European and Asian countries went on alert on Wednesday amid growing fears that the West African Ebola outbreak could spread to other continents as medical charity Doctors Without Borders warned the epidemic was out of control.
The doctor leading Sierra Leone's fight against the worst Ebola outbreak on record died from the virus on Tuesday, the country's chief medical officer told Reuters.
Sheik Umar Khan died less than a week after his diagnosis was announced. The doctor was credited with treating more than 100 patients.
His death came after the deaths of dozens of local health workers and the infection of two American medics in neighbouring Liberia, highlighting the dangers faced by staff trying to halt the disease's spread across West Africa.
As of July 20, the number of Ebola cases recorded in the months-long epidemic stood at 1,093, including more than 660 deaths, according to the World Health Organisation.
Guinea, Liberia and Sierra Leone have borne the brunt of the recent epidemic. Nigeria, Africa's most populous country, recorded its first death on July 25.
Here's what you should know about Ebola, one of several viruses responsible for haemorrhagic fever.
1. The World Health Organisation (WHO) calls it "one of the most virulent diseases known to humankind".
2. It can kill up to 90 per cent of the people who are infected.
Five "species" of Ebola have been identified so far, and have been named Bundibugyo, Sudan, Zaire, Tai Forest and Reston. The first three are particularly dangerous, with fatality rates of up to 90 per cent.
The Zaire is the one at the heart of the current epidemic. The Reston species has also been identified in China and the Philippines, but no associated deaths have been reported in those countries to date.
3. The virus first appeared in 1976 in Nzara, Sudan and in Yambuku, Democratic Republic of the Congo.
It took its name from the Ebola River, which was near the village in Yambuku where the outbreak occurred.
4. Ebola can be caught from both humans and animals.
It is transmitted through close contact with blood, secretions or other bodily fluids. Fruit bats are considered to be the natural host of the Ebola virus.
5. It spreads quickly through human-to-human transmission, as family and friends care for infected people.
Healthcare workers have frequently been infected while treating Ebola patients.
The virus has also been known to spread at burials where mourners touch the body.
6. Symptoms can appear from two to 21 days after exposure.
Early symptoms such as rashes and red eyes are common, making it hard to diagnose in the early stages.
7. The virus spreads in the blood and paralyses the immune system.
Ebola is often characterised by the sudden onset of fever, intense weakness, muscle pain, headache and sore throat.
This is followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, both internal and external bleeding such as from the nose or via a person's urine.
8. There is no specific treatment or vaccine available to people or animals.
With no vaccine, patients believed to have caught the virus must be isolated to prevent further contagion.
Sources: WHO, Medecins Sans Frontieres, Reuters, AFP
This article was first published on April 2, 2014, and updated on July 30, 2014.
This article was first published on July 30, 2014. Get a copy of The Straits Times or go to straitstimes.com for more stories.