About 15% of patients with typhoid fever develop serious neurological complications, including delirium and seizures, that are collectively described as acute encephalopathy. A new Yale study published May 8 in the journal Nature Microbiology provides critical insights into how typhoid fever leads to encephalopathy. Researchers found that typhoid toxin, a key virulence factor only produced by the bacterium Salmonella Typhi, does not directly damage brain cells, as previously thought. The Galán laboratory previously identified typhoid toxin as responsible for many of the disease’s symptoms. “Our findings strongly support the clinical use of corticosteroids in severe typhoid fever cases, providing a clear rationale for therapies targeting inflammation and BBB integrity,” Galán said.