No cure exists yet for the deadly Ebola virus disease carrying a fatality rate of up to 90 percent, which has recently plagued countries in West Africa, the first time of the disease's detection in the region. The latest figures show 157 people, including 101 deaths, have been infected with the Ebola virus in Guinea. As of Thursday, 66 cases have been confirmed by laboratory analysis. According to the World Health Organization (WHO), cases were first reported from forested areas in south-eastern Guinea. The outbreak has rapidly evolved and several districts and Conakry have reported cases and deaths caused by the Ebola virus disease. A small number of suspected cases and deaths has also been reported from neighboring countries with all of them having crossed from Guinea. Confirmed cases have been reported from Guinea and Liberia. WHAT IS EBOLA VIRUS Ebola virus was first discovered in 1976 in two simultaneous outbreaks in Sudan and in the Democratic Republic of Congo (DR Congo), taking its name from the Ebola River where the DR Congo outbreak was found in a nearby village. The WHO defines the Ebola virus disease, formerly known as Ebola haemorrhagic fever, as "a severe, often fatal illness" and "one of the world's most virulent diseases." The infection is transmitted by direct contact with the blood, body fluids and tissues of infected animals or people. Severely ill patients require intensive supportive care. During an outbreak, those at higher risk of infection are health workers, family members and others in close contact with sick people and deceased patients. Ebola virus disease outbreaks can devastate families and communities, but the infection can be controlled through the use of recommended protective measures in clinics and hospitals, at community gatherings, or at home. HOW DOES IT SPREAD In Africa, fruit bats are believed to be the natural hosts of Ebola virus. The virus is transmitted from wildlife to people through contact with infected fruit bats, or through intermediate hosts, such as monkeys, apes, or pigs that have themselves become infected through contact with bat saliva or faeces. People may then become infected through contact with infected animals, either in the process of slaughtering or through consumption of blood, milk, or raw or undercooked meat. The virus is then passed from person to person through direct contact with the blood, secretions or other bodily fluids of infected persons, or from contact with contaminated needles or other equipment in the environment. WHAT ARE THE SYMPTOMS Signs and symptoms of the Ebola virus disease often include the sudden onset of fever, intense weakness, muscle pain, headache, nausea and sore throat. This is followed by vomiting, diarrhoea, impaired kidney and liver function, and in some cases, both internal and external bleeding. Laboratory findings frequently include low white blood cell and platelet counts and elevated liver enzymes. The incubation period, the time interval from infection with the virus to onset of symptoms, is two to 21 days. People remain infectious as long as their blood and secretions contain the virus, a period that has been reported to be as long as 61 days after onset of illness. HOW TO DIAGNOSE AND TREAT THE DISEASE Definitive diagnosis of the disease is made through laboratory testing. Because samples from patients are a source of infection risk for others, testing is conducted under maximum biological containment conditions. No vaccine is available, nor is there any specific treatment. Severely ill patients require intensive supportive care. Patients are frequently dehydrated and require oral rehydration with solutions containing electrolytes, or intravenous fluids. HOW TO PREVENT IT Raising awareness of the risk factors for infection and the protective measures that should be taken is the only way to reduce human infection and subsequent deaths, says the WHO. Close unprotected physical contact with Ebola patients should be avoided. Appropriate use of gloves and personal protective equipment (including hand hygiene before putting on, and especially after taking off personal protective equipment) should be practiced when taking care of ill patients at home. Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home. Almost all transmission of the virus to health-care workers has been reported when basic infection control measures have not been observed. Health-care workers caring for any patient should practice standard precautions. When caring for patients with suspected or confirmed Ebola virus infection, health-care workers should apply, in addition to standard precautions, other infection control measures to avoid any exposure to patients' blood and body fluids and with possibly contaminated environments. Preparation for burial of the bodies of persons who have died from Ebola virus disease also carries high risks of transmission of the virus. Those who have died from the disease should be promptly and safely buried.