Enlarge / A Trichophyton indotineae infection on the back of an Indian man. (credit: Uhrlaß, S. et al. Journal of Fungi)

A dermatologist in New York City has reported the country’s first known cases of highly contagious ringworm infections that are resistant to common anti-fungal treatments—and caused by a newly emerging fungus that is rapidly outstripping other infectious fungi around the world.

In February, the dermatologist reported two cases to health officials in the state, which are described in a brief case study published Thursday in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report.

The two cases occurred a year apart and had no connection to each other. The first, from the summer of 2021, was in a 28-year-old pregnant woman who had no recent international travel history, no underlying medical conditions, and no known contact with anyone who had a similar rash. The case suggests that the fungus is quietly spreading in the community.