Coronavirus has been declared a global health emergency by the World Health Organization (WHO).
The warning, known as a ‘public health emergency of international concern’, is the highest alert the UN health agency can give.
Just one week ago, the organization decided to hold off the declaration as there was no evidence of human-to-human evidence outside of China.
This has changed with the first person-to-person case of coronavirus being confirmed in the US after a man in Chicago was infected from his wife, who traveled to China.
The man’s wife, who is in her 60s, became the second American after she returned from a trip to Wuhan, the epicenter of the outbreak.
Her husband has now tested positive for the virus, the Centers for Disease Control and Prevention (CDC) revealed on Thursday.
Previously, all confirmed US cases had been in patients who travel to Wuhan, where an outbreak has been ongoing since December 2019.
However, there have been cases of human-to-human transmission reported outside of China, including in Germany, Japan, Taiwan and Vietnam.
The four other cases have been confirmed in Maricopa County, Arizona; Orange County and Los Angeles County California; and Snohomish County, Washington.
Currently, 168 cases are under investigation in at least 26 states – 21 of those alone in Illinois.
The CDC say it is likely that more cases of the virus, known as 2019-nCoV, will be reported in the next several days and weeks.
Signs and symptoms of the illness include fever, cough, and shortness of breath, with 20 percent of cases becoming severe.
Meanwhile in China, the coronavirus death toll has risen to 170 as of Thursday afternoon and several countries – including the US and UK – have advised against non-essential travel to the nation.