A mosquito-borne virus that leaves victims in crippling pain and has triggered Covid-era restrictions in China is already in the US, experts say.Chikungunya virus can cause sudden, agonizing joint pain in the hands and feet, sometimes so severe that it leaves sufferers unable to move normally for months.Southern China is currently battling its largest outbreak since at least 2008, with more than 7,000 cases recorded in Foshan, at the epicenter, and infections in 12 other major cities. Heavy rains and warm weather have fueled a surge in mosquitoes, driving the outbreak.Dr Louisa Messenger, a mosquito researcher in Nevada, told the...