A mysterious fungus targets the brain.. Why are fatal infections increasing?
Amman4 min read
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The rise in cases of a rare fungus known as "Cladophialophora bantiana" has raised concerns among researchers, after a US reference laboratory recorded a notable increase in its detection, amid warnings about the danger of the infection, which can affect the brain and cause severe complications, with a mortality rate ranging between 60 and 70%.
According to a report issued by the US Centers for Disease Control and Prevention (CDC), 49 confirmed or probable cases of the fungal infection were identified in clinical samples collected between January 2009 and July 2026, noting that the absence of a comprehensive national surveillance system for this infection makes it difficult to estimate the actual scale of its spread.
How does the fungus attack the brain?
This fungus is a type of dark mold found in the environment, including soil and decaying organic matter. Its danger lies in its tendency to infect the central nervous system, where it can lead to the formation of brain abscesses that cause inflammation and swelling of the surrounding tissues.
The infection may manifest as headaches, neurological disorders, and vision or memory problems, depending on the location of the abscesses and the severity of the infection. Report data showed that 43 out of 49 cases were linked to samples taken from inside the skull, while the fungus was detected in six lung samples.
The mechanism of the fungus's transmission to the human body is not yet fully understood, but researchers suggest that infection may occur through inhalation or entry through a skin wound, before reaching the brain in some cases.
Increase in infections over two years
Data from the specialized reference laboratory at the University of Washington showed an increase in the number of detected cases, as the number ranged between one and five cases annually during the period from 2009 to 2023, before rising to eight cases in 2024, and then to 14 cases in 2025.
The detection rate of the fungus in central nervous system samples also increased by 210%, from an average of 8.4 cases per thousand samples during the period between 2017 and 2023, to 26 cases per thousand samples in 2025.
Infections were recorded in 21 US states, in addition to Washington D.C., with California topping the list with six cases, followed by Florida and Texas with five cases each, then Pennsylvania with four cases.
Does it affect healthy people?
One of the aspects that worries researchers is that the infection is not limited to people suffering from immune deficiency; medical literature cited by the report indicates that about half of the patients had no known prior conditions affecting the efficiency of their immune system.
Dealing with the infection is further complicated by the fact that its symptoms sometimes resemble other diseases, including brain tumors, in addition to the complexity of diagnosis and treatment, and the lack of sufficient evidence to establish a standardized treatment protocol that achieves the best results for all patients.
Is climate change behind the increase?
So far, there is no conclusive evidence to explain the recorded rise in cases. The US Centers for Disease Control and Prevention confirms that the causes of this increase remain unknown.
A French study published in 2024 examined 23 patients with the infection, while reports indicated a similar rise in cases in France during 2022, which saw record temperatures. However, the coincidence of rising infections with hot periods is not enough to prove a causal relationship between climate change and the spread of the fungus.
Have cases been recorded in the Arab world?
Documented cases were not limited to the United States and Europe, as a study published in the journal "Neurosciences" in 2023 examined twelve cases of brain infection caused by dark fungi, diagnosed at King Faisal Specialist Hospital and Research Centre in Riyadh.
One of these cases was caused by the fungus "Cladophialophora bantiana" and affected a young man who did not show any clear immune deficiency in his medical evaluation.
This case confirms the possibility of the infection occurring in the region, but it does not mean there is an outbreak of the fungus in Saudi Arabia or the Arab world.
The need for more accurate monitoring
Researchers call for enhancing the reporting of infections and documenting cases discovered by clinical laboratories, with the aim of identifying risk factors, potential sources of exposure, and better understanding the patterns of the fungus's spread.
The announced figures remain insufficient to determine the true number of infections, in light of the absence of a comprehensive national surveillance system and the possibility that some cases are not detected or correctly diagnosed, while the causes of the increase and the mechanisms of transmission still require further scientific research.
