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Should Americans or other people around the world be concerned about an Ebola virus outbreak?
A deadly Ebola virus outbreak has been reported recently in the West African nation of Guinea. As of the latest reports in April 2014, it that has claimed 122 human lives in Guinea and Liberia. However, this is a rapidly changing situation, and the number of reported cases, contacts under observation, and deaths are subject to changes due to ongoing surveillance and investigations.
No vaccine or cure currently exists for the hemorrhagic fever caused by Ebola, causing public health officials to be concerned about spread of the virus in these regions. However, the World Health Organization has not recommended any restrictions on trade or travel to Guinea and Liberia, or neighboring countries like Mali and Sierra Leone.
What is Ebola Virus?
The virus, named after the Ebola River in the Zaire, now known as the Democratic Republic of Congo, caused the first outbreak in 1976, in a Congolese village, followed by another outbreak in Sudan. These outbreaks were contained through public health measures, including quarantines. But in the past seven years, the worst outbreak has been reported in Guinea and Liberia, which lie within the range of Zaire Ebola.
Ebolaviruses belong to a family of viruses called Filoviridae, which also includes the cuevavirus and the marburgvirus. The ebolaviruses have five distinct species while the cuevavirus and the marburgvirus has one known species each. All known ebolaviruses can infect humans, causing similar symptoms of hemorrhagic fever. However, they differ in virulence and disease progression. The Reston ebolavirus, which has been found in pigs form the Philippines, causes no symptoms in infected humans. There is only one recorded case of non-fatal infection with the Taï Forest ebolavirus, a researcher who got the virus from a chimpanzee while he was performing a necropsy. The three other types are more deadly, with the Bundibugyo ebolavirus causing 40% mortality, the Sudan ebolavirus accounting for 50% mortality and up to 90% for Zaire ebolavirus.
Except for Reston ebolavirus, the only Asian species of these viruses, which has been discovered in pigs, Ebolaviruses are typically harbored by various species of fruit bats from central and sub-Saharan Africa. These viruses are believed to be introduced into humans through direct contact with the bats or through their secretions or excretions. They may also spread through contact with other hosts, such as great apes.
However, the virus is not as contagious as other viruses like colds, flu or measles.
Symptoms of Ebola Virus Infection
People infected with Ebola virus usually present with non-specific symptoms initially, and these include high fever, muscle aches, headaches, sore throat, vomiting and diarrhea. Hemorrhage (bleeding) occurs in less that 50% of cases. Eventually, the liver and kidneys begin to fail. Experts of infectious diseases report that patients can die quickly, within 7-14 days after the appearance of symptoms.
These symptoms may be due to suppression of immune function, increased leakiness (permeability) of the blood vessels, and impaired blood coagulation.