Tick Survey

2011-2012 Utah Tick Survey

 

Female western black-legged tick (Ixodes pacificus) tick collected in Harker Canyon, Tooele County.  Jared Kunz, USU.

 

1. Reason for Survey
2. Summary and Objectives
3. Survey Plan and Sites
4. Western Black-Legged Tick Biology and Distribution
5. Can I submit a tick for identification?
6. Tick Links

 

Current Results
Collection sites in Utah and Tooele Counties
Tick Survey Image Gallery



1. Reason for Survey

Since the initial diagnosis, Lyme disease has climbed to the top of the vector-borne diseases list in the US (Bacon et. al, 2008), affecting over 274,268 Americans between 1995 and 2009 primarily in the northeastern US (Center for Disease Control, 2011). In recent years Utah has received an average of eight Lyme disease cases per year, however, none of these cases are believed to have originated in Utah, but are due to out-of-state travel to areas where Lyme disease naturally occurs. In 2010, a few residents from Lehi, Utah were associated with a potential Lyme disease cluster (Utah Department of Epidemiology, 2010), prompting the Utah County Health Department (UCHD) and the Utah Department of Health (UDOH) to form a task force to examine the validity of these Lyme disease cases. UDOH and Utah State University (USU) are interested in understanding the prevalence of Lyme disease and it's tick vector (the western black-legged tick) in Utah. Money provided by Utah State University Extension, the Center for Disease Control, and the Utah Bureau of Epidemiology are funding the tick survey for 1 year. To date, the findings of the task force have yielded no confirmed cases of Lyme disease originating in Utah. 



2. Summary and Objectives

Human Lyme disease in Utah continues to be of public health concern, both in rural and suburban habitats.  Little research or outreach have been performed examining the presence of Lyme Borrelia in Utah. We will collect Western black-legged ticks in northern and southern Utah and test for presence or absence of Borrelia burgdorferi, the causal agent of Lyme disease, using molecular tests. Knowing the prevalence of Lyme disease in Utah, as well as identifying specific habitat where tick populations exist, is valuable information for private physicians, local, state and federal public health professionals, and the citizens of Utah. If Borrelia is detected in Utah, healthcare professionals could make faster, more accurate diagnoses for patients showing Lyme-like symptoms leading to proper treatment; citizens could take extra precautions when traveling in tick habitat; and, community-wide tick control programs could be implemented in high-risk habitats.  The information will also be important to bordering states so that health professionals can determine if Lyme disease exists in close geographical areas, where their citizens may pick up infected ticks while traveling in Utah. Objectives:

1. Select high-risk tick habitat in northern Utah and collect ticks
2. Identify and Test ticks for the presence of the Lyme disease-causing bacteria Borrelia burgdorferi
3. Distribute outreach education materials with our findings  



3. Survey Plan and Sites

Sites were selected based on their suitability as tick habitat. Prime habitat includes areas along forest/field edges, in low-lying river basins, or along game trails where hosts (e.g. rodents and deer) are abundant or frequently travel. These areas were selected using GIS host distribution and vegetation data provided by the Utah Division of Wildlife Habitat, areas of prior Ixodes pacificus collection, visual inspection, and on the recommendations of county Extension agents, state and federal wildlife or forest employees, and citizens. In spring/summer 2011, tick collection was focused in Utah and Tooele Counties.  With additional funding from the CDC and the Utah Bureau of Epidemiology, the survey was expanded to Washington and Juab counties in the Fall of 2011.  To view site pictures and descriptions for surveyed areas in 2011 click here. A map of sites surveyed in 2011 is below. (Images of sites surveyed after July 22 have not yet been added to this page). Fifty-one sites were surveyed in 2011.   


Map of collection sites in Utah,Tooele, Juab and Washington Counties in 2011. 

Sites surveyed for ticks in northern UT, 2011. Red marks indicate locations where ticks were found. The two red marks near Dutch Peak in the SW corner of the map (Tooele Co.) are where western black-legged ticks (Ixodes pacificus) were found.  

Sites surveyed in southern UT in 2011. Red marks indicate locations where ticks were found. The northern red mark SW of Enterprise is where 2 western black-legged ticks (Ixodes pacificus) were found.   



Ticks were collected using a 1 x 1.25m white flannel cloth (“flag”) with a dowel rod attached to the anterior end using staples, and a chain hemmed into the posterior end.  Rope was attached to the protruding ends of the dowel rod and the flag was dragged over vegetation where there were suspected questing tick populations.  Questing ticks that adhered to the flag were collected from the flag using forceps, and stored in individual vials containing 70% ethyl alcohol for identification and testing at a later date.

