The first patients ranging from 18 to 81 in age began arriving at a hospital near Yekaterinburg July 19. Regional health authorities said the illness had been caused by the Legionella pneumophillia virus, a strain of pneumonia first registered in the United States 30 years ago.
The health officials also said six people remained in intensive care, and 25 people were ready to be discharged.
Local health experts are studying the illness and the possibility of its further spread, while prosecutors have launched an inquiry into the deaths.
Most apartment blocks in Russia receive hot water via mains supply, directly from thermal plants, rather than from water heaters installed within buildings. The supply is shut down for a few weeks each summer for maintenance work.
