Hong Kong and mainland scientists have identified two antibodies that could be "promising candidates" to help develop a treatment for Middle East respiratory syndrome (Mers).
The team, led by Tsinghua University researchers, is turning its experience from the severe acute respiratory syndrome (Sars) outbreak of 2003 to the new virus, which some fear could mutate and become even more deadly - although any cure for Mers remains years away.
Their research has found two antibodies - proteins produced by the immune system to identify and neutralise foreign objects - which bind effectively with the Mers virus and prevent it from entering host cells, cutting off the infection process.
Team member Professor Yuen Kwok-yung, an expert in infectious diseases at the University of Hong Kong, said the results were promising at a time when the virus appeared to be spreading fast, with cases increasing since the middle of last month.
More than 300 cases of Mers - a coronavirus with similarities to Sars - have been diagnosed since it was identified two years ago, and 40 per cent have been fatal.
About 75 per cent of cases are from human-to-human transmission.
Scientists believe the virus may have spread from bats to humans via camels - much as Sars is thought to have spread to humans through civet cats.
"If that is indeed the case, the Mers coronavirus may undergo further genetic changes and one day become as transmissible as the Sars coronavirus," Yuen said.
"Therefore we must prepare for this scenario before it happens."
Sars infected more than 8,000 people around the world over the course of nine months in 2002 and 2003. One-fifth of the cases and 299 of the 774 deaths were in Hong Kong.
The team discovered that antibodies could form the basis of an effective treatment through their research into Sars and the 2009 swine flu outbreak.
They studied antibodies from 58 people contained in a US "library" of human antibodies, by putting them together with the Mers virus. Two of them bound to the virus' surface protein.
Mers has not yet spread to Hong Kong, though local doctors have been instructed to watch for symptoms and tourists travelling to affected areas have been told to exercise caution.