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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.