Shigella outbreak in 150 research primates yields vaccine targets

September 4, 2026 at 01:14 AM2 min

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A Shigella outbreak that sickened more than 150 non-human primates at the Wisconsin National Primate Research Center over two years has provided detailed immunological data for vaccine development. Researchers identified specific bacterial targets and antibody binding sites that could inform a Shigella vaccine. The findings were published in Science Translational Medicine.

Key Facts

The outbreak began in December 2022 at the Wisconsin National Primate Research Center in Madison and lasted over two years.
There were 169 microbiologically confirmed shigellosis cases among the non-human primates.
Researchers collected 151 Shigella isolates for serotyping and performed whole genome sequencing on 95 representative isolates.
Shigella strikes more than 200 million people worldwide each year and kills more than 200,000, mostly children.
The outbreak was caused by two related clusters of Shigella flexneri, a species that commonly infects captive non-human primates.

Outbreak Origins

The outbreak began in December 2022 at the Wisconsin National Primate Research Center in Madison. Non-human primates are natural hosts for Shigella, and sporadic outbreaks occur at such facilities. This outbreak was unusually large and prolonged, with some facility staff also falling ill. In total, 169 microbiologically confirmed shigellosis cases were recorded among the primates. The outbreak was caused by two related clusters of Shigella flexneri.

Vaccine Target Discovery

Researchers analyzed immunological data from the infected primates to identify bacterial components that trigger effective immune responses. They linked specific target molecules to specific types of antibody responses. The team also pinpointed precise sites on those molecules where the most potent antibodies bind. The study authors stated the findings reveal unexpected features of the anti-Shigella antibody response and represent a step toward rational vaccine design.

Global Disease Burden

Shigella infects more than 200 million people worldwide each year and kills over 200,000, mostly children. Survivors typically develop some protective immunity, but it is often limited to a narrow range of Shigella strains. Shigella strains are becoming increasingly resistant to antibiotics. Multiple vaccine development efforts are underway, but detailed molecular and structural data have been lacking.