- Andre Bernat
- Brazilian Section, BBC
Fungi of the family Sporothrix are found in soil, grow on some plants, and help in the process of decomposing organic matter in nature.
Until the mid-1990s, the fungus, Sporothrix brasiliensis, was little known. But it has since become a public health problem in Latin America because it causes deep skin wounds in cats and humans.
The first cases of infection with this pathogenic fungus began to attract attention in Rio de Janeiro, where researchers noted that transmission to humans came mainly from stray cats.
Soon, the infection spread to other Brazilian states. A study published last September stated that a public hospital in Sao Paulo had received an increasing number of cases over a 15-year period.
“We used to see one or two cases a year. Now, we see two or three cases a week,” said Dr. John Verender Vessey, one of the researchers who conducted the study, in statements to Medscape, a specialist in medical news on the Internet.
Last December, dermatologist Rossana Sethi posted photos on Instagram of a rash caused by a sporothrix infection.
The patient mentioned that there are cats in his workplace.
Sporothrix brasiliensis infection has also spread to Argentina, Paraguay, Bolivia, Colombia and Panama.
But what are the reasons for this spread?
The spread of this mysterious epidemic indicates that environmental imbalances can have sudden and unexpected consequences.
From a harmless mushroom to a dangerous one
The group of fungi to which Sporothrix belongs has been known to scientists since 1898. These fungi are generally found in soil, and they also grow on some plants.
Like other fungi, these species are crucial to the process of decomposing organic organisms in nature.
A veterinarian posted a picture of a cat with this infection that she was caring for.
However, in some rare cases, these microorganisms can cause diseases in humans that are generically called sporotrichosis.
Sporothrix braziliansis penetrates the superficial layers of the skin. The fungus colonizes the tissue beneath these layers and causes wounds.
The fungus also invades the lymphatic system and affects the eyes, nose, and even the lungs as well.
As mentioned above, these cases are rare. But their recurrence began to gain attention in the late 1990s in some areas of Rio de Janeiro.
contact with cats
Between 1998 and 2001, researchers at the Oswaldo Cruz Foundation diagnosed 178 cases of sporotrichosis.
“Of the 178 patients, 156 had physical contact with cats either at home or in the workplace, and 97 were bitten or scratched by those animals,” the researchers wrote.
But since then, the number of cases has increased rapidly.
“According to the latest statistics, there have been more than 12,000 cases of infection in humans since then,” says Dr. Flavio Telles of the Brazilian Infectious Diseases Association.
“This is in addition to the countless injuries among cats and dogs,” he adds.
image copyright US Centers of Disease Control
Sporothrix braziliansis transmission cycles involve a complex network of contact between plants, cats, rats, dogs and animals
Over time, researchers have been able to better understand the cycle of infection between humans and the animals that live near us.
“For some reason, the bodies of cats become a favorable environment for the fungus,” says Dr. Telles, who is also a professor at the Federal University of Paraná.
Professor Telles adds: “This happens because the battles that take place between them to defend their territories or in search of food or mating are part of the biological nature of cats, during which they scratch or bite each other.”
Experts interviewed by the BBC say that cats should not be blamed for sporotrichosis. They are victims just like dogs and humans, and the absence of public policies aimed at controlling fungus infection leads to its spread.
Imbalanceyou environmentalH
Microbiologist Marcio Rodriguez of the Oswaldo Cruz Foundation says the spread of the fungus Sporothrix brasiliensis is still being studied and speculated.
There is a direct relationship between [ارتفاع عدد الحالات] Occupying lands, destroying forests and building houses.”
“We have an imbalance in ecosystems that were previously balanced, and this leads to exposing animals and humans to new germs.”
Once the fungus reached feral cats, its jump to humans was relatively easy. These cats are widely spread in many Brazilian neighborhoods.
image copyright Getty Images
Destruction of forests is among the factors associated with the spread of infection
Children often play with stray cats, and adults welcome them because they help them control the rat infestation.
Ecological imbalance plus living close to the animals helped lead to contact with the fungus, which in turn started to make humans sick.
Although these observations help explain how infection with Sporothrix brasiliensis spreads, they do not allow us to understand how the problem spread outside Brazil.
Argentina
In Argentina, for example, cases of sporotrichosis in cats have more than quadrupled in the less than 10 years since 2011.
“Cats can cross land borders between states, and even countries,” says Dr. Flavio Telles.
“In addition, people who leave a neighborhood or a city sometimes take it with them,” he adds.
rats
image copyright Getty Images
Some reports indicate that rats transmit Spirotrix infection
Another possible explanation for the spread of Sporothrix across several countries in the Americas has to do with rats.
Some studies have claimed that these rodents can also be carriers of the fungus. These animals can move from one place to another “in secret” in food shipments on trucks and ships.
And in the new locations you go to, the rats are chased by the cats that live there. The cats, in turn, become infected, and a new cycle of sporotrichosis begins.
image copyright Getty Images
Stray cats are among the main victims of sporotrichosis
What can we do?
Compared to other fungi of the same family, Sporothrix brasiliensis has the ability to spread more easily and can cause more serious infections.
Also, treatment for the infection is not easy, as antifungal drugs may not be effective at first.
Treatment with drugs and drugs usually lasts 187 days on average, according to a study by the Federal University of Rio Grande.
The most important thing is an accurate diagnosis and start of treatment as soon as possible.
This would also prevent the fungi from becoming drug-resistant, which has caused repeated problems in recent years with other fungi.
image copyright Getty Images
Fungi in the family Sporothrix cause a number of health problems in humans
environmental impact
Marcio Rodriguez says cases like Sporothrix brasiliensis show that environmental imbalances caused by human actions have unpredictable consequences.
The microbiologist adds, “15 years ago, sporotrichosis wasn’t a problem.”
“Changes in ecosystems can result in exposure to germs that we have not been exposed to before. This, in turn, leads to a public health disaster.”
This, Telles adds, underscores once again the importance of viewing the health of people, animals and the planet itself as one.
“We are talking about a complex issue whose solution depends on an international approach,” he explains.
“We will need human doctors, veterinarians, epidemiologists, microbiologists, public health and environmentalists, and a number of professionals to be able to combat this. [الوباء] And other similar cases.