Scientists race to find out how Wuhan victims became ill

If this outbreak is still caused mainly by animals, it can be controlled. But all-out human transmission could spell disaster

Scientists are urgently seeking data to resolve one critically important aspect of the coronavirus outbreak that has killed at least 54 people and infected well over 1,000 since emerging in Wuhan, China.

Researchers say they desperately need to find out whether most cases have been caused by repeated spillover of the virus from animals into humans, or whether most cases are now being triggered by secondary human-to-human transmission.