Witches broom / rose rosette
Good morning and thank you for contacting Ask an Expert.
I am so sorry this rose nemesis has visited your garden!. If you wish to know for sure that it is Rose Rosette ideas a sample should be sent to Plant Diagnostics (https://pestid.msu.edu). Your local Extension office should be able to help you. From the pictures it is likely that this could be your problem. What you should do now is remove the affected plant immediately. Cover it with a bag, dig it out and throw it in the trash. Do not compost it. There is no cure for this disease which is cause by a virus and spread by a very small mite. Roses infected generally die within two years. I'm attaching some articles for you.
Yes it can spread via the mite as it's vector but do not assume the others will become infected. Public rose gardens have dealt with this problem and have not lost their collection. Monitor the other plants and remove immediately if they exhibit symptoms. I too have had this in my garden and still have roses. While I enjoy them I do not spray or coddle them. Carefully look at new rose purchases for symptoms as well. Refer to the articles if you wish to try a chemical control of the mite though I don't believe any are specific to this mite but that may have changed. if you choose to use a miticide, follow label directions.
Here are the links:
There is even a Facebook page! https://pestid.msu.edu
May your other roses continue to be healthy and bring you joy!