Portsmouth scientists discover new brain-altering parasite

University of Portsmouth marine biologist Dr. Alex Ford examines a shrimp infected by a trematode parasite Credit: University of Portsmouth

Scientists in Portsmouth have discovered a new species of a brain-altering parasite.

Marine biologist Dr Alex Ford at the city's university found amphipod shrimps in Langstone Harbour were infected with worm-like parasites that changed their behaviour to make them swim into the light, where they're more likely to be eaten.

The new species - which has not yet been named - is a type of parasite that lives inside a succession of hosts before eventually being consumed by birds. The parasite's eggs are then expelled in the birds' faeces, allowing a whole new life cycle to begin.

The research, published in Parasitology journal, showed that a hormone, serotonin, produced during the infection made the shrimp want to swim away from darkness and towards light.

Scientists are still investigating whether the serotonin is produced by the parasite or if the parasite's physical presence alters the shrimp's brain chemistry.

The study, funded by the Natural Environment Research Council (NERC), mapped the population of the shrimp in the harbour over 18 months, identifying the parasite as a previously unreported species.

According to Dr Ford, this is only the second trematode species recorded that manipulates the behaviour of its shrimp host.