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The Hanta Virus
The hanta virus is not a new foe to humanity. This mysterious and sometimes fatal disease has plagued humanity for over 1000 years. This virus, most likely originating in China over 1000 years ago, is transmitted by human contact with mice. Only relatively recently has the hanta virus captured the attention of the United States. Although the hanta virus has been known for such a long time, there is little known about the virus. In the United States most cases are found in the southwestern part of the country, although cases have been reported from all four corners of the country. Recently, there have been successful tests done on prospective vaccines for the hanta virus. Despite this, strains of the hanta virus kill many people a year for lack of an effective medicine or vaccine (www.pharminfo.com).
The hanta virus can be found in the North America, South America, Europe and Asia. In North America, most cases are found in the United States (www.pharminfo.com). Most of the cases of hanta virus in the United States occur in the “Four Corners” region. This is a reference to the area in which Arizona, New Mexico, Utah and Colorado meet. As of March 17, 1997, there were 26 states that had confirmed cases of the hanta virus (www.bepestfree.com). In South America, cases can be found in Argentina (www.latinolink.com). The European cases mostly originated in Scandinavia, western Europe and the Balkan mountains. The strain of the hanta virus found here is comparatively mild symptoms. In Asia, the hanta virus is primarily found in China, Korea and the eastern part of the former Soviet Union. The symptoms of this strain of the hanta virus are more severe (www.pharminfo.com). There are, as of March 1997, four different strains of the hanta virus that have been identified (www.bepestfree.com).
The hanta virus is usually transmitted by a species of mice commonly known as deer mice, or Peromyscus maniculatis. The mice are described as having “brownish-gray fur, a white stomach and disproportionately large ears” (www.slac.stanford.edu). An infected mouse can spread the hanta virus if a human comes in contact with its urine, feces, saliva or dead body. Inhalation of the dust or tiny particles that spread into the air when any of the above are touched or moved are what spread the virus (www.slac.stanford.edu). The virus is most active and likely to cause infection in temperatures between 45oF and 72oF (www.bepestfree.com). There can be no human to human transmission of this virus, therefore it is not spread by people but only by deer mice (www.slac.stanford.edu). Most infections of the hanta virus resulted from contact with mice or their droppings in homes while cleaning (Ince).
The first symptoms of the hanta virus are often characterized as flu-like. This includes a fever, coughing and muscle fatigue (www.pharminfo.com). Other beginning symptoms may also include chills, nausea, vomiting, diarrhea and stomach pain (www.bepestfree.com). Untreated or severe cases can lead to fluid in the lungs, causing respiratory failure and ultimately, death (www.nmus.edu). Not typically reported, the hanta virus can also cause kidney failure, again with the possibility of leading to death (www.latinolink.com). As of March 17, 1997, there were 158 confirmed cases of the hanta virus in the United States (www.bepestfree.com). As of July 1996 there were 133 cases of the hanta virus confirmed in the United States, and approximately half of these cases lead to death (www.nmsu.edu).
There are several steps that can be taken to reduce the risk contracting the hanta virus. One highly recommended measure is to spray mouse feces, dead mice or areas inhabited by mice with a water and bleach solution (5:1). After this, all work done around the area, such as cleaning, should be done while wearing rubber gloves and a dust mask. All contamination by mice should be removed from the area (www.slac.stanford.edu). It is good measure to thoroughly air out any closed buildings before entering them, so that the infectious particles have somewhat dissipated (www.bepestfree.com). As it is always stated, never move dead mice or droppings with a vacuum cleaner or a broom, as this will send the infectious particles into the air to be inhaled (www.slac.stanford.edu).
