The leaf has a downward curl.

We grow plants in a nursery. Yesterday we found atleast 400 chilli saplings with their leaf contracted.. They also stopped growing. Today, another 2-3 batches of saplings are also exhibiting the same problem. We are confused as to if this is a virus or something else. The leaves have contracted and curled downwards, in to themselves, like a circle. This is the only problem. They are not flat as they used to be. And the problem seems to be spreading. We have a papaya farm beside us(if this information helps)