Rwanda has placed a German student with Ebola-like symptoms in isolation, and is waiting for test results checking for the deadly tropical disease, the health ministry says.

"Samples from the suspected case have been sent for testing to an international accredited laboratory for approval, results will be available in 48 hours," the health ministry said in a statement on Sunday.

The patient is the first to be tested in Rwanda since the outbreak emerged in west Africa earlier this year. 

This outbreak of the virus, centred on Guinea, Sierra Leone and Liberia, is the worst recorded and has killed nearly 1,000 people. Last week the World Health Organisation declared the epidemic a global health emergency.

Agnes Binagwaho, Rwanda's health minister, said the patient was a German medical student who had recently spent time in Liberia.

He had a fever and malaria but for "100 percent security" Rwanda had quarantined him, until test results were back in two days, Binagwaho said.

Like other nations across east Africa, Rwanda said it had put in place measures against the deadly virus.

"Surveillance systems and emergency management systems have been established," the health ministry said.

"Health workers have been trained across the country and are vigilant."

Hong Kong test negative

As fears of the disease spread, Hong Kong's Centre for Health Protection said on Sunday night that a Nigerian man, earlier suspected of having the virus, had tested negative at the Princess Margaret Hospital.

It was Hong Kong's first suspected case of Ebola, which is spread through blood and body fluid, in the latest outbreak.

The 32-year-old man who had been vomiting and suffering from diarrhoea, both symptoms of the disease, had arrived in Hong Kong on Thursday.

After he went to the Queen Elizabeth Hospital, the man was transferred to the Princess Margaret Hospital and was quarantined there.

According to the centre, the man had never been to Ebola-effected countries such as Guinea, Liberia and Sierra Leone in the past month, nor had he had contact with Ebola-positive patients and animals.

The UK National Health Service website says an infected person will typically develop fever, headache, joint and muscle pain, sore throat and intense muscle weakness.

These symptoms start suddenly, between two and 21 days after becoming infected, but usually after five to seven days.