Kenya has confirmed its first imported Ebola case. Here is what the disease is and why health officials are on alert.

Ebola is a severe viral illness that spreads through direct contact with the bodily fluids of infected people, living or dead. Symptoms include fever, vomiting, diarrhoea and, in severe cases, internal and external bleeding. The Kenya case involves the rare Bundibugyo strain.

The patient, a Kenyan who had lived in the Democratic Republic of Congo for seven years, fell ill about a month ago, travelled to Nairobi via Uganda, and died on Monday night. Kenya has identified 28 contacts and is tracing fellow flight passengers, with quarantine for those at risk.

The DRC is facing its largest-ever Bundibugyo outbreak, with more than 8,000 cases and 4,000 deaths, according to Reuters. Nigeria has heightened surveillance. There is no specific cure; treatment is supportive care. Health agencies stress early isolation, contact tracing and safe burial practices to stop the spread.