The simple answer is no. PDF is a "final" format and there's really no way for your translators to do their work in that format, even if it was a good idea, which it isn't. PDF is either palces as essetially an image format, uneditable in ID, or you can use a commercial plugin to open a PDF and convert it to ID, but there's no guarantee of perfection.
Joel Cherney is our translation expert, and hopefully he'll see this in a few hours and comment, but I think the first thing to find out is what formats do your translation people normally use?
You can export the text to RTF and have them use that. Then create a new
document based on your English version and place the RTF files. Make
sure the translator does not style anything.