A new mosquito-bred virus has spread to the Americas.

Two cases of chikungunya, which had previously only been observed in Africa, have been confirmed in the French part of the Caribbean isle of Saint Martin, located off the eastern coast of Puerto Rico, between North and South America.

The World Health Organization confirms it was notified about the two cases by island authorities on Dec. 6. "This is the first time that locally acquired transmission of chikungunya has been detected in the WHO Americas Region," the health organization said in a statement.

Health officials released a Global Alert notifying people that a disease outbreak may be imminent.

According to a report on Nov. 18, there were five cases in the Saint Martin area of joint pain and fever. Health officials ruled out dengue fever, which has had an outbreak on the isle since last January

So, as of Dec. 10, "two confirmed, four probable and twenty suspected cases of chikungunya infection have been reported," the WHO announced.

Chikungunya typically spreads to humans through mosquito bite, with typical symptoms including fever, headaches and joint pain -- but it's rarely fatal.

Scientists discovered chikungunya in Tanzania in 1955. Since then, it appeared to be confined to sub-Saharan Africa and southern Asia.

India saw a massive outbreak in 2006, with over a million people sickened by the virus. Shortly after,the virus was apparently carried to Italy, where it mutated -- so that instead of being transmitted by the Aedes aegypti mosquito, as it had been, it started to spread through the Asian tiger mosquito, which can survive more moderate environs.

That latest host change made it more likely chikungunya would to spread into the Americas, since the tiger mosquito is found in the southern U.S. and even in some parts of the north.

Because there is no vaccine available for the disease, the WHO says that the best way to prevent an outbreak is to raise awareness of the risk factors and, equally important, find ways to halt mosquito proliferation.

"The health authorities on both the French and the Dutch side of [Saint Martin] are cooperating closely to respond to this outbreak, in close coordination with public health authorities in France and the Netherlands," the WHO stated.

The name "chikungunya" means "that which bends up" in Makonde, the language spoken by an ethnic group found in Tanzania and Mozambique in Africa. Chikungunya refers to the position and physique of people infected with the virus, as they may "bend over" in pain.