prevent

... The basic daily food rations shall be sufficient in quantity, quality and variety to keep prisoners of war in good health and to prevent loss of weight or the development of nutritional deficiencies. Account shall also be taken of the habitual diet of the prisoners. ...

... The Detaining Power shall be bound to take all sanitary measures necessary to ensure the cleanliness and healthfulness of camps and to prevent epidemics. ...

... Should military operations prevent the Powers concerned from fulfilling their obligation to assure the transport of the shipments referred to in Articles 70, 71, 72 and 77, the Protecting Powers concerned, the International Committee of the Red Cross or any other organization duly approved by the Parties to the conflict may undertake to ensure the conveyance of such shipments by suitable means (railway wagons, motor vehicles, vessels or aircraft, etc.). For this purpose, the High Contracting Parties shall endeavour to supply them with such transport and to allow its circulation, especially by granting the necessary safe-conducts. ...