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Monday, March 19, 2012

Contagion (The Movie)


The film follows several interacting plotlines, with no single protagonist nor antagonist, over the course of several weeks from the initial outbreak and attempts to contain it, to panic and decay of social order, and, finally, to the introduction of a vaccine.

After a business trip to Hong Kong, businesswoman Beth Emhoff (Paltrow) stops in Chicago for a dalliance with an old boyfriend before returning to her husband and family in suburban Minneapolis. At first she appears to have contracted a cold during her trip. Her son, Clark, also becomes symptomatic and is sent home from school. Beth's condition worsens and two days later she collapses with severe seizures in her home. Beth's husband, Mitch (Damon), rushes her to the hospital, but she continues to seize and dies of an unknown virus. Because it affects the brain and central nervous system, pathologists attribute it to a meningoencephalitis virus. Mitch returns home and finds that Clark has also died from a similar infection. Mitch is put in isolation but turns out to be genetically immune to the disease. He and his daughter attempt to flee the city, but a military quarantine has been imposed, and they are forced to return to their home to face decaying social order and rampant looting of stores and homes. Not knowing whether his daughter inherited his immunity, Mitch struggles to balance his teenage daughter's frustration with quarantine with his desire to protect her, while trying to come to terms with his own loss.

In Atlanta, representatives from the Department of Homeland Security meet with Dr. Ellis Cheever (Fishburne) of the Centers for Disease Control and Prevention and express fears that the disease is a bioweapon intended to cause terror over the Thanksgiving weekend. Cheever sends Dr. Erin Mears (Winslet), an Epidemic Intelligence Service officer, to Minneapolis to begin the investigation. In addition to tracing the outbreak back to Beth, Dr. Mears has to negotiate with local bureaucrats reluctant to commit resources. She later becomes infected with the disease after being in contact with contaminated fomites while staying at her hotel. The Minnesota National Guard arrives to quarantine the city, and a badly deteriorating Dr. Mears is moved to the field medical station she helped set up, where she later dies.

Investigations into cures via treatment protocols or vaccines initially prove fruitless as scientists cannot find a culture to grow the new virus, which has been named the Meningoencephalitis Virus One (MEV-1). Professor Ian Sussman (Elliott Gould) violates orders from a CDC scientist, Dr. Ally Hextall (Jennifer Ehle), to destroy his samples and identifies a line of bat cells that will support research of a vaccine. At the CDC, Dr. Hextall uses this breakthrough to begin to characterize the properties of the virus, which turns out to have a mix of genetic material from bat, pig and human viruses and appears to spread via fomites with a basic reproduction number of two. This later goes up to four after the virus mutates.
A conspiratorially minded freelance internet blogger, Alan Krumwiede (Law), posts videos about the disease, and in one of them appears sick and later claims that he recovered using a homeopathic cure called forsythia. Panicked people attempting to obtain forsythia overwhelm pharmacies, accelerating the contagion as infected and healthy people congregate. Krumwiede leaps to national attention and, during a television interview, accuses Dr. Cheever of informing friends and family to leave Chicago before a quarantine is imposed. It is later revealed Krumwiede was never sick with the virus, but was attempting to boost demand on behalf of investors in the companies producing and distributing the homeopathic treatment. He is arrested for conspiracy and fraud, but is soon released after his 12 million blog readers collect and pay his bail.

Dr. Hextall identifies a potential vaccine, using an attenuated (live) virus. Because of the difficulties of human subjects testing, she follows the precedent of other vaccine researchers and inoculates herself first. Hextall visits her gravely ill father in the hospital to expose herself to the virus and test the vaccine. Production of the vaccine is rapidly ramped up and the CDC awards vaccinations via a random lottery based on birth dates for one full year until every survivor is vaccinated. Dr. Cheever, feeling guilty for his past actions to protect those who are close to him, gives his fast-tracked MEV-1 vaccination to the son of a janitor he works with at the disease center. Dr. Hextall places the surviving samples of the MEV-1 virus in cryogenic storage with H1N1 and SARS.

