EBOLA VIRUS

Someone once said that the truth is sometimes stranger than fiction. This is not surprising because the author of fiction must maintain some level of credibility with his reader and is thereby limited in what he can say. Reality has no such limitations, as evidenced by the following article, which is a more terrifying and diabolical story than most fiction authors would ever dream of creating.

The following is a news clip taken from the 1996 update to the Funk and Wagnalls encyclopedia.


Ebola Outbreak Vexes Zaire
August 95

The spread of the deadly Ebola virus infection, an illness with no known vaccine or cure, continued in Zaire into the summer months, after a brief lull in May that had led health officials to mistakenly believe the virus was under control. Since mid-April, when doctors and nurses performed emergency surgeries on a 36-year-old man who had been infected with Ebola, the virus had claimed the lives of more than 200 people in the city of Kikwit and its outlying villages.

The man, a hospital technician whose job was to draw blood samples, died soon after his operations. Not long afterward, the doctors and nuns who had treated him became infected with the virus themselves. Initially, they experienced flulike symptoms: headaches, high fever, and diarrhea. But unlike persons experiencing the flu or a common cold, within a few more days they were vomiting a thick black substance-the highly contagious, virus-infected remains of their internal tissues. Soon they, like the initial victim, began to bleed massively from every orifice of their bodies, and then they died.

In mid-May, a team of international doctors and virologists arrived in Kikwit, a city with an estimated population of about 400,000, located about 400 km (250 mi) from Kinshasa, the capital of Zaire. By then, the virus had already raged throughout the hospital and had killed or infected most of the staff and patients. Those who had not fallen victim to the virus had fled the hospital in terror. Many who fled had unknowingly been infected with the virus, which has an incubation period of anywhere from 2 to 21 days, and they carried the virus with them.

Armed with sterilized needles and other sanitized hospital supplies and medical equipment, the team of health experts moved quickly to try to contain the outbreak and to educate the citizens of Kikwit about the nature and transmission of Ebola. Until this outbreak, the virus had not been seen among humans for 16 years. Like human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS), Ebola can only be transmitted through direct contact with the blood or bodily fluids of an infected individual. Ebola virus does not travel through the air. According to health experts, within days of the initial symptoms, Ebola virus attacks an individual's immune system and can destroy the body's soft tissues, including the liver, heart, and brain. After the first symptoms appear, the virus takes about a week to run its course. The only internal body parts the virus cannot destroy are muscle and bone.

Ebola was first identified in Zaire in 1976 and has resurfaced three times among humans in central Africa. In all four outbreaks, the main victims were doctors, medical staff, and patients exposed to the virus through unsanitary hospital conditions. Many hospitals in the impoverished region of central Africa lack fresh water, rubber gloves, gowns, and other sanitized supplies that can prevent the transmission of disease. Also, it is not uncommon for hospital workers in the region to use the same needle when drawing blood from different patients, further facilitating the spread of Ebola and other blood-borne diseases. Hospitals in central Africa are overcrowded, and often several patients share a single bed, which can consist of a soiled mattress lying on the floor. During the outbreak in Kikwit, where it is common practice to wash the body of a dead relative before burial, many family members of victims unknowingly contracted the virus.

The first reported cases of Ebola surfaced in Zaire and the Sudan. The virus was named after the Ebola River in Zaire, where in 1976 the virus spread to more than 55 villages located along the river's edge after an initial outbreak in the city of Yambuku. Soon after, the virus appeared in the western Sudanese cities of Nzara and Maridi. These early occurrences resulted in more than 500 cases of Ebola and more than 400 deaths. Before the May 1995 epidemic in Kikwit, the last outbreak of Ebola virus among humans occurred in Nzara, Sudan, in 1979. Of the 34 cases reported at that time, 22 resulted in death.

Despite 16 years of scientific research and field investigations, the origin of the Ebola virus remains a mystery. Researchers do know that Ebola is made up of seven proteins that surround a piece of genetically encoded material, but they know little about the inner workings of the virus. From Ebola's structure, scientists suspect it may be an ancient organism. In addition, Ebola and a related virus, called Marburg, are the only known filoviruses in the world. Under a microscope, most viruses are round in appearance, but filoviruses form long, curly, ropelike shapes.

Ebola and Marburg, along with certain other viruses, cause hemorrhagic fevers. All illnesses caused by hemorrhagic fever viruses begin with fever and muscle aches. Some of these viruses eventually cause massive internal bleeding, kidney and liver failure, respiratory problems, shock, and even death. However, not all hemorrhagic fever viruses are deadly, and the illnesses caused by some types never progress beyond mild flulike symptoms. No other known hemorrhagic fever virus causes as much bleeding as Ebola.

Most hemorrhagic fever viruses live in host organisms such as rodents or insects. Some of the viruses can jump to a new species when they come in contact with other populations of animals, such as monkeys or humans. Since the first reported cases of Ebola, investigators have tested the blood of thousands of mammals and insects captured near the sites of the initial African outbreak in an attempt to isolate the virus's host organism. Their attempts have been unsuccessful, and the source of the virus or where it circulates in between outbreaks is unknown.

