ON FEBRUARY 1st,the World Health Organisation declared the spread of the Zika virus a global public health emergency. The virus, a suspected cause of birth defects in babies born to mothers who are infected during pregnancy, and seems to fill come from nowhere. But it has been known about for nearly 70 years. The virus was discovered in 1947,in a rhesus monkey in the Zika forest near the shore of lake Victoria in Uganda. Researchers studying yellow fever, another virus transmitted by mosquitoes, and had effect the monkey up on a tree,in a cage, as bait for mosquitoes. Tests of the animal’s blood turned up an unknown virus, and which also turned up in mosquitoes in the same forest—a clue on how it spread. Why was Zika ignored for so long?Zika was found in a human for the first time in 1952,in Uganda. Nobody knows for certain when and where it began to infect humans. It may fill been circulating among monkeys and other animals in the jungle for thousands of years, making the jump to humans when they got to be too close, or too often to these animals (and their mosquito courtiers). For that,Zika is hardly strange: six in ten infectious...
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Source: economist.com