Summary:
The number of people killed by the Ebola virus in western Africa has passed the 1,000 mark.

Full article:
(CNN) -- A total of 142 deaths have been reported from the Ebola outbreak in Guinea and Liberia, the World Health Organization said. The virus is still limited to the two nations, the World Health Organization said Tuesday, despite rumors of it spreading to other countries. Nineteen suspected cases reported in Sierra Leone tested negative for the virus, it said. In a statement on its website, WHO said Guinea has reported a total of 208 clinical cases of Ebola, including 136 deaths. Liberia has reported 34 cases, including six deaths. Ebola is one of the world's deadliest viruses and kills up to 90% of those infected. It spreads in the blood and shuts down the immune system, causing high fever, headache and muscle pain, often accompanied by bleeding. It's the first emergence of Ebola in western Africa, which means doctors and health officials in the region don't have any experience with the virus. The aid organization Doctors Without Borders has called the outbreak unprecedented because previous cases have been limited to a small area. The virus is named after the Ebola River in the Democratic Republic of Congo. We're aliens in Ebola's world . A swift, effective and bloody killer . Why does it kill?