is really happening and ensure Lady Macbeth gets the right care.

Best,

- Dr. Paola

Help! I Think My Dog Has Gotten Sick from Me!

"Can dogs contract viruses from humans? I feel like I just gave my dogs June & Jett norovirus cause I had it, and then they both had days where they seemed to have a stomach bug. Is this actually a thing?"  - Sally 

Hi Sally,

I can see why you felt you might have passed on the norovirus to June and Jett, especially when you were all under the weather at the same time. The good news is that norovirus and most viruses that affect people are very species-specific, so while they can make us feel awful, they do not infect dogs. When dogs develop an upset stomach, the cause is usually unrelated to ours and can be linked to things like a sudden change in food, getting into the trash, stress, parasites, or dog-specific infections.

That said, there are a few bacteria and parasites that both people and dogs can share, such as Salmonella, Campylobacter, Giardia, and Cryptosporidium. These usually come from contaminated food, water, or the environment rather than directly from a person to a pet. If June and Jett’s upset was short-lived and they bounced back quickly, it may have been something minor. But if the diarrhea is severe, contains blood, or lasts longer than a couple of days, a veterinary checkup is important. Your veterinarian can run stool tests to look for parasites and bacteria, and help get them back on track quickly and safely. I hope you're all recovered now.

Sincerely,

- Dr. Paola