ULYANOVSK, November 25. /ITAR-TASS/. The mass disease outbreak in the city of Inza in the Ulyanovsk Region could be caused by rotavirus infection (intestinal flu), as most experts believe, said the region's Deputy Prime Minister and Health Minister Valentina Karaulova.

The final results will be known later this Monday.

Tests of water from sources in Inza have confirmed there was intestinal infection. Specialists of the local department of the Rospotrebnadzor federal public health control service believe one of the main causes of the mass disease was utilities' negligence to timely check and properly purify tap water. When experts examined the lines they found four ruptures. Everything has been repaired for the present.

In the group of risk are children under two. Symptoms of the disease are clear in one-three days. These are diarrhea, vomiting, stomach pain and high temperature, Karaulova said.

According to the Emergencies Ministry's Ulyanovsk regional department, a total of 255 cases have been reported — 53 adults and 202 children. Eighty seven people (12 adults and 75 children) remain in hospitals. Sixty six patients have been discharged. Thirty one new cases (eight adults and 23 children) were reported on Sunday. Thirty are outpatients, and one child was taken to the district's central hospital in Inza.

Regional police have opened a criminal case on charges of non-observance of sanitary and epidemiological regulations, which caused mass infecting of people. The regional prosecutor's office and the regional investigative department are continuing their inquiry.

Bottled water is supplied to the population according to schedule. Medics continue to visit homes to find out whether there are ill people.