For a decade, surveillance fixated on Ophidiomyces ophidiicola. New multi pathogen data from 509 wild snakes in the southeastern US shows the real ophidiomycosis risk is coinfection, especially with a python linked lung parasite.
For roughly a decade, herpetologists chasing "snake fungal disease" pointed almost every surveillance camera at one organism: Ophidiomyces ophidiicola (Oo). A new multi-pathogen survey of 509 wild snakes in the southeastern United States argues that the field has been looking through the wrong end of the telescope. The real risk of ophidiomycosis, the study finds, is driven by what is also living in the snake, particularly a python-linked lung parasite, Raillietiella orientalis, that arrived in Florida through the Burmese python invasion.
Published 26 May 2026 in Frontiers in Veterinary Science by a team led by Dr. Corinna Mishin at the University of Georgia, the study sampled 509 individual snakes across 29 species at two National Wildlife Refuges (Volusia County, FL and Jasper County, SC) plus opportunistic cases from Georgia and the Southeastern Cooperative Wildlife Disease Study between May 2022 and May 2024. Researchers screened for seven pathogens: Ophidiomyces ophidiicola, Raillietiella orientalis, Salmonella enterica, Hepatozoon spp., Mycoplasma spp., Cryptosporidium spp., and serpentoviruses.
The headline finding is statistical, not viral. Of 498 snakes with complete data, 44.0% carried two or more pathogens. Coinfection was the strongest predictor of apparent ophidiomycosis (p<0.0001), more tightly tied to visible disease than Oo detection on its own. A snake carrying Oo and another pathogen was far likelier to show the skin lesions, crusting, and facial deformity that define the disease than one carrying Oo alone.
The parasite doing the heaviest co-infecting is Raillietiella orientalis (Ro), a pentastome (tongue worm) that lives in the respiratory tract and is tied to the [Burmese python (Python bivittatus) introduction](https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2026.1754420/full). Ro was detected in 12.7% of Florida snakes (37/292) and in zero South Carolina snakes. The authors note that true Ro prevalence is almost certainly higher than 12.7%, because the parasite shows up in fecal samples and snakes eat infrequently, so many infections are missed. Ro-positive snakes also scored worse on body condition (p=0.0002), and Oo-positive snakes did too (p=0.0200). The two pathogens, in other words, are not just statistically associated; they are dragging the same animals down.
The species most exposed to this combined assault is the pygmy rattlesnake (Sistrurus miliarius). Of 34 pygmy rattlesnakes sampled, 12 were Oo-positive and 14 were Ro-positive, rates that translated into significantly elevated Oo detection (p=0.0479) and apparent ophidiomycosis (p=0.0148) with severe associated pathology. Pygmy rattlesnakes are Florida residents, and they are the species where the python's shadow falls hardest.
The survey's wider pathogen numbers, all from the paper's abstract, set a new empirical floor for free-ranging snake health in the region: Salmonella enterica 62.6% (306/489), Hepatozoon spp. 53.4% (205/384), Mycoplasma spp. 17.5% (78/445), Oo 16.1% (82/508), Cryptosporidium spp. 2.0% (10/489), and no serpentoviruses detected (n=447). The authors flag the Mycoplasma detection as the first documentation in free-ranging snakes in the United States, a careful claim, not a claim of emergence.
The paper's bigger move is methodological. Mishin and colleagues explicitly position the work as a step away from a roughly 10-year period in which free-ranging snake research had centered almost exclusively on Oo, the fungus behind the clinical syndrome first described in 2006 and now detected in more than 60 snake species globally. Population declines tied to Oo, including in the endangered eastern massasauga (Sistrurus catenatus), have driven the research agenda. The new baseline suggests that agenda needs to be wider.
The constraints are real. Sampling was concentrated at two refuge counties, opportunistic elsewhere, so the numbers describe presence and co-occurrence, not range-wide prevalence or trend. A cross-sectional survey cannot tell you whether disease incidence is rising, falling, or holding. The crisis framing in SciTechDaily's coverage reads detection as outbreak; the paper itself is more cautious. The honest summary is that the field finally has a broad pathogen map for southeastern snakes, and the most useful finding on it is a coinfection signal, not a single fungus, that future work will have to test against population-level outcomes.
What to watch: targeted surveillance in pygmy rattlesnake populations where Ro and Oo overlap, replication of the coinfection effect in eastern massasauga, and any move by the National Wildlife Refuge system to expand integrated pathogen panels beyond Oo-only screening. Those are the data points that will tell us whether a decade of focus on the fungus was a productive narrowing or a costly blind spot.