5 Things to Know About Being Bitten By A Viper

Sean O’Donnell is a member of the white fang club — which is to say that he’s one of a group of biologists whose been bitten by a venomous snake and lived to tell the tale.

In 2009, O’Donnell, PhD, now an associate department head of Biodiversity, Earth and Environmental Sciences (BEES) in Drexel’s College of Arts and Science, was involved in a program teaching tropical field courses for undergraduates in a lowland rain forest in Costa Rica. It was there, two years before he came to Drexel, that he was initiated to the club via a Central American bushmaster.

Bushmaster 2
A Central American bushmaster.

Bushmasters are the longest venomous snakes found in the western hemisphere, according to the Encyclopedia Britannica. Their venom is deadly, killing more than half of the people who suffer bites, and their genus, Lachesis, is actually derived from the name of one of the mythological Greek Fates — specifically the one who determined how long a person’s life lasted.

Here’s what O’Donnell’s learned about being bitten by a deadly viper.

  1. Even Taking the Best of Care, Vipers Can Still Strike

As an entomologist, O’Donnell’s research over the years has focused on insects like wasps and ants. One morning, O’Donnell and a group of students were following an army ant foraging column, known as a “raid,” through the forest.

As he followed the ants in the light of the morning, O’Donnell was wearing heavy boots that came up past his ankles to protect against anything that might be moving along the forest floor. He also walked deliberately, choosing his steps.

O’Donnell out in the field.

“I wasn’t risking a bite — running through the forest at night with sandals on without a flashlight,” O’Donnell said.

Eventually, the raid went through a gap in the forest created by a fallen tree. O’Donnell went around it — because he knew that’s where snakes tended to hang out.

It turned out this snake didn’t have that tendency.

  1. You May Never See the Snake That Bit You

O’Donnell took a moment to look with binoculars at a flock of birds following along with the ant raid. Birds are known to move with these ant columns and capitalize on the bugs they scare out of hiding.

At that moment, he was struck by an immense pain in his left heel.

“It was all at once,” O’Donnell said. “It was like being hit with a sledge hammer with a nail on the end. For many years, I worked on wasps and then these army ants. I get stung a lot. This wasn’t like anything I’ve ever felt.”

Whipping off his boot, O’Donnell didn’t see the scorpion or bullet ant he expected to find tumbling out. There was just a single, bloody puncture in his heel.

O’Donnell’s vision became blurry and dizzy. Following the voices of his students, he left the forest, and a pounding headache soon set in.

He never saw the snake.

“I’ve talked to some people in the field and they said these vipers are almost undetectable to the human eye when they’re in their environment,” O’Donnell said.

  1. And Not Seeing the Snake Could Be A Big Problem

After getting to the clearing for the field station where he was teaching , O’Donnell examined the wound further. He found that it was still bleeding and had become swollen.

It was then that he theorized that he was bitten by a snake but only one fang hit. Two fellow faculty members didn’t think that was the case and talked O’Donnell out of it, partly because there was no venom on the boot . They reasoned it must have been a bullet ant.

Later, after O’Donnell had returned home to Seattle, he and his wife examined the boot and found evidence of a second fang mark that hadn’t punctured through. O’Donnell believes the snake (which a herpetologist friend estimated was seven feet long after he measured the span between the fang marks) aimed for his right foot but missed and caught the left, striking from behind.

“If I had been hit with both fangs and their venom, it might have been much worse,” he said. “But we would have known it was a snake bite right away.”

  1. Your Best Problem Might Be Needing to Use the Bathroom

O’Donnell conducted the rest of his day fairly normally, eating lunch and dinner, going on a hike to plan a project and consulting with students.

He continued to have a headache and felt a lot of pain in his foot and lower leg, but was unaffected beyond a limp and able to go on a night research hike.

Bushmaster 1
A coiled Central American bushmaster.

Reflecting afterward, O’Donnell realized the hike probably made the bite even more dangerous, as his pumping blood likely circulated the venom faster.

Around 10 p.m., when he returned, O’Donnell used the bathroom and noticed a small amount of blood in his urine. That convinced him he’d been bitten by a snake and needed to get help.

“An ant sting definitely does not do that,” O’Donnell said. “A snake bite does.”

After a visit at a local clinic where, astoundingly, the doctor also dismissed his snake bite theory, O’Donnell was referred him to the capital for further treatment.

By the time he got to the hospital in the capital, his urine sample looked like it was almost completely blood.

“At that point I thought I might not survive the night. When I handed the cup to the lab attendants, they stared at me with grave expressions,” O’Donnell said. “I stammered, ‘Muy malo [very bad],’ and they nodded their heads.”

Once a doctor tested him, O’Donnell’s blood appeared to have zero coagulation ability — “the time to coagulation was estimated as ‘infinite’” — and he was given 10 vials of anti-venom, a tremendous amount.

By the next morning, he showed vast signs of improvement and realized he might survive after all — thanks to being alert during his bathroom break.

  1. It’s Probably Going to Leave You a Little Shaky Afterward

Roughly six years after the bite, O’Donnell shows no physical signs of the incident. He has no limp and hikes just fine while out on his new research projects.

A dark mark on his heel that stayed after the incident eventually went away, too.

“I wanted to keep that as a little trophy,” O’Donnell laughed. “But it’s gone. So I have nothing.”

But he remains a little wary in the field.

“I’m almost all the way back,” O’Donnell said.

Subsequent research brought him back to the same area in Costa Rica. He’s continued to hike through the rain forest, but when encountering the spot where he was bitten, O’Donnell generally stays away.

“It’s funny. That fascinates me,” O’Donnell said. “I know, scientifically, that snake is not there. But I don’t really go through that spot. I leave it alone.”

And since then, O’Donnell’s upgraded his equipment a bit: He’s now the proud owner of Kevlar snake-proof boots that go up almost to his knees.

An account O’Donnell wrote of his experience with the bushmaster will soon appear in Natural History magazine.

Media inquiries can be directed to Frank Otto at 215.571.4244 or at fmo26@drexel.edu.

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