Volume 84, Issue 3
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



In the United States, tickborne diseases occur focally. Missouri represents a major focus of several tickborne diseases that includes spotted fever rickettsiosis, tularemia, and ehrlichiosis. Our study sought to determine the potential risk of human exposure to human-biting vector ticks in this area. We collected ticks in 79 sites in southern Missouri during June 7–10, 2009, which yielded 1,047 adult and 3,585 nymphal , 5 adult , 19 adult , and 5 nymphal . Logistic regression analysis showed that areas posing an elevated risk of exposure to nymphs or adults were more likely to be classified as forested than grassland, and the probability of being classified as elevated risk increased with increasing relative humidity during the month of June (30-year average). Overall accuracy of each of the two models was greater than 70% and showed that 20% and 30% of the state were classified as elevated risk for human exposure to nymphs and adults, respectively. We also found a significant positive association between heightened acarologic risk and counties reporting tularemia cases. Our study provides an updated distribution map for in Missouri and suggests a wide-spread risk of human exposure to and their associated pathogens in this region.


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  1. Anderson JF, Magnarelli LA, , 2008. Biology of ticks. Infect Dis Clin North Am 22: 195215.[Crossref]
  2. Hall-Baker PA, Enrique Nieves J, Jajosky RA, Adams DA, Sharp P, Anderson WJ, Aponte JJ, Jones GF, Aranas AE, Rey A, Lane B, Wodajo MS, , 2009. Summary of notifiable diseases—United States, 2007. MMWR Morbid Mortal Wkly Rep 56: 194.
  3. Bacon RM, Kugeler KJ, Mead PS, , 2008. Surveillance for Lyme disease—United States, 1992–2006. MMWR Morb Mortal Wkly Rep 57: 19.
  4. Eisen RJ, Eisen L, , 2008. Spatial modeling of human risk of exposure to vector-borne pathogens based on epidemiological versus arthropod vector data. J Med Entomol 45: 181192.[Crossref]
  5. Diuk-Wasser MA, Gatewood AG, Cortinas MR, Yaremych-Hamer S, Tsao J, Kitron U, Hickling G, Brownstein JS, Walker E, Piesman J, Fish D, , 2006. Spatiotemporal patterns of host-seeking Ixodes scapularis nymphs (Acari: Iodidae) in the United States. J Med Entomol 43: 166176.[Crossref]
  6. Eisen RJ, Lane RS, Fritz CL, Eisen L, , 2006. Spatial patterns of Lyme disease risk in California based on disease incidence data and modeling of vector-tick exposure. Am J Trop Med Hyg 75: 669676.
  7. Randolph SE, , 2004. Tick ecology: processes and patterns behind the epidemiological risk posed by ixodid ticks as vectors. Parasitology 129: S37S65.[Crossref]
  8. Eisen L, , 2007. A call for renewed research on tick-borne Francisella tularensis in the Arkansas-Missouri primary national focus of tularemia in humans. J Med Entomol 44: 389397.[Crossref]
  9. Centers for Disease Control and Prevention, 2002. Tularemia–United States, 1990–2000. MMWR Morb Mortal Wkly Rep 51: 181184.
  10. Petersen JM, Mead PS, Schriefer ME, , 2009. Francisella tularensis: an arthropod-borne pathogen. Vet Res 40: 7.[Crossref]
  11. Spach DH, Liles WC, Campbell GL, Quick RE, Anderson DE, Fritsche TR, , 1993. Tick-borne diseases in the United-States. N Engl J Med 329: 936947.[Crossref]
  12. Farlow J, Wagner DM, Dukerich M, Stanley M, Chu M, Kubota K, Petersen J, Keim P, , 2005. Francisella tularensis in the United States. Emerg Infect Dis 11: 18351841.[Crossref]
  13. Hair JA, Howell DE, , 1970. Lone star ticks: their biology and control in Ozark recreation areas. Oklahoma State University Agricultural Experiment Station Bulletin B-679: 347.
