Fungal infections affect over a billion people globally each year. Although there are an estimated 1 to 5 million fungal species, only a few hundred are known to cause disease in humans. Common infections like ringworm and yeast infections are typically mild, but fungi can also cause severe, even deadly illnesses, particularly in people with weakened immune systems.1
Treatment options are limited to a small number of antifungal drugs, and resistance is becoming an increasing concern. While large-scale fungal outbreaks are rare, some have followed extreme weather events, highlighting the evolving environmental risk landscape.1
The latest issue of Emerging Infectious Diseases from the CDC explores several significant developments in fungal disease research, including the global spread of drug-resistant Trichophyton, severe infections caused by Aspergillus flavus in France, and a surprising discovery of Histoplasma in a Spanish tourist hotspot.
Terbinafine-Resistant Trichophyton indotineae in Brazil Linked to European Travel
A case study from São Paulo, Brazil, reports a previously healthy man in his 40s who developed T indotineae tinea cruris in 2024 after traveling to France, Spain, and the United States. Despite undergoing 9 weeks of oral terbinafine treatment, his symptoms worsened, prompting further investigation. Laboratory testing confirmed terbinafine resistance with an SQLE F397L mutation (MIC >4 mg/L). DNA sequencing and MALDI-TOF with the MSI-2 database confirmed the identification of T indotineae.2
Whole-genome sequencing revealed that the strain was closely related (21 SNPs) to a 2022 strain from Germany, indicating a rising global spread of antifungal-resistant T indotineae. The patient’s condition improved after 8 weeks of itraconazole therapy (MIC .016 mg/L). This case emphasizes the need for clinicians to be vigilant about antifungal resistance and the global spread of resistant fungal pathogens, as well as the importance of using advanced diagnostic tools.2
Invasive Aspergillus flavus in France: Distinct Risk Factors and High Mortality
A retrospective study conducted between 2012 and 2018 on 54 cases of invasive Aspergillus flavus (IA) in France found a 30-day mortality rate of 39.2% and a 90-day mortality rate of 47.1%. Most infections were localized (87%), primarily affecting the pleuropulmonary region (33 cases) and the ear, nose, and throat (ENT) area (13 cases). Risk factors for pulmonary infections included malignancy (70% of cases), while ENT infections were often associated with diabetes (61.5%).3
What You Need To Know
The case in Brazil highlights the global spread of antifungal-resistant T indotineae, emphasizing the need for advanced diagnostics and vigilance in treatment.
High mortality in A flavus infections calls for increased clinician awareness, particularly for diabetics and immunocompromised patients, with attention to geographic and anatomical factors.
The detection of Histoplasma capsulatum in Spain raises concerns about local exposure risks, urging enhanced surveillance in ecotourism areas.
Treatment predominantly involved voriconazole monotherapy (67%), but the high mortality rate underscores the challenges in treating A. flavus infections. Despite being the second most common IA pathogen in France, A flavus accounted for only 8.7% of total IA cases (74 out of 845) during the study period, suggesting its prevalence is higher in other regions, such as Asia and the Middle East. The study calls for increased clinician awareness, especially among diabetic and immunocompromised populations, and consideration of geographic and anatomical variability in managing IA.3
Histoplasma Found in Spanish Tourist Site: Environmental Detection Raises New Concerns
For the first time, researchers have detected Histoplasma capsulatum in bat-inhabited tunnels along the Camino de Hierro, a popular tourist route in northern Spain. Histoplasma is a fungal pathogen that causes histoplasmosis, a lung infection typically acquired by inhaling spores from bird or bat droppings. While Histoplasma is known to be endemic in parts of the Americas and Africa, its presence in Europe has been rarely documented.4
The study found that 42% of guano samples from two tunnels tested positive for Histoplasma DNA. Genetic analysis of the samples revealed similarities to several Histoplasma species and confirmed that local bat species, particularly Myotis blythii, could serve as fungal reservoirs and vectors. Although most histoplasmosis cases in Spain are imported, this environmental detection raises concerns about local exposure risks, particularly for tourists and workers in ecotourism environments. The study highlights the need for further surveillance and precautionary measures in high-risk areas.4
References
1. CDC. Fungal Diseases Spotlight. Emerging Infectious Diseases. https://wwwnc.cdc.gov/eid/spotlight/fungal
2. de Almeida J, dos Santos AR, Trindade MS, et al. Trichophyton indotineae Infection, São Paulo, Brazil, 2024. Emerging Infectious Diseases. 2025;31(5):1049-1051. doi:10.3201/eid3105.250048.
3. Bertin-Biasutto L, Paccoud O, Garcia-Hermoso D, et al. Features of Invasive Aspergillosis Caused by Aspergillus flavus, France, 2012–2018. Emerging Infectious Diseases. 2025;31(5):896-905. doi:10.3201/eid3105.241392
4. García-Martín J, Soto López J, Lizana-Ciudad D, et al. Molecular Detection of Histoplasma in Bat-Inhabited Tunnels of Camino de Hierro Tourist Route, Spain. Emerging Infectious Diseases. 2025;31(5):1010-1014. doi:10.3201/eid3105.241117.
