Scientists at the University of Portsmouth in the United Kingdom discovered a new species of parasite that is capable of altering the brain of other creatures it infects.
In a new study published in the journal Parasitology, Dr. Alex Ford, a marine biologist from Portsmouth, observed that a species of worm-like parasite was able to change the behavior of amphipod shrimps found in Langstone Harbor.
The tiny creatures infected the shrimps and then proceeded to alter their brain to make the shrimps swim into the light. This effectively allowed other animals, such as birds, to easily eat the mind-altered shrimps.
The new parasite species, which is yet to be named, can be found living inside the bodies of a succession of host creatures before being eaten by birds. The eggs of these parasites are then expelled along with the feces of the birds in order to begin a new life cycle.
Ford and his team noted that a hormone known as serotonin is what caused the behavioral changed in the shrimps. The hormone is produced during the parasites' infection of its prospective host.
They have yet to determine whether hormone is produced by the parasite species itself or if its microorganism's physical presence is what alters the brain chemistry of the shrimp.
While serotonin has long been known to control the behavior of animals, including humans, the response observed on the shrimps, which was to move toward the light, appear to be a unique trait of crustaceans.
The University of Portsmouth study mapped the shrimp populations in Langstone Harbor for more than 18 months to identify the new parasite species.
"We think we know all the species that live on our doorstep, so it's really exciting when we find a new one," Ford said.
"I expect that shores around the UK will be harboring other parasites that are completely unknown to science at the moment."
Ford added that the newly-discovered parasite is only the second species of trematode ever found that is capable of manipulating the behavior of its host.
The study showed that the presence of the parasite had a significant impact on the population of shrimp.
Ford explained that when the number of the parasites goes up, the host's numbers typically goes down. This corresponds to the idea that the parasite species wanted its host to be eaten by the birds because it needed to infect the animal to begin a new life cycle.
He said that when they tried to place the shrimps in dark or light environments, those that were infected with the parasites chose to go to the light while the ones that were not infected stayed in the dark.
Ford said that their research is designed to identify which specific genes are associated with the hormone serotonin have been changed by the parasite.
