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It is rare for an animal typical of the humid and warm jungles of Central and South America to be so hairy. It is also rare that such a monkey-like species is rather familiar to the armadillo. As strange as that wild mammal appears in so many photographs of tourists to the point that Costa Rica ended up formally naming it a national symbol in 2021. As unusual as the number of living beings that inhabit the fur with microcracks, sometimes green, of one of the most sympathetic animals in the forest - the sloth bear (which is not even a bear).
Now it is known that the peculiarities of this animal that does not weigh even 10 kilos and that lives mostly in the trees go beyond the naturalistic or tourist interest. Chemistry and medicine have a lot of work ahead with sloths now that researchers from the University of Costa Rica (UCR) found in the fur bacteria with the potential to produce antibiotics for human benefit, after wondering how this small but rich ecosystem manages to balance itself to prevent fungi from making the animal sick.
Judy Avey-Arroyo, owner of the Costa Rican Sloth Sanctuary in the province of Limón, oversees the recovery of a specimen on March 10, 2023.EZEQUIEL BECERRA (AFP)
The work is far from over, but the path seems certain. In 2022, the presence of the bacteria was verified through research published in the scientific journal Environmental Microbiology, which aroused the interest of French researchers who now collaborate with UCR scientists in the immediate phase: identify these molecules, compare with other antibiotics already discovered and test the usefulness against pathogens harmful to humans.
This is the stage of work in the university laboratories in San José, about 200 kilometers from the shelter for sloths where the hair samples were extracted, in Cahuita de Limón, the Caribbean town that any day allows you to see a specimen in the forest or, bad news, crossing the street by the public lighting cables. It is much more likely that in the shelter they receive beaten or injured animals, because from pathogens they seem to be protected.
"An ecosystem of moths"
The coordinator of the study is Max Chavarría, an expert in microbial biotechnology at the Center for Research in Natural Products (Ciprona) of the UCR and the National Center for Biotechnological Innovations (CeniBiot). "At first we wanted to analyze exotic environments that have not been studied, environments to which not everyone has access and that makes the work attractive," he explained to América Futura. "The sloth's fur is not like that of a teddy bear, it is a whole ecosystem with moths, insects and full of organisms. That led us to think that such a complex ecosystem surely has systems that help control the proliferation of other living beings that can make the animal sick. What makes the animal not sick? With that hypothesis of beneficial bacteria we decided to start this project and look for bacteria there. The hypothesis was fulfilled because we found bacteria with that ability to produce antibiotics," he explains.
Dr. Max Chavarría at the University of Costa Rica, on April 18, 2023.EZEQUIEL BECERRA (AFP)
The analyses made at the National Nanotechnology Laboratory indicated that the premise about the presence of these bacteria that produce substances to placate others that also lodge in the sloth bear was correct. Its original fur allows it to retain a lot of moisture and condition the house for a variety of living beings, including algae that allow the animal to blend in amid the green of the leaves of the trees, a protection service against predators in exchange for nutrients consumed by these organisms, as other studies have shown.
However, there is still much knowledge pending about the relationships between living beings that occur on board the very slow animal that often seems to have a pleasant smile, despite the vulnerability it suffers from the destruction of its natural habitat and illegal trafficking.
Two of the six species of sloths were declared a national symbol by the Legislative Assembly of Costa Rica in 2021, based on the iconic value in the ecotourism market of the Central American country. The approved law mandates the development of awareness and education campaigns on the preservation of these animals and says to stimulate scientific research such as the one led by Chavarría with his team at the UCR that, despite limited resources, managed to position the research in the journal EnviromentalMicrobiology and capture the attention of other researchers in France. who collaborate with the project in the chemical work phase.
"Much remains to be done. We are in a phase that has a difficulty, that of seeing the antibiotic molecules. Then compare with those that are already known and continue with the research, with the possibility of even patenting them. In a promising scenario, then will come the tests of antibiotic activity in different models and rule out that they cause any harm to humans, "explained Chavarría, optimistic about the work of the "100% Costa Rican" team, but also because of the international interest in the project.