What are sea lice? Australian teen leaves hospital lice free

An Australian teenager was thoroughly shocked on Saturday night, along with the biologists from around the world, when he emerged from the ocean to find his ankles bleeding profusely.

Sixteen-year-old Sam Kanizay had been on instagram while standing in the cool ocean water for half an hour after a soccer game. But when he went to put his shoes on, he realized that blood was pouring from his ankles where the water had been lapping, and it wasn’t stopping. After noticing thousands of tiny pin-holes in his legs, Kanizay’s parents rushed him to the hospital.

As Australians laugh off their country’s reputation overseas for its “awesome array” of dangerous animals, many have been keen to identify the culprit that caused Kanizay’s ghastly flesh-wounds.

On Monday, Museum Victoria announced that it had identified some sea critters that were collected by Kanizay’s father from the site of the incident the night after it occurred. In an effort to determine what had bitten his son, Mr. Kanizay decided to do a little detective work of his own, and left some beef mince in the water. After 15 minutes, he found hundreds of tiny sea critters swarm on the carrion, devouring the red meat.

The critters were later identified at the museum as lysianassid amphipods, commonly known as ‘sea fleas‘. They are a type of marine crustacean distantly related to shrimp and crabs.

But are these sea fleas responsible for the bites that left Kanizay’s ankles dripping with blood?

Lysianassid amphipods are known scavengers. Associate Professor Alistair Poore, a marine invertebrate expert from the University of New South Wales, explains that there are many different types of scavengers in the ocean that are attracted to carrion, “There are all sorts of little animals that clean up dead fish and dead whales. Otherwise the ocean would be full of all this rotting meat.”

Poore says “the jury is still out on whether those were the ones that did the damage to his [Kanizay’s] legs,” referring to the amphipods. He says that although lysianassid amphipods probably bite, they are not known to bite humans or leave the pin-sized wounds that were found on Kanizay’s legs.

Poore noted that as the father did not collect the amphipods at the time when Kanizay was bitten, it is difficult to confirm the real culprit that caused the teenager’s wounds. Poore believes that sea lice are the more likely culprits as they have biting mouthparts that can easily break the skin. Sea lice are small marine copepods, also a type of crustacean.

Most people associate a different kind of marine animal that causes skin rashes with sea lice. Poore explained that these more common symptoms are a false association. The nasty rashes are instead caused by jellyfish tentacles or larval jellyfish that are about half a millimeter long and get stuck between bathing suits and the skin. But jellyfish do not cause any bleeding. Sea lice are know blood-suckers that bite.

A similar, but less serious incident was reported on a nearby beach in Sandringham in 2015, which marine experts also attributed to sea lice. Professor Michael Keough, a marine biologist from the University of Melbourne, told the Herald Sun, “They have sharp jaws, so the bite is quick and a bit painful, but nothing beyond that.” The victim was another teenage boy cooling his feet in the cold ocean water after soccer training in the first week of August.

Luckily for Kanizay, neither sea lice nor amphipods are venomous.

Kanizay left the hospital in a wheelchair on Tuesday after the thousands of pin-sized wounds finally stopped bleeding. The wheelchair helps to keep pressure off the wounds.

“He can’t walk around freely without pain so the wheelchair will help with the pain and help him recover at home once we get him out of hospital.” Kanizay’s father told the Express. Kanizay is expected to make a full recovery soon.

Associate Professor Richard Reina from Australia’s Monash University reassured those concerned about swimming in the ocean in a Facebook post.

“There’s no need to stay out of the water,” he explained. “It’s a bit like if you allowed hundreds of mosquitoes to keep feeding on your arm for half an hour—you’d get an extreme reaction then too, but it’s not something that people normally do.”

“We don’t want people to fear the bay because we aren’t,” Kanizay told the Herald Sun. “Our family will continue swimming and celebrating the ocean.”

Poore said these marine crustaceans are not just “an Australian thing” and can be found in oceans all around the globe.