Slow onset, initially no obvious symptoms.

起病缓慢，初期无明显自觉症状。

youdao

Slow onset of the disease, with the cyclical increase mitigation, many for several years, the slow process of evolution.

本病起病缓慢，呈周期性加重与减轻，多有数年的缓慢演变过程。

youdao

Supplements derived from apple skins, red wine and tumeric might someday help slow the onset and progression of Alzheimer's and related diseases, according to accumulating evidence.

越来越多的证据显示，不久的将来，苹果皮、红酒和姜黄里的营养物质有望减缓阿尔兹·海默症和相关疾病的攻击与扩散。

youdao

But if it can also slow the onset of Alzheimer's disease, sales could be much greater.

FORBES: Magazine Article

Longer-term, what the United Nations Food and Agricultural Organization (FAO) calls "slow-onset" climate change is seen as likely to have a heavy impact on food production in developing nations.

CNN: , Special for

They also want the UN to monitor and assess losses, and to find new approaches for addressing loss and damage, particularly for slow-onset events like, say, sea level rise.

BBC: Climate compensation row at Doha