The second wave of SARS began when some complicated SARS cases from satellite cities were transferred to the major hospitals in Guangzhou for better medical care. The index case in Guangzhou was a seafood merchant who was admitted in late January of 2003. After staying in the hospital for 18 hours, more than 30 hospital staff were infected. Family members and relatives of the patient who had close personal contact with the patient had also become ill with the disease. This index case caused many secondary infections that further spread and gave rise to the outbreak in Guangzhou.