Rita Lesina was born in 1920 in Odessa as Riva Kigel (only in 1938, after being issued an ID document, was she registered as "Rita"). The family was religious: In the 1920s, they regularly visited a synagogue and tried to observe the Sabbath and the Jewish holidays. In the 1930s, the younger Kigels – Riva and her two brothers – drifted away from religion. Riva’s father Menashe was recruited to fight in World War I. After his discharge, he ran a grocery store. The Soviet authorities nationalized his business in the mid-1920s, whereupon he went to work at a factory. In 1928-38, Riva attended school. At the insistence of her mother, Riva (now named Rita) Kigel entered the Medical Institute (University) in Odessa, and was able to complete three years of medical studies before the outbreak of the Soviet-German War in June 1941. Riva’s father died in 1934, and her mother died in 1940.
After the outbreak of war, the Medical Institute was evacuated to Rostov-on-Don in southern Russia. In August 1941, Rita and her younger brother arrived to Rostov; she began to work as a nurse at a hospital. During the first German occupation of Rostov on November 20-28, 1941, Rita and her brother stayed at the hospital and survived, but rumors of the anti-Jewish atrocities (the marking of Jews with special badges and their killings) reached her. In February 1942, Rita volunteered to join the 56th Army of the Red Army, which was deployed in Rostov and the vicinity. She was attached to Hospital #31/98 in nearby Bataisk as a medical orderly (feldsher). In July 1942, during the second Soviet retreat from Rostov, the hospital left the area without notifying Rita and the other medical orderlies. The girls had to catch up with the hospital on foot; they walked hundreds of kilometers, until they reached the Black Sea coast. Here, Rita was wounded. After recovering, she was transferred to another hospital as a senior nurse. The new hospital treated soldiers wounded during the defense of the so-called "Small Land", a Red Army bridgehead on the Black Sea coast (February-September 1943), one of the toughest operations of the war. The service at the hospital put the personnel in considerable danger.
Rita requested to be transferred to one of the units that were poised to liberate her native Odessa, but was refused. In early 1944, she was wounded once again, and, after her release from hospital, she was attached to the 88th Guards Rifle Regiment of the 33rd Guards Division. With this division, Rita went through Ukraine, Belorussia, and Lithuania, and met V-E Day in East Prussia. Her highest rank was guards lieutenant; she was awarded the Order of the Red Star and a number of medals.
After the war, Rita Kigel was released from military service for health reasons, whereupon she returned to Odessa. She worked as a sanitary doctor in the city and the surrounding region. Unable to have children of her own, she adopted a Ukrainian (non-Jewish) girl. In 1973, Rita married a Jewish man whose last name was Lesin; they divorced in 1986. However, Rita Lesina reregistered her adopted daughter under the Russian-sounding name "Lesina" – in her mind, this was necessary because of the persistence of state antisemitism in the Soviet Union.
One of Rita’s brothers, Yakov, died in the war in unclear circumstances. Her younger brother Yisrael survived.