There are plenty of dangerous lifeforms we could realistically stamp out -- grizzly bears, for example. The pertinent question is whether it would be worth the cost. This organism can be defeated forever with handmade water filters, and we'll never miss it. But we could burn all the swamps in the world (along with countless "bystander" species) and still fail to wipe out malaria.
Alpha predators like brown bears kill so few humans that they aren't worth the effort to chase down and exterminate (see Monster Of God by David Quammen). The real monsters are mosquitos and the disease bearing organisms they vector.
> There are plenty of dangerous lifeforms we could realistically stamp out -- grizzly bears, for example.
Your facetious comment aside, it really depends on what we consider a "lifeform". A number of viruses and bacteria can be wiped out without affecting other species ... largely, because we are their entire ecosystem, almost like this worm.
Are most potent weapons are vaccines, antibiotics, and proper hygiene. With a combination of those, we can eliminate much of what currently ails us.
Except we don't have a vaccine for many viruses and on the antibiotics front we're fighting a war against evolution; and arguably we're not using our ammunition very wisely. Or is that fear mongering?