An infection of the throat can be caused by many reasons however, drinking cold water is not one of them. There are many viral causes including, adenovirus which is a common cause of a sore throat. Influenza virus can be another cause. Infectious mononucleosis due to Epstein-Barr virus causes swelling to the lymph glands and tonsillitis. Herpes virus, measles, and the common cold virus can all produce a throat infection. As for a common bacterial cause, there are streptococcal germs which can be diagnosed by a throat culture and cured with antibiotics. There can be throat infections due to fungi such as Candida albicans, which produces oral thrush, and leaves a white coating in the throat and on the tongue. Non-infectious agents can irritate the throat, but, not cause an "infection" and these include--mechanical, chemical or thermal irritants. If for example, someone burns the back of their throat eating hot food, it can produce an irritation, rather than an infection.