What is the plague, and why are county health alerts making headlines in the U.S. this August 2025? In the past two weeks, new cases have been confirmed both in California and in Colorado, reminding the public that while the plague is rare, it is not just history.
A resident of South Lake Tahoe, California tested positive for the plague earlier this month. This marks the first human case in the Lake Tahoe area since 2020. Local officials believe the resident was exposed while camping, most likely through a flea bite. The individual received quick medical care, and all indications point to a positive recovery.
In Colorado, Jefferson County Public Health reported its first animal case of the year. A pet cat in Evergreen, near Cub Creek Park, contracted the disease and sadly did not survive. Veterinarians stress that such cases are uncommon but do occur in the warmer months.
What is the Plague?
The plague is an infectious disease caused by the bacterium Yersinia pestis. It naturally lives in wild rodent populations and can be transmitted to humans and pets through flea bites or direct contact with infected animals. Without fast treatment, the plague can be fatal, but antibiotics are highly effective if started early.
Key Points Summary – August 2025
For those who want the essential facts at a glance, here’s what you need to know:
- 1 new confirmed human case in South Lake Tahoe, California this month
- 1 animal case (domestic cat) reported in Jefferson County, Colorado
- Plague spreads mainly through flea bites from infected wild rodents or contact with sick animals
- Typical symptoms include fever, chills, headache, nausea, and swollen lymph nodes
- Prompt antibiotics make recovery likely when treatment comes early
- Fewer than 7 human plague cases appear in the U.S. each year
- Highest risks are in the western United States during warmer months
Details on Latest Cases and Wildlife Surveillance
California public health officials have recorded evidence of plague exposure in 45 ground squirrels and chipmunks from 2021 to now across the Lake Tahoe Basin. This matches established patterns: wild rodent activity tends to increase cases in summer, and staff regularly monitor and test local wildlife.
El Dorado County’s latest human case is receiving strong attention. The patient was likely bitten by an infected flea while camping—a recognized risk in the Tahoe wilderness. Health advisories call for everyone visiting local forests and mountains to take precautions.
In Colorado, the Jefferson County cat’s diagnosis is the region’s first animal case since 2023. According to local authorities, animal cases among pets are sometimes the earliest signals of plague activity in a community.
How to Recognize and Respond to Plague Symptoms
In humans:
- Sudden high fever
- Chills
- Headache
- Weakness
- Painful, swollen lymph nodes (called buboes)
In pets:
- High fever
- Lethargy
- Loss of appetite
- Swollen lymph nodes
Most U.S. cases are the “bubonic” type, which shows up within 2–8 days of being bitten by an infected flea. The disease can become severe if not treated fast, so anyone with sudden fever and swollen lymph nodes after outdoor exposure should consult a doctor.
Prevention Tips for Humans and Pets
Health departments in both states stress practical, simple steps for anyone spending time outdoors:
- Avoid contact with wild rodents and dead animals
- Do not camp near rodent burrows
- Wear long pants and use bug repellents with DEET
- Tuck pants into boots to limit flea exposure
- Keep pets leashed and away from wildlife
- Use flea preventive products on dogs and cats
- Never feed wild rodents or allow pets to interact with them
These habits dramatically reduce the risk for both people and pets.
Plague Outlook for Summer 2025
While rare, U.S. plague cases draw attention because the disease’s historic impact is unforgettable. Today, modern healthcare and animal surveillance keep outbreaks small and outcomes good. Travelers and residents in California, Colorado, and other western states are encouraged to stay aware, especially during the summer.
If you have spent time in high-risk areas or have concerns about symptoms, reach out to your healthcare provider.
If up-to-date public health data becomes available later this month, this page will be updated. As of August 2025, no additional new cases have been reported.
Have you visited the Lake Tahoe area or Colorado’s parks this summer? Share your thoughts or questions below to help others stay informed.