New CDC reports reveal pet dogs are spreading two rare diseases

Pet dogs have been found to harbor dangerous pathogens that public health experts fear could pose a threat to humans.

A new CDC report published Wednesday identified two New Jersey dogs – a golden retriever and a cocker spaniel – that became infected in spring of 2023 with an antibiotic-resistant bacteria resembling a pathogen that had previously caused an 81-person outbreak that same year. 

The bacteria in the outbreak were similar to but not identical, and public health officials still do not know how the dogs became infected.

Both dogs were treated at the same veterinary facility, which is where they are believed to have picked up the pathogen. 

The bacteria pseudomonas aeruginosa that infected them is resistant to many antibiotics, making it especially concerning because infections become more difficult to treat.

A second CDC report published on the same day detailed a similar outbreak of a fungal infection in dogs in Wisconsin from 2022. While the infection did not travel from dogs to humans, five people and six dogs became sick from breathing in fungal spores in the same general area.

The fungus, Blastomyces, infects a person or a dog when they breathe in spores that settle in soil and leaves and explode into the air when either is disturbed. Direct transmission from dogs to humans is extremely rare.

Instead, experts fear the areas where dogs are exposed, such as walks through the woods, also expose the dogs’ owners, potentially getting them sick with blastomycosis as well.

In the first study in the CDC’s latest collection, they detailed two cases of Multidrug-Resistant Pseudomonas aeruginosa in New Jersey in March and June 2023.

The first was in a seven-year-old golden retriever with a chronic cough for months. The second was a six-year-old cocker spaniel. Both were treated in the same vet hospital.

The bacteria isolated from the dogs was very similar to bacteria found in a multistate human outbreak linked to contaminated artificial tears. 

Neither the dog owners nor household members reported any exposure to outbreak-related ophthalmic products since March 2022. 

However, the second dog was being treated with a different over-the-counter artificial tear solution that may have been harboring the virus. 

A later inspection by the New Jersey Department of Health found lax hand hygiene standards, PPE protocol and cleaning and disinfection procedures at the vet hospital.

The outbreak linked to artificial tears sickened 81 people and killed four across 18 states, but the two dogs were the only animal cases identified.

Pseudomonas infection can affect the skin, blood, lungs, GI tract, and other parts of the body. 

Pseudomonas infections can range from minor issues, like swimmer’s ear and hot tub rash, to serious, life-threatening conditions, especially in people who are already weak or ill. 

Symptoms depend on the infection site, with possible signs including green-blue pus in wounds, ear pain from swimmer’s ear, coughing from pneumonia, or fever and fatigue from a systemic infection. If the infection spreads to the bloodstream, it can cause high fever, chills, confusion, and shock. 

In Wisconsin, a 2022 outbreak of blastomycosis – caused by the fungus Blastomyces – infected four people and five dogs in St Croix County.

The latest CDC report found the numbers increased to five human cases, with two hospitalizations and one death. Most patients had underlying health issues and reported symptoms like cough, fatigue, and fever.

Six canine cases were confirmed, with symptoms like lethargy, appetite loss, and breathing difficulties. Sporting breeds seemed more affected.

The CDC report said: ‘The population at risk was defined as persons living within a 1.5-mile diameter of where the human and canine cases occurred [in St Croix County].

‘Although we were unable to identify a definitive exposure as the likely cause of this cluster, several sites such as the riverbank, riverside trails or yards, or construction dust, could have plausibly been sources of Blastomyces spores.

‘Dogs that walked on the trails, specifically those that walked off-leash had a higher prevalence of antibodies compared with dogs who did not. Dogs who lived closer to the river had a higher prevalence of antibodies.’

Blastomyces — which infects around 6,700 Americans and kills 60 each year — causes a lung infection that can trigger fever, coughs, chest pain, fatigue, and night sweats.

In severe cases, the spores can spread from the lungs to other parts of the body, including bones, joints, and even the brain and spinal cord.