The Worlds Fight Against Microbes Essay Research

The Worlds Fight Against Microbes Essay, Research Paper

The Worlds Fight Against Microbes

Many infectious diseases that were nearly eradicated from the

industrialized world, and newly emerging diseases are now breaking out all over

the world due to the misuse of medicines, such as antibiotics and antivirals,

the destruction of our environment, and shortsighted political action and/or

inaction.

Viral hemorrhagic fevers are a group of diseases caused by viruses from

four distinct families of viruses: filoviruses, arenaviruses, flaviviruses, and

bunyaviruses. The usual hosts for most of these viruses are rodents or

arthropods, and in some viruses, such as the Ebola virus, the natural host is

not known. All forms of viral hemorrhagic fever begin with fever and muscle

aches, and depending on the particular virus, the disease can progress until the

patient becomes deathly ill with respiratory problems, severe bleeding, kidney

problems, and shock. The severity of these diseases can range from a mild

illness to death (CDC I).

The Ebola virus is a member of a family of RNA (ribonucleic acid)

viruses known as filoviruses. When these viruses are magnified several thousand

times by an electron microscope they have the appearance of long filaments or

threads. Filoviruses can cause hemorrhagic fever in humans and animals, and

because of this they are extremely hazardous. Laboratory studies of these

viruses must be carried out in special maximum containment facilities, such as

the Centers for Disease Control (CDC) in Atlanta, Georgia and the United States

Army Medical Research Institute of Infectious Diseases (USAMRIID), at Fort

Detrick in Frederick, Maryland (CDC I,II).

The Ebola hemorrhagic fever in humans is a severe, systemic illness

caused by infection with Ebola virus. There are four subtypes of Ebola virus

(Ebola-Zaire, Ebola-Sudan, Ebola-Ivory Coast, and Ebola-Reston), which are not

just variations of a single virus, but four distinct viruses. Three of these

subtypes are known to cause disease in humans, and they are the Zaire, Sudan,

and Ivory Coast subtypes. Out of all the different viral hemorrhagic fevers

known to occur in humans , those caused by filoviruses have been associated with

the highest case-fatality rates. These rates can be as high as 90 percent for

epidemics of hemorrhagic fever caused by Ebola-Zaire virus. No vaccine exists to

protect from filovirus infection, and no specific treatment is available (CDC

II).

The symptoms of Ebola hemorrhagic fever begin within 4 to 16 days after

infection. The patient develops chills, fever, headaches, muscle aches, and a

loss of appetite. As the disease progresses vomiting, diarrhea, abdominal pain,

sore throat, and chest pain can occur. The blood fails to clot and patients may

bleed from injection sites as well as into the gastrointestinal tract, skin, and

internal organs (CDC I).

The Ebola virus is spread through close personal contact with a person

who is very ill with the disease, such as hospital care workers and family

members. Transmisson of the virus can also occur from the reuse of hypodermic

needles in the treatment of patients. This practice is common in developing

countries where the health care system is underfinanced (CDC I).

Until recently, only three outbreaks of Ebola among people had been

reported. The first two outbreaks occurred in 1976. One was in western Sudan,

and the other in Zaire. These outbreaks were very large and resulted in more

than 550 total cases and 340 deaths. The third outbreak occurred in Sudan in

1979. It was smaller with only 34 cases and 22 deaths. Three additional

outbreaks were identified and reported between 1994 and 1996: a large outbreak

in Kikwit, Zaire with 316 cases and 244 deaths; and two smaller outbreaks in the

Ivory Coast and Gabon. Each one of these outbreaks occurred under the

challenging conditions of the developing world. These conditions including a

lack of adequate medical supplies and the frequent reuse of needles, played a

major part in the spread of the disease. The outbreaks were controlled quickly

when appropriate medical supplies were made available and quarantine procedures

were used (CDC I).

Ebola-Reston, the fourth subtype, was discovered in 1989. The virus was

found in monkeys imported from the Philippines to a quarantine facility in

Reston, Virginia which is only about ten miles west of Washington, D.C.

(Preston 109). The virus was also later detected in monkeys imported from the

Philippines into the United States in 1990 and 1996, and in Italy in 1992.

Infection caused by this subtype can be fatal in monkeys; however, the only four

Ebola-Reston virus infections confirmed in humans did not result in the disease.

These four documented human infections resulted in no clinical illness.

Therefore, the Ebola-Reston subt

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