The extinct aquatic fungi of several amphibians that spend all or part of their life cycle in water also threaten terrestrial amphibians. In Brazil, FAPESP-backed researchers have detected unprecedented mortality in a genus of small frogs called pumpkin toads that live in Atlantic forests far from the aquatic environment. The animal was heavily infected with chytridiomycosis (Batrachochytrium dendrobatidis), This causes chytridiomycosis.
Studies published in the journal Biological protectionShows that fungi are also a threat to terrestrial amphibians with important ecological functions such as controlling insects that carry diseases such as dengue, yellow fever and Zika.
“The fungus attacks amphibian skin. Amphibian skin is the place where gas is exchanged with the external environment. Infections cause physiological imbalances and animals eventually die of heart attacks,” the article said. The first author, Diego Moura Campos, said. The study was conducted during a master’s study at the Campinas University Institute of Biology (IB-UNICAMP) in the State of São Paulo with a scholarship from the Ministry of Education of Brazil’s Higher Education Staff Improvement Coordination (CAPES).
The study was linked to the FAPESP Research Program on Biodiversity characterization, Conservation, Restoration and Sustainable Use (BIOTA-FAPESP) and coordinated by Luis Felipe Toledo in the Brazilian Chitrid Bacteria: Origins and Results. It was carried out with the support of. He is a professor at IB-UNICAMP and a co-author of the article.
“We studied fungi from several angles, but rarely had the unfortunate opportunity to see animals die from wild fungal infections. This was the first to show this phenomenon in Brazil. A study. Even if an amphibian dies and becomes infected, that does not mean that the fungus caused its death. It may coexist with the pathogen without developing the disease. In this case, the animal loses weight, I was convinced that it was the cause of the death because I showed proper symptoms such as severe skin shedding and a very high infection load, “said Toledo, a senior researcher on another focused project. About understanding how fungi spread in nature.
Researchers believe that directly-occurring species (which breed on land, lack tadpoles, and hatch terrestrial eggs as fully formed miniature adults) are not further adapted to the fungus. Aquatic species have been in contact with the pathogen for a longer period of time and may have developed some resistance to infection.
Moura-Campos observed the morbidity and mortality of infected frogs during a field survey conducted from May 2018 to May 2019 at the Seradojapi Biological Reserve in Jundiaí, São Paulo. Brachycephalus rotenbergae Discovered after an atypical period of drought.
“These animals are very small and hard to find. After they die, they quickly break down. Guilherme Becker, a professor at the University of Alabama and the last author of the article, said: ..
According to Becker, a visiting professor at UNICAMP under the Graduate Program in Ecology, the study found that as global climate change accelerates in the coming decades, the frequency of this type of disease will increase and the causative agent will become more common. Shows that it can be toxic As already shown, hybrids will emerge Early group study..
“The lack of soil moisture in the forests in which they live may have caused these animals to seek hydration in streams and become more polluted by fungi than usual,” he said.
Another hypothesis raised by researchers is that periods of drought endanger the frog’s immune system, making it more vulnerable to fungi.
Cosmopolitan pathogen
The fungus originates in Asia and is spread around the world, probably as a result of the frog meat trade. Species consumed by humans for this purpose, such as the bullfrog (Rana catesbeiana), are resistant to fungi and can be carriers without infection.
According to the paper Published in 2018 In the journal Chemistry Co-authored by Toledo, the fungus originated on the Korean Peninsula and spread to other parts of the world in the early 20th century.
Another study contributed by Toledo found that fungi are causing a decline in the population of at least 501 amphibians worldwide. In Brazil alone, at least 50 species or populations have been affected, 12 have become extinct and 38 have declined.
“Amphibians are very important for the functioning of many ecosystems. Their biomass in forests is huge. They serve as food for a variety of other animals, feed on wild arthropods, and are an inverter community. Controls, “says Becker. “Most of the aquatic species are herbivores at the tadpole stage and consume phytoplankton. Without tadpoles, they can overwhelm the aquatic environment. These animals are aquatic and terrestrial ecosystems. If an outbreak of tadpoles occurs, the consequences are significant. “
As an example, Becker Recent research Scientists belonging to institutions in the United States and Panama have amphibian populations Frog chytridiomycosis It was associated with increased malaria outbreaks in Panama and Costa Rica in the 1990s and 2000s.
More accurate observations over the years are needed to more accurately estimate the global impact of chytridiomycosis on amphibian populations, according to Becker, Toledo, and collaborators.
Reference: “Fungal disease cluster of tropical terrestrial frogs predicted by low rainfall” by Diego Moura Campos and Sasha E. Greenspan. Graziera V. Direnzo. Wesley J. Neely.Luis Felipe Toledo and C. Guierme Becker, July 28, 2021 Biological protection..
DOI: 10.1016 / j.biocon.2021.109246
Aquatic fungi have already wiped amphibians off the map – now threatening the survival of terrestrial frogs
https://scitechdaily.com/aquatic-fungus-has-already-wiped-amphibians-off-the-map-now-threatens-survival-of-terrestrial-frogs/ Aquatic fungi have already wiped amphibians off the map – now threatening the survival of terrestrial frogs