Given the task definition and input, reply with output. In this task, you are given one French sentence. The major part of the sentences talk about health-related topics, but some of the them describe an organization and its activities. Your job is to translate the given sentences into English.

Après une période d’incubation de 10 à 90 jours (trois semaines en moyenne), les manifestations cliniques apparaissent:

After an incubation period of 10 to 90 days (three weeks on average) clinical symptoms appear: