The arrival of the team came the same day China said it had set a new daily record for deaths from the virus. It said 97 people had died the day before.

The overall death toll is now 908 people, which surpasses the toll from the SARS epidemic of 2002-03, according to official data. The number of confirmed infections in the country rose to 40,171, and 3,062 new cases were recorded in the preceding 24 hours, most of them in Hubei Province.

Since W.H.O.’s director general, Tedros Adhanom Ghebreyesus, visited Beijing in January, the organization had tried to send a team, but the Chinese government balked. The delay raised questions about China’s sensitivity to accepting outside help in combating the epidemic.

In a series of posts on Twitter, Dr. Tedros said countries that have seen only a few cases with no direct connection to China could yet see a jump in new infections.

“We may only be seeing the tip of the iceberg,” he wrote.

He called on all countries to share information about the coronavirus “in real time” with the organization.

It’s a mammal. It eats ants. And it just might be tied to the coronavirus.

In the search for the animal source or sources of the epidemic in China, the latest candidate is the pangolin, an endangered, scaly, ant-eating mammal that is imported in huge numbers to Chinese markets for food and medicine.

The market in pangolins is so large that they are said to be the most trafficked mammals on the planet. All four Asian species are critically endangered, and it is far from clear whether being identified as a viral host would be good or bad for pangolins. It could decrease the trade in the animals, or it could cause a backlash.