LYME DISEASE RISK ASSESSMENT, LAKE CITY ARMY AMMUNITION PLANT, INDEPENDENCE, MISSOURI, 13-18 JUNE 1993 DEPARTMENT OF THE ARMY US Army Environmental Hygiene Activity-West Fitzsimons Army Medical Center Aurora, Colorado 80045-5001 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: HSHB-AW-P (40-5f) 26 July 1993 LYME DISEASE RISK ASSESSMENT NO. 16-66-A12D-93 LAKE CITY ARMY AMMUNITION PLANT INDEPENDENCE, MISSOURI 13-18 JUNE 1993 1. REFERENCE. See Appendix A for a list of references. 2. AUTHORITY. a. AEHA Form 250-R, U.S. Army Health Services Command, 7 July 1992. b. Memorandum, USAEHA, HSHB-ME, 21 September 1992, subject: U.S. Army Environmental Hygiene Agency Scehdule of Field Services, FY 93. 3. PURPOSE. The purpose in performing this risk assessment was to survey for Lyme disease vectors, to determine the prevalence of the infective agent (Borrelia burgdorferi) in rodents and ticks, and to assess the risk of Lyme disease to Lake City Army Ammunition Plant (LCAAP) personnel. See Appendix B for other assistance that can be obtained from the U.S. Army Environmental Hygiene Activity-West (USAEHA-W). 4. GENERAL. a. This Activity's Entomological Sciences Division has been providing educational training to give people a better understanding of Lyme disease. During this survey, a video tape, "Lyme Disease, A Growing Threat", was shown to the Coordinator, Natural Resources and five personnel from the Missouri Department of Health, Bureau of Communicable Disease Control. b. Risk Definition. The term "risk", as used in this report, is a non- statistical determination of qualitative and quantitative information available to evaluate the potential to acquire Lyme disease. To the extent available, information evaluated includes the following elements of the Lyme disease cycle: (1) History of Lyme disease in the area. (2) The presence or absence of the tick vector, the black-legged tick, Ixodes scapularis, and the mammalian host population needed to sustain a viable population of the vector. (3) The presence of the Lyme disease-causing spirochete, B. burgdorferi, in the tick population or in the mammalian reservoir host population. (4) The presence of antibodies to B. burgdorferi in the mammalian host population. The criteria for risk categorization are: Low risk - Some element of the Lyme disease cycle identified in nearby areas but not on the installation. Moderate risk - Some elements of Lyme disease cycle identified from the installation or human cases of Lyme disease identified from the local area. High risk - All elements of the Lyme disease cycle are present on the installation. c. Dr. Lester D. Hale and PV2 Michael Watson, the Survey Officers, discussed the findings and recommendation with LCAAP personnel. See Appendix C for a list of personnel contacted. d. The field survey portion of the Lyme Disease Risk Assessment was conducted at LCAAP on 13-18 July 1993. The laboratory analyses of ticks and rodent ear biopsies were conducted between 21 June - 13 July 1993. 5. BACKGROUND. a. Lake City Army Ammunition Plant is located in northeastern Jackson County, seven miles east of Independence, Missouri. The Plant lies between U.S. Highway 24 on the north and Interstate Highway 70 on the south, and is bordered by Missouri State Highway 7 on the west. The installation encompasses approximately 4000 acres, much of it covered by black ash and green walnut trees. The primary mission of the Plant is to manufacture small caliber ammunition and associated explosive/pyrotechnic materials. Personnel of the Ballistic Service Office perform tests and examinations of the small caliber ammunition on firing ranges. b. Missouri reported 101 cases of Lyme disease for 1992 (Reference 1); this included seven cases from Jackson County. No cases of Lyme disease have been reported from LCAAP. 