There's a lot of research into anti-Plasmodium drugs in general (because they can be used in treating infected humans), but none have come close to being usable

There's a lot of research into anti-Plasmodium drugs in general (because they can be used in treating infected humans), but none have come close to being usable for general environmental dispersal that would try to eliminate the wild reservoir. Mixture of cost, resistance developing too quickly, and effects on other wildlife, so doing something like dropping quinine into forests from planes has never been a real option. This is in general very unlikely to work for diseases that have a significant non-human reservoir. Smallpox was able to be eliminated because it exclusively infects humans, so you only need to eradicate it from human hosts, not also from another extremely populous host like wild mosquitoes. Another approach is to try to genetically engineer mosquitoes resistant to infection and have them replace the unmodified carrier versions, but that's essentially just a variant of the idea to eradicate the carrier-type mosquitoes: https://www.nih.gov/news-events/nih-research-matters/engineering-malaria-resistance-mosquitoes https://www.nih.gov/news-events/nih-research-matters/enginee...