Lyme Disease Risk Assessment No. 16-07-2713-95, Fort Knox, Kentucky, 19 November 1994 DEPARTMENT OF THE ARMY U.S. Army Center for Health Promotion and Preventive Medicine Direct Support Activity-North Fort George G. Meade, Maryland 20755-5225 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: MCHB-AN-ES (40-5f) 2 July 1996 MEMORANDUM FOR Commander, U.S. Army Training and Doctrine Command, ATTN: ATBO-SE, Fort Monroe, VA 23651-5451 SUBJECT: Lyme Disease Risk Assessment No. 16-07-2713-95, Fort Knox, Kentucky, 19 November 1994 1. Copies of subject report with Executive Summary are enclosed. 2. Please call me at DSN 923-5281/6205, extension 208, if you require additional information on this risk assessment or support in the areas of occupational and environmental health. FOR THE COMMANDER: [signed by] RICHARD N. JOHNSON MAJ, MS Chief, Entomological Sciences Division ----- DEPARTMENT OF THE ARMY U.S. Army Center for Health Promotion and Preventive Medicine Direct Support Activity-North Fort George G. Meade, Maryland 20755-5225 [Seal of Department of Defense, United States of America] EXECUTIVE SUMMARY PEST MANAGEMENT STUDY NO. 16-07-2713-95 LYME DISEASE RISK ASSESSMENT FORT KNOX, KENTUCKY 19 NOVEMBER 1994 1. PURPOSE. To provide a Lyme disease (LD) risk assessment to the Installation Commander, Fort Knox, Kentucky and to assess the need for continued surveillance and eduction of military and civilian personnel on or in the vicinity of the installation. 2. FINDINGS. No LD vector ticks, Ixodes scapularis Say, were found on any of the 100 deer examined on the above subject survey date at Fort Knox, Kentucky. Eight of the 100 deer sera tested positive for the presence of anitbodies against LD causal agent. 3. RISK. The risk on contracting LD at Fort Knox is presently moderate, this conclusion is based on the results of the survey combined with information from the Kentucky Department of Health Services (KDHS) regarding human case reports and LD vector tick collection records from sites relatively near Fort Knox. 4. RECOMMENDATIONS. Educate military, civilian, and dependent personnel using Ft. Knox for ourdoor training or recreation on the use of personal protective measures, as addressed in Appendices D, E, and F of this report. Take measures to conduct periodic surveys for Lyme disease reservoirs (deer or small mammals), vectors (ticks), and/or evidence of prevalence of the LD pathogen to monitor risk level for Lyme disease. ----- DEPARTMENT OF THE ARMY U.S. Army Center for Health Promotion and Preventive Medicine Direct Support Activity-North Fort George G. Meade, Maryland 20755-5225 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: MCHB-AN-ES LYME DISEASE RISK ASSESSMENT NO. 16-07-2713-95 FORT KNOX, KENTUCKY 19 NOVEMBER 1994 1. REFERENCES. See Appendix A. 2. AUTHORITY. AEHA Form 250-R, TRADOC, 1 October 1993. 3. PURPOSE. To asses the risk of Lyme disease (LD) to Fort Knox personnel by examining deer for vectors of LD, especially Ixodes scapularis Say, and to assay ticks and deer blood for evidence of the LD etiologic agent, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in accordance with AR 40-5, paragraph 10-7.f. 4. GENERAL a. Risk Definition. The term "risk", as used in this report, is a non-statistical evaluation of qualitative and quantitative information on LD locally. To the extent available, information evaluated included the following elements: (1) History of LD in the area, (2) The presence of the principal tick vector of LD (I. scapularis) and host populations needed to sustain viable populations of this vector, (3) The presence of the LD-causing spirochete (B. burgdorferi) in the local tick population, and (4) The presence of antibodies against B. burgdorferi in the blood serum of local mammal hosts. Once gathered, this information was used to help determine the general relative risk level as follows: Low - Some elements of the LD cycle have been identified nearby, but not on the installation. Moderate - Some elements of the LD cycle have been identified from the installation or human cases of LD have been reported from the local area. High - All elements of the LD cycle have been found (are present) on the installation. b. Personnel Contacted. The purpose and methodology of this assessment were discussed with 1LT Riccelli, Environmental Science Officer, Preventive Medicine Service (PVNTMED Svc), Fort Knox, Kentucky. Ms. Patricia Beeler, Health Data Survey Technician, Kentucky Department of Health Services (KDHS), was contacted for information on cases of human Lyme disease in the State of Kentucky. COL Lyman Roberts, Entomology Consultant, Department of the Army (DA), Office of the Surgeon General (OTSG) was contacted for information on reported cases of human Lyme disease for Army installations. c. Survey Conduct. All deer were examined for ticks. Deer sera were assayed for the presence of antibodies against Lyme disease via indirect fluorescent antibody (IFA) tests by personnel of the DoD Veterinary Laboratory at Fort Sam Houston, Texas. Because no ticks were collected, none were assayed for tick-borne human pathogens. d. