The threat of a new potential epidemic is already real: the World Health Organisation (WHO) warned over the weekend that the brain-deforming Zika virus can spread from Brazil—its country of origin—to the entire Western Hemisphere.

This menacing virus is carried around the world by tiny, white-speckled mosquitoes called Aedes aegypti, which used to thrive only in the African continent.

How did these insects manage to travel across continents from Africa? They are believed to have hitched a ride with colonists traveling to the West, according to a report by NBC News.

Even before carrying the Zika virus, the Aedes aegypti mosquito already caused the death of thousands of American troops due to yellow fever during the Spanish-American war.

During the mid-20th century, these mosquitoes were almost completely wiped out in the Western Hemisphere owing to concerted eradication programme, but were able to return.

This happened "due to lack of commitment and financial backing necessary to maintain the eradication programme," according to a 2005 study by researchers from the University of Florida.

Now, Brazil's health minister admitted that his nation is having a difficult time battling the Zika virus, which is believed to have caused mental deformities to hundreds of Brazilian babies.

"The mosquito has been here in Brazil for three decades, and we are badly losing the battle against the mosquito," Brazilian health minister Marcelo Castro said, as quoted by Yahoo! News.

More than 220,000 members of Brazil's Armed Forces are being deployed across the country to help out in the door-to-door effort to eradicate the mosquito.

In the United States, President Barack Obama urged the medical and scientific communities to work extra hard to find a vaccine or treatment against the Zika virus.

"The president emphasised the need to accelerate research efforts to make available better diagnostic tests, to develop vaccines and therapeutics, and to ensure that all Americans have information about the Zika virus and steps they can take to better protect themselves from infection," the White House said in a statement, as quoted by Reuters.