Diphtheria is an acute infection caused by the bacteria Corynebacterium Diphtheriae.
It is characterized by sore throat, low fever & an adherent membrane on the tonsils, pharynx and/or nasal cavities. Diphtheria is a virus. Diphtheria can affect a person's ability to breath as air passages become barricaded by a dense gray coating, in addition diphtheria bacteria generate a toxin that can damage the nerves associated with the facial muscles, throat, arms & legs. Indication of Diphtheria-induced nerve damaged include trouble swallowing or restricted motion of the eyes.
You can prevent it by getting a vaccine. DTap, Tdap , DT & Td. They both prevent Diphtheria Tetanus it also prevents Pertussis. The best advice is to get the vaccines when they are in.