A leading Chinese respiratory expert who was infected by the Wuhan coronavirus while visiting the city last week said inadequate eye protection might have been the cause.
Wang Guangfa, a respiratory specialist from Peking University First Hospital in Beijing, confirmed his infection and subsequent recovery on his personal Weibo account on Wednesday.
He caught the public's attention two weeks ago when he told media that the Wuhan outbreak was "preventable and controllable".
Wang, who returned to the capital before falling ill, said on the Twitter-like platform that he was getting better and his fever had gone after a day.
"I have the energy to browse WeChat [China's most popular messaging app], text messages and the internet. I am touched to see so many people's blessings and encouragement for me."
Wang was regarded as one of the heroes in China's fight against severe acute respiratory syndrome, or Sars, in 2003.
He said he knew that he had been ridiculed in some quarters, including elements of the Hong Kong media, for saying the disease was controllable and then falling ill himself.
But he insisted it was still possible to control the disease but said stronger measures may be needed, adding that the situation in Wuhan was different to that in other areas.
The handling of the initial outbreak, linked to the Huanan Wholesale Seafood Market, had been "swift and efficient", he said, adding that the pathogen had been quickly identified, which was a major improvement compared with the Sars outbreak.
He said it was difficult to reach an early conclusion about how quickly the virus would spread and how vulnerable people were to infection because the experts did not have all the information they needed.
"Before I went back to Beijing, while visiting some fever clinics, I realised the situation had apparently deteriorated," he said.
"However, it is still preventable and controllable, although society will have to pay a price for that," he said, arguing that the measures needed to control the disease could affect everything from personal relationships to the economy.
Wang said he had been trying to work out how he became infected after visiting fever clinics and temporary isolation wards in Wuhan.
"At that time we were highly vigilant and wore N95 masks," he said. "But then I suddenly realised that we didn't wear protective glasses."
He said that after he returned to Beijing, his left eye developed conjunctivitis and two to three hours later he started to come down with a fever and catarrh.
He said he initially thought he had the flu because he had not seen any Wuhan patients with conjunctivitis. But anti-flu treatments proved ineffective and he continued to suffer intermittent fevers.
Wang said the most likely explanation was that the virus had entered his body through his eyes.
Li Lanjuan, a member of the National Health Commission's senior-level expert panel who visited Wuhan over the weekend, told Beijing Youth Daily that medical staff needed to wear protective glasses given that they had direct contact with fever patients, but ordinary people only needed to wear face masks.
She also told the newspaper that researchers were working on a vaccine for 2019-nCoV.
This article was first published in South China Morning Post.