Dr. Leonora Orantes (Cotillard), a World Health Organization epidemiologist, travels to Hong Kong to trace the origins of the infections. She collaborates with Sun Feng (Chin Han) and other local Chinese epidemiologists and public health officials and they identify Emhoff as patient zero. As the virus spreads, Feng kidnaps Orantes to use her as leverage to obtain the first MEV-1 vaccines for his village. Orantes spends months living in rural China with the villagers until the vaccine is announced. Feng exchanges Orantes for the vaccines, which turn out to be placebos. Orantes rushes away when she is informed of this, presumably to warn the village.
The film concludes by tracing the origin of the virus from a bat nesting in a tree being cleared by Emhoff's mining corporation. The bat flies to a nearby pig sty and drops a banana where it is eaten by the pig, presumably transferring the bat virus into the pig. The pig is sold to and butchered by a chef in a Macau casino, who greets Beth Emhoff without washing his hands of the pig's blood, transferring the bat-pig hybrid to her and creating the MEV-1 human strain.

Meningoencephalitis Virus One

Meningoencephalitis Virus One (MEV-1) is the fictional highly contagious and lethal meningoencephalitic virus that appears in the film. Its origin and symptoms are based on the Nipah virus.

The virus itself is a paramyxovirus that infects both the lungs and the brain, causing a hacking cough and fever and a severe headache, followed by a seizure, brain hemorrhage and ultimately death. With a fast incubation period, MEV-1 kills a person within 3–4 days of contracting the virus, with symptoms emerging only hours after infection. The virus itself is transmitted via respiratory droplets and fomites, surfaces that infected individuals have come into contact with.

In the film, the virus is portrayed as being one of the most dangerous infectious agents, combining a fast and hard-to-control form of transmission and a mortality rate in excess of 20%. The film itself does not tell the audience the exact number of deaths attributed to the virus, but towards the end of the film, a newscaster announces the death toll to be near 26 million globally.


Infectious Agent

In order for an infection to occur there must be an infectious agent. In essence, no bugs – no disease. For example, consider walking near someone who sneezes as you pass by. Are you exposed to a communicable disease? If the person who sneezes did so because of some external irritant such as pepper entering the nose, there is no infectious agent. Without an infectious agent, you cannot become ill. In another example, consider you encounter a patient who has partied a bit too hearty. While assessing his condition, the patient proceeds to vomit on your shirt and the stench of an alcoholic beverage now permeates your clothing. Have you been exposed to a communicable disease? Not unless there is an infectious viral or bacterial agent present in the patient’s stomach or the patient has gastric bleeding.

As the situation progresses, your partner begins to vomit. Was your partner exposed to an infectious disease from the patient? Most likely, your partner is having a sympathy reaction to the patient’s vomiting.

Disinfecting surfaces such as counters or equipment with a specific cleanser can also destroy infectious agents. Without an infectious agent, there is no Chain of Infection.


To be considered infectious, there must be a sufficient quantity of bugs to cause an infection. One bacterium or virus will generally not cause an infection. Further, these bugs need to be concentrated in a specific location such as the airways, lungs, blood, or other body area. But, the body is not the only reservoir that can harbor these bugs. Consider the sharps container or any piece of soiled equipment. Once a needle has been used, it is placed into a sealed sharps container. This container is a reservoir for infectious diseases and, if opened, could pose a serious threat to the employees.

Not only is the sharps container a reservoir, so is dried blood. While drying destroys many infectious agents, some organisms are not affected by drying. Some bacteria form spores while viruses merely become inactive. When the circumstances are better, the bacteria and viruses reactivate and infect. Cleaning contaminated equipment does two things – it destroys the infectious agent and eliminates the reservoir.

Portal of Exit

From the reservoir, the bugs need a way out of the body. The passage out of the body can include the nose, mouth, open injury, or any other way to leave the reservoir. If an infectious agent is trapped inside the reservoir and cannot leave, there is no risk of infection. For example, think about that sharps container mentioned earlier. There is an infectious agent and reservoir, but because the container is sealed, there is no way for the agent to get out.

In another example, consider drawing a vial of blood from a patient with Hepatitis B for testing at the hospital. You have drawn the blood that is in a sealed container. Is there an infectious agent? Yes. Is there a reservoir? Yes. Is there a portal of exit? No, the vial is sealed. Because the vial is sealed, the Chain of Infection is broken.

Mode of Transmission

The infectious agent must have a way from its reservoir to the new host. In thinking about the vial of blood above, if the cap to the vial was removed, there would be a portal of exit, but the blood must still get from the vial onto you. If the blood spills onto your clothing or hands, there is a mode of transmission. In another example, consider a person with the flu and chest congestion. The infectious agent is the flu virus, the reservoir is the patient’s lungs and airways, and the portal of exit is the mouth and nose. When coughing, the patient expels infectious fluids from the airways into the air. This creates a droplet mode of transmission that transports the agent to the new host. Can this mode of transmitting the flu virus be blocked? Covering the mouth when coughing is a courtesy to those nearby and reduces, but does not eliminate the risk of transmitting the illness.

