The cause is obvious and being ignored.
While global attention has been focused on strengthening health systems in West Africa in the aftermath of the Ebola outbreak there, a new wave of tropical infectious disease is threatening southern Europe, North Africa and the Middle East.
The unprecedented appearance of tropical diseases in southern Europe in recent years has been well-documented. Dengue fever appeared on Madeira off the coast of Portugal in 2012, and chikungunya arrived in Spain this year. Malaria has returned to Greece after being eliminated in the 1960s, and West Nile virus has gained a foothold throughout southern Europe. These infections are transmitted by mosquitoes that now inhabit the region. Schistosomiasis, a parasitic blood fluke infection transmitted by snails, just made its first recorded appearance on the island of Corsica, while outbreaks of opisthorchiasis, a liver fluke that causes bile duct cancer, have occurred in Italy.
We are still investigating the forces responsible for the transformation of southern Europe into a tropical disease “hot zone.” Among the possible causes are the severe economic downturns in Greece, Italy and Spain, which may have slowed national public-health efforts, and global warming, which is creating temperature and rainfall conditions better suited for insects and other carriers of disease adapted to tropical climates.
But a third factor must also be considered: the conflicts in the Middle East and North Africa. Ebola arose in Guinea, Sierra Leone and Liberia, in part because the health systems of the affected countries had been weakened by years of conflict and human migration. That same combination is now present in the Islamic State-occupied areas of Syria, Iraq and Libya, as well as in Yemen.