A mosquito-borne virus from east Africa is slowly spreading around the world.
The Chikungunya virus was first discovered in 1952, and was given its name from the Makonde language of the area, meaning “to walk bent over”. The virus is rarely fatal, but can be crippling, with flu-like symptoms (fever, joint pain, nausea). It is often mistaken for Dengue, due to its similarities in symptoms and transmission by mosquitoes. There are now more than 3 million diagnosed cases across the world, making it an international threat.
The virus has spread out of Africa before, but never on this scale, and it always abated before it could take hold. This time, there was a difference. After spreading to the island of Réunion in the Indian Ocean, the disease mutated to be able to survive in a new mosquito host. Usually carried by Aedes aegypti, infamous for the many diseases it carries (also including Yellow Fever and Dengue), the virus adapted to thrive in Aedes albopictus– the Asian tiger mosquito. You may have heard of this mosquito, and that’s because it is common around the world (thanks to increased good transport and international travel). The fact that this mosquito is so common, and tends to travel far on transport means that the disease is able to spread across the world.
After devastating Réunion in 2005/6, the disease swept through other Indian Ocean nations (Madagascar, Mauritius, Seychelles) before reaching India and spreading throughout southern and south-east Asia. The disease has now spread to the Western hemisphere by way, it is thought, of a human carrier. Researchers from the Center for Disease Control and Prevention in Fort Collins, Colorado, USA think that a traveller infected with the disease visited a Caribbean island, where he was bitten by a local mosquito. This would have gone on to spread the disease to other humans and mosquitoes, and the disease has now been spotted across the American continents, as far north as Florida. There have even been cases recorded in Europe, with reports in 2014 from France and Italy.
There is no current anti-viral treatment or vaccine specific for the disease, so the symptoms are treated with anti-pyretics, optimal analgesics and fluids. It is unclear how the disease will continue to spread as it appears in more temperate climates with fewer mosquitoes, so researchers and global organisations like the WHO are keeping a close eye on its evolution.
Read in more detail over at Science News, who include an interactive map on the spread of the disease, and a in depth explanation of the research behind potential treatments..
Image credit: “CDC-Gathany-Aedes-albopictus-1” by James Gathany, CDC – This media comes from the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL), with identification number #2165.