Researchers have found the first evidence of a respiratory infection – potentially with flu-like symptoms – in a dinosaur that lived 150 million years ago.

The discovery made in the fossilised neck bones of a young diplodocid – a young long-necked sauropod dinosaur like Brontosaurus, allows scientists to better understand the illnesses that affected the animals.

The herbivore, nicknamed “Dolly”, was discovered in 1990 in south-west Montana in the US, and walked the Earth in the late Jurassic Period.

While examining the specimen, researchers identified abnormal bony lumps with an unusual shape and texture that had never been seen before.

They were in the area of the bone where they would have been penetrated by air-filled sacs, Cary Woodruff, of the Great Plains Dinosaur Museum in Malta, Montana, and his colleagues found.

According to the researchers these air sacs would have ultimately connected to Dolly’s lungs and formed part of the dinosaur’s complex respiratory system.

Scans of the irregular protrusions revealed they were made of abnormal bone that most likely formed in response to an infection that could have caused symptoms such as coughing and a fever.

Dr Woodruff said: “Given the likely symptoms this animal suffered from, holding these infected bones in your hands, you can’t help but feel sorry for Dolly.

“We’ve all experienced these same symptoms – coughing, trouble breathing, a fever, etc – and here’s a 150-million-year-old dinosaur that likely felt as miserable as we all do when we’re sick.”

Based on the location of these protrusions, the researchers suggest they formed in response to a respiratory infection in Dolly, which ultimately spread into these neck vertebrae.

The researchers speculate this respiratory infection could have been caused by a fungal infection similar to aspergillosis, a common respiratory illness that affects birds and reptiles today and can lead to bone infections.

According to the researchers, if Dolly had been infected with an aspergillosis-like respiratory infection, it was likely to have experienced flu or pneumonia-like symptoms such as weight loss, coughing, fever, and breathing difficulties.

The infections can be fatal in birds if untreated, and a potentially similar infection in Dolly could have ultimately caused the death of the animal, they add.

Dr Woodruff said: “This fossil infection in Dolly not only helps us trace the evolutionary history of respiratory-related diseases back in time, but gives us a better understanding of what kinds of diseases dinosaurs were susceptible to.”

The findings are reported in the Scientific Reports journal.