How are cold flu whooping cough and legionnaires disease transmitted?

Cold and flu viruses are primarily transmitted through respiratory droplets when an infected person coughs, sneezes, or talks. Whooping cough, caused by the bacterium Bordetella pertussis, spreads similarly through droplets and can also be passed through direct contact with respiratory secretions. Legionnaires' disease, caused by the Legionella bacteria, is transmitted through inhalation of aerosolized water droplets from contaminated sources, such as cooling towers or Plumbing systems, rather than through person-to-person contact.