Japan's National Institute of Infectious Diseases says one of its researchers has developed typhoid fever.

The institute says the researcher was dealing with the bacterium Salmonella Typhi at work. A public health center is currently looking into the route of infection.

Officials at the institute say the researcher was hospitalized last Friday and diagnosed with typhoid on Tuesday. They say the patient has a fever and complains of abdominal pain.

The officials say labs and restrooms the researcher is thought to have used have already been disinfected. They say no others at the institute have complained of health problems so far.