A new virus that has killed more than 100 people in the Middle East has been found in the United States for the first time, in an Indiana health care worker who recently returned from Saudi Arabia, federal health officials said Friday.
The man -- whose name, age and exact occupation have not been released -- is in stable condition in an Indiana hospital, said Anne Schuchat, director of respiratory diseases at the federal Centers for Disease Control and Prevention in Atlanta. He is in isolation and receiving oxygen.
A single American case of the virus -- called MERS, for Middle East respiratory syndrome -- is "a very low risk," Dr. Schuchat said. The CDC is not recommending that anyone change travel plans to the Middle East.
But a team from the agency will travel to Indiana to assist in treatment and to retrace the patient's contacts. He flew April 24 from Riyadh, Saudi Arabia, to Chicago via London, and then reached Indiana by bus. He fell ill Sunday and was hospitalized the next day.
The typical incubation period for MERS is five days, and the patient is not known to have infected anyone else. Airline passenger lists will be used to contact everyone who sat near him. But because bus companies often do not know who bought tickets, or who sat where, "that bus ride may be a challenge," said CDC spokesman Tom Skinner.
MERS is a coronavirus similar to SARS, or severe acute respiratory syndrome, which killed hundreds of people, mainly in China, in 2002 and 2003.
The newer virus was first reported in 2012 in Saudi Arabia. Since then, about 400 cases have been reported to the World Health Organization; about a third have been fatal. (The numbers are inexact because of delays in laboratory confirmations.)
The virus is thought to have originated in bats, but it is also widespread in camels. While it has not spread easily between humans, there have been outbreaks within families and in hospitals, where patients have infected paramedics, nurses and doctors.
For unknown reasons, cases began surging in Saudi Arabia in March. Some experts fear that mutations made the virus more transmissible, while others believe that more camels are transmitting it, and that carelessness in hospitals has helped it spread.
The classic symptoms are fever and shortness of breath, which indicates pneumonia, but there have been mild cases and unusual symptoms. The WHO suggests that hospitals test any patient who has returned from the Middle East within 14 days. There have been large recent outbreaks in Saudi Arabia and in Abu Dhabi, United Arab Emirates, and the first case in Egypt was just reported. Cases have also been reported in Jordan, Kuwait, Oman, Qatar, Tunisia and the United Arab Emirates, and there have been isolated cases in travelers returning to European countries.
There is no cure. Patients may be put on ventilators and given antibiotics to prevent secondary bacterial infections, in the hope that their immune systems will slowly defeat the virus.
Scientists going through libraries of antibodies, which can prevent a virus from invading new cells, have found two that attach to MERS. But antibody treatments take time to produce, and there is no vaccine so far.
Travelers to the Middle East have been warned to stay away from farm animals, and camels in particular. Camels are raised for meat and milk, for racing and to haul goods. So-called beauty camels are kept as pets and entered in beauty contests. Experts suspect that raw camel milk and meat transmit the virus. The Saudi government has warned its citizens against consuming either.
Michael T. Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy, said cases might have surged in March because camels are born between November and March. Young camels are most susceptible to the virus and could spread it to their mothers, who are still being milked then.
The WHO is investigating how long the virus can live on surfaces such as bedsheets and hospital equipment. Any hospital with a suspected case of MERS should have all personnel wear masks, gowns, gloves and face shields to prevent breathing in respiratory droplets or contact with bodily fluids.
Although the WHO has not issued travel warnings, Saudi Arabia suggested last year that older Muslims, young children and people with chronic diseases put off making their pilgrimage to Mecca. The next hajj week is in October, but some Muslims also visit Mecca at other times.
The worst recent outbreak of cases has been in Jeddah, Saudi Arabia's second-largest city, which is the gateway for pilgrims arriving by ship or air, but also a commercial center in its own right. A WHO team is investigating cases in Jeddah.
Only a few strains of the virus can jump from camels to humans, but those strains appear to grow best in deep lung tissue, said W. Ian Lipkin, who heads a disease-hunting lab at Columbia University's Mailman School of Public Health. That suggests that it is most easily transmitted in hospitals with respirators or other machines that aerosolize coughs.