February 2003 TularemiaOverviewTularemia (also known as deerfly fever or rabbit fever) is an infectious disease caused by the bacterium Francisella tularensis. It is naturally found in small mammals such as rabbits, rodents, and hares, as well as the insects that feed on these animals. The bacteria can survive for weeks at low temperatures in water, moist soil, hay, straw, or decaying animal carcasses. Tularemia was first described by scientists in 1911, and its ability to infect whole populations was seen during outbreaks of waterborne disease in Europe and the Soviet Union in the 1930s and 1940s.There are about 200 reported cases of human tularemia in the United States every year. Most occur in rural areas in the south-central and western states. Of these cases, less than 2 percent are fatal. The MicrobeF. tularensis has two subspecies.
TransmissionThe most common ways people contract tularemia are
Tularemia also can be spread by
In Europe, there have been cases of the disease caused by inhaling airborne bacteria generated during farm work, such as moving infected hay. Laboratory workers also can become infected by inhaling bacteria while examining an open culture plate, for example. There are no documented cases of human-to-human transmission. SymptomsTularemia infection varies from a mild illness to acute sepsis (serious infection of the blood or other tissues) and rapid death. After exposure to the bacteria, a person will usually develop symptoms within 3 to 5 days, but they can take up to 21 days to appear. Symptoms include
In most patients, progressive weakness leads to a dry cough and pneumonia. Tularemia-induced pneumonia can cause chest pain, bloody sputum, and trouble breathing. Depending on how a person was exposed to the bacteria, other symptoms may include
The inhalation form of tularemia begins 3 to 5 days after exposure. In some cases, pneumonia develops after several days or weeks. If left untreated, the disease could lead to respiratory failure. DiagnosisHealth care workers can diagnosis tularemia by doing laboratory tests on blood or sputum.TreatmentAntibiotics, such as doxycycline or ciprofloxacin, can effectively treat people with tularemia. A tularemia vaccine strain is being reviewed by the U.S. Food and Drug Administration, but its future availability is uncertain, mainly because of the length of time it takes for the vaccine to work (about 2 weeks).The U.S. Department of Defense also has developed an experimental tularemia vaccine. To date, health officials have limited the use of this vaccine to laboratory and other high-risk workers. How common is tularemia?Health experts believe that tularemia is underrecognized and underreported. There are approximately 200 reported cases in the United States each year. Most cases occur in rural areas from June through September (tick season) and generally infect hunters. From 1995 to 1997, approximately half of all U.S. tularemia cases were reported from Missouri, Oklahoma, Kansas, and Arkansas. Worldwide, the disease occurs in Eurasia-most commonly in northern and central Europe-and almost always in rural areas.ResearchThe National Institute of Allergy and Infectious Diseases (NIAID) is part of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services. NIAID supports research on the diagnosis, prevention, and treatment of infections caused by microbes, including those that have the potential for use as biological weapons. The research program to address biodefense includes both short- and long-term studies targeted at designing, developing, evaluating, and approving specific tools (diagnostics, therapies, and vaccines) needed to defend against possible bioterrorist-caused disease outbreaks.Institute research goals to diagnose, prevent, and treat tularemia include
More InformationNational Institute of Allergy and Infectious Diseases31 Center Drive, MSC 2520 Bethesda, MD 20892-2520 http://www.niaid.nih.gov National Library of Medicine U.S. Centers for Disease Control and Prevention Johns Hopkins University Center for Civilian Biodefense Studies
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