The transmission of influenza viruses will be studied as a model of respiratory pathogens that are carried cross-border with infected people and are transmitted between people by direct contacts and secretion droplets. The degree of transmission across the borders can be estimatedby studying the seroepidemiology of type-specific infections in towns or communities near the interested border. Burkholderiapseudomallei is a dangerous pathogen that can be transmitted with the soil contaminating road vehicles. Their transmission across countries can be studied by examining the genotypes of the bacteria in the soil on both sides of a border. Methods for to control the transmission, such as cleaning the tires, will be evaluated. Salmonella is an important food-borne pathogen, which can also be transmitted by human. Evaluation of the bacterial genotypes of isolates from human and environments will provide the degree of transmission and shedding. The study plan for each organism is provided as in the following sections.