  14. Hopla CE, , 1960. The transmission of tularemia organisms by ticks in the southern states. South Med J 53: 9297.[Crossref]
  15. Taylor JP, Istre GR, Mcchesney TC, Satalowich FT, Parker RL, Mcfarland LM, , 1991. Epidemiologic characteristics of human tularemia in the southwest-central states, 1981–1987. Am J Epidemiol 133: 10321038.[Crossref]
  16. Washburn AM, Tuohy JH, , 1949. The changing picture of tularemia transmission in Arkansas; a study of 704 case histories. South Med J 42: 6062.[Crossref]
  17. Eisen RJ, Mead PS, Meyer AM, Pfaff LE, Bradley KK, Eisen L, , 2008. Ecoepidemiology of tularemia in the southcentral United States. Am J Trop Med Hyg 78: 847847.
  18. Dennis DT, Cohen J, Powderly W, , 2003. Tularemia. , eds. Major Tropical Syndromes by Body System: Systemic Infections. London: Mosby, 16491653.
  19. Hardin LE, Satalowich FT, , 1998. Tick-borne disease summary—1997. Missouri Epidemiologist 20: 69.
  20. Assal N, Blenden DC, Price ER, , 1967. Epidemiologic study of human tularemia reported in Missouri, 1949–65. Public Health Rep 82: 627632.[Crossref]
  21. Burg JG, , 2001. Seasonal activity and spatial distribution of host-seeking adults of the tick Dermacentor variabilis . Med Vet Entomol 15: 413421.[Crossref]
  22. Kollars TM, Oliver JH, Durden LA, Kollars PG, , 2000. Host associations and seasonal activity of Amblyomma americanum (Acari: Ixodidae) in Missouri. J Parasitol 86: 11561159.[Crossref]
  23. Kollars TM, Oliver JH, Masters EJ, Kollars PG, Durden LA, , 2000. Host utilization and seasonal occurrence of Dermacentor species (Acari: Ixodidae) in Missouri, USA. Exp Appl Acarol 24: 631643.[Crossref]
  24. Zimmerman RH, Mcwherter GR, Bloemer SR, , 1987. Role of small mammals in population-dynamics and dissemination of Amblyomma americanum and Dermacentor variabilis (Acari, Ixodidae) at Land-Between-the-Lakes, Tennessee. J Med Entomol 24: 370375.[Crossref]
  25. Koch HG, , 1984. Survival of the lone star tick, Amblyomma americanum (Acari, Ixodidae), in contrasting habitats and different years in southeastern Oklahoma. J Med Entomol 21: 6979.[Crossref]
  26. Ginsberg HS, Ewing CP, , 1989. Comparison of flagging, walking, trapping, and collecting from hosts as sampling methods for northern deer ticks, Ixodes dammini, and lone-star ticks, Amblyomma americanum (Acari, Ixodidae). Exp Appl Acarol 7: 313322.[Crossref]
  27. Lane RS, , 1996. Risk of human exposure to vector ticks (Acari: Ixodidae) in a heavily used recreational area in northern California. Am J Trop Med Hyg 55: 165173.
  28. Durden LA, Keirans JE, , 1996. Nymphs of the Genus Ixodes (Acari: Ixodidae) of the United States: Taxonomy, Identification Key, Distribution, Hosts, and Medical/Veterinary Importance. Lanham, MD: Entomological Society of America.
  29. Keirans JE, Durden LA, , 1998. Illustrated key to nymphs of the tick genus Amblyomma (Acari: Ixodidae) found in the United States. J Med Entomol 35: 489495.[Crossref]
  30. Keirans JE, Litwak TR, , 1989. Pictorial key to the adults of hard ticks, family Ixodidae (Ixodida, Ixodoidea), east of the Mississippi River. J Med Entomol 26: 435448.[Crossref]
  31. Lillesand TM, Kiefer RW, , 1994. Remote Sensing and Image Interpretation. New York: Wiley.
  32. Crist EP, Kauth RJ, , 1986. The tasseled cap de-mystified. Photogramm Eng Remote Sensing 52: 8186.
  33. Lancaster JL, , 1957. Control of the lone star tick. Arkansas Agricultural Experiment Station Report Series 67: 116.
  34. Centers for Disease Control and Prevention, 1997. Case definitions for infectious conditions under public health surveillance. MMWR Recomm Rep 46: 155.
