 [ Symptoms ] what is a renal ultrasound  a renal ultrasound is a video taken of the kidneys using ultrasonic waves a probe placed against the skin reflects high energy sound waves off the kidneys and a computer converts the information into images on a screen [ Disease ] most helpful answer no colds and influenza are caused by viruses not temperature changes viruses enter the body through the nose eyes or mouth not through the skin you can run outside naked if you want and you will not be any more vulnerable to getting a cold or the flu it is okay if your grandmother or mother disagrees with this statement hi ok i think i see what you mean no he is right you cant get a cold by being cold or working outside without extra clothing and the same for flu there both virus is and can only be passed on from somebody else working outside in fresh air is very good for you do hope this helps you good luck