Africa and the Atlantic Slave Trade. Before the 16th century, Europeans were not deeply involved in slave trading on the West African coast. However, there was some movement of African labour to Madeira and the Canary Islands by the early Portuguese explorers from 1470 onwards.
urticaria is not contagious you cannot pass it on to another person acute urticaria or acute hives when symptoms last less than 6 weeks it is called acute urticaria this is by far the most common type 25 % of people with acute urticaria also have angioedema swelling in the deeper layers of skin
However, the viruses that cause colds (for example, rhinoviruses) are not the same as those that cause the flu (influenza viruses). Although the typical incubation period for influenza is about one to four days, some adults can be contagious from about one day before onset of symptoms for up to two weeks. Other people who develop complications, such as pneumonia, may extend the contagious period for a week or two. For colds, most individuals become contagious about a day before cold symptoms develop and remain contagious for about five to seven days.