Wuhan virus: Coronavirus spreading in Munich shows difficulty in halting new bug

(BLOOMBERG) - A business event in Munich set off a chain of coronavirus infections that began with an infected colleague from Shanghai who showed no symptoms during a trip to the German city. It is the largest reported cluster of cases caused by human-to-human spread outside China.

Five employees from a German auto-parts supplier have been infected with the new coronavirus, the cause of a massive pneumonia outbreak in China that the World Health Organisation declared a global emergency on Thursday (Jan 30).

The infection appears to have been transmitted during the incubation period of the virus in a Shanghai-based colleague. The woman attended meetings from Jan 19 to 22 near Munich with no signs or symptoms of infection, but she became unwell on her Jan 22 flight back to China. She tested positive for the 2019-nCoV virus four days later, doctors said in the New England Journal Of Medicine on Thursday.

The cases show the difficulty of controlling the contagion using methods such as fever-screening at airports. Almost 10,000 people across 20 countries are confirmed to have been infected with the new virus, which was first reported in the central Chinese city of Wuhan a month ago.

"The fact that asymptomatic persons are potential sources of 2019-nCoV infection may warrant a reassessment of transmission dynamics of the current outbreak," Dr Camilla Rothe and colleagues at the University Hospital LMU Munich said in a letter to the medical journal.

The first four cases in Germany had "mild" symptoms and were hospitalised primarily for public health purposes, the doctors said. They queried "whether such patients can be treated with appropriate guidance and oversight outside the hospital".

The first of the German cases occurred in an otherwise healthy 33-year-old businessman, who became ill with a sore throat, chills and muscle ache last Friday. He had a fever and a cough the next day, but by the evening of the following day, he started feeling better and went back to work on Monday, the same day his China-based colleague told company officials that she was ill.

Swabs of the back of the man's nose and throat, and a sputum sample tested positive for 2019-nCoV. Follow-up tests found that he still harboured high levels of the virus in his sputum on Wednesday, a day after three other employees tested positive, including two who had not been in contact with the colleague from China.

All the patients with confirmed 2019-nCoV were isolated in a Munich infectious diseases unit.

The Bavarian Ministry of Health reported the fifth related case late on Thursday, and said it would release more details on Friday.