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting the Chief, Entomological Sciences Division, this Activity, commercial (310)677-5281/6502 or DSN 923- 5281/6502. 5. BACKGROUND a. Lyme disease (LD) is a multi-symptomatic infectious disease caused by the spirochete, Borrelia burgdorferi Say [sic], which is transmitted to humans by the bite of an infected tick. This disease is usually called Lyme disease or Lyme arthritis in the United States. Over the past few years, it has become the most prevalent arthropod- borne disease in North America. Its geographic range is expanding and the number of reported cases has continued to rise nearly every year since 1989. b. The lack of a rapid, sensitive, reliable, and cost-effective diagnostic test for LD results in proactive treatment before case confirmation and, consequently, under-reporting. The increased burden of reports on medical treatment facilities may also be a factor. Personnel concerned with LD prevention and control should not assume that human risk of LD has changed based solely on numbers of reported cases. c. Epidemiologic information from the Kentucky Department of Health Services (KDHS) revealed 3 confirmed cases of human Lyme disease in 1995 in Hardin County, where Fort Knox is located. Statewide totals of 24 and 16 human cases were reported for Kentucky in 1994 and 1995, respectively. 6. METHODS a. Deer examinations. The heads, ears, necks, and briskets of a portion of hunter-killed white-tailed deer (Odocoileus virginianus Zimmermann) were examined for the presence of ticks. The hair of stated areas was rubbed against the direction of its normal lay, using the edge of one or both hands. If ticks were detected, they were pulled off using fine-tipped forceps, placed into plastic vials, and forwarded to this Activity (DSA-North) for identification and possibly further testing. b. Serum collection and testing. Blood which had pooled in deer body cavities was collected using clean, wide-tipped 4mL. disposable plastic pipettes, into 7mL. labeled glass tubes, held for greater than or equal to 1 hour at ambient temperature (greater than or equal to 40 degrees F; less than or equal to 90 degrees F) to clot, and spun at greater than or equal to 1,500 rpm for greater than or equal to 5 minutes. The serum was drawn off into small plastic vials, labeled, frozen, and shipped to this Activity on dry ice (-32 degrees C). These sera were later shipped, on dry ice, to the DoD Veterinary Laboratory, ATTN: MCVS-SCL-D, 2472 Schofield Road (Bldg. 2632), Fort Sam Houston, TX 78234-6232. They were tested via indirect fluorescent antibody (IFA) techniques to detect the presence of any antibodies that the deer (from which each respective serum sample was taken) may have developed against B. burgdorferi, the Lyme disease causal organism. If the sample showed a "positive" response at a 1:128 serum dilution, as compared to a known positive standard, the deer from which the sample was drawn was considered to have been infected with B. burgdorferi. c. Tick Collection. Deer, the preferred host for the adult stage of the Lyme disease tick vector, I. scapularis, were examined at the check station at Fort Knox. Deer examined were local deer from on or near Fort Knox. The heads, ears, and necks of 99 hunter-shot white-tailed deer, Odocoileus virginianus, were examined immediately before the weighing and tagging process. The hair on deer was stroked contrary to the natural lay, using the hand edge, to search for ticks. Total examination time per carcass was approximately 5-10 minutes. d. Tick Testing. Collected ticks were tested via a two-phase DFA assay. Ticks were first tested using a polyclonal DFA procedure that tests for the presence of spirochetes belonging to the genus Borrelia. Ticks identified as containing these Borrelia spp. spirochetes would have been tested further by a species-specific DFA procedure to ascertain if the spirochetes were B. burgdorferi. However, since there were no ticks positive for Borrelia spp., this second phase DFA procedure was not performed. 