Research Program Spotlight: Disease Sampling
- Alec Jarboe
- Jun 18
- 4 min read
Approaching halfway through 2025, one thing is for certain: it has been a busy year, especially for our Jacksonville office! Between travelling for classes, installing and monitoring our artificial refugia project, and selecting from some awesome applicants for our annual grant cycle, the months have flown by! One subject I'd like to expand on is our disease surveillance program. A cause of a lot of sweat, tears and gas mileage but one worth doing! For a bit of background, initial screening samples taken during another project led to the detection of a novel Ferlavirus coinfection (that is infection at the same time) with Snake Fungal Disease (SFD). Continued sampling from that site revealing more SFD cases and then a second novel disease strain, this time an Atadenovirus - pretty concerning, right?
Well, potentially concerning...

When it comes to disease, we have to understand that some may be endemic, some may be benign, some may have been in snake populations for generations. However, some may be truly novel, some may be invasive, and some may pose serious threats to snake populations. At the moment, there is no way to know without further investigation.
So when the situation demands investigation, we investigate. In our case, investigation includes a labor of sweat and blood diving into the thick underbrush of Florida's natural areas - through palmetto, wiregrass, broomsedge and muscadine alike, through misty mornings and humid evenings. It includes strategic cooperation with other partners - such as University of Florida's Zoological Medicine Diagnostic Lab (ZMDX), and a network of others who have expressed interest and began swabbing snakes in their local areas. It also includes opportunistic snakes encountered during other events, be they other research efforts or even our our Level 2R: Introduction to Field and Research Techniques!
A wild Pygmy Rattlesnake (Sistrurus miliarius) detected during our Level 2R class!
I've talk about what we do, I've dabbled in how we do it, but let's get into the why.
Species listing decisions, such as federal decisions under the Endangered Species Act (ESA) are often made focusing on the "Three R's", those being: 1) Redundancy
Redundancy is having multiple populations across a species’ range, which provides a buffer against localized threats. A species which has just 3 populations has much lower redundancy (and thus much greater risk of extinction or extirpation) than does a species which has over 30 effective populations across its range. In short, redundancy can be summarized as "having backup populations".
2) Resiliency
This is a population’s ability to withstand environmental stressors through any means. A species which is slow to give birth, undergoes vulnerable life stages or cannot easily migrate to and from habitats following disturbances (such as catastrophic fire or flood) has much lower resiliency (and thus greater risk of extinction or extirpation) than a species which can repopulate quickly following a severe event. Resiliency can likewise be summed up as "having the ability to withstand or bounce back"
3) Representation
This ensures that the genetic and ecological diversity of a species is conserved. Representation is a bit harder to quickly summarize, or give a good example, but a well-represented species is one that will have a broad and active gene pool found in a wide variety of habitats while one with low representation will have a narrowing gene pool and be found in limited or fragmented habitats.
So what do these "Three R's" have to do with snake disease?
Redundancy? Disease can deplete small, isolated populations. In the case of Timber Rattlesnakes in their northern ranges, a single outbreak can cause severe mortality of a denning species. Disease can also impair efforts to reintroduce snakes into areas they once occupied.
Resiliency? On their own, diseases can be considered one of the environmental stressors resiliency is required to withstand. However, the world is not a vacuum, and very rarely do stressors act alone. Disease can exacerbate existing environmental events (such as floods or storms) and wreak havoc among stressed individuals. Likewise, by causing mortality or even sub-lethal effects (to make sick but not kill) healthy adults, diseases could potentially impair the reproductive success and ability to rebound following another cause of population collapse.
Representation? Diseases are likely to act on the genetic diversity of snakes through several pathways including population bottlenecks, altered selective pressures, and varying effects on the same species in different environments.
Okay, you've made it this far so please enjoy some more cool pics:
Left: In-situ of a wild Eastern Diamondback sampled in North Florida. Center: TRC team taking cloacal samples from a different individual wild Eastern Diamondback. Right: A non-venomous Eastern Pinesnake also swabbed due to shared habitats with all three species rattlesnakes and conservation concern.
While listing decisions are not the exclusive concern - though nor are they off the table, especially as it relates to the forthcoming USFWS decision on the Eastern Diamondback - the "Three R's" explained above can be used a baseline to understand the threat posed by snake disease and why we strive to learn more.
Right now, we are in the discovery phase; where we aim to get a better idea of what kind of pathogens are out there. Next, as the last few years' worth of effort turns into test results and a map of positive disease findings begins to take shape, we'll move into the focused study phase, where we take a closer look at specific pathogens in specific hotspots and compare body condition & health data between infected snakes and "clean" snakes - as well as comparing information between those sites and other "healthier" locations. Finally, we will then move into the "action" phase, which will consist of testing and implementing available and novel practices to mitigate the impacts of diseases of concern in wild snake populations. Until then, we continue to practice the best available degree of sanitation between sites and between each snake sampled.
Want to help our efforts? You can always help your local snakes by ensuring that you sanitize your shoes, hiking sticks and any snake-handling gear with a solution such as dilute bleach or 70% alcohol between different wildspaces and especially between captive snakes and wild areas. Another way to support us is check out one of our industry-standard setting Venomous Handling Certification Classes or for a long-lasting hands-off approach you can consider becoming a sustaining member! Support from our members ensures that programs such as this can continue and expand!