A year after first death in china, coronavirus source still a puzzle.

WUHAN : it is the world's most pressing scientific puzzle, but experts warn there may never be conclusive answers over the source of the coronavirus, after an investigative efforts marked form the start by disarray, Chinese secrecy and international rancor.

January 11th marks the anniversary of China confirming its first death from Covid -19, a 61 years old man who was a regular at the now notorious Wuhan wet market.

Nearly two million deaths later, the pandemic is out of control across much of the world leaving tens of million  ill, a pulverized global economy and recriminations flying between nations.

Yet China , Which has broadly controlled the pandemic on its soil, is still frustrating independent attempts to trace the virus's origin and the central question of how it jumped from animals to humans.

There is little dispute that the virus which brought the world to its  knees  sparked its first known outbreak in late 2019 at a wet market in the central Chinese city of Wuhan where wildlife was sold as food, and the pathogen is an believed to have originated in an undetermined bat species.

but the trail ends there, clouded by a mishmash of subsequent clues that suggest its origin may predate Wuhan as well as conspiracy theories - amplified by US President Donald Trump - that it leaked form a Wuhan lab.

Establishing the source is vital for extinguishing future outbreak early, leading virologists say, providing clues that can guide policy decision on whether to cull animal population, quarantine affected persons, or limit wildlife hunting and other human animal interactions.

"if we can identify why they (viruses) keep emerging, we can reduce those underlying drivers, "said Peter Daszak, president of Ecohealth Alliance, a global NGO focused on infection disease prevention.

China won early kudos for reporting the virus and releasing its gene sequence in a timely manner, compared with its cover-up of the 2002-03 SARS outbreak.

But there has also been secrecy and shifting stories. Wuhan authorities initially tried to cover up the outbreak and later spent precious weeks denying human to human transmission.

Early on, Chinese officials declared flatly that the outbreak began at the Huanan Seafood Market in Wuhan.

But Chinese data in January 2020 showed that several of the first cases had no known links to the now shuttered market, suggesting a source elsewhere.

China's story morphed again last March when top Chinese disease control official Goa Fu said the market was not the source, but a "victim", a place where the Pathogen was merely amplified. But Cina has since failed to publicly connect any dots, releasing scant information on animal and environmental samples taken at the market that could aid investigators, experts say.

And it has kept foreign experts at arm's length, with a planned mission by world Health Organization virus sleuths now in limbo after China denied them entry.

On Saturday, a top Chinese health official said the country was now "ready" for the 10 strong team and opened the door to a visit to Wuhan. 

Yet "the specific time is being determined", National Health Commission vice minister Zeng Yixin told reporters.

What the scientists will be allowed to see or may expects to find a year on is also in doubt. Experts say authorities may have destroyed or scrubbed away crucial evidence in a panicked initial 

"every outbreak goes the same way. It's chaotic and dysfunctional, "said Daszak.

Diana Bell, a wildlife disease expert at the University of East Anglia who has studied the SARS  virus, Ebola and other pathogens, said focusing on a particular origin species is misguided.

She sys the overarching threat has already been exposed : a global wildlife trade that fosters a "combustible mix " of trafficked species, a known breeding ground for disease outbreaks.