Earlier reports said the 23-year-old Chinese woman could have died of double pneumonia or Severe Acute Respiratory Syndrome (SARS), a respiratory disease that can be spread through the air.
"The autopsy has shown that the death of the Chinese national occurred as a result of acute respiratory viral infection, pulmonary and cerebral edema. Blood samples have been sent to Moscow for analysis," a statement said.
The train travelling from the Far East Russian city of Blagoveshchensk was stopped at Zuyevka station central Russia's Kirov Region, where 52 Chinese passengers and seven Russians were sent to a local hospital.
"All of the people who were taken to hospital yesterday were admitted. Their health is described as satisfactory," a hospital source said without giving further details.
The carriage in which the woman was travelling was decoupled from the rest of the train, which then continued on its way to the capital. The train arrived in north Moscow's Yaroslavl train terminal early on Thursday following a one-hour delay.
The Chinese woman was accompanied by her husband, mother and father, who all had slight temperatures. The relatives said the woman had been ill since April 11 and they thought she had been poisoned.
Sanitary cordons were set up in Russia's Far East to prevent the spread of the suspected disease. Security measures were tightened to control the entry of Chinese citizens entering Russia. All passengers had to pass a medical examination before they were allowed to travel.
