The US Department of Health (Dengue fever) has issued a level 1 global travel advisory for 16 countries with an increased risk of contracting the disease, which can cause brain bleeds, bloody vomit, and death. The advisory was issued after a higher than expected number of cases were detected among US travelers returning from Afghanistan, Bangladesh, Bolivia, Colombia, Cook Islands, Cuba, Guyana, Maldives, Mali, Mauritania, New Caledonia, Pakistan, Samoa, Sudan, Timor-Leste and Vietnam. Most US cases are due to international travel, as the disease was virtually eradicated in the 1970s. The World Health Organization estimates that around half of the world's population is at risk of dengue, with an estimated 100 to 400 million infections occurring each year.