Lobsters can detect disease, report says
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BY A.J. HOSTETLER
TIMES-DISPATCH STAFF WRITER

Don't you wish you could tell whether your co-worker was infectious before he sneezed in your face?

The usually congenial Caribbean spiny lobster can tell when its seemingly fit buddies are dying of a communicable disease.

So, does the healthy lobster deliver chicken soup to its doomed pal? Nope, it abandons its diseased comrade. Experts say this ability to detect infection even before symptoms appear and then get the heck away was unknown in animals in the wild.

"It would be nice to be able to recognize infection and, clearly, that's what lobsters are able to do," said Old Dominion University marine biologist Mark Butler, one of the researchers reporting the antisocial but self-protecting behavior in today's Nature.

"It's unlikely that this kind of behavior evolved in just one organism," Butler said. "It's possible, given how many social animals there are out there, that similar kinds of behaviors exist and that we just haven't recognized it."

The spiny lobster, the most prevalent lobster worldwide, is a significant catch for the warm-water fisheries of Florida and the Caribbean.

In 1999, a team of Virginia biologists including Butler found the first virus known to infect lobsters. PaV1 is a lethal virus that mostly infects juvenile Caribbean spiny lobsters. Infected lobsters become lethargic, stop molting and drip a milky, discolored blood that refuses to clot.

They roll like a gymnastic team into a porcupine-like ball to fend off predators with their antennae. Like many human viruses, the lobster virus spreads through physical contact. The smallest juveniles transmit the pathogen through seawater.

After discovering the virus, the biologists noticed that sick juveniles tended to be found alone, away from the communal dens.

They had been abandoned, according to Butler and his colleagues, ODU research associate Donald Behringer and Jeffrey D. Shields of the Virginia Institute of Marine Science.

The researchers gave healthy lobsters a choice between an empty den and one containing either a healthy or an infected roomie. Unlike the diseased lobsters that didn't care what they roomed with, healthy lobsters gave infected crustaceans the cold shoulder.

"They wouldn't go anywhere near them," Butler said.

He speculates that healthy lobsters may detect a "death" chemical cue given off by those infected. Such chemical cues play a role in mating and other spiny lobster behavior.

Significantly, many of the healthy lobsters steered clear of infected individuals even before they appeared sick or became infectious, Butler said.

Lobsters inoculated in the lab developed symptoms after six weeks and became infectious two weeks later. Most healthy lobsters avoided those infected starting about four weeks after infection, or two weeks before symptoms.

Rick Cawthorn, a parasitologist specializing in crustaceans at the University of Prince Edward Island, credited "excellent detective work" by the Virginia team in uncovering the virus and the avoidance behavior that seems to prevent the spread of infection. No viruses are known to infect the Atlantic lobsters in the cold waters off Virginia north through the Canadian Maritimes, he said.

The Virginia scientists are now studying how the lobster's avoidance behavior can thwart infection and limit disease in the wild.

Butler said the research may offer a lesson to infectious-disease researchers who fail to consider "the ways individuals can interact with others to lessen the chance of disease."

"This could be sort of a natural barrier some species have to reduce a virus' spread," he said.

Contact staff writer A.J. Hostetler at or (804) 649-6355.