The Emergence of Human Coronavirus EMC: How Scared Should We Be?

Chan, Renee W. Y.; Poon, Leo L. M.

It is not known whether HCoV-EMC is going to be fully established in humans. Extensive efforts have been made and will continue to be needed to fight against this possible epidemic. If we are "lucky" enough to control this novel disease, more resources should be allocated to different areas of coronavirus studies. Currently, we know some animal coronaviruses in wildlife only at the nucleotide level. In fact, the number of bat species tested for coronaviruses is only a fraction of the total number (Ͼ1,200) of bat species. In addition, there is a lack of biological/biochemical characterization of these animal viruses. Ideally, we should develop an effective universal strategy to treat and prevent human infections caused by animal coronaviruses. The phylogenetic relationships of coronaviruses (Fig. 1) suggest that there have been a number of introductions of animal coronaviruses (e.g., SARS-CoV and 229E) into humans in the past. The great diversity of coronavirus in bats will surely increase the odds of yet another zoonotic event occurring in the future.