7. RESULTS. (Also see Appendices B and C) a. No ticks of the genus I. scapularis were collected from the 100 white-tailed deer examined on Fort Knox. b. Three A. amblyomma [sic] ticks were collected from 2 of the 100 deer examined, none were tested. Five hundred and twenty nine D. albipictus ticks were collected from 88 of the 100 deer examined. Three hundred and twenty five of these ticks from these 88 deer were tested for spirochetes by personnel of this activity. Eight of the three hundred and twenty five ticks tested were positive for Borrelia spp. c. Two of 97 (2%) deer serum samples collected tested positive (greater than 1:128) titer level for antibodies to B. burgdorferi. 8. DISCUSSION. The significance of the presence of non-burgdorferi, Borrelia spp. in ticks is yet to be determined. Research institutions and the Centers for Disease Control and Prevention (CDC) are currently investigating differences in Borrelia species and strains relative to their geographic occurrence, host tick species, and the pathogenic implications. 9. CONCLUSIONS. The presence of antibodies to B. burgdorferi in the deer population and the information from the KDHS on the epidemiology of Lyme disease in the surrounding area, indicate that the risk of contracting human Lyme disease on Fort Knox is Moderate. 10. RECOMMENDATIONS. a. Periodically remind and retrain all military, civilian, and dependent personnel at Fort Knox concerning the information on repellents which is contained in Appendices D, E, and F of this report. b. Assist this Activity, or take other steps, to ensure the conduct of periodic (suggested annual) surveys of deer, small mammals, or the environment for host-seeking ticks, and evidence of the presence and prevalence of B. burgdorferi, to determine the risk level of contracting LD at Fort Knox. c. Report any LD cases to the DA OTSG and Kentucky State Epidemiologist (AR 40-5, paragraph 3-2 and AR 40-400, paragraph 6-16). 11. ADDITIONAL ASSISTANCE. Additional direct support in the fields of pest management, pesticide risk management, water supply management, wastewater management, hazardous waste management, worksite hazards management, health care hazards management, ergonomic evaluation, sanitation and hygiene, and installation industrial hygiene management is available, and may be requested from USACHPPM, DSA-North at DSN 923- 6502/5281/6205, or commercial (301)[677-]6502/5281/6205. [signed by] RICHARD N. JOHNSON MAJ, MS Chief, Entomological Sciences Division ----- APPENDIX A REFERENCES 1. AR 40-5, Preventive Medicine, 15 October 1990. 2. DoD Directive 4150.7, Department of Defense Pest Management Program, 24 October 1983. 3. Armed Forces Pest Management Board Technical Information Memorandum No. 26, Lyme Disease: Vector Surveillance and Control, March 1990. 4. Lyme Disease Surveillance Summary, Vol. 4, No. 3, Centers for Disease Control and Prevention, June 1993. 5. Oliver, J.H., M.R. Owsley, H.J. Hutcheson, A.M. James, C. Chen, W.S. Irby, E.M. Dotson, and D.K. McLain. 1993. Conspecificity of the ticks Ixodes scapularis and Ixodes dammini (Acari: Ixodidae). J. Med. Entomol., 30(1): 54-63. ----- APPENDIX B DATA SUMMARY SHEET DOD LYME DISEASE RISK ASSESSMENT U.S. ARMY CENTER FOR HEALTH PROMOTION AND PREVENTIVE MEDICINE DIRECT SUPPORT ACTIVITY - NORTH FORT KNOX, KENTUCKY 19 NOVEMBER 1994 # Deer Examined 100 # Deer With Ixodes scapularis[1] 0 # Deer With Ticks 90 # Deer Serum Samples Tested 97 # Deer Serum Samples Positive[2] 2 # Human Lyme Disease Cases, 1995 - Hardin Co., KY 3 # Human Lyme Disease Cases, 1995 - Kentucky 16 ------------------------------------------------------------------------ 1 Ixodes dammini Spielman, Clifford, Piesman, and Corwin and Ixodes scapularis Say were synonymized by Oliver et al. (1993). 2 Screening dilution level greater than or equal to 1:128 (= titer greater than or equal to 128). ----- APPENDIX C TICK TESTING, SERUM TESTING, AND CO2 TICK TRAP RESULTS FORT KNOX, KENTUCKY 19 NOVEMBER 1994 Table 1. Identification and Analysis of Amblyomma americanum Ticks Collected from Two Deer Examined at Fort Knox, 19 November, 1994 ------------------------------------------------------------------------ Ticks Test by FA For stage number Borrelia spp.[1] Borrelia burgdorferi[2] #Tested #Positive %Positive3 #Tested #Positive %Positive3 ======================================================================== Larvae 0 0 0 0 0 0 0 Nymphs 0 0 0 0 0 0 0 Females 0 0 0 0 0 0 0 Males 3 0 0 0 0 0 0 ======================================================================== Total 3 0 0 0 0 0 0 ------------------------------------------------------------------------ 1 Direct Fluorescent Antibody 2 Indirect Fluorescent Antibody 3 % Positive of those tested Table 2. Identification and Analysis of Dermacentor albipictus Ticks Collected from 88 Deer Examined at Fort Knox, 19 November 1994 ------------------------------------------------------------------------ Ticks Test by FA For stage number Borrelia spp.