They are pome fruits so yes fireblight spreads between them and others in that family. Here is additional information for those not familiar with the disease to help diagnose it
https://www2.gov.bc.ca/gov/content/industry/agriculture-seafood/animals-and-crops/plant-health/insects-and-plant-diseases/tree-fruits/fire-blight#:~:text=Fire%20blight%20is%20a%20destructive,Columbia%20pear%20and%20apple%20orchards.
If you need to change varities its no big deal switch to a fireblight resistant type of fruit Top working Pears weather permitting