The first US case of Middle East Respiratory Syndrome (MERS) has been confirmed after an American health worker was hospitalised in Indiana after returning from Saudi Arabia.
The man was diagnosed with the disease after arriving in the US from the kingdom, officials said on Friday.
The Centres for Disease Control and Prevention are investigating the US case to track down anyone the patient had been in close contact with recently.
The recent diagnosis highlights growing concerns over the virus spreading beyond the kingdom's borders as more cases are reported.
The news comes just after Saudi Arabia announced that its number of MERS cases had doubled in April with 26 new diagnoses reported on Tuesday and Wednesday.
Millions of pilgrims are also set to visit the kingdom during the fasting month of Ramadan in July, followed by millions more for the annual Islamic Haj pilgrimage in October.
Questions over transmission
Of the 371 people who caught the disease in Saudi Arabia, 107 have died since it was identified two years ago.
While the World Health Organisation (WHO) has said the disease, which is from the same family as the SARS virus, is difficult to pass between humans, most of the cases reported in Saudi Arabia have been transmitted between people rather than from animals.
But health experts believe that animals, most likely camels, were the initial source of the illness.
On Tuesday acting health minister Adel Fakeih said Saudis should avoid close contact with camels, or consuming their raw milk or meat.
Traders and others at Riyadh’s camel market on Monday said they had not been officially notified of any link between MERS and camels or of any precautionary measures to be taken, according to Reuters.
Saudi Arabia and the WHO have advised very old people, children and those suffering long-term disease to delay their Haj this year because of MERS, but have stopped short of imposing other restrictions such as on visa numbers.
MERS cases have also arisen in Qatar, Kuwait, Jordan, the United Arab Emirates, Oman and Tunisia as well as several countries in Europe.