Fungal infections are emerging as a major medical challenge, and a team led by researchers at Baylor College of Medicine has developed a mouse model to study the short-term consequences of fungal infection in the brain.

The researchers report in the journal Nature Communications the unexpected finding that the common yeast Candida albicans, a type of fungus, can cross the blood-brain barrier and trigger an inflammatory response that results in the formation of granuloma-type structures and temporary mild memory impairments in mice. Interestingly, the granulomas share features with plaques found in Alzheimer’s disease, supporting future studies on the long-term neurological consequences of sustained C. albicans infection.

“An increasing number of clinical observations by us and other groups indicates that fungi are becoming a more common cause of upper airway allergic diseases such as asthma, as well as other conditions such as sepsis, a potentially life-threatening disease caused by the body’s response to an infection,” said corresponding author Dr. David B. Corry, professor of medicine-immunology, allergy and rheumatology and Fulbright Endowed Chair in Pathology at Baylor College of Medicine.

Importantly, explains Corry, fungal infections causing airway allergic diseases and sepsis have been associated with increased risk for dementia later.

“These observations led us to investigate the possibility that fungus might produce a brain infection and, if so, the consequences of having that kind of infection,” said Corry, who also is a member of the Dan L Duncan Comprehensive Cancer Center.

The researchers began their investigation by developing a mouse model of a low-grade fungus infection with the common yeast C. albicans that would not cause severe disease, but might carry implications for brain function. They tested several doses and finally settled on one dose of 25,000 yeasts.