Russian troops in
Focşani, Moldova discovered the first signs of plague in January 1770; the disease, indigenous to the area, was contracted through prisoners of war and booty. The news was hailed and exaggerated by adversaries of Russia, and Catherine wrote a reassuring letter to
Voltaire, arguing that "in spring those killed by plague will resurrect for the fighting". Commanding general Christopher von Stoffeln coerced army doctors to conceal the outbreak, which was not made public until
Gustav Orreus, a Russian-Finnish surgeon reporting directly to Field Marshal
Pyotr Rumyantsev, examined the situation, identified it as plague and enforced quarantine in the troops. Stoffeln, however, refused to evacuate the infested towns and himself fell victim to the plague in May 1770. Of 1,500 patients recorded in his troops in May–August 1770, only 300 survived. The epidemic blocked the logistics of Rumyantsev's army, and as the state tried to push more reserves and supplies to the theatre, peacetime quarantine controls had to be lifted. Plague swept into
Poland and
Ukraine; by August 1770 it reached
Bryansk. Catherine refused to admit the plague in public, although she was clearly aware of the nature and proportions of the threat, as evidenced by her letters to Governor of Moscow
Pyotr Saltykov. == Moscow plague ==