Amid the chaos of the current quad-demic, another infection quietly sees a spike in cases
Key Takeaways
Patient Buzz
"It's due to its extreme infectivity, 1 bacterium is enough. Usually takes millions to get sick. Happened at Martha's vineyard from lawnmowers running over rabbits." — Reddit user @h08817
"I got [rabbit fever] two years ago. It took four doctors to diagnose it. [A]ll of them pumped me full of antibiotics so much [so] that I now have a penicillin sensitivity." — Reddit user @leonieihavenoidea
A rare infection might not grab your attention—until its numbers start climbing. Tularemia, also known as rabbit fever, has seen a 56% increase in reported cases in the US over the last 10 years, according to a recently released report from the CDC.[][]
Given its relatively low prevalence, diagnosis doesn't come easily for affected patients—and without treatment, it can become life-threatening. Perhaps most chilling of all is the potential for Francisella tularensis, the bacterium that causes rabbit fever, to serve as a particularly effective agent of bioterrorism, per the CDC.[]
So, what’s driving the current spike? And, given the spate of viruses currently dominating headlines—from bird flu to HMPV to a particularly gnarly stomach bug—will rabbit fever soon be added to your list of things to worry about?
@abricott47 You get an extra fun fact today because I forgot to post this yesterday 🙃 #tularemia #tick #fever #disease #zoonoticdisease #funfact #hiking #naturevibes ♬ original sound - Abri Cott
Cases are up, but why now?
Several factors likely contribute to the uptick in tularemia reports.
Improved diagnostics and reporting
In 2017, the CDC began including polymerase chain reaction (PCR) testing in its criteria for probable cases. This change, coupled with better awareness and access to testing, has likely inflated the numbers—at least to some degree. Between 2011 and 2022, 60% of cases were classified as probable, a sharp contrast to 35% in the previous decade.[]
Environmental and behavioral factors
Changes in land use and human behavior could be creating more opportunities for exposure. Lawn mowing over infected animal nests—a surprisingly effective way to aerosolize F. tularensis—has been linked to outbreaks, including one on Martha’s Vineyard in 2000.[] Meanwhile, populations living near endemic wildlife, such as in central US states, face heightened risk.[]
Climate and ecological shifts
Though not explicitly studied in the CDC report, climate changes could be influencing vector and host populations. Warmer temperatures and altered precipitation patterns might expand the habitats of ticks and deer flies that carry the bacterium.
Are we worrying?
Yes and no. Tularemia remains rare overall—just one case per 200,000 people annually. However, it’s a disease that demands quick recognition and action due to its diverse clinical presentations and potential severity if untreated.
Fatality rate: Under 2% in most cases, but this can climb depending on the infecting strain and form of the disease—primary pneumonic tularemia, for example, has a mortality rate as high as 60% if left untreated.[]
High-risk groups: Incidence is five times higher among American Indian and Alaska Native populations, with other vulnerable groups including children aged 5-9, men 65-84, and individuals in central US states.[]
The bacterium’s classification as a Tier 1 Select Agent due to its bioterrorism potential also keeps it on the radar for public health authorities.[]
In the clinic
As a healthcare provider, your role is pivotal. Tularemia’s symptoms vary widely depending on the route of transmission—ulceroglandular, glandular, pneumonic, and typhoidal forms all require distinct clinical approaches.[]
Think tularemia in unusual cases: Patients with a compatible history—tick bites, exposure to rabbits or rodents, or even outdoor activities like gardening or mowing in endemic areas—warrant consideration.
Act fast: Antibiotics are highly effective but require prompt initiation. Misdiagnoses can lead to delayed treatment and worse outcomes.
@cady_s_ Replying to @Richard Starwars ive been in and out of the hospital since 2014 #chronicillness #tularemia #piccline #mayoclinic #potssyndrome ♬ original sound - Cady S
The rise in tularemia cases presents both a challenge and an opportunity for healthcare professionals. Enhanced diagnostic tools and greater awareness can help mitigate the disease’s impact, especially in vulnerable populations. For those practicing in areas where tularemia is endemic, maintaining a high index of suspicion is vital when evaluating patients with compatible symptoms and exposure histories.
Read Next: HMPV outbreak sparks panic: Everything you need to know about surging cases