As of June 1997, there was at least one program dedicated to discovering more about the deer mouse and its connections to humans and the hanta virus. The Montana State University and the Centers for Disease Control and Prevention (CDC) are both funding a project known as “Mouse in the House”. Since mice must come into close contact with humans for the hanta virus to be spread, studies are being done on the mice that live near humans, not in fields. Biology professor Rick Douglass and microbiologist Clifford W. Bond have worked on the program since it began in 1994. Douglass commented that though many people would think that mice that live in homes have been thoroughly studied and understood, this is a misconception. The information that is known about mice that live in homes usually does not deal with deer mice, the prime vectors of the hanta virus. Don White Jr., a research professor, leads the necessary trapping and cataloging of the deer mice surrounding the buildings of two chosen ranches in Montana. These mice have blood samples taken from them, which are sent to a lab to determine if they carry the hanta virus. Some of these mice are outfitted with tiny radio transmitters, approximately the size of a pencil eraser. Others are marked with paint which can only be seen under a black light. The deer mice are then tracked to see where and how they live in the vicinity of humans. This three year program ended approximately in October of 1997. The final data and results are still not available, but the hope of the “Mouse in the House” project team was to help in the understanding of deer mice and the hanta virus, and preventing further deaths (www.montana.edu).
Late in 1996, there was an outbreak of the hanta virus in a small town of Argentina, named El Bolson. The town consisted of 18,000 people, most of whom depended on the town s tourist industry to survive. Since ten members of the community had died within three months, the town has been virtually boycotted. A lack of correct information and a overzealous media have caused nearby towns to refuse to accept all products from the town, such as fruits and vegetables. The hanta virus is only able to be contracted by contact with mice and their feces, however this fact seems to have been lost. Politicians attempted to comfort travelers by saying that there is little or no chance of infection to a mere tourist, however this did not bring business back to El Bolson. The town had fought the virus, disinfecting all their homes and attempting to kill off all the mice in the area. This is an example of how miscommunication and public fear, fanned by the outbreak of a virus, can easily ruin a local economy. Ten people have died, but 18,000 were suffering in El Bolson (www.latinolink.com).
Recently there has been much work done in the attempt to find a medicine to alleviate the symptoms of infected persons. A vaccine for the hanta virus is a long term goal which has not been obtained. However, two experimental medicines for persons infected with hanta virus are being tested, with promising results.
In China, where 100,000 people a year contract the hanta virus, antiviral ribavirin is being tested as a treatment to the hanta virus. Antiviral ribavirin decreases the severity and the length of the symptoms of the hanta virus. In order to be effective, the drug must be given to the patient within five days of contraction of the virus. This can be difficult, because the hanta virus first symptoms resemble that of the flu. Antiviral ribavirin is now being used and tested in seven hospitals in the United States, in Arizona and New Mexico. Throughout the world, ribavirin is used to treat viral infections, such as herpes and hepatitis. In the United States, this drug is only used to treat infant respiratory syncytial viral infection. Ribavirin is used for many viral infections because it is proven to block the synthesis of viral nucleic acid, although it is not clear as to why this occurs. The Centers for Disease Control and Prevention say that, ” ribavirin is 100 percent lethal to vitro against all known hanta viruses” (www.pharminfo.com). This drug is produced by ICN Pharmaceuticals, which calls the product Virazole (www.pharminfo.com).
Another potential aid in the fight against the hanta virus is a drug called Bradycor, produced by Cortech Incorporated. This drug is also being tested in the Southwestern part of the United States. Bradycor is a new bradykinin antagonist, which is, ” a potent vasodilator and inflammatory mediator ” (www.pharminfo.com). This antagonist is naturally found in elevated levels in patients with the hanta virus. It is believed that additional bradykinin may help people who have contracted the hanta virus survive the ordeal. The drug is currently being tested in 45 centers throughout the United States, for patients thought to have been infected with the hanta virus (www.pharminfo.com).
The hanta virus has become a growing threat in the United States. Although the number of cases of hanta virus in the United States has dropped since 1993, much research must be done on this deadly rodent borne virus (www.nmsu.edu). Not enough information about the deer mice that carries this disease has been obtained, although this is being remedied. As with all deadly viral infections, the main goal is prevention. A vaccine is being researched, however this break through may not occur in the near future. Right now, alleviating the symptoms of the hanta virus is an obtainable goal. Although neither of the two drugs mentioned herein are in general use, they may become standard weapons in the war against the hanta virus. A big step towards preventing hanta virus infection is to be careful around any sort of mouse or mice feces. Simply taking the steps mentioned in this report could reduce the risk of people contracting the hanta virus and possibly dying.
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