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Recently, Brazilian researchers have turned their attention to the Sporothrix brasiliensis, a Brazilian fungus unknown until the mid-1990s, which at the time only affected felines. Today the Sporothrix it is already a public health problem that affects not only cats, but also dogs and even humans. Last Wednesday (8), the Brazilian Society of Infectious Diseases issued a statement explaining a little more about the fungus and raised awareness throughout the country.
According to some publications, the transmission started in the city of Rio de Janeiro, initially proliferating among stray cats. Subsequently, new circulations of the microorganism were detected in other Brazilian states and even in other countries, such as Bolivia, Colombia, Argentina, England and the United States.
The Sporothrix brasiliensis
Fungi of the genus Sporothrix are known since 1898, appearing especially in soil and some plants. They are essential species for decomposing organic matter. In some rare cases, however, these microorganisms can cause diseases in humans, known generically as sporotrichosis. In case of Sporothrix brasiliensis, for example, it infiltrates the superficial layers of our skin and colonizes the subcutaneous tissue, causing wounds. The fungus is also able to invade the lymphatic system and affect the eyes, nose and even the lungs.
Since 1990, the number of cases has increased rapidly. Between 1998 and 2001, the Wire diagnosed 178 cases of sporotrichosis. “Of the 178 patients, 156 had some contact at home or at work with cats that also had this disease, and 97 were bitten or scratched by these animals”, indicates the study. According to the latest statistics, there have been more than 12 cases in humans since then.
With the increase in the number of cases, scientists began to study the fungus better and, over time, were able to better understand the cycle of infection not only among people, but also in animals that live close to our homes.
For some reason, the fungus has adapted to cats. In them, the pathogen causes disseminated disease, which causes wounds on the face and paws. And an infected cat transmits it to others, in addition to passing it on to dogs and humans.Flavio Telles, physician at the Brazilian Society of Infectious Diseases
It is noteworthy that the cat, as well as humans, are victims and are not to blame for sporotrichosis. The problem exposes another degrading situation, which is the lack of public policies to prevent the spread of the fungus.
Reasons for the problem
the microbiologist Marcio Lourenco Rodrigues, from FioCruz Paraná, said that the rise of the fungus is still being studied. However, he claims that the imbalances in nature caused by the actions of human beings are some of the reasons for the increase in the number of cases observed in recent years in the country.
Why was he already there on the ground and all of a sudden it became a public health emergency? There is a direct association between this fact and land occupation, deforestation and housing construction. That is, you start to have a disorganization of ecosystems that were previously in balance and this exposes animals and humans to new pathogensMarcio Lourenço Rodrigues, microbiologist at FioCruz Paraná
In addition, the proximity of felines to humans, which keeps them close, therefore, along with the natural imbalance, contamination is almost “natural”. However, it does not explain how it spread. “Cats transit through a territory and can cross dry borders of states or even countries”, pointed out Telles. “In addition, people who move from neighborhood or city can transport them”.
Another possible explanation for the spread of Sporothrix brasiliensis across several countries in the Americas is in rats. Studies conducted by scientists show that rodents are able to “carry” the fungus and go from one place to another when transporting food by trucks or ships. Thus, the cat, natural predator of the mouse, ends up becoming infected and starting a new cycle of sporotrichosis.
Compared with other fungi of the same genus, the Sporothrix brasiliensis has a different characteristic: that of being more transmissible, that is, it spreads more easily and quickly, in addition to being capable of causing more serious infectious conditions. To complete, the current treatment is not the easiest, since antifungal drugs do not always respond at first. On average, the treatment usually lasts about 107 days, according to the Federal University of Rio Grande (FURG).
The key, guarantee other articles published in recent years, is making the correct diagnosis and starting treatment as soon as possible. This even prevents the creation of drug resistance — this, incidentally, has been a frequent problem in recent years with other species of fungi, which are becoming increasingly difficult to combat.
“15 years ago, sporotrichosis was not a problem. The alteration of ecosystems provides possible exposure to pathogens that did not happen before”, said Rodriguez. “And this generates public health crises that are increasingly difficult to face”.
Yeast infections run rampant
Talking about yeast infections has been in the spotlight since the series The Last of Us, from HBO, debuted on its streaming platform. In it, fungal parasites manipulate humans to infect communities around them. In real life, the species of fungus that inspired the story, Ophiocordyceps, infects insects and does not cause problems for people. However, the threat from fungal pathogens is increasing, experts say, and could get much worse in a hotter, wetter and sicker world.
We are always surrounded by mold spores. We've lived with them since we made beds in the Savannah 500.000 years ago, before we even evolved into modern humans. And we had to adapt this exquisite immune system that we have to defend against spores, because many of them are potentially pathogenic..doctor Matthew Fisher, professor of medicine at the School of Public Health at Imperial College London
Scientists discover new fungi all the time – four were found in the last year alone – but not all of them are a threat to humans. Of the estimated 4 million diverse fungal species, scientists have identified only 300 as human pathogens that can cause disease. Per annum, over a billion people have what the Society for Microbiology considers “superficial” yeast infections.
Infections include well-known ones, such as athlete's foot, a scaly rash that may itch or burn; thrush, white lesions that develop on the tongue or the inside of the cheek; and even dandruff are mostly caused by one of these superficial fungal infections. They are annoying, but luckily, treatments still work on them. On the other hand, some infections are more serious and can lead to death. All around the world, about 1,5 million people die each year from complications caused by fungal infections.
Last year, the World Health Organization released a priority list with the 19 types of fungi that the world must observe. Among them is the cryptococcus neoformans, a pathogenic yeast that lives in the soil. People can inhale fungal cells and most don't get sick. But in those with a suppressed immune system, it can affect the lungs and spread to the nervous system and blood. Over the years, this fungus has become resistant to some treatments.
another is the Candida auris, a yeast that can linger on surfaces and medical equipment and can spread quickly from person to person. It has caused an increasing number of hospital outbreaks around the world, a threat that has grown even more during the Covid-19 pandemic. Worst of all, there are no vaccines for any of the fungal infections on the WHO's critical list.
According to researchers, the people most at risk of a serious yeast infection are those with underlying conditions such as HIV, cancer or diabetes, and those with compromised immune systems due to age, illness or medications they take. Others are vulnerable to the more serious consequences of yeast infections because they don't have access to medications that are more commonly available in the West.
And why are mold threats growing by leaps and bounds around the world? According to studies, the number of serious fungal infections has increased in part due to the growing number of immunosuppressed people. “We have aging populations and we use a lot of chemicals in the environment that force fungi to adapt, and our clinical antifungals are being degraded by antimicrobial resistance”, explains Fisher.
To try to curb the increase in the number of cases, the WHO encourages countries to improve their capacity to diagnose fungal infections and increase surveillance. It also recommends more money invested in research, drugs and testing for these infections. Currently, fungal infections receive less than 1,5% of all infectious disease research funding, the WHO said.
reviewed by Glaucous