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Pests provide clues to useful medicines

Alan Braunholtz

Wasps are predatory and do a great job killing off all sorts of garden pests like leather jackets and caterpillars. They’ve adapted well to us, and our buildings provide plenty of cavities for nests.

Unfortunately, one lot of yellow jackets has established a nest in the door frame of Gayle’s apartment. Every time I let the door slam, the 20 or so guarding the entrance get all riled up. Swat one and you’re really in trouble. A dying wasp emits a pheromone that signals the others to attack. They now associate me as a threat, have a great sense of smell and follow me to the car, quicker than I can hobble on crutches. There’s something very scary about little buzzing attack drones locked onto you and when a couple snuck in the car the truce was off. A can of wasp-be-gone raised the stakes and we are now at war.

Wasps may soon be used by the military in real wars for detecting chemical weapons (me with a can of wasp-be-gone!). A wasp’s sense of smell is 100,000 times better than the best electronic nose, and they can be trained in minutes to detect certain smells. Expose them to a weak puff of chemical, then give them some sugar water; repeat three times. After that they will head for that chemical. Devices in which captive wasps trigger a sensor when they react to a smell are now being tested. Amazing the uses we can get from bugs.

Mosquitoes also seem to be surviving this drought. A mosquito egg only needs four days to transform into an adult, so any puddle will do. There are 43 species of mosquito in Colorado.

Only the females bite. They need the protein for their eggs. The whine comes from wings beating at up to 600 beats per second. Females use this to attract males, who respond to different frequencies. They can choose the deep sexy female at 250hz or go for the bubbly blonde chipmunk type at 500hz. You can attract males with a tuning fork if you wish.

The recent West Nile virus scare created more mosquito awareness. Hopefully, no more tropical diseases will follow the warming climate. Though if they do, it’ll be good for Africa. Currently drug companies put minimal effort into curing tropical diseases. It seems starving and poor people are not a profitable market. But if rich people got the diseases, there’d be lots of research. An example: African sleeping sickness is a huge problem. The traditional medicine (developed in the “40s) contains cyanide and kills one in 20 patients. A new medicine without these unwanted side effects was discovered, but no one wanted to make it (despite Doctors Without Borders’ humanitarian pleading), since it would cost too much to set up production. Recently someone noticed this same chemical being used in a face cream. Doctors Without Borders then managed to cajole the pharma giants to make it in IV form, since it was now already being produced.

Researchers are starting to look at parasitic bugs as a source of new medicines. The bugs have spent millions of years developing ways to outwit our defenses and feed off us. This evolutionary arms race has created some pretty potent chemicals.

A mosquito uses an anaesthetic, so we don’t feel the prick and an anticoagulant so she can slurp away without the blood clotting. It’s our immune response to the anticoagulant that causes the itching.

We’ve used leeches for years, and they’re still used in microsurgery to drain blood. In fact genetically engineered bacteria are producing their anticoagulant (hirudin) for use after surgery. Hirudin’s letdown is that our immune system eventually recognizes it and breaks it down so it can’t be used long term.

Hookworms live in animal guts for long periods, so they’ll need an anticoagulant that can stay low key. Sure enough, research has isolated a nematode anticoagulant protein (NAPc2). In trials of NAPc2 with knee replacement surgery the percentage of patients getting blood clots dropped from 25 percent to 12 percent.

Ever wondered how a tick can stay unnoticed for days while a little splinter causes itching and swelling. Ticks practiced on the dinosaurs and now have it down. They have over 300 chemicals that affect our blood and immune system. One of these, a histamine blocker, is being tested to see if it helps with asthma and hay fever, both diseases of an overly sensitive immune system. Sand flies’ saliva contains the strongest vasodilator yet discovered, which fits into its smash-and-grab approach to feeding.

Nice to know we’re hijacking these bugs’ weapons for our benefit and we have 40,000 species to look at, uurgh!

Mosquitoes always challenge my appreciation of nature in all its forms, though biologically they make sense. They fill a niche and their larvae convert organic matter in standing water into higher nutrients that then enter the food chain. Without mosquitoes I wouldn’t see the spectacular flights of nighthawks chowing down as a small funnel of beak feathers sweeps them into its mouth.

Dragonflies depend on mosquitoes, so I guess they all fit together. Apparently mosquitoes are quite beautiful with intricate patterns of colored scales on their wings and gossamer antennae, though I usually see them in the more common splattered profile.

Omnipotent deity wise, they make no sense, especially when sitting around outdoors after a few. Why create a mosquito? The Tlingkit Native Americans have a good story on how. An immortal giant terrorized their people, killing them then drinking their blood. A brave warrior struck the giant down, chopped him up, burnt his flesh and then scattered the ashes into the wind. Hoping to utterly destroy this evil giant. These ashes are still drinking our blood.

Alan Braunholtz, raft guide and ski instructor, writes a weekly column for the Daily.


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