Outbreak

Filoviruses

Viruses are microscopic intracellular parasites that can only reproduce within a host cell. Viruses lack the enzymes for the process of metabolism and contain no ribosomes or other parts to make their own proteins.

The types of cells a virus can infect are limited to its host range. Filoviruses (Figure 1) belong to a virus family called Filoviridae and can cause severe hemorrhagic fever in humans and nonhuman primates. Filovirus virons appear in several shapes; these shapes are known as pleomorphism. They may either appear as long, often branched filaments, shorter filaments, or in a circle formation. The filaments can measure up to 14,000 nanometers in length, and have some have a diameter of up to 80 nanometers. Each is coated in a lipid membrane and contains a molecule of negative-sense RNA. Replication of filoviruses occurs through the production of buds on the surface of the host cell (See Figure 1).

The two types of filoviruses that have been identified are the Marburg virus and Ebola virus. There are four different subtypes of the Ebola virus: Ivory Coast, Sudan, Zaire, and Reston. Ebola-Reston does not cause any severe disease conditions in humans it can however, be fatal within monkeys.

Marburg

The Marburg disease (Figure 2) was first seen in the August, 1967 in Marburg, Germany. Three workers that were employed by Behringwerke AG, a vaccine-producing branch from pharmaceutical company, Hoechst AG were suffering from muscle aches and mild fevers.

The conditions the workers had were similar to characteristic of the flu, but it was strange to have the flu in the summer. They were then hospitalized. The following day they became nauseated. Their spleens became enlarged and their eyes became bloodshot. The demeanors grew morose but aggressive. In addition, the nurse and doctor who were taking care of the three patients became ill. By September 23, the number of patients suffering from this Marburg grew to 23. Two other outbreaks were occurring in Frankfurt and Yugoslavia. The people sick were also employees of pharmaceutical research or were in the field of patient care.

Many people feared that this deadly virus was airborne. A great deal of mystery surrounded the illness since no one was aware of how it was transmitted, what an effective treatment might be, or how many more people could potentially get sick.

Each patient exhibited the same symptoms and went through the same process before dying. After two days had passed, the patients had flu-like muscle aches and fever, large lymph nodes in throat, an inflamed spleen, a drop in the number of white blood cells, and a shortage of platelets that are necessary to stop bleeding. These are ordinary responses to viremia. This is when the circulatory system is flooded with new viruses. Once the sixth day have passes, the skin becomes covered in rashes that makes to skin extremely sensitive, the throat becomes too sore to eat. The next days are followed by severe diarrhea and the skin turns to a red color because the skin capillaries have been clogged with clots. The nerves send messages because of the lack of oxygen circulation, and this causes extreme pain. On the tenth day the patients begin vomiting up blood.

Many patients die because of the brain damage caused by clots or heart attacks because of the strain of pumping the thick coagulated blood. If they do survive to 21 days, the blood becomes pouring from the body and the skin peels off.

Of the 31 people who were infected with Marburg, seven died. The people who had survived experienced damage to their liver and psychosis, and it led to impotence in men.

Ebola

Ebola (Figure 3) is a filovirus that shares is genetically similar to the Rhabdoviruses and the Paramyxoviruses. Ebola virus is transmitted by contact with blood, feces or body fluids from an infected person or by direct contact with the virus, as in a laboratory. People can be exposed to Ebola virus from direct contact with the blood or secretions of an infected person. This is why the virus has often been spread through the families and friends of infected persons: in the course of feeding, holding, or otherwise caring for them, family members and friends would come into close contact with such secretions. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions. The incubation period --the period between contact with the virus and the appearance of symptoms, ranges from 2 to 21 days. The initial symptoms are usually high fever, headache, muscle aches, stomach pain, and diarrhea. There may also be sore throat, hiccups, and red and itchy eyes. The symptoms that tend to follow include vomiting and rash and bleeding problems with bloody nose, spitting up blood from the lungs and vomiting it up from the stomach, and bloody eyes. Then finally come chest pain, shock, and death.

A protein on the surface of the virus has been discovered that is responsible for the severe internal bleeding. The protein attacks and destroys the endothelial cells lining blood vessels, causing the vessels to leak and bleed. The chemical released by the Ebola macrophages is "cytokine storm." The white blood cells in the surrounding area go through apoptosis when they come in contact with the cytokines. This results in the weakening of the immune system. The cytokine storm triggers blood clotting that generates many fibrin clots in organs such as the spleen. The hemorrhaging effect most likely occurs when the clotting factors are used up.

Ebola Zaire

The very first case of Ebola was in Zaire, now the Democratic Republic of Congo, in 1967. There were 312 cases 88% of which died. This disease occurred in Yambuku and surrounding area. Disease was spread by close personal contact and by use of contaminated needles and syringes in hospitals/clinics. This outbreak was the first recognition of the disease.

This virus attacked every organ of the body and tissue except the skeletal muscle and bones. It was a hemorrhagic virus and was not airborne either. The disease was contained by changing social behaviors such as burying the dead immediately and the homes of the deceased were burned. The disease was contained by changing social behaviors such as burying the dead immediately and the homes of the deceased were burned.

In 1977, there was another threat of Ebola Zaire. One person was a victim of the virus in the village of Tandala. The next outbreak of Ebola Zaire did not occur until 1994. This occurred in Gabon Mйkouka. 49 people were infected, 59% of which died. It was initially thought to be yellow fever however,