[1] Borrelia burgdorferi[2] #Tested #Positive %Positive3 #Tested #Positive %Positive3 ======================================================================== Larvae 0 0 0 0 0 0 0 Nymphs 92 71 0 0 0 0 0 Females 256 121 2 1.7 2 0 0 Males 181 133 6 4.5 6 0 0 ======================================================================== Total 529 325 8 2.5 8 0 0 ------------------------------------------------------------------------ 1 Direct Fluorescent Antibody 2 Indirect Fluorescent Antibody 3 % Positive of those tested ----- APPENDIX C (cont.) TICK TESTING, SERUM TESTING, AND CO2 TICK TRAP RESULTS FORT KNOX, KENTUCKY 19 NOVEMBER 1994 Table 3. Identification and Analysis of Amblyomma americanum Ticks Collected from six CO2 traps Examined at Fort Knox, 19 November, 1994 ------------------------------------------------------------------------ Ticks Test by FA For stage number Borrelia spp.[1] Borrelia burgdorferi[2] #Tested #Positive %Positive3 #Tested #Positive %Positive3 ======================================================================== Larvae 0 0 0 0 0 0 0 Nymphs 23 23 0 0 0 0 0 Females 19 19 0 0 0 0 0 Males 20 20 0 0 0 0 0 ======================================================================== Total 62 62 0 0 0 0 0 ------------------------------------------------------------------------ 1 Direct Fluorescent Antibody 2 Indirect Fluorescent Antibody 3 % Positive of those tested Table 4. Identification and Analysis of Dermacentor albipictus Ticks Collected from one CO2 trap Examined at Fort Knox, 19 November 1994 ------------------------------------------------------------------------ Ticks Test by FA For stage number Borrelia spp.[1] Borrelia burgdorferi[2] #Tested #Positive %Positive3 #Tested #Positive %Positive3 ======================================================================== Larvae 0 0 0 0 0 0 0 Nymphs 0 0 0 0 0 0 0 Females 1 0 0 0 0 0 0 Males 1 0 0 0 0 0 0 ======================================================================== Total 2 0 0 0 0 0 0 ------------------------------------------------------------------------ 1 Direct Fluorescent Antibody 2 Indirect Fluorescent Antibody 3 % Positive of those tested ----- APPENDIX D Lyme Disease Risk Reduction Measures 1. Emphasize public awareness programs to educate troops, family members, civilian employees and visitors on personal protective measures and Lyme disease (and other tick-borne diseases). Methods should include, but not be limited to: a. Distribution of printed Lyme disease handouts, such as "tick- borne diseases" cards (GTA-8-5-56), pamphlets, and fact sheets. b. Notifications in the installation newsletter, local media, and post electronic media (e.g., closed-circuit TV), especially prior to the high-risk months (April-July). c. Making the following videos available for general viewing: "Lyme Disease: A Growing Threat (FAUPIN No. 504494DD, Army TVT No. 8-196) and "Application of the Arthropod Repellent System" (No. 708575, Army TVT No. 8-232). 2. Submit tick specimens (both field-collected ticks and those removed from individuals) alive for identification and DFA testing to USACHPPM, DSA-North, Fort Meade, Maryland 20755-5225. 3. Stock Permethrin Arthropod Repellent (NSN 6840-01-278-1336, box of 12 cans for $36.99), and 3M[1] 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)] through proper channels to both military and civilian public health authorities. 5. Identify high risk foci in cantonment areas via tick dragging/ flagging, small mammal trapping, deer checks and the assaying of collected ticks for B. burgdorferi (or other human pathogens). Sampling should be done in early summer when I. scapularis nymphs (the life stage responsible for most human Lyme disease infections) actively seek hosts. Post DA Poster 40-5, to identify high-risk areas. 6. Avoid high tick population areas for troop training or recreation. Such areas can be identified by tick dragging or flagging prior to use. Case-by-case surveillance is necessary due to the patchy distribution of I. scapularis and most other human disease vector ticks. 7. 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/dragging prior to habitat modification. Clear such sites in low-risk months (i.e., January-February). 8. As a contingency, prepare to treat high-use areas with pesticides to reduce tick populations if surveillance yields large numbers of ticks (especially if any are found to contain human pathogens) and if non- chemical techniques (e.g., brush removal, mowing, raking) do not provide adequate control. -------------------------------------- 1 3-M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053. ----- APPENDIX E REPELLENTS 1. Several arthropod repellents 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 clothing, they provide personal protection against a wide variety of medically important insect/arthropod pests. Availability and current prices can be obtained by calling the DGSC at DSN 695-4865 or commercial (804) 790-4865. Repellents available for use are described below: a. