VLADIVOSTOK, Russia (AP) _ Four people in Russia's Far East who had scavenged through a dump for food have come down with cholera, sanitary officials in the region said Thursday.

Doctors were treating the four victims and 39 people who came in contact with them over the last few days, said Tatyana Vershkova, chief physician at the Sanitary Monitoring Center in the Pacific port city of Vladivostok.

The source of the infection hasn't been confirmed, but the four people, who lived in a small hut on the outskirts of Vladivostok, had recently eaten food they recovered from a nearby dump, Vershkova said.

Several people living near the dump sift through it for food to supplement their diets.

Three truck drivers returning to Vladivostok from China also came down with cholera in early August. Russian doctors said the three acquired cholera while in China.

Cholera is an infectious, intestinal disease caused by bacteria. Symptoms include diarrhea, vomiting and cramps. Cases have appeared with increasing frequency in Russia in recent years, and health officials blame worsening economic conditions.