People who do not show symptoms of novel coronavirus may still spread infection, researchers claim

People who do not show any symptoms of being infected by the novel Chinese coronavirus may spread it to others, according to a report published by researchers which, if confirmed, may make it harder to contain the virus that has so far killed 213 individuals, and infected nearly 9,700 others.

According to a case report, published in The New England Journal of Medicine, a 33-year-old, otherwise healthy German businessman became ill with a sore throat, chills, and muscle pain on January 24.

On the following day, he developed a fever of about 39 degree Celsius, along with wet coughs, the researchers, including those from the University Hospital LMU Munich in Germany, said.

By the evening of the next day, he started feeling better and went back to work on January 27, the report stated.

However, on January 20 and 21, he had attended meetings in Munich, Germany with a Chinese business partner, who had visited Germany between January 19 and 22.

According to the report, she had been well with no signs or symptoms of infection during her stay in Germany, but had become ill on her flight back to China, where she tested positive for the coronavirus (2019-nCoV) on January 26.

She informed the company about her illness, and the German businessman was sent to the Division of Infectious Diseases and Tropical Medicine in Munich for further assessment, the report added.

"At presentation, he was afebrile and well. He reported no previous or chronic illnesses and had no history of foreign travel within 14 days before the onset of symptoms," the scientists wrote in the report.

However, samples tested from his respiratory tracts revealed they were positive for the coronavirus.

Further assays found that he had a high load of 108 copies of the virus per millilitre in his sputum during the following days, with the last available result on January 29, the report stated.

According to the researchers, three additional employees at the company tested positive for the coronavirus on January 28.

All the patients with confirmed 2019-nCoV infection were admitted to a Munich infectious diseases unit for clinical monitoring and isolation with none of the four confirmed patients showing signs of severe clinical illness, the report said.

The researchers believe that the infection may have been transmitted during the incubation period of the index patient, the German businessman, in whom the illness was brief and nonspecific.

They cautioned that people who do not show symptoms of infection may also be potential sources of 2019-nCoV, warranting a reassessment of transmission dynamics of the current outbreak.

However, the scientists added that all four patients who were seen in Munich had mild cases, and were hospitalised primarily for public health purposes.