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
They are frequently caused by allergic reactions; however, there are many nonallergic causes. Most cases of hives lasting less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) is rarely due to an allergy. The majority of chronic hives cases have an unknown (idiopathic) cause. In perhaps as many as 30â40% of patients with chronic idiopathic urticaria, it is caused by an autoimmune reaction.