1 Although any individual may develop a case of pinworms, the infection occurs most frequently in school children between 5 to 10 years of age.  Pinworm infections occur in all socioeconomic groups; however, human-to-human spread is favored by close, crowded living conditions. Spread among family members is common.
Before they start collecting, stamp collectors try to identify the types of stamps. These will help them segregate and sort stamps according to their classification. On its basic concept, there are three main classifications of stamps â special, commemorative, and definitive.
A decade later, the Elvis stamp is still one of the most talked-about stamps ever issued by the Postal Serviceâand the most popular U.S. commemorative stamp of all time. The U.S. Postal Service commissioned eight artists to develop potential designs for an Elvis stamp.