A novel virus has been identified as the possible cause of a common but mysterious disease that kills a significant number of pet snakes all over the world, thanks to research led by scientists at the University of California, San Francisco (UCSF) -- and three snakes named Juliet, Balthazar and Larry. The virus, previously not thought to infect snakes at all, appears to cause "inclusion（包含） body disease." Long the bane（毒药，祸害） of zoo officials and exotic pet owners, the deadly illness spreads among boas（蟒蛇） and pythons in captivity, causing micro clumps of clustered proteins to form inside the snake, leading to bacterial infections, neurological problems, anorexia（厌食） and withering, leading to death.

The new work, described this week in the American Society for Microbiology's new open-access journal mBio, paves the way toward developing diagnostics and treatments, which may make it possible to eradicate the disease from snake collections worldwide.

"It's a devastating disease when it gets into a collection, zoo or aquarium because it's essentially fatal every time," said Joe DeRisi, PhD, the senior author of the study, a Howard Hughes Medical Institute investigator (HHMI) and vice chair of the Department of Biochemistry and Biophysics at UCSF.

Surprisingly, he said, the cause of the illness appears to be a completely new set of viruses of a type known as an arenavirus（沙粒病毒）. The discovery came as a complete a shock to the team of scientists because, while arenaviruses are common in rodents and cause extremely nasty infections in other mammals, nobody knew they could infect reptiles.

"Now we have found that they infect snakes, as well," said Mark Stenglein, PhD, a postdoctoral fellow at UCSF who is the first author on the paper.

Stenglein, DeRisi and their colleagues isolated at least two strains of the arenaviruses from half a dozen snakes afflicted with inclusion body disease. They could find no traces of the same viruses in snakes that were free from disease.

Arenaviruses infect mostly rodents but occasionally people, and can cause fatal hemorrhagic diseases like Lassa fever, which kills thousands of people every year in Africa. There is no evidence, however, that a snake has ever transmitted an arenavirus infection to a person despite the fact that snake owners and veterinarians（兽医） handle infected snakes all the time, said DeRisi.