Epidemiologic Characteristics of Human Tularemia in the Southwest-Central States, 1981–1987

Abstract

From 1981 through 1987, a total of 1,041 cases of tularemia in humans were reported in Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas; this represents 60% of the cases reported in the United States during this same time period. The state of Arkansas reported the highest total (420 cases). Annual incidence rates per one million population ranged from 36.3 in Arkansas to less than 5.0 in Kansas, Louisiana, and Texas. Epidemiologic data were available for 1,026 cases. The majority of cases were white (88%) and male (75%). May, June, and July were the months of onset of symptoms for 52% of the cases. For the cases with known exposure history, 63% reported an attached tick and 23% had exposure to rabbits. Other animals associated with human infection were squirrels, cats, and raccoons. The case-fatality ratio was 2%. Public health efforts to prevent human tularemia cases in the six southwest-central states should focus on reducing exposure to ticks.

Histologic and molecular diagnosis of tularemia: a potential bioterrorism agent endemic to North America

“…1,3,4 Although the number of cases in the United States has declined since the mid-1900 s, many authorities think that tularemia is both markedly under-recognized and under-reported. 1,[3][4][5][6]16 Tularemia affects over 250 mammalian species including humans, and has also been found in invertebrates, water, mud, and feces. 1,3,17,25 Exposure from animals occurs primarily through skinning and dressing game, but ingesting contaminated meat and animal bites may also cause disease.…”

“…1,31 Typical symptoms and physical findings include fever (often high with chills), cutaneous ulcers, lymphadenopathy, headache, malaise, and fatigue; less common signs and symptoms include cough, sore throat, myalgias, chest pain, nausea, vomiting, diarrhea, and mental status changes. 1,5,16 The onset of symptoms is typically acute, following an average incubation period of 2-5 days (range 1-21 days). 1,2,7 Mortality in general is less than 10% with treatment; however, it increases dramatically to 30-60% if untreated, or if there is significant pulmonary involvement.…”

“…[1][2][3][4][5][6] This zoonotic bacterium is associated with arthropod vectors, and both wild and domestic animals (particularly cats that have eaten infected rodents or rabbits); transmission through water contaminated by infected rodents has also occurred. 2,7 Most human infections are acquired from arthropod bites, exposure to infected animals from skinning and dressing game, or inhalation of contaminated dust, dirt, and lawn clippings.…”

“…10,11 Approximately 200 cases per year are reported to the Centers for Disease Control and Prevention (CDC), mostly from the south-central United States. [4][5][6] However, FT has recently received an increased amount of attention as a Category A potential agent of bioterrorism, along with anthrax, smallpox, viral hemorrhagic fevers, and Yersinia pestis. 1,4,12 Owing to the high risk of inhalational infection from even low numbers of organisms (10-25 organisms required to produce disease by aerosol delivery), and a high mortality rate (30-60% for untreated inhalational FT), tularemia could potentially be a very effective bioterroristic weapon.…”

Characterization of secA-sod operon in Borrellia burgdorferi.

“…Additionally, A. americanum also may harbor Francisella tularensis, the etiologic agent of tularemia (Taylor et al, 1991), and E. chaffeensis, which is responsible for human monocytic ehrlichiosis (Dumler and Bakken, 1995).…”