The close relative of SARS appeared out of thin air, poised to descend on humanity like wildfire. Then, just as abruptly as cases had appeared, they disappeared — the reports, not the sick people, it would seem.

Edited: This story was edited on Jan 21 to add US cases and after for clarity and brevity.

The close relative of SARS appeared out of thin air, poised to descend on humanity like wildfire. Then, just as abruptly as cases had appeared, they disappeared — the reports, not the sick people, it would seem. A week later, cases arose in Thailand, Japan, Korea, and the US.

China, believing animal markets to be the source, shut them down for cleaning on Jan 1, 2020, but multiple cases reported not having visited the animal markets. The Wuhan Municipal Health Commission reported 59 cases of this pneumonia on Jan 5, 2020. Vendors at local markets were among the sick, so follow-up with anyone who had contact may be impossible, and people may be reluctant to seek help or not realize what they have.

The WHO lists 63 reported cases in China, but whether the country officially confirms it is unclear. Appearing as fever, chill, and muscle pain, the virus complicated breathing in the original outbreak victims. Doctors found fluid called “pulmonary infiltrates” in their lungs, a substance that is denser than air, often blood and pus.

China reports no cases after Jan 3 in a Jan 11 statement, but Japan, Thailand, and now Korea all confirm cases of travelers to China (Wuhan Municipal Health Commission, 2020; WHO, 2020).

The woman flew from Wuhan City, China, to Thailand in a packed airplane on Jan 8, 2020. Monitoring continues for at least 182 people who met the woman.

Japan also found the virus in a Japanese citizen who recently traveled to Wuhan City, China. DNA testing identified it as 2019-nCoV. Hirofumi Umeda from the Infectious Diseases Information Division in Japan confirmed the details of the cases on Jan 15, 2020.

The Korean case today casts doubt on the Chinese report of no new infections. None report traveling to the animal markets, not the Korean woman, nor the Japanese or Thai people.

The Korean case showed symptoms starting Jan 18 in Wuhan City, China, where a doctor diagnosed the woman with a cold before she traveled to Korea through Incheon International Airport. The Korea Centers for Disease Control found the virus through DNA testing (WHO, 2020).

Most worrying, the Wuhan doctor diagnosed a Korean woman on Jan 18 with a cold (WHO, 2020). How many more cases are there?

The estimated numbers exponentially outnumber China’s reported incidents, and SARS makes clear that we must be cautious about the reliability of reporting.

The dates of infection and travel give pause.

Potentially, human-to-human like SARS. SARS Coronavirus incubation took 4 to 6 days, with extremes of 2 to 14 days. That suggests this virus has already spread into the community, meaning we must contemplate the possibility of many more cases in Asia — and in the US. Cases almost certainly extend beyond the recognized number.

Air droplets can suspend in the air for hours after an infected person has left. Finding everyone who trekked through airports seems unlikely. SARS had an infamous ability to capitalize on super-spreaders. An airplane with one case could become an airplane with tens of cases by the flight’s end.

Nothing indicates that mild infections cannot happen, meaning infected people may be totally unaware. This is most worrying given that a Wuhan doctor diagnosed the woman on Jan 18 with a cold. How could he have missed this? Who else has been missed?

The expected numbers are much higher than the numbers reported, which has potentially grim implications.

Imperial College London, a leader in global epidemiology, published a report on Jan 17 that affirmed my fear — only a student, I lack confidence in my conclusions:

Originally published on January 20, 2020.