VietnamVietnam Conflict: A conflict occurring from 1954 through 1975 within the Republic of Vietnam. It involved neighboring nations and the United States and other members of the Southeast Asia Treaty Organization.Defoliants, Chemical: Herbicides that remove leaves from trees and growing plants. They may be either organic or inorganic. Several of the more persistent types have been used in military operations and many are toxic. (From Hawley's Condensed Chemical Dictionary, 11th ed)2,4,5-Trichlorophenoxyacetic Acid: An herbicide with strong irritant properties. Use of this compound on rice fields, orchards, sugarcane, rangeland, and other noncrop sites was terminated by the EPA in 1985. (From Merck Index, 11th ed)Veterans: Former members of the armed services.Amputation, Traumatic: Loss of a limb or other bodily appendage by accidental injury.2,4-Dichlorophenoxyacetic Acid: An herbicide with irritant effects on the eye and the gastrointestinal system.Trematode Infections: Infections caused by infestation with worms of the class Trematoda.Combat Disorders: Neurotic reactions to unusual, severe, or overwhelming military stress.Influenza in Birds: Infection of domestic and wild fowl and other BIRDS with INFLUENZA A VIRUS. Avian influenza usually does not sicken birds, but can be highly pathogenic and fatal in domestic POULTRY.Asia, Southeastern: The geographical area of Asia comprising BORNEO; BRUNEI; CAMBODIA; INDONESIA; LAOS; MALAYSIA; the MEKONG VALLEY; MYANMAR (formerly Burma), the PHILIPPINES; SINGAPORE; THAILAND; and VIETNAM.Trematoda: Class of parasitic flukes consisting of three subclasses, Monogenea, Aspidogastrea, and Digenea. The digenetic trematodes are the only ones found in man. They are endoparasites and require two hosts to complete their life cycle.Rural Population: The inhabitants of rural areas or of small towns classified as rural.