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New study uncovers why vultures don’t get sick from eating rotten carcasses

  • Researchers sequenced genome of the cinereous vulture or the Eurasian black vulture and compared it to that of the closely-related bald eagle.
  • Study found the cinereous vulture has variations in genes associated with their immune system, as well as genes associated with gastric acid secretion in their digestive tract.
  • The immune system genes identified could be useful targets in humans for protection against infection, researchers say.
A vulture breeds in a mongo nest. Photo by Woon Kee Paek.

We may cringe at the thought of diving our heads into a rotting carcass. But vultures relish such putrid meals. In fact, by removing carcasses, vultures prevent diseases from spreading to other animals. But the scavengers themselves do not normally get sick from eating decaying carcasses teeming with pathogens. Why?

The secret lies in their unique sets of genes that give them super-strong stomachs and immune system, a new study published in Genome Biology has found.

Vultures can eat flesh of an animal coated with the anthrax bacteria, co-author Jong Bhak from Ulsan National Institute of Science and Technology, told Reuters. He added that the scavengers “can also eat meat infected with rabies and many other diseases that would otherwise be lethal to many other scavengers.”

To find out what adaptations may have helped vultures thrive on putrid meat without falling ill, researchers from 14 institutions sequenced the genome of the near-threatened cinereous vulture or the Eurasian black vulture (Aegypius monachus), and compared it to that of the closely-related bald eagle (Haliaeetus leucocephalus).

The team found that the cinereous vulture had variations in genes associated with the immune system, as well as genes associated with gastric acid secretion in their digestive tract.

Cinereous vultures have super powerful digestive and immune systems that help them eat decaying carcasses without falling ill. Photo by Woon Kee Paek.

Selection of the genes linked to gastric acid production suggest that “the acidic gastrointestinal tract of vultures is a strong filter of the microbiota ingested from decaying carcasses, which likely plays a role in enabling the vulture’s scavenging lifestyle,” the authors write.

Moreover, genes linked to the immune system may play a role in combatting pathogens that come with the decaying meal, the team speculates, complementing the role of gastric secretion.

“This is the first Old World vulture genome that has been reported, and we can see that the cinereous vulture has genetic signatures for resisting infection from eating decaying flesh,” Bhak said in a statement.

Understanding the genetic make-up of such extreme life forms has potential for improving human health, he added. “The immune system genes we’ve identified could be useful targets in humans for protection against infection.”

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