Chikungunya to spread worldwide
21st September 2009
An African mosquito-borne illness is set to infect people in the United States and Europe, the same way West Nile virus did a decade ago.
Though the virus left Africa in 2005, cases of chikungunya virus have only recently begun to appear in France and Italy.
Prior to that, it had spread to islands in the Indian ocean and the French island of Reunion, where outbreaks led to many fatalities.
James Diaz of the Louisiana University Health Sciences Centre said that he and his colleagues are very worried.
He said that an outbreak of chikungunya is unlike outbreaks of West Nile virus, in which most infected people are asymptomatic.
He said that the disease can be fatal, and that everyone infected will have symptoms of the serious disease, for which there is no vaccine.
Chikungunya causes fever, fatigue, rash, muscle pain, vomiting, and headache, as well as arthritic symptoms which can last months after the initial infection.
Though medical researchers first discovered the disease in Tanzania in 1952, it became a global threat with the spread of the Asian tiger mosquito, which can carry the disease, to all of the continents of the world.
The name chikungunya derives from the Makonde language, spoken in northern Mozambique and southeastern Tanzania, and means “that which bends up.”
The Asian tiger mosquito species is classified as one of the world’s 100 worst invasive species.
Though it is native to the Southeast Asian tropics, it has adapted to tolerate snow and freezing, which allows it to live year-round in temperate climates.
The spread of the disease worries local health officials in Indian Ocean islands such as Mauritius, Seychelles, and Reuinion, which are frequented by tourists.
Diaz said that the disease is hyper-endemic in the islands of the Indian Ocean, and that travel by air will eventually import the infected mosquitoes and humans no matter what people do.
Cities with large slums and poor water systems, such as Mumbai and Mexico City, will be large breeding grounds for the disease.
The Asian tiger mosquito first arrived in Europe roughly 30 years ago, in a shipment of Chinese goods bound for Albania.
The pest was probably also introduced a second time to Europe in the early 1990s, in shipments of used tyres brought from the US to Italy.
Since then, the mosquito has been found in places as far flung as the northern Alps of Switzerland, the Netherlands, and Belgium.