Great white sharks are washing up dead on beaches with enlarged brains in what is becoming a spiralling marine mystery.

Scientists in Canada and the US are becoming increasingly alarmed by the spike in deaths and what is causing the inflammation.

In over 30 years, the Canadian Wildlife Health Cooperative (CWHC), which studies wildlife health issues, had never come across a dead white shark.

But in August 2023, a great white was found dead on a beach in a national park on Prince Edward Island, Canada with no signs of injury, puzzling scientists.

The cause of death was eventually found to be meningoencephalitis, an inflammation of brain tissues that eventually disrupts normal cognitive functions.

Four more great white sharks then appeared on beaches in eastern Canada.

“Three of these five seem to have the same potentially infectious disease affecting their brain,” Dr Megan Jones, a veterinary pathologist and regional director of the CWHC told The New York Times.

“We need to know more about what that is,” she added.