Californian red-legged frog, Rana draytonii
Photo: Conservación de Fauna del Noroeste
Creationist mode: 
Long-term readers of this blog my recall how I wrote about a fungal infection, chytridiomycosis, that is devastating populations of frogs and other amphibians throughout the world. I concluded that, if as Creationists claim, these organisms are intelligently designed by a god, to do exactly what they do, the only conclusion was that this putative god must hate frogs and is trying to exterminate them, without going to the extremes it went to when it decided to exterminate another of its mistakes - humans - when in a fit of pique and a loss of self-control, it drowned everything else too.
I also wrote about the disease in my popular, illustrated book, The Malevolent Designer: How Nature's God is not Good.
In that earlier blog from October 2013, I described how scientists had discovered just how clever the designer of the fungus had been. It had taken a common, normally harmless soil fungus of the widespread chytrid family, Batrachochytrium dendrobatidis (Bd) and modified it to not only infect the skin of amphibians but to paralyse their immune systems too, making it easier to kill its victims by thickening their skin so they are no longer able to breathe through it, and then use their dead bodies to make more fungi, to kill more amphibians. Sheer, genius, eh?
Now, nine years later, scientists working for the University of California, Santa Barbara, CA, USA (UC Santa Barbara), Universidad Autónoma de Baja California, Tijuana, Mexico and Conservación de Fauna del Noroeste, A.C., Ensenada, Baja California, have discovered that, not only is the devastation continuing in both Southern California and Baja California but that there is something going on in Baja California that is enabling Bd to hit the frogs there much harder than it is hitting them in Southern California, despite the fact that the species are the same and the environment is very similar.
From the UCSB news release:
Scientists are hard at work investigating the disease’s origin, trajectory, genetics and impact in an effort to safeguard vulnerable and valuable biodiversity. Biologists from Southern and Baja California have published the first major account — and most comprehensive study — of the amphibian disease chytridiomycosis in the Mediterranean region of Baja California. Their results, which appear in Global Ecology and Conservation, indicate that the disease is more prevalent on the peninsula than in similar areas of Southern California.
Contrary to what we had expected, what’s going on in Baja California is very different than what’s going on with chytrid fungus in Southern California, where the species are pretty much the same, and the environment is very similar.Chytrids form a large group of mostly soil-dwelling fungi. They’re quite common, and generally pose no harm. However, two species have evolved to infect the skin of amphibians. In highly infected animals, the skin responds by thickening.
Andrea J. Adams, lead author
Assistant researcher
Earth Research Institute
UC Santa Barbara, CA, USA
This has a downside. “You probably heard frogs drink through their skin,” Adams said. It’s true. They also exchange salts and minerals through their skin. So when their skin thickens, it can be a death sentence for many individuals.
We knew chytrid was here, but we didn’t know how it was affecting different species or which variables mattered most.The team wanted to know what environmental and biological factors influence chytrid infection in Baja California, particularly at different elevations. Unfortunately, there has been little research on the topic in the Mediterranean region of Baja California… Conservación de Fauna del Noroeste, [is] a nonprofit organization dedicated to research and conservation in Baja California, especially for less charismatic species.
Anny Peralta-García, co-author
Director of Conservación de Fauna del Noroeste
Ensenada, Baja California, Mexico
Location of the study area and sampling sites in the Mediterranean Region of Baja California, Mexico.
The difference was particularly striking for California red-legged frogs. In another study in Southern California, only 30% of the species was infected. “In Baja California, we found that 99% of the California red-legged frogs at the highest-elevation site were infected,” Adams remarked.
Not only was the disease more prevalent, infected animals also carried a higher pathogen load in Baja California. The team was curious when the fungus first arrived in Baja California. If it appeared recently, that could help explain the high infection intensities compared with Southern California. “When the fungus first arrives to a place it can cause die-offs and declines in susceptible species,” Adams explained.
[…]
For comparison, the first record of the fungus in Southern California was found in specimens from Los Angeles County in 1915. This makes some sense, as invasive species often arrive at ports of entry and then fan out into the landscape. The combined ports of Los Angeles and Long Beach are the largest on the West Coast.
So, if chytrid has been in both places — Baja California and Southern California — for about the same amount of time, what could explain the differences the team found?
Much like the SARS-CoV-2 virus, the chytrid fungus has evolved over time. As the fungus mutates and adapts, more virulent or infectious strains may emerge in different locations.
AbstractSo, it appears that Creationism's favourite pestilential malevolence has copied the technique it developed with the SARS-CoV-2 virus and modified the Bp fungus to make it much more virulent in in the Baja California peninsula. Or so any Creationists who has a grasp of the implications of believing a magic creator is responsible for each and every change in any organism, must believe.
Amphibians are declining globally, and the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis, has been the culprit in many of these declines. In the Mediterranean region of Baja California, Mexico—a biodiversity hotspot—native amphibians are also in decline, and Bd is present. To determine which factors best predict Bd infection prevalence and intensity in Baja California anurans, we conducted Bd sampling at three disparate sites at varying elevations. We observed an overall Bd prevalence of 68%, and found that species was an important predictor of pathogen prevalence and burden (load) both across and within sites. Pathogen prevalence and load increased positively with elevation. The highest Bd load we detected was 139,188 zoospore equivalents (ZE) in a western toad (Anaxyrus boreas)—more than 10 times the pathogen burden at which chytridiomycosis is lethal in some species. We observed high Bd prevalence (84 – 99%) and Bd loads (> 44,000 ZE) in the California red-legged frog (Rana draytonii)—a cause for concern in this threatened anuran, especially at La Grulla—the highest elevation (2050 m) site for this species across its range. We sampled museum specimens to determine how long Bd has been present in the region, and detected the pathogen as early as 1932. Contemporary Bd prevalence and load in Baja California are considerably higher than would be expected given similar habitats and the same community composition as in southern California, USA. We therefore highlight the importance of historical context and comparative analyses in examining contemporary Bd dynamics, as well as adhering to strict biosecurity measures when implementing reintroductions and translocations.
Adams, Andrea J.; Peralta-García, Anny; Flores-López, Carlos A.; Valdez-Villavicencio, Jorge H.; Briggs, Cheryl J.
High fungal pathogen loads and prevalence in Baja California amphibian communities: The importance of species, elevation, and historical context
Global Ecology and Conservation 2022 33; e01968; DOI: 10.1016/j.gecco.2021.e01968
Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY [4.0)
To people who have even a rudimentary grasp of biology, the simple explanation for this phenomenon will be obvious: the fungus has evolved by natural selection in the Baja California peninsula because that's where the advantageous mutations arose. There is no magic designer with an obsession with frogs who has a special hatred for those in part of Mexico.
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