6. METHODS. a. Field Survey Procedures. (1) Tick surveys. The tick collecting methods at LCAAP included using tick drag cloths, tick flags, and carbon dioxide traps. Ticks were also removed from the ears of trapped rodents. All ticks were kept alive by placing them in water-moistened vials as described in the USAEHA-W, Entomological Sciences Division (ESD) Standing Operating Procedures (SOP) No. 6 and No. 8. For each collection site, all collected ticks were identified, counted, and placed into a marked vial. Ticks collected at different sites were kept segregated and placed into separately marked vials and hand-carried to the USAEHA-W, ESD Laboratory. (a) Tick Drag Techniques. Two narrow boards (1x2x36-inch) were attached on opposite ends of a 3x3-foot white flannel cloth. A cord was fastened to the ends of one board. The cloth was then pulled slowly over vegetation for approximately 10 meters before examination for attached ticks. Ticks were then removed from the cloth and placed in a marked vial for that particular dragging operation. (b) Tick Flag Technique. A 3x3-foot piece of white flannel cloth was dragged over the tops of large vegetation, i.e., sagebrush or was used on steep slopes. Attached ticks were then removed from the cloth and placed in a marked vial for each collection site. Approximately 15,895 linear meters were covered by team members doing the dragging and the flagging. (c) Carbon Dioxide Traps. A 2x2-foot piece of white flannel cloth was placed on the ground with the edges weighted down with stones. An aluminum foil covered pie plate was placed upside down in the middle of the cloth. Approximately 2 pounds of dry ice were wrapped in newspaper and placed on top of the plate. The area around each trap and the cloth were checked for ticks after 2 to 3 hours. (2) Rodent Surveys. Rodents trapped at LCAAP were identified using " A Field Guide to the Mammals, North America, north of Mexico" (Reference 4). All rodents were handled in accordance with the guidelines outlined in the National Institutes of Health Publication No. 85-23, Revised 1985, "Guide for the Care and Use of Laboratory Animals" and USAEHA-W, ESD SOP No. 7. (a) Small mammals were captured in live traps (3x3x10 inches) on LCAAP. At each site, several trapping locations were selected and one or more trap lines were set in each area. The traps were usually located near stream beds, ponds, and on wooded hillsides with traps located approximately 10 meters apart. From 20 to 42 traps were set at each location for a single night. (b) Each rodent was anesthetized before removing any ticks or taking an ear biopsy. The ear biopsy was placed in a labeled vial containing a phosphate buffer solution and then frozen on dry ice. (3) Specimen Handling Procedures. The ticks collected from rodents and from dragging and flagging vegetation during 13-18 June were hand-carried to the USAEHA-W, ESD Laboratory for identification and analysis. b. Laboratory Assay Procedures. (1) All rodent ear biopsies were surface decontaminated, cut into small pieces, and placed in BSK II, a liquid culture medium specially developed to promote the growth of B. burgdorferi. If any of the trapped rodents were serving as the reservoir hosts for Lyme disease, the spirochetes should grow in the medium. (2) Ticks collected from the rodents and from vegetation were processed by using either darkfield or immunofluorescent microscopy or by using the Polymerase Chain Reaction (PCR) technique. 7. FINDINGS AND DISCUSSION. a. Tick Collections. Ticks were collected by dragging and flagging over the vegetation and from the carbon dioxide traps. Table 1 shows the sites, map coordinates, number, and tick species collected by the various methods at LCAAP. There were 2 Ixodes dentatus, 1369 Lone Star ticks, Amblyomma americanum, and 5 American dog ticks, Dermacentor variabilis, collected from dragging and flagging. There were 211 A. americanum, and 4 D. variabilis collected from carbon dioxide traps. Table 2 shows the number and life stage of D. variabilis removed from the 19 captured rodents. TABLE 1. Number of Ixodes dentatus, Amblyomma americanum, and Dermacentor variabilis, Collected by Dragging, Flagging, and from Carbon Dioxide Traps at Lake City Army Ammunition Plant, Independence, Missouri. --------------------------------------------------------------------------- NUMBER OF TICKS ------------------------------------------ SITE I. dentatus A. americanum D. variabilis --------------------------------------------------------------------------- Veterans Lake 0 30A,126N 0 (941305, 390615)* Firebreak West of Veterans Lake 0 22A,25N 0 (941310, 390620) Landfill Area 1N 128A,248N 4A (941350, 390620) Residential Hill Area 0 63A,128N 0 (941640, 390505) Residential Timber Tract 1N 56A,88N 0 (941640, 390525) 1600 Yard Firing Range 0 12A,50N 0 (941430, 390540) 1600 Yard Firing Range Firebreak 0 70A,277N 1A (941425, 390550) Compost Area 0 86A,103N 4A (941550, 390505) Residential Stream 0 55A,13N 0 (941610, 390455) -------------------------------------- TOTAL 2A 522A,1058N 9A * Map coordinates given as longitude and latitude; based on Lake City Army Ammunition Plant Photography Map (Independence, Missouri, 1 inch = 600 feet) dated 30 March 1988. A - Adult N - Nymph --------------------------------------------------------------------------- b. Rodent Collections. Four species of rodents were captured at six sites on LCAAP (see Table 2). The deer mouse was the most common rodent captured. Dermacentor variabilis was the only species of tick removed from these rodents. c. Laboratory Results. Detailed information on the laboratory results, are given in Appendix D. (1) Ticks. The A. americanum and D. variabilis examined by darkfield microscopy, immunofluorescent microscopy were negative for B. burgdorferi. (2) Rodent Ear Biopsies. Nineteen rodent ear biopsies were cultured in BSK II media for spirochetes. All samples were negative for B. burgdorferi, suggesting that the spirochete had not circulated within the small number of rodents sampled at LCAAP. TABLE 2. Number of Dermacentor variabilis Removed from Rodents at Lake City Army Ammunition Plant, Independence, Missouri. --------------------------------------------------------------------------- RODENTS --------------------------------- SITE No. SPECIES Dermacentor variabilis --------------------------------------------------------------------------- Veterans Lake 1 Peromyscus maniculatus 4L (Deer mouse) 1 Peromyscus leucopus 1N (White-footed mouse) Landfill Area 1 Peromyscus maniculatus 1L (Deer mouse) Residential Stream Area 4 Peromyscus maniculatus 5N (Deer mouse) Residential Timber Tract 5 Peromyscus maniculatus 3N,2L (Deer mouse) Building 3 North Field 1 Spermophilus tridecemlineatus 0 (Thirteen-line ground squirrel) 2 Microtus ochrogaster 0 (Prairie Vole) Little Blue Project 4 Peromyscus maniculatus 9N Control (Deer mouse) ----- --------- TOTAL 19 18N,7L N - Nymph, L - Larva. --------------------------------------------------------------------------- d. Lyme Disease Risk. (1) During the field survey portion of this Lyme disease risk assessment, many ticks were collected by dragging and flagging, and from carbon dioxide traps. This information reflected comments from installation personnel that ticks were often encountered by people exposed to outdoor field environments on LCAAP. (2) No Lyme disease spirochetes were recovered from either the ticks or from the rodent ear biopsies collected during this assessment. (3) The categories defined in paragraph 4b were used to describe the human health risk from Lyme disease at LCAAP. The data collected during this assessment indicated that one criterion for acquiring Lyme disease were present--human cases of Lyme disease have been documented from the local area. No human cases, however, have been documented as originating on the installation. While the Risk Definition criteria suggest a Moderate risk, the actual risk to LCAAP personnel may be Low because no I. scapularis were found on the installation. While Ixodes scapularis may be a competent vector of Lyme disease and is found in other parts of Missouri, personnel from the State of Missouri and Jackson County Health departments stated that I. scapularis had not been found in Jackson County. Two other species of ticks, I. dentatus and D. variabilis, were found on the installation, but these ticks are probably not potential vectors of Lyme disease to humans. Ixodes dentatus feeds primarily on rabbits and birds (Reference 7 and 8), and rarely bite humans, and therefore it is not considered an important vector of Lyme disease to humans. However, there is a possibility that I. dentatus may be capable of transmitting Lyme disease among animals. A Lyme disease study (Reference 8) demonstrated that infected I. dentatus nymphs experimentally transmitted the B. burgdorferi to a healthy rabbit. Dermacentor variabilis, the American dog tick, is not considered a vector of Lyme disease. (4) There is some question concerning what tick is the main vector of Lyme disease in Missouri, I. scapularis or A. americanum. Ixodes scapularis is probably the most competent vector. The ability of Amblyomma americanum to transmit Lyme disease is still in question. Some researchers suggest there is a "Lyme-like" disease that is transmitted by ticks, most probably A. americanum. This disease is call "Lyme-like" because the symptoms of this disease resemble the classical Lyme disease, but the etiological agent, B. burgdorferi, has not been found in patients with the "Lyme-like" disease. Hundreds of A. americanum have been examined for the spirochete that causes Lyme disease with negative results. In addition, many people with a history of tick bites become sick and their illness has been diagnosed as Lyme disease; unfortunately, the spirochete that causes Lyme disease cannot be found in these patients. If A. americanum is the vector of Lyme disease, positive cultures of spirochetes should be obtainable. (5) Although no human cases of Lyme disease have been diagnosed as originating on LCAAP, personal protective measures to guard against tick bites would be prudent. Risk of contracting any tick-borne diseases such as Lyme, "Lyme-like" disease, and Rocky Mountain Spotted Fever (also found in Missouri) can be minimized by the proper wearing of clothing, avoiding areas known to harbor high tick populations, and by using repellents (see Appendix E for repellent products available in the Defense General Supply Center or Self-Service Supply System). General Lyme disease reduction measures can be found in Appendix F. (5) Ticks may be sent to our USAEHA-W, ESD Laboratory; we will identify and analyze submitted specimens for Lyme disease. Continuing surveillance should further define the presence and distribution of ticks and the risk of acquiring Lyme disease on LCAAP. Additional collections of ticks should be made from deer during the hunting season in the fall of 1993. Collection kits will be sent to the Facilities Manager at LCAAP. 8. CONCLUSIONS. The Lone Star tick, Amblyomma americanum, a suspected vector of Lyme disease, was collected at LCAAP. The Black-legged tick, Ixodes scapularis, another suggested vector of Lyme disease in the state of Missouri, was not collected. Two Ixodes dentatus were collected at LCAAP; however, this tick is not implicated as a vector of Lyme disease to humans. Borrelia burgdorferi, the causative agent for Lyme disease, was not found on the installation. Though personnel training, working or residing on LCAAP are at Low risk for acquiring Lyme disease, implementation of personal protective measures for all military, civilians, and dependents using LCAAP for outdoor training or recreation is recommended as a good preventive medicine practice. [signature of Thomas P. Gargan II] for LESTER D. HALE Entomologist APPROVED BY: [signature] THOMAS P. GARGAN II MAJ, MS Chief, Entomological Sciences Division APPENDIX A REFERENCES 1. Morbidity and Mortality Weekly Report, Volume 41, No. 51, December 1993, Massachusetts Medical Society. 2. USAEHA-W, ESD SOP No. 6, 24 April 1991, Tick Collection Procedures. 3. USAEHA-W, ESD SOP No. 8, 25 April 1991, Small Mammal Tick and Ear Tissue Collections. 4. Burt, W. H. and R. P. Grossenheider, A Field Guide to the Mammals North America, North of Mexico, Third Edition, Houghton Mifflin Company, Boston, 289pp. 5. National Institutes of Health Publication No. 85-23, Revised 1985, Guide for the Care and Use of Laboratory Animals, U.S. Department of Health and Human Services. 6. USAEHA-W, ESD SOP No. 7, 25 April 1991, Procedures for Trapping and Handling Small Mammals. 