The Story of Ebola Virus

• This means that it is a lethally infective agent.

• The Ebola virus has a prime directive to replicate, like any other known virus on this planet.

• The reservoir species of the Ebola is UNKNOWN, thus the major part of the

LIFE CYCLE of the virus is UNKNOWN .• Fruit Bat is the most common culprit of

the Ebola Virus

Ebola : A “Hot Virus”

Zaire = Democratic republic of Congo

The Name EbolaAugust 26, 1976 in Yambuku, a town in the north of Zaïre. A 44-year-old school teacher returned from a small hike. His went to the doctor and because of his high fever they gave him a quinine shot which is good against malaria.

A week later, he had uncontrolled vomiting, bloody diarrhea, trouble breathing and then bleeding from his nose, mouth, and anus.

He died ~14 days after the onset of symptoms.

He started an epidemic that killed 280 of the 313 infected persons (88%).

Ebola

The virus kills gorillas and chimpanzees and other monkeys. Because it kills apes in such high percentage – they are not likely to be its natural host.

Towards Detecting the Natural Host of the Virus

Three trapping expeditions in areas close to infected gorilla and chimpanzee carcasses in Gabon and in Congo.

1,030 animals were tested including 679 bats, 222 birds and 129 small terrestrial vertebrates (PCR).

Viral nucleotides were discovered in 3 species of bats.

The Ebola virus, once inside a host, begins to replicate. The seven proteins that make up the body of the virus begin to consume the host cell as the virus starts making copies of itself .

Replication Using Proteins

Ebola multiply extremely rapidly and powerfully that within no time the infected cell becomes packed with crystal like blocks of virus particles . These virus particles are themselves getting ready to replicate. The crystal like blocks, or bricks, form at the centre of the cell and begin to grow outwards, migrating to the cell wall. On reaching the cell wall, the brick dissolves into hundreds of individual virus particles The Ebola virus particles then infiltrate the bloodstream of the host and keep attaching themselves to cells everywhere. Here the procedure of replication is repeated until the tissue becomes saturated with virus crystal bricks.

Virus Bricks

This amplification continues till even a droplet of blood of the host can contain up to 100 million virus particles. The Ebola virus thus destroys its host and “seeks” a new one. Like any other virus, the Ebola cannot survive by itself and needs either a reservoir or host for its continued existence.

Amplification of the Virus

It is believed that the virus is mainly transmitted through contact with the blood of an infected person or primate, either directly or indirectly, for example through the use of an infected syringeIt is known that the Ebola virus is spread from person to person through direct contact with body fluids (e.g., blood, semen, vaginal fluid, organs) of an infected person.

Transmission

The incubation period of the Ebola virus ranges from 2 to 21 days.symptoms often begin within a few days of becoming infected, with the sudden onset of high fever, weakness, muscle pain, headache and sore throat. This is quickly followed by more severe symptoms including vomiting, diarrhea, rash, decreased kidney and liver functioning, and internal and external bleeding. Specific laboratory blood tests can confirm diagnosis.

Symptoms

1. Hosts•The life cycle of the virus has been explained. The Ebola virus has so far two known hosts – primates and Homo sapiens. As explained, the virus is termed as a level 4 agent, which means that it is extremely infective and lethal

Pathology

2. Mode of Action•Ebola is extremely destructive to the host, which could probably explain the fact why it has not yet been as successful in penetrating the human species as AIDS. The extreme speed at which it spreads through the body and destroys it, prevents it from transmitting itself from host to host with a high rate of success. While AIDS is a silent stalker, Ebola is a violent, bloody predator

Pathology

3. Affinity for Connective tissue•Most strains of Ebola attack every part of the human body with the exception of skeletal muscle and bone•The skin develops haemorrhages under itself. Ebola has a particular affinity for connective tissue, which is the tissue that holds the internal organs together. By its action, the virus actually acts on the collagen (the protein which is a component of connective tissue) and converts it into a soft mush and under layers of the skin die.

Pathology

4. Destruction of the Host•The virus kills a huge amount of tissue and converts it into a digested slime before it finally kills its host.• Internal organs slough tissue and even the heart itself begins to bleed inside itself.•At the end of the process the host is totally destroyed in a process called ‘crashing out’ where the host dies and begins to bleed from every possible orifice, including the skin pores. This could be viewed as a mechanism for the virus to ‘seek’ a new host

Pathology