Plague (Yersinia pestis) in Cats: A Vet’s 2025 Guide to Recognition, Treatment & Zoonosis Prevention 🐾

Hello, I’m Dr. Duncan Houston BVSc, veterinarian and founder of Ask A Vet. Though rare in domestic cats, plague—caused by the bacterium Yersinia pestis—is a serious zoonotic disease that can threaten both feline and human health. This 2025 guide provides in-depth, medically accurate insight into recognizing clinical signs, confirming diagnosis, initiating treatment, and implementing vital isolation and public-health protocols.

📘 1. What Is Plague?

Yersinia pestis is a gram-negative, bipolar-staining coccobacillus spread via infected fleas, direct contact with infected wildlife or fluids, ingestion of prey, or rarely respiratory droplets in pneumonic cases :contentReference[oaicite:3]{index=3}. In North America, it is most common in the southwestern U.S.—including Arizona, New Mexico, Colorado, California, Nevada, and Oregon :contentReference[oaicite:4]{index=4}.

⚠️ 2. How Cats Become Infected

• Flea bites: from rodent fleas carrying plague bacteria :contentReference[oaicite:5]{index=5}.
• Ingestion of infected prey: hunting rodents and rabbits :contentReference[oaicite:6]{index=6}.
• Direct contact or scratches: with infected animal tissue or fluids :contentReference[oaicite:7]{index=7}.
• Respiratory droplets: rare pneumonic spread from infected cats or humans :contentReference[oaicite:8]{index=8}.

👀 3. Clinical Forms & Signs

In cats, plague manifests most commonly as bubonic or septicemic forms; pneumonic cases are less frequent but pose the highest zoonotic risk :contentReference[oaicite:9]{index=9}.

• Bubonic Plague

• High fever, anorexia, lethargy
• Enlarged—often abscessed—submandibular or cervical lymph nodes (“buboes”) :contentReference[oaicite:10]{index=10}.
• Painful swelling, discharge, ulceration, oral ulcers, eye or skin lesions :contentReference[oaicite:11]{index=11}.

• Septicemic Plague

• Fever, vomiting, diarrhea, hypotension, tachycardia
• Signs of DIC: clotting disturbances, pale or brick-red mucous membranes, bleeding :contentReference[oaicite:12]{index=12}.
• No lymphadenopathy.

• Pneumonic Plague

• Progresses from septicemia or inhalation exposure
• Severe respiratory signs: cough, dyspnea, harsh lung sounds :contentReference[oaicite:13]{index=13}.
• Most dangerous form—cats can aerosolize bacteria :contentReference[oaicite:14]{index=14}.

🧪 4. Diagnosis: Steps to Take

1. Physical exam & history: note fever, swollen lymph nodes, and outdoor or hunting exposure :contentReference[oaicite:15]{index=15}.
2. PPE & isolation: mask, gloves, eye protection; isolate suspected cases :contentReference[oaicite:16]{index=16}.
3. Samples: aspirates or fluid from lymph nodes, blood, sputum for Gram/Giemsa/Wayson stain—bipolar, safety-pin appearance is characteristic :contentReference[oaicite:17]{index=17}.
4. Cultures & PCR: confirmative; pre-treatment samples preferred :contentReference[oaicite:18]{index=18}.
5. Additional testing: CBC/chemistry, chest radiographs if pneumonia suspected.

⏱️ 5. Treatment Protocols

Plague is life-threatening and requires immediate antibiotic therapy—even before definitive lab confirmation :contentReference[oaicite:19]{index=19}.

• Antibiotics: doxycycline, tetracycline, chloramphenicol or fluoroquinolones; 10–21 days depending on severity :contentReference[oaicite:20]{index=20}.
• Hospitalization: supportive care with IV fluids, antiemetics, nutritional support, and oxygen therapy for pneumonia :contentReference[oaicite:21]{index=21}.
• Flea control: immediate application of rapid-acting flea treatment to prevent further transmission in hospital :contentReference[oaicite:22]{index=22}.

🛡️ 6. Isolation & Zoonotic Precautions

• Maintain acne-level isolation for at least 72 hours after starting effective antibiotic therapy :contentReference[oaicite:23]{index=23}.
• PPE for human caregivers includes N95 respirator, gloves, eye protection, gowns—especially with pneumonic cats :contentReference[oaicite:24]{index=24}.
• Notify public health authorities—plague is reportable; contact tracing and prophylaxis may be required :contentReference[oaicite:25]{index=25}.
• Warn household members about exposure risk; human post-exposure prophylaxis may be advised :contentReference[oaicite:26]{index=26}.

📈 7. Prognosis & Outcomes

• Cats responding to early antibiotic therapy often recover fully :contentReference[oaicite:27]{index=27}.
• Mortality increases with septicemic and pneumonic forms: untreated mortality may exceed 40%, sometimes approaching 90% in pneumonic cases :contentReference[oaicite:28]{index=28}.
• Cats considered non-infectious after ~72 hours from starting antibiotics and with clinical improvement :contentReference[oaicite:29]{index=29}.

🏠 8. Prevention Strategies

• Keep cats indoors in endemic areas and discourage hunting :contentReference[oaicite:30]{index=30}.
• Implement year-round flea control with vet-approved products :contentReference[oaicite:31]{index=31}.
• Minimize rodent exposure—remove food, debris, and rodent habitats around the home :contentReference[oaicite:32]{index=32}.

📚 9. Case Studies

“Loki,” an indoor-outdoor cat from New Mexico, presented with high fever and swollen neck lymph nodes after returning from wandering. Aspirate Gram stain revealed bipolar-staining rods. Doxycycline, IV fluids, flea control, and isolation were initiated. Loki stabilized within 48 hours and was considered non-infectious at 72 hours. He completed 14 days of doxycycline and remains healthy.

“Daisy,” a kitten, developed septicemic plague with fever and lethargy after hunting rodents. She required IV fluids, broad-spectrum antibiotics, and oxygen support. Full recovery followed 21 days of therapy. No zoonotic transmission occurred.

🚨 10. When to Seek Immediate Veterinary Attention

• Sudden fever, lymph node swelling, respiratory distress, seizures, or collapse
• Known contact with wild rodents or fleas in an endemic region
• Lack of appetite or worsening illness despite treatment

✨ 11. Final Thoughts

Although uncommon, feline plague demands swift recognition, aggressive antibiotic therapy, and strict isolation to protect households and veterinary teams. Cats serve as crucial sentinels in sylvatic plague cycles—vigilance and preventive measures save lives. Ask A Vet offers tele-triage support, medication reminders, and public-health guidance to help cats recover safely and prevent zoonotic risks 🐾❤️.

For customized isolation protocols, treatment tracking, and public-health support, visit AskAVet.com or download the Ask A Vet app. We’re here to back you through crisis and recovery.