But Texas health officials said they did not believe that a deputy sheriff who was admitted to hospital after suffering possible Ebola symptoms was at risk of the disease.
Sergeant Michael Monnig had entered the Dallas apartment of Thomas Eric Duncan, a Liberian man who died of Ebola in Texas this week. Doctors said that he was being treated out of an "abundance of caution".
Zimbabwe also experienced an Ebola scare when the main infectious disease hospital in Harare was closed following the admission of a Congolese student who was vomiting and bleeding. That case also turned out to be a false alarm as the young woman later tested positive for malaria.
In Prague, however, a 56-year-old Czech man with Ebola symptoms was being tested for the virus yesterday. A spokesman for the Bulovka hospital said the man, who had recently travelled in Liberia, was in isolation, and that tests had been carried out and sent to a laboratory in Berlin. Results should be known today, he said.
In New York, cabin cleaners at LaGuardia Airport went on strike partly because of fears about the risk of Ebola, saying they were not receiving the proper equipment or training.
"The workers are really worried because they tend to be exposed to bodily fluids, including by cleaning out bathrooms on airplanes," said Amity Paye, a union spokesman.
The union is holding its own training sessions, claiming that the airlines are not preparing workers to handle airplanes that might carry Ebola-contaminated material.
The US Government will this weekend begin checks at five major airports of the temperatures and health histories of passengers who began their journeys in Guinea, Sierra Leone and Liberia.
More than 8000 people in west Africa have so far officially been diagnosed with Ebola and the fatality rate is nearly 50 per cent. But the World Health Organisation believes the true tally of infected and dead is much higher.
Meanwhile, the first trial of an Ebola vaccine in Africa started in Mali with the vaccination of three health care workers. The vaccine, one of several now being tested, was developed at the US National Institute of Allergy and Infectious Diseases and a consortium led by the University of Maryland is carrying out the trial.
Mali has not experienced any Ebola cases but medical experts want to conduct the trials in the region that has been hit by the crisis. Tests are also expected to begin in Gambia soon.
Plane passenger's joke sets off alert
A full-scale alert was sparked when a man on a flight from the United States to the Dominican Republic joked, "I have Ebola! You are all screwed."
Passengers were ordered to stay in their seats as emergency medical teams dressed in protective suits boarded the aircraft at Punta Cana airport to confront a traveller who had been coughing during the trip from the US.
A few minutes later the man, said to be a 54-year-old from the US, was escorted from the US Airways aircraft protesting, "I ain't from Africa. S***."
The Dominican authorities said after an investigation that they were satisfied the passenger had been making a joke.
- Independent