Did tobacco become popular because it kills parasites?

While reading about the conditions in a Burmese prison around the turn of the previous century (The History and Romance of Crime: Oriental Prisons, by Arthur Griffiths)(not good) it occurred to me that there might have been some beneficial effect of the large amounts of tobacco smoke inside the prison. Sure, in the long run, tobacco is highly likely to give you cancer, but in the short run, is it noxious to fleas and other disease-bearing pests?

Meanwhile in Melanesia, (Pygmies and Papuans,) a group of ornithologists struggled up a river to reach an almost completely isolated tribe of Melanesians that barely practiced horticulture; even further up the mountain they met a band of pygmies (negritoes) whose existence had only been rumored of; the pygmies cultivated tobacco, which they traded with their otherwise not terribly interested in trading for worldy goods neighbors.

The homeless smoke at rates 3x higher than the rest of the population, though this might have something to do with the high correlation between schizophrenia and smoking–80% of schizophrenics smoke, compared to 20% of the general population. Obviously this correlation is best explained by tobacco’s well-noted psychological effects (including addiction,) but why is tobacco so ubiquitous in prisons that cigarettes are used as currency? Could they have, in unsanitary conditions, some healthful purpose?

From NPR: Pot For Parasites? Pygmy Men Smoke out Worms:

On average, the more THC byproduct that Hagen’s team found in an Aka man’s urine, the fewer worm eggs were present in his gut.

“The heaviest smokers, with everything else being equal, had about half the number of parasitic eggs in their stool, compared to everyone else,” Hagen says. …

THC — and nicotine — are known to kill intestinal worms in a Petri dish. And many worms make their way to the gut via the lungs. “The worms’ larval stage is in the lung,” Hagan says. “When you smoke you just blast them with THC or nicotine directly.”

Smithsonian reports that Birds Harness the Deadly Power of Nicotine to Poison Parasites:

Smoking kills. But if you’re a bird and if you want to kill parasites, that can be a good thing. City birds have taken to stuffing their nests with cigarette butts to poison potential parasites. Nature reports:

“In a study published today in Biology Letters, the researchers examined the nests of two bird species common on the North American continent. They measured the amount of cellulose acetate (a component of cigarette butts) in the nests, and found that the more there was, the fewer parasitic mites the nest contained.”

Out in the State of Nature, parasites are extremely common and difficult to get rid of (eg, hookworm elimination campaigns in the early 1900s found that 40% of school-aged children were infected); farmers can apparently use tobacco as a natural de-wormer (but be careful, as tobacco can be poisonous.)

In the pre-modern environment, when many people had neither shoes, toilets, nor purified water, parasites were very hard to avoid.

Befoundalive recommends eating the tobacco from a cigarette if you have intestinal parasites and no access to modern medicine.

Here’s a study comparing parasite rates in tobacco workers vs. prisoners in Ethiopia:

Overall, 8 intestinal parasite species have been recovered singly or in combinations from 146 (61.8 %) samples. The prevalence in prison population (88/121 = 72.7%) was significantly higher than that in tobacco farm (58/115 = 50.4%).

In vitro anthelmintic effect of Tobacco (Nicotiana tabacum) extract on parasitic nematode, Marshallagia marshalli reports:

Because of developing resistance to the existing anthelmintic drugs, there is a need for new anthelmintic agents. Tobacco plant has alkaloid materials that have antiparasitic effect. We investigated the in vitro anthelminthic effect of aqueous and alcoholic extract of Tobacco (Nicotiana tabacum) against M. marshalli. … Overall, extracts of Tobacco possess considerable anthelminthic activity and more potent effects were observed with the highest concentrations. Therefore, the in vivo study on Tobocco in animal models is recommended.

(Helminths are parasites; anthelmintic=anti-parasites.)

So it looks like, at least in the pre-sewers and toilets and clean water environment when people struggled to stay parasite free, tobacco (and certain other drugs) may have offered people an edge over the pests. (I’ve noticed many bitter or noxious plants seem to have been useful for occasionally flushing out parasites, but you certainly don’t want to be in a state of “flush” all the time.)

It looks like it was only when regular sanitation got good enough that we didn’t have to worry about parasites anymore that people started getting really concerned with tobacco’s long-term negative effects on humans.