Ebola is a virus that causes severe, often fatal disease. It is a filovirus, meaning it looks like a thread when viewed with an electron microscope.
Various viral proteins help replicate the RNA genome and make new viral particles.
Definition of the Ebola Virus
News of an Ebola outbreak can easily spread panic and fear. The Ebola virus, a severe viral infection with a very high mortality rate is not airborne, but it can still spread easily, especially in healthcare settings. Ebola spreads through direct contact with bodily fluids, such as blood and urine. During outbreaks, fatality rates range from 25% to 90%. Outbreaks are normally limited, since they must begin in a rural area and the virus kills so quickly.
However, improved transportation is one of the factors that allowed the virus to spread into major cities in multiple countries in western Africa in 2014.Ebola virus disease begins with very vague symptoms: fever, fatigue, body aches, vomiting, and diarrhea. It quickly escalates to involve internal and external bleeding, and kidney and liver damage. The main cause of death is low blood pressure from dehydration and septic shock. There are no vaccines or antiviral medications available against Ebola, so treatment is normally supportive, such as keeping the patient hydrated, to counteract the effects of the disease.
Structure of the Ebola Virus
Ebola is categorized as a filovirus. This means that it looks like a piece of thread, or filament, that’s been curled up a bit. Like all viruses, Ebola is not able to replicate on its own. It requires help from a host cell.
Ebola can infect a variety of cell types, including white blood cells, liver cells, and cells of the adrenal glands. Ebola is an enveloped virus, meaning it takes part of the host cell’s membrane with it when it leaves the cell.Ebola stores its genetic information as a single strand of RNA, termed a negative strand. This RNA must first be paired up with a complementary strand before it can be used to make the seven necessary viral proteins.
The complementary strand is called the positive strand. It is used to make new copies of the original negative strand, as well as viral proteins.A viral protein called the large or L protein helps to make the second RNA strand. The virus then takes advantage of the host cell’s protein-making machinery to make more viral particles, effectively turning the cell into a virus-producing factory.
The viral RNA is held in the virus by the nucleoprotein (NP). The nucleoprotein gets its name because it is a protein that acts like a nucleus, holding the genome.The outside of the viral particle contains glycoproteins, proteins with small carbohydrates attached. It’s believed that these glycoproteins most likely help the virus bind to and enter the host cell.Another set of proteins, viral protein (VP) 40 and VP24 are believed to make up the matrix of the virus.
The matrix of a virus helps hold the outside of the virus, the envelope, to the inside, called the nucleocapsid. It’s similar to how peanut butter helps hold the top and bottom pieces of bread together in a sandwich.
Replication of the Ebola Virus
As mentioned above, Ebola uses some of its own proteins and some of the host cell’s proteins to complete its life cycle.
The Ebola RNA genome is copied and used to make proteins. The proteins assemble then leave the cell. As the new virus particles leave, they take some of the host cell’s membrane with them, creating an envelope. The envelope helps act as camouflage, hiding the virus from the host’s defenses.
Ebola virus disease is a severe viral infection, with a very high mortality rate. It’s caused by the Ebola virus, a filovirus, which means it looks like a piece of thread, or filament, that’s been curled up a bit.
It’s also an enveloped virus, meaning it takes part of the host cell’s membrane with it when it leaves the cell. Ebola has a single-stranded RNA genome holding its genetic information. This RNA provides the instructions for the host cell to make new viral proteins, which are then released to infect more cells. The binding and entering of other cells is helped by glycoproteins, which are proteins with small carbohydrates attached while the virus’s nucleocaps and envelope is held together by the virus’s matrix.