A smidgen of real scientific research about levamisole in cocaine (instead of our decidedly nonscientific, shoestring journalism) is trickling onto the web. This study for the Annals of Emergency Medicine tracked people who wound up in US hospitals between mid-October 2009 and the following May. (The wheels of science turn slowly.)

Of the 46 potential cases reported from 6 states, half met eligibility criteria and had medical chart abstractions completed (n=23; 50%). Of these, close to half of the patients were interviewed (n=10; 43%). The average age was 44.4 years; just over half were men (n=12; 52%). The majority of patients presented to emergency departments (n=19; 83%). More than half presented with infectious illnesses (n=12; 52%), and nearly half reported active skin lesions (n=10; 44%). The majority of interview respondents used cocaine greater than 2 to 3 times a week (n=9; 90%), used cocaine more than 2 years (n=6; 60%), and preferred crack cocaine (n=6; 60%). All were unaware of exposure to levamisole through cocaine and of levamisole's inherent toxicity (n=10; 100%).

Our anecdotal evidence showed that levamisole poisoning was more frequent in regular users and in crack users—but I'm surprised to see that crack users make up only slightly more than half of this sample. And it's showing up in heroin, too, but only three percent of the seized herion, per the most recent numbers. (And three percent sounds small enough to be an accidental contamination or a whatever's-lying-around cut, not an actual economic strategy.)

And an anonymous commenter on The Stranger's first story about levamisole recently wrote:

Levamisole here in vancouver canada is mostly used to cut crack , because they doble their money , if a dealer cooks one ounce of coke, he adds another ounce of levamisole to it , becoming all together two ounces , and the users cant tell abd they think its base rock because they see only oil in the pipe and no dust left from the old cut that was baking soda .. Thats the reality of why they add levamisole to cocaine here in vancouver .. They sell the levamisole here for 1000 per kilo ..

That matches one of the theories we'd originally proposed—that levamisole makes a good cut, even though it's rarer than something like baking soda—because it has a chemical relationship with cocaine that passes street tests. Dealers (on a corner level or on an international level) who use purer-seeming cuts will be more popular than dealers who use obvious cuts.

But official sources—medical, governmental—have yet to officially solve the mystery of the tainted cocaine.