WUHAN, China (AFP) - It is the world's most pressing scientific puzzle but experts warn there may never be conclusive answers over the source of the novel coronavirus, after an investigative effort marked from the start by disarray, Chinese secrecy and international rancour.January 11 marks the anniversary of China confirming its first death from COVID-19 - a 61-year-old man who was a regular at the now-notorious Wuhan wet market.