  35. Burnham KP, Anderson DR, , 2002. Model Selection and Multi-Model Inference: A Practical Information—Theoretic Approach. New York: Springer-Verlag.
  36. Kollars TM, Durden LA, Keirans JE, Oliver JH, , 1995. First records of Haemaphysalis (Aboimisalis) chordeilis, Ixodes (Ixodes) brunneus, and Ixodes (Pholeoixodes) banksi (Acari, Ixodidae) from Missouri. J Entomol Sci 30: 511512.
  37. Kollars TM, Oliver JH, , 2003. Host associations and seasonal occurrence of Haemaphysalis leporispalustris, Ixodes brunneus, I. cookie, I. dentatus, and I. texanus (Acari: Ixodidae) in southeastern Missouri. J Med Entomol 40: 103107.[Crossref]
  38. Hopla CE, , 1953. Experimental studies on tick transmission of tularemia organisms. Am J Hyg 53: 101118.
  39. Calhoun EL, Alford HI, Jr, 1955. Incidence of tularemia and Rocky Mountain spotted fever among common ticks of Arkansas. Am J Trop Med Hyg 4: 310317.
  40. Calhoun EL, , 1954. Natural occurrence of tularemia in the lone star tick, Amblyomma americanum (Linn.), and in dogs in Arkansas. Am J Trop Med Hyg 3: 360366.
  41. Koch HG, , 1988. Suitability of white-tailed deer, cattle, and goats as hosts for the lone star tick, Amblyomma americanum (Acari, Ixodidae). J Kans Entomol Soc 61: 251257.
  42. Koch KR, Burg JG, , 2006. Relative abundance and survival of the tick Amblyomma americanum collected from sunlit and shaded habitats. Med Vet Entomol 20: 173176.[Crossref]
  43. Childs JE, Paddock CD, , 2003. The ascendancy of Amblyomma americanum as a vector of pathogens affecting humans in the United States. Annu Rev Entomol 48: 307337.[Crossref]
  44. Paddock CD, Yabsley MJ, , 2007. Ecological havoc, the rise of white-tailed deer, and the emergence of Amblyomma americanum-associated zoonoses in the United States. Curr Top Microbiol Immunol 315: 289324.
  45. Eisen RJ, Eisen L, Girard YA, Fedorova N, Mun J, Slikas B, Leonhard S, Kitron U, Lane RS, , 2010. A spatially-explicit model of acarological risk of exposure to Borrelia burgdorferi-infected Ixodes pacificus nymphs in northwestern California based on woodland type, temperature, and water vapor. Ticks Tick Borne Dis 1: 3543.[Crossref]
  46. Eisen RJ, Eisen L, Lane RS, , 2006. Predicting density of Ixodes pacificus nymphs in dense woodlands in Mendocino County, California, based on geographic information systems and remote sensing versus field-derived data. Am J Trop Med Hyg 74: 632640.
  47. Eisen L, Eisen RJ, Lane RS, , 2006. Geographical distribution patterns and habitat suitability models for presence of host-seeking ixodid ticks in dense woodlands of Mendocino County, California. J Med Entomol 43: 415427.[Crossref]
  48. Kitron U, Kazmierczak JJ, , 1997. Spatial analysis of the distribution of Lyme disease in Wisconsin. Am J Epidemiol 145: 558566.[Crossref]
  49. Merten HA, Durden LA, , 2000. A state-by-state survey of ticks recorded from humans in the United States. J Vector Ecol 25: 102113.
  50. Hopla CE, Downs CM, , 1953. The isolation of Bacterium tularense from the tick, Amblyomma americanum . J Kans Entomol Soc 26: 7273.

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  • Received : 18 Oct 2010
  • Accepted : 21 Nov 2010

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