The Odd Rabies Case in ChiTown

By now, you’ve likely heard about this strange case of rabies in a young Chicago dog. The case made the news, as Chicago hadn’t had a rabid dog reported since 1964.

The Odd Part

The history is a bit concerning to some, and likely to call vaccination efficacy into question.

To start, the pup originated in Georgia, became part of a rescue org in Florida, and was sent to Chicago to be adopted in May 2025. A traveling rescue, which sounds pretty typical these days. I guess it’s a supply/demand issue, so rescue animals relocate to increase their chances of finding a home.

I’ve had concerns, alongside the US ag import folks, when that relocation goes international, with animals coming from countries with lax rabies control, but this was apparently not at play here.

Once in the Chicago placement group, after he reached the appropriate age, the dog was vaccinated against rabies in June 2025, but “always had behavioral issues.”

This dog bit a human on December 11, and went into a 10 day quarantine to ensure this wasn’t a bite due to developing rabies.

Well, that behavior started looking more dangerous (like the furious form of rabies) so…

The dog was euthanized on December 18, 2025 due to the dog’s behavior, and rabies was confirmed through laboratory testing on December 19, 2025. The dog tested positive for rabies by direct fluorescent antibody testing, and a repeat test was also positive.”

A Mistaken Dx?

Someone asked if it was possible the positive test was a result of having been vaccinated, so let’s get some clarity on this. To date, the only authoritative test for the rabies virus is a brain exam, employing the direct fluorescent antibody test.

It uses fluorescein‑labeled anti‑rabies antibodies to bind rabies virus antigen in brain smears. Under the microscope, a positive test shows as apple‑green fluorescence in infected tissue. This demonstrates rabies viral antigen directly.

A vaccinated dog would not have rabies antigen in his brain, only antibodies in the blood, so there’s no chance of confusion.

This has long been the gold standard test to tell if an animal had rabies or did not.

And it can only be run on brain tissue, so vets and animal control folks know they have to be sure the brain is intact in a euthanized animal, and the head is rushed to a testing facility on ice.

But: Vaccinated?

There are two words operant in this question of why a vaccinated dog got rabies.

• Vaccination: the act of installing a vaccine, usually by injection, but some vaccines are intranasal.

• Immunization: the response by the vaccinated animal to mount an immune response, which is the ultimate goal of vaccination.

Vaccination doesn’t guarantee immunization. Chief reasons include:

• Vaccinated too young. Not the case in this dog, but an all too common practice of breeders. Podcast Ep 11: Breeders: Please STOP Doing This!

• Vaccine problems.

The USDA is testing the vaccine lot to see if there are problems there.

• There’s also vaccine handling, like poor refrigeration.

That’s more critical in MLV (modified live vaccines) than the usual killed rabies vaccines, all we’ve had available for the decades of rabies control efforts to date.

So, even sloppy handling of the vaccine seems a long shot in this case.

An aside: as of this date, the newer “NXT” RNA rabies vaccine is not available to US vets due to “contractual obligations” from Merck. It has rolled out in Canada, so my Canadian readers will want to read my earlier posts on why I’d recommend avoiding this shot: Vital Animal News August 3, 2025]

Rabies (and FeLV and Dog Flu) vaccines now with RNA tech, free masterclass on rabies coming soon, dental work w/o antibiotics, search dogs post Texas flood, autistic insights in animals, and monsoons. Let’s dig in, shall we?

Immunization Fail

My best guess is this dog lived a life of chronic stress, albeit a short one.

Not much history here except the abandonment, common to many orphans.

Early life nourishment may well have been lacking as well.

But also, there’s the never normal behavior, indicating perhaps an always on edge state of survival.

That chronic stress depresses the immune system, true in all species.

So, while he was vaccinated against rabies, perhaps that immune suppression didn’t allow the hoped for immunization to take place.

Still Unknowns + The Exposed

Up to this point, the source of the rabies in this dog is unclear, as is the type (raccoon, skunk, bat variants, for example). Chicago exposure to the virus has been ruled out. And the CDC is in the midst of testing, which can be a prolonged effort.

Littermates of this pup were given booster vaccines and 45 day home quarantines but none have displayed signs of rabies.

And 13 people with direct exposure are undergoing treatment to be sure they’re not going to develop the disease.

As we get more answers, I’ll convey them, but for now, this appears to be a fluke. Not the parasite, but a turn of phrase.

Still a rarity in domestic animals, rabies makes the news periodically when people are involved.