People infected with a deadly virus that emerged in Saudi Arabia last year may have caught it from one-humped camels.
Scientists say they have found strong evidence that coronavirus is widespread among dromedary camels in the Middle East.
The virus can cause coughing, fever and pneumonia and has been reported in humans in the Gulf, France, Germany, Itally, Tunisia and Britain.
The World Health Organisation says 46 people have died from the virus.
Study leader Chantal Reusken, of the National Institute for Public Health and the Environment in the Netherlands, says different types of contact between humans and the animals could lead to the transmission of the virus, Reuters reports.
Experts not involved in the study have hailed its findings as a major step towards solving the mystery of the virus and, ultimately, controlling it.
The World Health Organisation has also welcomed the study but says it has not provided any insight into how humans become infected.
Most of those with the disease who were not infected by other humans did not have contact with camels either.
