The China Country Office of the World Health Organisation has reported cases of pneumonia of unknown etiology (unknown cause) detected in Wuhan City, Hubei Province of China. A  total of 44 patients with pneumonia of unknown etiology have been reported to WHO by the national authorities early January. Out of the total cases detected so far, 11 were severely ill, while the remaining 33 patients are in stable condition. The causal agent has not yet been identified or confirmed. National authorities report that all patients are isolated and receiving treatment in Wuhan medical institutions. The clinical signs and symptoms are mainly fever, with a few patients having difficulty in breathing, and chest radiographs showing invasive lesions of both lungs. Based on the preliminary information from the Chinese investigation team, no evidence of significant human-to-human transmission and no health care worker infections have been reported.