I remember about 10-15 years ago walking into a local drug store, on the shelf in a bin were a bunch of enema bag replacement parts, including nozzles. Who would have thought they would all go away, I should have bought them. Most enema bags, at least from my experience use a barb fitting for the hose connection, but I have at least one bag with threaded nozzles. I don't think it is very likely that the threads would be the same, and if they were, where would you buy one, unless somebody on the group wants to give something up.
I bought an antique enema can a while back on ebay, I had to test it out of course. Less than a day later, somehow the bakelite nozzle gets smashed, no idea how it happened. It was only a few inches long, somewhat bat shaped, can't find the pieces. Bakelite is a thermo-setting plastic and is very brittle. I bought some delrin the other day and am experimenting building a new nozzle on the lathe. The nozzle was all done, had the hole bored, the proper contour, and I was just machining the barbs, and the tool bit grabbed and shattered the plastic. I need to change the order of operations on the next one.
The reason I'm saying this, I just of well could have created threads on the nozzle end, but chose to do barbs. For a skilled machinist, single point threading on a lathe is not a big deal, it's a matter of how you hold the nozzle while you turn the threads, or, turn the threads before you build the nozzle, in my case, I weakened the piece of plastic.
An option for you is to have somebody machine a new nozzle, you could even choose the dimensions. Another option is to find a plastic part with the correct threads and glue it to the broken nozzle, probably not the best route. To fabricate a new nozzle, the threads would have to match, you would have to measure the outside diameter of the male threads, and do a thread count, how many threads per inch. If it was metric, how much distance from thread to thread, the thread pitch. The last part, the two parts would have to screw together, sometimes a bit of touch up is necessary.
How important is it for you to get a replacement nozzle? I'm sure there are several machinists in this group looking for a project.
the hoseman1