What to know about plague amid reports of Russian lab worker

U.S. and world health officials are calling on Russia to share more information after Russian media reports said a scientist at an infectious disease research facility in Siberia died after possibly contracting plague during a lab accident.

Dr. Céline Gounder, a CBS News medical contributor and editor-at-large for public health at KFF Health News, echoed that belief on "CBS Mornings" on Tuesday.

Still, an official cause of death has not been made public and a lack of transparency from Russia has led some experts to question if the lab worker had the plague.

The World Health Organization said Shipilova died of severe pneumonia overnight into Oct. 2.

The WHO said it was told by Russia on Oct. 6 that no plague was detected. The global health agency said it asked Russian authorities to provide information about which pathogen caused Shipilova's illness.

Secretary of State Marco Rubio on Tuesday called on Russia to be more transparent, and said the nation should "share more information with the world." The WHO said it is following the situation closely and requesting further information from Russian authorities.

Plague is caused by the Yersinia pestis bacteria. There are three main types of plague: bubonic, septicemic and pneumonic.

Septicemic plague happens when the Yersinia pestis bacteria enters the bloodstream. Patients may develop fever, chills, extreme weakness, abdominal pain, shock and possible internal bleeding. Some skin may turn black and die.

Pneumonic plague typically occurs when the other forms of plague are not treated and the Yersinia pestis bacteria infects the lungs. Patients develop pneumonia and may show fever, headache, weakness, shortness of breath, chest pain, cough and bloody or watery mucus. The pneumonia could cause respiratory failure. This is considered the most serious version of plague, and is always fatal if left untreated.

Pneumonic plague can be spread between people. In cases of pneumonic plague, droplets emitted when a sick person coughs can lead to others becoming infected.

Researchers who regularly work with plague can also be vaccinated for it, Gounder noted.

About seven plague cases are reported each year in the United States, according to the Centers for Disease Control and Prevention. More than 80% of the cases in the U.S. are bubonic plague, the agency said.