Jared Kunz constructs tick drag.

Finished tick drag.

Jared Kunz drags for ticks at Harker Cn.

All ticks were identified using a light stereoscope. After identification, the DNA was extracted from Ixodes pacificus ticks using a Qiagen DNeasy extraction kit.  The DNA was then used to perform a nested PCR technique to detect presence or absence of Borrelia burgdorferi.  Finally, the PCR product will undergo DNA sequencing for further genetic analysis.  



  4. Black-Legged Tick Biology and Distribution in Utah


Ixodes pacificus
 is a hard tick in the family Ixodidae. The exact life cycle of Ixodes pacificus in Utah is unknown, however it follows the typical three-host tick cycle as outlined by Sonenshine (1991). Adult females take a blood meal from a large invertebrate host (e.g. deer, canine, human), drop to the ground, mate, and lay eggs. Feeding of the adult female may occur in fall or spring, or when conditions are appropriate. Upon egg hatch, six-legged larvae emerge and search for small invertebrate hosts (e.g. rodents, lizards).  If a host islocated, a blood meal may be taken over several days. Fed larvae drop and molt into eight-legged nymphs, which quest for hosts in fall, or the following spring. Nymphs that successfully feed will molt to adults, which feed in fall, or spring of the following year.  Feeding is mandatory for reproduction and molting between developmental stages. The life cycle in Utah likely takes two to three years to complete as it does in northern California (Padgett and Lane, 2001).

 

Typical life cycle of a 3-host tick.  Image taken from the Center for Disease Control. 

 

Tick activity and development depend on environmental factors such as habitat type, temperature, and humidity (Padgett and Lane, 2001; Eisen, et al., 2002; Eisen et al., 2010). In Utah, Ixodes pacificuscan be found in varied habitats from hot, dry desert scrub, to cool, moist higher elevation coniferous forests (Allred et al., 1960).  The location and timing of Ixodes pacificus activity, in addition to host preference, can be extrapolated from historic tick collection data (Allred et al. 1960) (see map below). In Utah, Ixodes pacificus ticks have been collected from Beaver, Juab, Millard, Tooele, and Washington counties, but most frequently from Utah County, our targeted collection area.  Collection dates for Ixodes pacificus in Utah range from April to November.  Allred (1960) reports larvae and nymphs from April and July, adult males and females in July and October, and adult females also in November.  In general, we expect that ticks in hotter, arid parts of the state (e.g. Washington County) to reach peak activity in April and May, and ticks at higher elevations (e.g. Provo Canyon in Utah County) to be active from May through July.  Ticks at all geographical locations can be active in the fall when temperatures cool and moisture increases. In Utah, ticks were collected from hosts such as: mule deer (Odocoileus hemionus), humans (Homo sapiens), cactus mouse (Peromyscus eremicus), deer mouse (Peromyscus maniculatus), pinyon mouse (Peromyscus truei), magpie (Pica hudsonia), and dogs (Canis familiaris).
 

Historic records of western black-legged tick (Ixodes pacificus) in Utah.  Adapted from Allred, Beck, and White 1960.

 



5. Can I submit a tick for identification? 

Submitting ticks collected from any UT location is encouraged.  Ticks can be submitted to the Utah Plant Pest Diagnostic Lab free of charge, however, prompt identifications and responses will not be provided.  Information from resident-collected ticks will be compiled with data from the survey and will be published in an Extension fact sheet on ticks and on this website.  When submitting a tick be sure to include the following information: 

  1. Your Name
  2. Date of tick collection
  3. Specific location of tick collection (place name or gps coordinates)
  4. What the tick was collected from: human, dog, deer, elk, etc. 
  5. *Place ticks in a vial containing 70% ethanol for submission (water and rubbing alcohol will work)
  6. Send Ticks to:

    Utah State University
    5305 Old Main Hill
    Logan, UT 84322
     

If you want a tick identified as part of our normal services, which includes an identification and quick response, please follow the submission directions ($7.00 fee and submission form required).

 


 

6. Tick Links

Biology

University of California, Davis 


Lyme in Utah

Bureau of Epidemiology 1 
Bureau of Epidemiology 2
Center for Disease Control

General

Center for Disease Control
Ticks Commonly Encountered in CA
How to Remove a Tick