A rare case of plague transmitted by a cat has alerted U.S. health authorities

A 73-year-old man contracted the plague after caring for his sick cat. This case is notable for its atypical nature: the infection occurred in the middle of winter, a time typically considered “out of season” for this disease, which is endemic to the American West.  

Direct transmission: rare but documented

The animal, a young domestic cat with an abscess on its neck, was examined by a veterinarian and then treated at home by its owner. On January 25, the owner accidentally cut his finger with a knife while treating his cat’s wound. A few days later, signs of severe infection appeared (a wrist ulcer, cellulitis, fever, and swollen axillary lymph nodes). The diagnosis of Yersinia pestis infection, confirmed by bacterial culture and PCR, was made in early February. The patient was promptly treated and recovered after a nine-day course of antibiotics consisting of gentamicin and levofloxacin. The cat, however, did not survive.  

A Changing Seasonal Pattern

Traditionally, cases of human plague in the United States are rare (an average of seven per year) and occur between May and August, the peak activity period for the vectors that transmit the disease. However, this case—the earliest ever recorded in Oregon in over 90 years—has reignited the debate on the impact of climate change on vector dynamics. Abnormally mild winter temperatures (above 10 °C) could promote the activity of infected fleas, making it possible for the pathogen to circulate year-round. Veterinary and public health authorities are urging people not to rule out the risk of plague during the cold season, particularly in endemic areas of the southwestern and central United States.  

Cats: A Discreet but Formidable Host

Although wild rodents are the primary reservoirs of Yersinia pestis, cats play an increasing role in transmission to humans. Several documented cases in recent years reveal that domestic cats, when exposed to infected fleas or sick rodents, can develop severe forms of the disease and transmit it through direct contact, scratches, or bites. This case highlights the importance of heightened vigilance: any suspicious abscess in a cat living in a rural or semi-rural area should alert veterinarians. Similarly, pet owners must be informed of simple yet crucial preventive measures, such as wearing gloves when caring for their pets or administering regular antiparasitic treatments.  

A “One Health” Approach Is More Necessary Than Ever

Plague remains a rare but potentially serious zoonosis that requires cross-sector coordination among human health, animal health, and environmental health. The case in Oregon demonstrates that the boundaries between seasons and between reservoir species are becoming increasingly porous, calling for an update to surveillance, diagnostic, and prevention protocols.