Scientists have identified four different strains of Ebola virus: Zaire, Sudan, Reston, and Tai. Virus strains are usually named after the place where they were first discovered. Ebola Zaire is the deadliest known strain of the virus. With a fatality rate as high as 90 percent, it attacks every organ and tissue in the human body, except muscle and bone. It creates blood hemorrhages under the skin, dissolves connective tissue, and destroys the brain. According to researchers, the virus in the Kikwit outbreak is Ebola Zaire, virtually identical in structure to the strain seen nearly 20 years ago during the initial outbreak along the Ebola River. This similarity is an unusual phenomenon, since viruses are unstable organisms that usually mutate over time-some become weaker, while others become more virulent. The main difference between the two outbreaks of Ebola Zaire is that the strain responsible for the outbreak in Kikwit has an average incubation period of four days, while 20 years ago the virus had an average incubation period of seven days.

Ebola Sudan, while still extremely lethal, is half as strong as Ebola Zaire. Ebola Reston was named after a 1989 outbreak that occurred among monkeys imported to the United States from the Philippines and housed in a facility in Reston, Virginia, just outside Washington, D.C. All the imported monkeys tested positive for Ebola and either hemorrhaged to death or were sacrificed during a covert operation by federal health officials to control the virus. The Reston strain of Ebola was not lethal to any of the humans exposed to it.

In November 1994 a new strain of Ebola virus, known as Ebola Tai, was discovered. The new strain was named after the Tai Forest in the western African republic of Cote d'Ivoire, where it was found. A Swiss zoologist developed symptoms of hemorrhagic fever after performing an autopsy on an infected chimpanzee. She was flown to a hospital in Switzerland, where she soon recovered. Blood samples and other immunological tests confirmed that she had come down with a new strain of Ebola. The zoologist had been part of a team of scientists sent to the Tai Forest to study a band of chimpanzees that had been dying of hemorrhagic fevers. None of her colleagues from the expedition had been infected with the new strain of Ebola. The case marked the first time that a human Ebola infection was directly linked to wild African monkeys.

Despite the extremely high fatality rate of certain strains of Ebola, health officials maintain that, under sanitary conditions, the virus is actually difficult to contract. Like HIV, Ebola spreads through direct contact with an infected person's blood or bodily fluids. Unlike HIV, which can live inside an individual and be passed along to others for ten years or more before symptoms appear, Ebola has a relatively short incubation period. Once the symptoms of Ebola appear, precautions can be taken to halt its spread to others. Health officials say that because Ebola kills its victims so quickly, the chance of the virus ever becoming widespread among human populations is low.

Like all viruses, Ebola needs a constant supply of host organisms to survive and propagate. Outside of a host organism, viruses survive as inert genetic material encircled by a shell of proteins waiting to be activated. Inside a host organism, however, viruses become active and are able to attach to or inject their genetic material into the host's cells. The virus's genetic material redirects the cell to produce more viruses. The newly created virus cells are then capable of infecting other cells. During the replication process the virus usually destroys the host cell. Scientists hypothesize that apart from occasional human outbreaks, Ebola survives among a population of wild animals and then jumps species when a human comes in contact with the virus's host organism. Scientists do not know specifically where the virus lives between outbreaks.

Ebola is one of several types of deadly viruses detected over the last 25 years. Other lethal African viruses that have emerged among human populations during the late 20th century include Marburg, Lassa, Rift Valley Fever, and HIV. Seven out of 31 people died in 1967 after being infected with Marburg virus by Ugandan green monkeys. Marburg is closely related to Ebola, although it is far less deadly. Lassa, another hemorrhagic fever virus, infects 200,000 to 400,000 annually in West Africa. Approximately 5000 of those infected die from the disease. Rift Valley Fever, a mosquito-borne virus, reached epidemic proportions when it infected more than 10,000 people along Egypt's Nile River Delta in 1977. The virus was first detected in Kenya in the 1950s. HIV is perhaps the most deadly virus, believed by health experts to have originated on the African continent. Since its emergence during the 1970s, HIV has infected more than 13 million people worldwide, and experts expect that number to climb to 40 million by the year 2000.

In addition to Africa, outbreaks of newly reported lethal viruses have appeared in North America, South America, Asia, Australia, and Europe. Scientists note that the emergence of these deadly viruses, in most cases, coincides with the recent encroachment of human beings on tropical rain forests and once-isolated rural villages. Experts believe that the original hosts of these deadly viruses are somewhere in these areas. Health experts hypothesize that newly built roadways connecting urban centers with small villages in western and central Africa, the development over the last few decades in tropical rain forests, the advent of jet travel, large-scale farming, and a massive trend toward urbanization have facilitated the spread of these previously unknown viruses among human populations.


Tropical Diseases


 

December 4, 2012
© 1997-2012 Phillip Landmeier