Ebolavirus (EBOV), a viral genus, is the disease Ebola hemorrhagic fever (EHF), a viral hemorrhagic fever (VHF). The virus gets its name from the Ebola River Valley in the Democratic Republic of the Congo where the first outbreak occurred in 1976. The virus was obscure until 1989 when several widely publicized outbreaks occurred among monkeys in the United States.
The virus disrupts the endothelial cells lining the interior surface of blood vessels. The platelets become unable to coagulate as the blood vessel wall becomes damaged, leading to hypovolemic shock. It is transmitted through bodily fluids. There are five recognized species within the ebolavirus genus consisting of a number of specific strains. The Zaire virus is the type species, the first discovered, and the most lethal.
The filoviridae family has two specific genera: Ebola-like viruses and Marburg-like viruses. The rates of genetic change are on the same magnitude of Hepatitis B. According to these rates Ebolavirus and marburgvirus diverged several thousand years ago.
The incubation period is usually 5 to 18 days but can range from 2 to 21 days. Illness is characterized by rapid fever, malaise, muscle pain, headache, and inflammation of pharynx. Later vomiting, diarrhea, and bleeding at needle sites and bodily orifices.
Reston ebolavirus, although fatal in monkeys, is non-pathogenic to humans. Zaire and Sudan ebolavirus are the most common and include symptoms of abdominal pain, fever, headache, bloody vomit, maculopapular rash, malaise, joint and muscle pain, and chest pain.
Micrographs of the genus Ebolavirus show them to have the characteristic thread-like structure of a filovirus. Since these viruses are acellular they don’t grow through cell division but through machinery and metabolism of a host cell to produce multiple copies of themselves. Ebola is often mistaken for malaria, typhoid fever, dysentery, influenza, or other infections which may be endemic to the region. A large outbreak in Uganda in 2000 made officials realize they needed to be quicker to respond to outbreaks. In order to diagnose Ebola saliva and urine samples are needed. It is then diagnosed with an Enzyme-Linked ImmunoSorbent Assay (ELISA) test. The tests results, however, are not always accurate during non-outbreak situations. It sometimes shows positive results in areas when there is no history of Ebola infection. Tom Kzaisek created more complex test to combat these false positives. Neither of these tests are available commercially. Polymerase Chain Reaction (PCR) has been used to successfully detect ebola virus.
Early stages of the Ebola are not necessarily contagious. As the virus progresses bodily fluids become a hazard. Large epidemics usually occur in poor areas and areas without modern hospitals. In non-human primates vaccines were successful but to slow to be practical during an epidemic. So in 2003 a vaccine using an adenoviral was used to that successfully protected the monkeys after only 28 days. A study that began in 2006 and ended in 2008 was the first human trial for a vaccine that was successful.
Since there is no standard treatment for Ebola hemorrhagic fever usually balancing electrolytes, replacing lost coagulants, maintaining oxygen, and treating and complicated infections are the most common medicinal actions taken. In 2010 scientists at the National Emerging Infectious Diseases developed a drug that prevented reproduction of the virus in monkeys.
Bats are the most likely carriers of Ebola. Many animals are infected because they eat fruit dropped by bats. It is also transmitted through body fluids as well as through air which makes them Category A biological weapons. Even though it is highly contagious it has never spread on a large scale. Even after death bodies are infectious. Most outbreaks have been restricted to Africa. Outbreaks in human populations usually occur from handling wild animal carcasses therefore declines in animal populations often precede an outbreak.
In the chimpanzee population 88% of the population decline since 2003 is contributed to Ebola.