News Column

New Snakebite Treatment Could Save Millions

August 9, 2013

David Perlman

The idea came to Dr. Matthew Lewin as he flew back to California from the Philippines: Could snakebite victims be saved from paralysis and death without a doctor there to administer a crucial injection?

Now the Corte Madera physician hopes the solution he proposed will save countless thousands of snakebite victims in developing countries who would otherwise die from the paralyzing venom of snakes because they can't get to hospitals where vital antivenom and drug injections are available.

Lewin had been in the Philippines two years ago with his snakebite kit, accompanying researchers from the California Academy of Sciences on an expedition to collect little-known species of plants and animals.

When he flew home, he left his kit behind in case venomous snakes should strike, although many of the expedition scientists told him they were nervous about injecting themselves -- or treating anyone else nearby.

"But wouldn't it be nice if you really didn't need injections for snakebite at all?" Lewin said he wondered. "Wouldn't that be cool?"

And not just for a few scientists, he thought, for everyone in the world.

A million snakebites

In India alone, Lewin said, a million people every year are bitten by venomous snakes, such as cobras and kraits, and 35,000 to 40,000 die from bites that quickly paralyze the muscles of the diaphragm so their victims can't breathe. The World Health Organization reports the global numbers are far higher: More than 100,000 die from snake venom annually.

Lewin calls it "the neglected epidemic."

Its victims -- mainly impoverished children and young adults -- die because they can't get to hospitals for the injections that might save them.

Treating the bites of venomous snakes is difficult at best: Antivenom preparations are hard to come by and so are drugs called "anticholinergics." Both must be injected by doctors in hospitals or clinics -- and the drugs are rare in the developing world.

Doctors in modern hospitals use anticholinergics, including the drug called neostigmine, in a simple nasal spray to treat episodes of paralysis due to unexpected operating room problems, as well as for neuromuscular disorders like myasthenia gravis.

During that plane trip from the Philippines two years ago, Lewin pondered whether the same kind of nasal spray might also work against snake bites.

So back in San Francisco this past April, Lewin and his old friend, Dr. Philip Bickler, an anesthesiologist at UCSF, tried an experiment with the help of colleagues at the university's research center.

The volunteer

A healthy 45-year-old man weighing 166 pounds, whom Lewin identified only as a "fellow-scientist," volunteered to be injected in the hospital with a curare-like drug that would simulate the fatal paralysis of a cobra's bite.

Hospital officials approved the experiment, and doctors stood by with emergency injections of an anticholinergic drug as the experiment began.

The curare-like injection began taking effect within minutes. The volunteer's eyesight weakened, and after an hour and a half, he had difficulty swallowing; he couldn't raise his head from the bed; and his breathing grew difficult.

Then the doctors sprayed the man's nasal passages with neostigmine, and quickly his symptoms of paralysis began fading. Less than 20 minutes later, all his symptoms were gone.

The experiment has since been reported in a medical journal called Clinical Case Reports.

Later in April, Lewin described his hopes and his team's experiment in a speech at a medical meeting in Chicago. In the audience was an Indian physician named Dr. Stephen Samuel, who often works in the southern Indian state of Tamil Nadu.

Samuel was interested and the two doctors agreed to collaborate, Lewin said, so he flew to India, where the two made treatment plans for patients at a hospital in Krishnagiri, a city of nearly 2 million.

Putting it to use

In June, Dr. Saundara Ra at the Krishnagiri hospital used the nasal spray containing one of the common anticholinergic drugs to treat a snakebite patient. Despite antivenom injections, the patient had suffered persistent paralysis from a bite by a krait, a member of the cobra family.

Using nasal spray alone, the paralysis ended within 30 minutes, Lewin reported.

Now back in San Francisco, he and his colleagues have begun experiments with mice to determine what combinations of anticholinergic drugs might work best in nasal sprays and to plan for clinical trials of the sprays in India for victims of cobra bites. One of the team members is Dr. Brett D. Mensh, an adviser to the prestigious Howard Hughes Medical Institution's Janelia Farm research campus in Ashburn, Va.

"It all could take years and a lot of money," Lewin said.

He's staying home now, treating patients in his local office, and advising scientists headed for new expeditions in his role as director of the Academy of Sciences' Center for Exploration and Travel Health.

He has more than 20 expeditions under his belt, but now he has a compelling new interest.

"Expeditions can wait," Lewin said.

David Perlman is a San Francisco Chronicle science editor. E-mail dperlman@sfchronicle.com

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(c)2013 the San Francisco Chronicle

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Source: Copyright 1SF 2013


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