Hantavirus (Forensic Science)
Although hantaviruses have been known to exist since the 1950s, the first reported case of hantavirus pulmonary syndrome (HPS) occurred in May of 1993 in the American Southwest. Over the next fourteen years, according to the Centers for Disease Control and Prevention, more than 450 confirmed cases of HPS occurred in the United States, and at least 35 percent of these resulted in death. Most of the incidents took place in the southwestern United States, but cases of HPS have been confirmed in thirty states.
The Sin Nombre virus (SNV) is transmitted primarily through the inhalation of aerosolized droplets of rodent saliva, urine, or feces. The deer mouse has been implicated as the primary carrier, although other carriers have been identified, including the cotton rat, the rice rat, and the white-footed mouse. It is possible that other rodents carry the virus as well. Transmission of the virus by other methods is rare, but cases have been found in which infected persons contracted the virus by being bitten by infected rodents, by eating foods contaminated with infected rodent bodily fluids, or by touching contaminated surfaces and then touching mucous membranes, such as inside the mouth.
Hantaviruses are composed of a spherical fatty envelope surrounding a three-segmented RNA (ribonucleic acid) genome. HPS has an incubation period of one to five weeks; early symptoms can include a high fever, headache, aching, dizziness, chills,...
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Further Reading (Forensic Science)
Casil, Amy Sterling. Hantavirus. New York: Rosen, 2005.
Fleming, Diane O., and Debra Long Hunt. Biological Safety: Principles and Practices. Washington, D.C.: ASM Press, 2000.
Schmaljohn, Connie S., and Stuart T. Nichol. Hantaviruses. New York: Springer, 2001.
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Causes and Symptoms (Magill’s Medical Guide, Sixth Edition)
Hantavirus, which is distantly related to Ebola virus, is transmitted through contact with the urine and droppings of wild rodents, such as the deer mouse and cotton rat. Contact usually involves the inhalation of contaminated particles in dust. Hantavirus is not transmissible between humans.
Infection takes two major forms. In South America, one strain causes hemorrhagic fever with renal syndrome, involving kidney failure, hemorrhaging, and shock. In the United States, another strain results in hantavirus pulmonary syndrome. Early symptoms mimic influenza; they include fever, chills, muscle aches, nausea and vomiting, malaise, and a dry cough. After initial improvement, increasing shortness of breath follows and may progress to pulmonary edema, internal bleeding, respiratory failure, and death.
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Treatment and Therapy (Magill’s Medical Guide, Sixth Edition)
Diagnosis of hantavirus pulmonary syndrome involves physical examination for hypoxia, hypotension, and adult respiratory distress syndrome. Laboratory tests show an elevated white blood cell count and a decreasing platelet count, and chest X rays may reveal edema. The presence of hantavirus is confirmed through serological testing.
There is no cure for hantavirus pulmonary syndrome; treatment is focused on alleviating the symptoms. This condition must be treated in the intensive care unit (ICU) of a hospital, as careful monitoring of respiratory function and blood gases is essential. In severe cases, the use of an endotracheal tube and a ventilator becomes necessary. Experiments have been performed with intravenous ribavirin therapy; the efficacy of this treatment is being evaluated. Unfortunately, even with aggressive measures, the death rate ranges from 50 to 80 percent.
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Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
The incidence of hantavirus pulmonary syndrome seemed to rise sharply in the 1990’s. Epidemiologists were uncertain whether the number of cases increased or more cases were reported following identification of the virus in the United States in 1993.
Because much remains to be learned about the transmission, development, and treatment of hantavirus infection, public health efforts have been in education and prevention. Hikers and campers are thought to be at a greater risk; they are urged to avoid exposure to rodent droppings and questionable water sources. People entering cabins, sheds, or other buildings that have not been used recently should air out the building first and use disinfectant on all surfaces.
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For Further Information: (Magill’s Medical Guide, Sixth Edition)
Centers for Disease Control. http://www.cdc.gov/ncidod/diseases/hanta/hps.
Cockrum, E. Lendell. Rabies, Lyme Disease, Hanta Virus, and Other Animal-Borne Human Diseases in the United States and Canada. Tucson, Ariz.: Fisher Books, 1997.
Kumar, Vinay, et al., eds. Robbins Basic Pathology. 8th ed. Philadelphia: Saunders/Elsevier, 2007.
Meyer, Andrea S., and David R. Harper. Of Mice, Men, and Microbes: Hantavirus. San Diego, Calif.: Academic Press, 1999.
Murray, Patrick R., Ken S. Rosenthal, and Michael A. Pfaller. Medical Microbiology. 6th ed. Philadelphia: Mosby/Elsevier, 2009.
Pan American Health Organization. Hantavirus in the Americas: Guidelines for Diagnosis, Treatment, Prevention, and Control. Washington, D.C.: Author, 1999.
Sompayrac, Lauren. How Pathogenic Viruses Work. Boston: Jones and Bartlett, 2002.
Strauss, James, and Ellen Strauss. Viruses and Human Disease. 2d ed. Boston: Academic Press/Elsevier, 2008.
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