Three hours later they arrived at the camp, and Isolomo began checking the fishing lines he’d set up the day before. Feeling resistance on one, he thrust his hand into the murky water.

A sharp pain sent him reeling. Blood oozed from two puncture wounds on his hand. Just below the surface, a yellowish snake with black rings—probably a banded water cobra—slithered from view.

Isolomo’s companions helped him into the canoe and paddled frantically back to their village of Iteli. By the time they arrived, about three hours after Isolomo was bitten, he was slipping in and out of consciousness.

“His eyes had changed color, and he was vomiting,” his wife, Marie, recalls, starting to cry. After a traditional healer applied a tourniquet,