Aware of such dangers, Zhou keeps himself safe as best he can. He always keeps three areas of his clothing tight, his collar, wristbands and the legs of his trousers.

In winter, Zhou rejects all social activities and just sits in front of his computer to write. He has collected a huge amount of firsthand information and wanted to write it all down in the form of books. "Also, I had to make sure that my words are beautiful and precise," he says.

Zhou's book on medicinal plants in Northeast China has been published by Heilongjiang Science and Technology Press, after five years of editing, proofreading and designing by over 30 staff members.

According to Xiang Lifu, editor of the book, the company published a book on medicinal plants in Northeast China in 1989.

"It was published in a black-and-white version, with mostly words. Even though it is a bit hard for readers to refer to the book to identify plants in the wild, it has long been sold out as it was useful to people specializing in the field then," Xiang recalls.