7. Keirans, J. E. and C. M. Clifford, 20 July 1978, The Genus Ixodes in the United States: A Scanning Electron Microscope Study and Key to the Adults, Journal of Medical Entomology, Supplement No. 2: 1-149. 8. Telford III, S. R. and A. Spielman, March 1989, Competence of A Rabbit-Feeding Ixodes (Acari: Ixodidae) as a Vector of the Lyme Disease Spirochete, Journal of Medical Entomology, 26(2):118-121. APPENDIX B TECHNICAL ASSISTANCE Technical advice and/or consultation on pest management problems, to include on-site assistance, may be obtained by telephone from our Activity at DSN 943-8090. Please inform your Major Command Pest Management Consultant if you desire to request on-site assistance from our Activity. Technical services that we can assist you with are as follows: 1. Entomological laboratory support 2. Environmental laboratory support 3. Hazardous waste management 4. Industrial hygiene management 5. Medical systems safety and health 6. Sanitation and hygiene 7. Wastewater management 8. Water supply management 9. Worksite hazards management 10. Cholinesterase testing management For assistance in any of the above listed programs, please call: Environmental Health and Engineering Division - DSN 943-8100 Field sanitation and hygiene; potable, recreational and wastewater quality; hazardous waste management; document/design reviews. Industrial Hygiene Division - DSN 943-8881 Industrial hygiene; hazard communication; protective equipment programs; document/design reviews. Environmental Laboratory Division - DSN 943-3293 Routine and emergency analysis of water, soil, and occupational health- related samples. Cholinesterase Laboratory Division - DSN 943-3318 Testing of red blood cell-cholinesterase (RBC-ChE) specimens and quality assurance consultations and training for RBC-ChE labs. During non-duty hours calls will be recorded by an answering machine and returned the next day. Many additional services are available from our parent organization, the U.S. Army Environmental Hygiene Agency, and are described in AEHA Pamphlet 40-2, Directory of Services (published annually). We will gladly coordinate any additional services you request and that we cannot provide with our parent organization. APPENDIX C PERSONNEL CONTACTED 1. Mr. Kenneth Davison Facilities Management Specialist DSN 463-9163 2. Mr. Michael Fobbs Communicable Disease Coordinator Missouri Department of Health Bureau of Communicable Disease Control Commercial (314) 751-6113 3. Mr. Charles Jon Hinkle Communicable Disease Coordinator Missouri Department of Health Bureau of Communicable Disease Control Commercial (816) 632-2107 4. Dr. Patrick E. Phillips, D.V.M., M.S.P.H. Consultant Epidemiologist Missouri Department of Health Department of Enviornmental Health and Epidemiology Commercial (314) 751-6079 5. Mrs. Sue Tippen Communicable Disease Coordinator Missouri Department of Health Bureau of Communicable Disease Control Commercial (314) 840-9720 6. Mr. Charles F. Triplett* Coordinator, Natural Resources and Quality Assurance Evaluator, Olin Corp. DSN 463-9477 --------- * Individual received an exit briefing. APPENDIX D LACK CITY ARMY AMMUNITION PLANT TICK LOG 1993 [Data omitted - data summarized in above report] APPENDIX E REPELLENTS 1. Several repellent products are available through the Defense General Supply Center (DGSC) or Self-Service Supply System. When used in accordance with label directions and in conjunction with the proper wearing of the uniform, they provide personal protection against a wide variety of medically important insect/arthropod pests. Availability and current pricing can be obtained by calling the DGSC at DSN 695-4865 for: a. