"Some evacuees are suffering from diseases such as cough and influenza caused by cold weather after being too long staying in wet areas," said Chief of Mentawai Islands health service, Warta Siritoitet, here on Monday.
According to him, the victims are also prone to suffering from itching, fever, diarrhea, and respiratory tract infection.
He said that the evacuees also had difficulties getting fresh water.
The health service has deployed at least 12 medical personnel e divided into two teams with each team consisting of a specialist, two general physicians and three nurses.
The institution has also established health monitoring posts in several sites such as Mongapola Village of N Siberut and Salappa Hamlet of S Siberut to facilitate health services for the flood victims.
"We still have enough medical supplies. What we urgently need is medical persons," Warta said.
Heavy rain that occurred since Wednesday (April 3) has made rivers near the areas to overflow on Saturday morning flooding residential areas there.
The flood also blocked access from and into the areas.
Meanwhile, Chief of Mentawai Regional Disaster Mitigation Agency (BPBD) Elisa Siriparang said thousands of citizens had been forced to evacuate after their houses were inundated by wate up to the height of 2.5 meters.
Among the supplies badly needed by evacuees are tents, clothing, blankets, instant noodle, milk, rice, medicines and sanitary napkins.
Weather conditions in North Siberut and South Siberut on Monday morning were cloudy and pools of water still remained in several areas in the region.