Portal of Entry

Once the infectious agent has found its way out of the reservoir, it must have a way into the new host. This portal of entry can be the new host’s nose, mouth, airways, eyes, gastrointestinal system, or skin. Each of these areas of the body can permit the entry of invading bacteria or viruses. Yet, each of these areas has natural barriers against invasion. The nose and airways are lined with mucus-producing tissue containing hair-like fibers called cilia. This tissue traps larger particles of dust and contaminants, preventing entry into the body. To clear the nose, a person either sneezes or blows the nose to remove the trapped debris.

The smaller airways are also lined with tissue that contain cilia and produce mucus. Smaller particles are trapped in the lower airways and, by the action of the cilia, are swept up and out of the airways. On reaching the throat, the mucus is coughed and either spit out or swallowed. Think about clearing your throat!

Infectious agents contacting the eyes may be washed away by tears. However, some of those bug-containing tears may be rinsed into the tear ducts and into the nose. It is important not to rub your eyes without washing your hands.

The mouth contains enzymes in the saliva that begin to destroy the bacteria or viruses as they enter the body. The stomach acid may destroy the bugs that survive the mouth before entering the intestines. However, some bacteria may survive the mouth and stomach, and enter the small intestines. The intestines, through mucus production and peristalsis help block the bacteria or viruses from entering invading the lining of the intestines and getting deeper inside the body. Think about food poisoning and what happens after the bacteria enter the gastrointestinal system. The stomach goes into ‘reverse’ and vomiting begins. This helps eliminate the infectious agent from the system. The intestines move the infectious material though the system quickly, which may produce the cramping sensations. Mucus production along with reduced water absorption in the intestines ‘rinses’ the bacteria from the system and causes diarrhea.

The skin has natural barriers including oils containing fatty acids that tend to destroy infectious agents or make the skin a less hospitable environment. Additionally, the outermost layer of the skin, epidermis consists of dead cells that slough away with washing. Washing away these dead cells also washes away the infectious agent.

In addition to our natural barriers, we use other barriers that prevent an infectious agent from entering the body. Universal precautions are designed specifically for this purpose. Latex gloves prevent direct contact of an infectious agent with the skin. A face mask, goggles, and gown also prevent contact of the agent with the skin. In some cases, a respirator is used as a barrier against the infectious agent. A respirator is worn when in contact with a tuberculosis patient and is designed to filter the small bacterial particles from the air so that the bugs are not inhaled.

Again, there must be a portal of entry into the body for the risk of infection to be present. If the portal of entry is blocked, the Chain of Infection is broken and there is no risk.


In order for an infectious agent to cause an infection, the last link of the Chain, the new host must be susceptible to the disease. Susceptibility is affected by a number of factors including number of organisms and the immune system’s status against the microbes. The number of organisms is important. One or two bacteria or viruses are generally not sufficient to cause infection. While some infections can be caused by as few as 10 organisms, most infections require hundreds to thousands for an infection to develop.

The body’s immune system also plays a role in susceptibility. While the components of the immune system are too detailed to discuss in this article, there are a couple of concepts to know. First, when an infectious agent enters the body it is not recognized by the body, which does not know how to fight the invasion. The body’s immune system does, however, act to produce antibodies that will respond to the agent and destroy it in the future. For example, as a child you may have had the chickenpox. When you first contracted the illness, the body did not recognize the virus and did not know how to fight it. Your body did develop antibodies to the virus and, when the virus tries to invade your body in subsequent years, your immune system recognizes and destroys it quickly.

Vaccinations work the same way. By getting a vaccination against a particular illness, you stimulate the immune system to fight the invading bug. Because the body can successfully defend against the organism, you are not susceptible to the illness.

The body needs to be working at peak performance. Stress, fatigue, and inadequate nutrition can reduce the effectiveness of the immune system and increase the susceptibility to disease. Getting rest, avoiding stress, and eating properly will enhance the immune systems ability to fight viruses or bacteria that try to invade.

As with other links in the chain, if you are not susceptible to the infectious agent, the Chain of Infection is broken and you will not become ill.
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