The U.S. Centers for Disease Control and Prevention are expected to announce Tuesday afternoon that the first case of the Wuhan coronavirus has been reported in the United States. The person was hospitalized with pneumonia last week in Washington State and had recently traveled to Wuhan, China, where the mysterious virus originated last month, according to authorities. The person—whom officials declined to identify but said is quite ill—tested positive for the presence of the virus over the weekend. The disease has infected more than 300 people and killed six. The outbreak has reportedly spread to five countries, including the United States. The head of a Chinese government team of experts said Monday that human-to-human transmission had been confirmed in the outbreak of the virus, which could cause it to spread more quickly and widely. The World Health Organization will reportedly meet tomorrow to decide whether to declare the outbreak an international public health emergency, as information about the virus remains scarce.