At least 57 persons have been killed and thousands forced to flee their homesteads due to landslides and floods in Nepal since Monday.According to the Nepal's Ministry of Home Affairs, at least 20 people have gone missing and seven dozen houses have been destroyed by the floods and landslides across the country.At least 14 districts of Nepal are hit by the flash floods and landslides. The worst hit is Pyuthan district where deaths touched 24 by Wednesday evening, according to local media reports. Scores of houses and some bridges have been swept away in several parts of the country. Thousands of people have been displaced after flood waters inundated their settlements, the home ministry said in a statement.Water level in the Saptakoshi river has been on the rise due to incessant rainfall for the past 10 days. Water flow in the river was measured at 277,410 cusecs on Wednesday morning, the highest for this year. Thirty-seven of the 56 floodgates have been opened.The home ministry has cautioned the people about water-borne diseases. Medical teams have been deployed in the affected areas.