Hong Kong's health authorities stepped up surveillance against the deadly Ebola virus yesterday as a Hong Kong woman who fell ill after visiting Kenya tested negative for the disease. This came as a British man quarantined with fever after a flight from Nigeria tested negative in Birmingham, England, for the virus that is spreading through West Africa in the worst outbreak in history. Hong Kong should remain "highly alert" for Ebola, health minister Dr Ko Wing-man said after leading an emergency meeting with experts to discuss contingency plans in the event of an outbreak. READ MORE: Ebola epidemic unlikely outside West Africa, says scientist who helped discover deadly virus British Foreign Secretary Philip Hammond said the outbreak in Africa posed "a very serious threat" to the United Kingdom. Watch: What is the Ebola virus? Since March, there have been 1,201 cases of Ebola and 672 deaths in Guinea, Liberia and Sierra Leone. "There are no direct flights from West Africa to Hong Kong, but infectors could still be coming to the city by plane," Ko said. "Since Ebola is a very infectious disease, suspected cases will be put into isolation as soon as they are identified." The chairman of the Centre for Health Protection's scientific committee on infection control, Dominic Tsang Ngai-chong, said public hospitals would begin to report and test all those who developed fever after travelling to three affected countries in Africa within 21 days. The patients would be placed in one of 59 isolation rooms at Princess Margaret Hospital in Kwai Chung while their Ebola test results were pending. Cathay Pacific Airways said it was monitoring the situation although it had no direct or connecting flights to West Africa. "We will continue to coordinate closely with health authorities in Hong Kong and in all the airports that we operate flights to," a spokeswoman said. The 39-year-old Hong Kong woman who tested negative developed a fever on Tuesday, a source at Queen Elizabeth Hospital in Jordan said. She was in stable condition in isolation.