Either make Kuru less deadly, or make Prions harder to get.

[Don]

Still doesn't stop the problem of prions being ridiculously easy to get and Kuru being ridiculously deadly in comparison of how easy it is to get prions.

It actually would take a good amount of work getting multiple doses of 5 units. You'd take up a good 30 minute chunk getting a huge amount of them, and at that point I think it's OK if it's strong.

Once you have your first unit of a chemical, you can turn it into 40 and be in a position to mass produce it after two to ten minutes depending on your access. If you want to make it hard to hoard, you have to make the first unit hard to get or give the chemical an expiration date. I'm lean to the latter. The problem could be solved if prions die from not being within a food. It would still be possible to weaponize kuru, but it would take effort that match its lethality.

Or maybe you should roll a 10% chance of self-infection every second you hold an object with a disease reagent in your hands if you're not wearing a full hazmat suit. That would be the more SS13-ish way.