It could be rose "rosette" which is a form of witches broom in roses, spread by a tiny mite. Sterilizing your pruning shears does not prevent it. However, some herbicide sprays that have spread onto a rose bush can cause a similar appearing appearance in rose bushes. I would take a sample to your local extension office for confirmation. If it is rose witches broom, the only treatment is to immediately destroy the bush carefully, making sure the bush removed does not touch any other nearby bushes, double bagging it (not composting) and ensuring it does not have the opportunity for the mites to affect any others.

http://msue.anr.msu.edu/news/rose_gardeners_should_learn_the_symptoms_of_rose_rosette_virus