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces), NSN 6840-01-0284-3982. The lotion is not labeled for ticks, but will repel chigger mites and many biting flies. b. Permethrin Arthropod Repellent, Insect Repellent, Clothing Application (aerosol, 6 ounces), NSN 6840-01-278-1336. Seventy-five percent of the can is used to apply to the field uniform and the remainder is used to treat mosquito netting. The product provides protection from ticks and mosquitoes through six normal launderings. c. Insect Repellent Fabric Treatment (liquid, 5.1 fluid ounces), NSN 6840-01-334-2666. The contents are added to 2 gallons of water and applied with the 2-gallon sprayer from a field sanitation kit at a pressure of 50 pounds per square inch to field uniforms, mosquito netting, and tent fabric to provide protection from ticks, biting flies, and other insects. Since most sprayers are not equipped with the required pressure gauge (NSN 3740- 01-332-8746), it will be necessary to obtain a pressure gauge and filter (NSN 4330-01-332-1639), in order to complete the retrofitting. Proper application can provide protection for the normal life of the uniform, six launderings of mosquito netting, and 6-9 months of treatment for tent fabric, depending on the climate. 2. Detailed directions for the use of these and other repellents can be found in the U.S. Army Environmental Hygiene Agency Technical Guide (TG) 174, Personal Protective Techniques Against Insects and Other Arthropods of Military Significance. 3. The U.S. Army Medical Department Tick-Borne Disease Card (7189) is available from the USAEHA-W, ESD. APPENDIX F LYME DISEASE RISK REDUCTION MEASURES 1. Emphasize public awareness programs to educate troops, dependents, civilian employees, and visitors on personal protective measures and Lyme disease. Methods should include but are not limited to: a. Distribution of printed Lyme disease handouts such as tick identification cards (USAMD-7189), pamphlets, and fact sheets. b. Notifications in the installation newsletter, especially prior to the high-risk months (April - September). c. Making available for viewing video and 35mm slide format presentations on Lyme disease; both are available from this Activity. 2. Forward any collected live tick specimens (either field-collected ticks or those that have been removed from individuals) for identification and immunofluorescent staining or darkfield microscopy testing to the Entomological Sciences Division, U.S. Army Environmental Hygiene Activity- West, Fitzsimons Army Medical Center, Aurora, CO 80045-5001. 3. Stock Permethrin Arthropod Repellent (NSN 6840-01-278-1336, box of 12 cans for $36.99), and 3M [Trademark] Insect Repellent (NSN 6840-01-284- 3982, box of 12 tubes, $29.30) for distribution. Emphasize tick habitat avoidance, proper wearing of clothing, and use of repellents. 4. Report all confirmed and suspected cases of Lyme disease [e.g., suspicious febrile illnesses, arthralgias, rashes, (erythema migrans)] by special telegraphic report [MED-16(R4)] for all soldiers and civilian beneficiaries. 5. Identify high-risk foci in cantonment areas via tick dragging/flagging, small mammal trapping, deer checks and the assaying of collected ticks for Borrelia burgdorferi. Sampling should be performed in early spring when Ixodes scapularis nymphs (the life stage responsible for most human Lyme disease infections) are active. 6. Post DA Poster 40-5, and thereby identify high-risk areas. DA Poster 40-5 can be obtained by writing to the Commander, U.S. Environmental Hygiene Agency, ATTN: HSHB-MR-E, Aberdeen Proving Ground, MD 21010-5422, or telephone DSN 584-3613 or Commercial (410) 671-3613. 7. Avoid high tick population areas for troop training or recreation. Such areas can be identified by dragging or flagging for ticks prior to use. Case-by-case surveillance is necessary due to the patchy distribution of I. scapularis. 8. Eliminate tick habitat in heavily used, infested areas (e.g., wooded recreation areas) by removing low brush and leaf litter. Tick infestations should be verified via tick flagging or dragging prior to habitat modification. Clearing should be done in low-risk months (i.e., November to February). 9. Prepare, as a contingency, to treat high-use areas with pesticides to decrease tick numbers if surveillance reveals high tick numbers and if nonchemical control techniques (e.g., brush removal, mowing, raking) do not provide adequate control. --- Trademark 3M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053