Beijing, July 19 : Netizens in China have signed an open letter to the World Health Organisation (WHO), demanding it probe the shutdown of the US Army Medical Research Institute of Infectious Diseases (USAMRIID) at Fort Detrick, Maryland, media reports said. The netizens asked the health body to investigate the US military biological lab to prevent a future epidemic, the Global Times reported on Sunday. The letter comes as China is subject to fresh rounds of scrutiny over alleged leak of SARS-CoV2, the virus causing Covid-19, from the country's infamous Wuhan Institute of Virology (WIV). The netizens posted the letter on its WeChat and Weibo platforms on Saturday, which garnered half a million signatures within 24 hours. The open letter particularly noted the Fort Detrick lab, which stores the most deadly and infectious viruses in the world, including Ebola, smallpox, SARS, MERS, and the novel coronavirus. The leak of any of them would cause severe danger to the world, the report said. "But this lab has a notorious record on lab security. There have been scandals of anthrax bacterium from the lab being stolen, causing poisoning to many and even death. There has been a leakage incident in the lab in the autumn of 2019 right before the outbreak of the Covid-19 epidemic, however, detailed information had been withheld by the US under excuses of national security," said the letter. The USAMRIID was temporarily shut down in 2019 after a US Centers for Disease Control and Prevention (CDC) inspection. Although this mysterious lab reported the reason for the closure as "ongoing infrastructure issues with wastewater decontamination," the explanation was not persuasive enough. "What is more perplexing is that, when China allowed virologists from Western countries and even US mainstream media to visit the Wuhan Institute of Virology, the US has not opened the Fort Detrick lab, let alone shared the original data with countries including China that are independent from US geopolitical influence," the joint letter noted. Further, the netizens stated that the US even purposely neglected and distorted the Chinese people's call to investigate the Fort Detrick lab -- referring to the questions raised in the letter as a "conspiracy theory," and at the same time, used untenable and flawed rumours to attack the WIV, said the open letter. While, the WHO has already made their evaluation about the "Wuhan lab leak theory" during their trip to China, questions remain for other labs over whether the virus was leaked from them, Zeng Guang, former chief epidemiologist of the Chinese Center for Disease Control and Prevention, was quoted as saying to the Global Times. /IANS