Writing in The Lancet Infectious Diseases, the researchers say their findings need to be verified by other studies, but meanwhile, detailed case histories should be taken of people who have had MERS to find out if they had been exposed to camels or their milk or meat.

Some researchers praised the study. Dr. W. Ian Lipkin, a virus expert at Columbia University who has been studying MERS, said, “I think it’s compelling evidence that dromedaries are infected with MERS or a related coronavirus.” The study does not prove that the animals have infected humans, he added, but he said it was plausible because people in the Middle East have a great deal of contact with camels as racing animals, pets and sources of food.

William Karesh, a veterinarian and executive vice president of EcoHealth Alliance, a group also studying MERS, said that finding the virus itself in an animal would be stronger and more convincing evidence. But he said the new research was well done and added, “All the clues in a mystery are valuable.”