Many frog species are affected by a deadly pathogen, but the effects vary by species


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A new study conducted by scientists at Western Sydney University examines a deadly fungal infection that is causing significant biological disturbance for frogs and evaluates how reactions vary across species.

The study, which was published in Functional Ecology, analyzed the chytrid fungal infection, which is responsible for the decline of at least 501 amphibian species and is often regarded as the most devastating single disease on biodiversity.

Dr. Nicholas Wu of the University of Hawkesbury’s Institute for the Environment, who authored the paper, claims that chytridiomycosis is responsible for the biggest loss of biodiversity due to a single illness; however, it is unknown if frogs infected with this fungus show the same symptoms.

According to Dr. Wu, using a meta-analytic method, the study demonstrated there are significant similarities in symptoms across frog species that offer a clearer understanding of the cause of the disease and, thus, mortality.

For the sake of conservation, it is possible to rely on these symptoms to predict how frogs that have not been exposed to chytrid could espond if they become infected. Swabbing a wild frog that appears ill and then determining the pathogen load allows researchers to make judgments about the frog’s condition in lieu of any direct experimental testing.

According to the results, hosts may only experience skin disturbance and changes in immune response at low pathogen load, but at high pathogen load, they will undergo changes in reproduction and body condition.

Dr. Wu noted that meta-analytic techniques might be a beneficial tool for better understanding disease dynamics in an ecological setting, especially in context of the increasing number of emerging infectious illnesses.

Emerging infectious diseases are a major factor in the decreasing trend of animal and plant species across the planet. There are a lot of things in the environment and there are variances between the host and the pathogen, so how species react to infectious diseases is all over the place.

Understanding the similarities in trait sensitivity can provide light on the effects of illness and aid in wildlife management. Different ‘traits’ associated to an animal’s fitness, such as physical condition, reproduction, or metabolic rate, may be more susceptible to pathogen load.

Sources:

Nicholas C. Wu, Pathogen load predicts host functional disruption: A meta‐analysis of an amphibian fungal panzootic, Functional Ecology (2023). DOI: 10.1111/1365-2435.14245

https://phys.org/news/2023-01-lethal-pathogen-widespread-biological-disruption.html