A Russian lab worker died from pneumonia, prompting the World Health Organization to investigate the cause, according to local media. The worker was involved in plague research. The death occurred in a laboratory setting. Authorities are still determining the exact cause of the illness. The WHO has not yet confirmed the source of the infection. The incident has raised questions about lab safety protocols. The worker had no known prior health conditions. The laboratory is under review for compliance with safety standards. The case highlights ongoing concerns about infectious disease research. No other cases have been reported so far. The situation remains under close monitoring by health officials.