It is an Opal Plum.

BTW, my first search results agree with my palette ^‿

Some call plum ‘Opal’ the most delectable of all fruit. https://www.gardeningknowhow.com/edible/fruits/plum/caring-for-opal-plum-trees.htm

Picked straight from the tree it’s probably the best tasting of all the plums. https://gardenfocused.co.uk/fruitarticles/plums/variety-opal.php

PS: If you really want to be technical, it is the pathogen that is transmissible. Infection is what happens when the pathogen “invades” the tissues and/or afterward (different uses). Some dictionaries (e.g., Merriam-Webster) literally put the word disease in the definition of infection. But yes, the pathogen is being transmitted, not the disease, as in the spread of HIV, not the spread of AIDS.

My mum has a sweet plum that fruits in July in Dfb (Poland). It is amazing, it gives a lot of fruit every two years, a real treat, my favorite.

If you want to plant a pear, look out for juniper in the neighborhood. There is a common disease that transfers between these two.