He has analysed, monitored and responded to several emerging infectious diseases, including the SARS outbreaks of 2003 in China, Hong Kong and Canada, the subsequent H5N1 bird flu in South East Asia and Egypt, H1N1 flu in Egypt, nipah virus in Bangladesh, MERS in the Middle East and Republic of Korea, Ebola in Western Africa, Zika in Brazil, yellow fever in China, chikungunya in Pakistan, H7N9 in China and plague in Madagascar, followed by the 2018–20 Ebola epidemic in the Democratic Republic of the Congo and the ongoing pandemic of coronavirus disease, caused by SARS-CoV-2, which began in 2019.