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces), NSN 6840-01-0284-3982. This is for application to exposed skin, 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. Approximately 75% of one can should be applied to each field uniform, and the remainder used to treat other items (e.g., mosquito netting). This product provides protection from ticks and mosquitoes for a maximum of five weeks or five launderings. Apply more frequently if "buddy checks" reveal attached ticks. c. Insect Repellent, Fabric Treatment (liquid, 5.1 fluid ounces), NSN 6840-01-334-2666. The contents of one bottle are added to two gallons of water and applied with a 2-gallon sprayer (like the ones in field sanitation kits) at a pressure of 55 psi, to field uniforms, mosquito netting, or tent fabric to provide protection from ticks, biting flies, and other insects. Since many sprayers are not equipped with the required pressure gauge (NSN 3740- 01-332-8746), it may be necessary to obtain this type of pressure gauge and filter (NSN 4330-01- 332-1639), to retro-fit an available sprayer. Proper application, followed by complete drying of the fabric, can provide protection for the normal life of the uniform (180 days in the field), six launderings of mosquito netting, or 6-9 months effectiveness for treated tent fabric, depending on the climate of deployment site(s). 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, June 1991. 3. The "Tick-Borne Diseases" cards (GTA 8-5-56) should be ordered through normal military publications channels. Limited numbers of these cards may be obtained from the Entomological Sciences Division, USACHPPM, DSA-North, at DSN 923-5281 or commercial (301)677-5281. ----- APPENDIX F FACT SHEET - MOSQUITO AND TICK REPELLENTS 1. Repellents containing DEET (N,N-diethyl-3-methylbenzamide, formerly N,N-diethyl-m-tolumide) offer good protection against mosquitoes, and are made for application to skin. 2. Repellents containing Permethrin offer excellent protection against ticks, and are formulated for application to clothing. 3. DEET also offers protection against ticks, keeping them from attaching to treated skin (sometimes for long periods). Ticks do not generally attach in exposed areas, the primary areas to which DEET is to be applied (refer to any given product's label directions). 4. Permethrin, conversely, offers considerable protection against many mosquito species, but it can't be applied to exposed skin (refer to any given product's label directions), the main area(s) mosquitoes usually bite. Permethrin is useful for treating bed netting and tents. 5. Combined use of DEET on exposed skin (as for mosquito repellency) and Permethrin on clothing (as for tick repellency) offers maximum protection against both these (as well as many others). Always read and follow the label directions before using any compound. 6. Do NOT use flea or tick collars. A toxic reaction can result. Humans have many sweat glands in their skin that can serve as avenues for chemical absorption. Dogs (and cats), do not have sweat glands in their skin and cool themselves by panting. In addition, most breeds of these pets have a thick hair layer (barrier) whichprotects their skin from direct contact with collars. Humans have very limited hair covering. 7. Various lotion products claim protection against mosquitoes. Professional literature both supports and refutes benefits from lotions. Controlled tests have shown that mineral oil, a major component of most such lotion products, does reduce biting by several species of mosquitos on areas of treated skin. However, this reduction in biting is small when compared to the reduction by an wqual amount of DEET in concurrent tests by USDA labs. 8. Controlled tests have shown that products containing high concentrations of DEET (greater than or equal to 50%) do not offer greater protection than products containing 30-50% DEET. 9. The following practices enhance the effectiveness (degree of protection) against mosquitoes and ticks when used in conjunction with repellents: - Cover as much exposed skin as possible. Consider wearing loose- fitting long-sleeved shirts in summer. - Tuck pants legs inside tops of socks or boots. - Wear light-colored clothing to make ticks easier to see as they crawl. - Plan ahead and treat clothing with permethrin before starting your outdoor activity. Permethrin binds with fabric and is persistent through several detergent washings. ("Dry cleaning" will remove it immediately.) - Store treated clothing in a plastic bag to help preserve repellent effectiveness, and to help identify which clothing has been treated. -----