Human-to-human transmission can easily occur, and pandemic will therefore break out.

很容易出现人际传播，而且会因此爆发大流行病。

youdao

After visiting Wuhan, Dr. Zhong spoke out frankly about human-to-human transmission and suggested evidence-based prevention.

在武汉之行后，钟南山医生坦率地说出了人际传播的事实，并建议采取循证预防措施。

youdao

There is no direct human-to-human transmission.

没有直接的人际传播。

youdao

The increase to level 5 indicates that there is sustained human-to-human transmission in communities in different geographical locations.

VOA: standard.2009.04.29

The WHO's Phase 5 threat warning signals that a global pandemic could be imminent, but has yet to develop, with human-to-human transmission occurring in many geographical locations.

VOA: standard.2009.04.30

There has also been occasional human-to-human transmission, according to the World Health Organization.

FORBES: China H7N9 Bird Flu Cases Rise By Five; Four Provinces Report Illnesses In One Day

But the WHO says there is currently no evidence of human-to-human transmission of the virus.

BBC: WHO confirms five deaths from China bird flu

The World Health Organisation (WHO) said there was no evidence yet of human-to-human transmission.

BBC: China bird flu: Reported H7N9 cases rise to 60