Fire blight is caused by the bacteria, Erwinia amylovora. The bacteria overwinter in bark or cankers. Quince trees are very susceptible to fire blight infection in open flowers during bloom. In the spring infected trees have dead flower clusters and shoots, along with oozing in young tissues. The disease is prevented primarily by the use of bactericide sprays. Infected plant parts are periodically cut well below the infection zone. Cuttings should be removed and burned to prevent bacterial spores from spreading throughout the tree and orchard (UC IPM website, pear, 2014).
We don't yet have photos of diseases on quince, however the images below of fireblight on pear illustrate typical symptoms of the disease. These photos are accessed from the UC ANR Repository, are available courtesy of University of California research and extension personnel and programs, including the UC Statewide IPM Project.