at a Jan. 24, 2020, press briefing.
The first U.S. case, a traveler who entered the United States at Seattle-Tacoma International Airport, was confirmed on Jan. 20.
A Chicago resident returning from Wuhan, China, on Jan. 13, 2020, developed symptoms of the disease and contacted her health care clinician and is currently being treated in isolation at an unnamed hospital, according to, director of the National Center for Immunization and Respiratory Diseases at the CDC. The patient, a woman in her 60s, is in stable condition and remains hospitalized. She was not symptomatic on her flight to Chicago but developed symptoms in the following days after her return from Wuhan. She had limited contacts after her return, and all potential contacts are being tracked.
Dr. Messonnier said the CDC expects more cases in the United States but stressed that, although this is a serious public health threat, the risk to the American public is low. She noted that the situation is evolving rapidly and that the CDC is following the developments hour by hour.
, chief medical officer and state epidemiologist with the Illinois Department of Public Health, said public health preparations made it possible to quickly identify and arrange appropriate hospitalization for this patient. , Chicago Department of Health commissioner, said the Illinois Department of Health partnered with the CDC to test specimens quickly, which led to the diagnosis in this patient.
So far, 63 U.S. patients have been investigated for possible infection with the 2019-nCoV; 11 so far have tested negative and 2 have tested positive. Testing of the remaining potential cases and others is ongoing.
Currently, samples from patients with suspected 2010-nCoV infections are being sent to the CDC for testing, Dr. Messonnier said. The turnaround for testing is currently 4-6 hours. Respiratory samples and some blood samples are being tested by the CDC labs.
The CDC is developing diagnostic kits for public health authorities in the United States for local testing and will work with the World Health Organization to make these kits available to the international community when possible.
Dr. Messonnier said that, at present, the incubation period for this disease appears to be about 14 days, but she suggested that further study will be required to identify the range of time for contagion. She also said it is premature to compare the 2019-nCoV with previous coronavirus outbreaks, such as severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS), in terms of contagion or fatality rates.
Meanwhile,, the Walther Professor in Cancer Structural Biology and head of the department of biochemistry at Purdue University, West Lafayette, Ind., said on Jan. 24 in a that 2019-nCoV is genetically similar to the SARS variant. “MERS virus and the SARS virus are more different genetically,” noted Dr. Mesecar, whose team received the genome of 2019-nCoV on Jan. 17 and analyzed it the next day. “But the Wuhan virus is genetically almost identical to the SARS virus and, therefore, it is expected to look and act nearly the same. In another week or two, we’ll be able to begin to see if the virus is mutating.”
Dr. Messonnier said that nonessential travel to Wuhan is not recommended. In addition, she said, and all other visitors to China need to take appropriate precautions, such as handwashing and avoiding other individuals with respiratory illness.
Screenings at five U.S. airports will continue. So far, approximately 200 flights and 2,000 travelers have been screened as of Jan. 23. No cases were reported, but one traveler has been identified for further for evaluation. Possible contacts with those suspected of infection have been identified and alerted in 22 states.
The CDC will continue to update the public and will post information on the CDC newsroom.